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- čas přidán 3. 06. 2024
- Often viewers ask in the comments: Why do you still use batteries and not supercapacitors for your projects? Good question. Do you know the answer?
Supercapacitors are super like Superman or Superwoman. Otherwise, they only would be called “Capacitors.” Right? Where are they “super” and where not? Where can we use them, and how? And the most important question: Are they better than batteries?
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1 Farad = 1Coulomb /Volt , i.e. the amount of charge per volt that can be held. Charge can be written as current times time C = A*s. Voltage is energy per charge, i.e. V = J/C= J/(A*s). So we get F = A*s²/J. Now, energy is force * distance, J = N*m. Force is mass times acceleration, N = kg*m/s². So J = kg*m²/s² and F = A²s⁴/(kgm²) in SI units.
Thanks for the explanation! Seems logical.
It's kilogramm because this is the standard (SI) unit for mass (remember the "Urkilogramm"). vy 73
_E = 0.5 · C · U²_
wikipedia.org/wiki/Basisgr%C3%B6%C3%9Fe
The easiest way to solve physics-exercises at school: Solve, without any plan, knowledge or backthinking. Check the SI-unit of your solution. If you´ve nailed the unit, your solution-pathway was possibly the correct one, as is the solution itself (probably ;-)
Nice video. I found 2 usecases for those supercaps so far: UPS stuff to help between the different stages of recovering power for IT stuff, and this one: charge one up, and throw it to someone you dislike. The person will catch it, and you will have fun for a short period of time. Disclaimer: do not try this at home ;)
I am not sure about the second "use case" (if 2.7volts are enough). The 400 volt cap from the coil gun probably would create more fun ;-)
@@AndreasSpiess we used so called gold caps, but this was many years ago. I do not remember of any details except the result
The first usecase is a good idea especially for outside ups system. No maintenance as well.
Pilfer the cap from a camera flash for your second use case.
Excellent video as usual. Two comments:
- the unit of capacitance is defined using primary SI units. As it turned out, our world as we know it can be described using only 7 different physical quantities. Sometimes their combination could look funny indeed.
- Another use case for the supercaps is for keeping low power RTC ticking when the external power is removed intermittently. I think many GPS receiver modules are equipped with a supercap to allow for the warm start, especially in mobile systems in cars where the supply voltage can drop when the engine starts.
1. You are right with the SI units. But also for me they sometimes look funny.
2. I thought the GPS modules have small batteries. But I am not sure. At least I had some issues with T-Beams where the "battery" was discharged when they arrived from China and the application did not work anymore. I had to use a sketch to reset the GPS module. It seems to be a problem well known to the specialists.
Great video once again! I use the TPS63900 Buck-Boost converter in combination with a BQ25504 energy harvester and two supercaps in series in a sensor project. Works great! The TPS63900 is a relatively new buck-boost converter (1.8V to 5.5V, 75nA IQ) from TI for low power applications. Unfortunately, the chip is currently hard to get.
This TPS63900 seems to be a great chip. Together with the BQ25504 it gives a good design for an indoors light harvester like thee Enocean sensors. What kind of MCU do you use for the project?
NCP1402 is cheap and comparatively close if you are ok with fixed output
Why not use the BQ25570 or parts from other vendors like the AEM10941 which have buck boost regulators onboard?
@@jR060t About 2 years ago I made a prototype PCB with the BQ25570. It is a very good chip, but not suitable for the current design, because it has only an output current of max 100mA (the TPS63900 delivers up to 400mA -> required for NB-IoT / CAT-M1) and because with the required output voltage of 3.3V you need also at least 3.3V at the supercap (the output stage has only a buck converter). Thus only 3.3V - 5.5V can be used from the supercap's voltage range. With the TPS63900 on the other hand the full voltage range from 1.8V to 5.5V can be used (buck-boost converter), which results in about 40% more capacity.
@@Mr.Leeroy I did not yet know the NCP1402. A glance at the datasheet shows me that the Iq is 30uA, this would be too high for my design (The Iq of the TPS63900 is only 75nA) and it looks like it's a boost converter only (see also answer above)
If you have a project that uses a battery whose inner resistance is getting higher and higher over time, a supercap can also be very helpful. Espacially if you need higher currents over a short period of time (motor, communication...) it can be used to reduce the voltage drop over the inner resistance.
Interesting idea. So far I usually replaced the battery because it also lost capacity.
@@AndreasSpiess I use it to get the longest battery lifetime out of primary cells. It works really well.
@@tinkerdave3157 So the supercap essentially acts as a sort of buffer?
@@spicybaguette7706 It is a capacitor, so yes - it acts as a buffer if/when a batterys internal resistance goes up.
Unfortunately super capacitors also has a (sometimes quite) limited life span, before they also starts to degrade.
This might also work well to assist batteries used in cold environments; internal resistance of most battery chemistries goes up substantially in the cold, even for fairly new cells. A supercap in parallel could provide sufficient buffering for bursty high-current loads in outdoor projects expected to handle below freezing temperatures.
9:45 I believe you did miss something, the reason behind the hype for super capacitors is probably their cycle life/capacity. So in the long run a single super capacitor will be able to store and discharge more energy, even if batteries have a large capacity their cycle life is very limited, thus their lifespan is weak. With the constant obsession over "sustainability" this fact would be a major driving force behind the super-capacitor hype.
I agree. And I thought I mentioned the fact.
I recently used a supercapacitor on an ESP32 project, in combination with a Lithium Thionyl battery. The ESP32 was used as a wireless sensor, mainly powered by the battery, but because lithium Thionyl batteries can only supply really low currents the supercapacitor was used to assist with the current delivery during wireless transmission! Was really interesting to design
What was the challenge?
@@AndreasSpiess We were building these wireless sensors that would send measurement data wirelessly to a central gateway using ESP-Now. These sensors were powered using Lithium Thionyl (didn't want to use Li-ion/Li-po for safety reasons) batteries which can only supply very low current (50mA continuous, 200mA peak). This was fine for the measuring but during sending we had to add a supercap. But to be able to use the supercap we had to limit the charging, because otherwise the charing of the capacitor would put too much strain on the battery, so we had to limi that with a resistor, then we needed a way to use the full power of the supercap while discharging (using a P-Channel MOSFET).
The measurements are taken from the temperature of the room of a house and the temperature of the water going into/coming out of the boiler for central heating. With these measurements the aim is to create a model to improve efficiency for heating of homes
Is your diagram public domain? I am sure it would be interesting also for other viewers!
@@AndreasSpiess Unfortunately not yet. It is planned to become open source (both the hardware and the software) when the development is finished. I will post a comment here with a link to the schematic and firmware for the devices!
Very informative video!! One application for supercapacitors which has proven very useful is in model railroading. They are used in what's called "Keep Alive" circuits which can be commercially purchased or home-built. Very often, they already come installed in newer model railroad engines. Momentary disruptions in the track voltage due to dirty track or short track gaps are not good. So the supercaps only need to supply energy for very short periods of time ... like seconds. However, the voltage requirement is higher ... typically 15 to 20 volts. If you use supercaps which are too big in farads, maybe the train engine wheels will keep going if you have engine derailment!!! My application is for an ESP32-CAM module which is built into a HO-scale boxcar for wireless train video. For this, I use two 0.330 (or 0.500) farad, 9-volt supercaps in series. This seems to work well.
Interesting application. I am a sponsor of such a model railroad club (morges-trains.ch) which is operated by a relative of mine :-)
Thank you for the interesting contribution and the realistic calculation. About 6 years ago, I designed grid failure detection units. First I used supercaps to deliver the energy for the transceiver informing me after power loss. Studying the data sheet of the availabe types (6 years ago), I missed any statement about lifetime and endurance of the supercaps. But there was a hint about drying out over the years. And the low temp range was limited to -20°C or so. So, I created a parallel design using lithium primary AA batteries. These are rated for 20 years shelf time typically. Perfect for that application - and cheaper and easier to use. And the temperature range for these batteries is great, too -40°C to 60°C.
My "Windwächter" which retracts the awning in case of high windspeeds uses a super cap and a solar panel. I assume they wanted it to be completely maintenance free and therefore avoided batteries. It is now nearly 10 years old and still seems to work. But I am not sure because I added my own system in parallel because I wanted it also extended with a lot of sun.
AA batteries for low power applications still are a very good choice. And now with my supply of nearly unused Lithium AA batteries from my hunted weather balloons I am not short in supply. And they easily seem to work down to -60 degrees on 35'000 meters.
@@AndreasSpiess Yes, that is a very special method of "harversting" very good batteries! Im my vicinity there are no ballons landing. All captured by you!. So, I keep it easy and follow the former ETH expert Rolf Zinniker and CH "Kassensturz" (2014). Using batteries of south German discounters for general use. And these lithium ones for special use. AA are cheap and versatile. I have many zigbee motion sensors, attached and kind of integrated on/in furitures. There, I am using external AA batteries instead of the internal coin cells. Cheaper, higher capacity - and replacing batteriers without touching and re-adjustment of the sensor's position.
I have 3 Aquara sensors in the lab and after month of usage they still report nearly 100% battery. I am curious when I have to change them. A wonderful technology... And I agree with Rolf's analysis (as a former ETH student I probably should).
BTW: I do not drive far over the German border for the balloons. There a few others are also chasing and I am too slow ;-)
@@AndreasSpiess Wow
What is that weather balloon hunting? Are these weather balloons that some makers launch and you shot them down for spare parts? Or why do you even want to shoot it down? Is that legal to destroy other people's apparatus? :D
Or is it some sort of national fun? :D
BTW We too have to deal with balloons, that ruzzians launch to distract our anti-air defense.
I'm using supercaps in parallel to LiSOCl2 AA-Batteries (non rechargeable, e.g. SAFT LS14500, 3.6V 2.6Ah, ~3€) for powering ESP8266 (ESP-01) boards in combination with BME280 sensors. They provide p,T,h readings every 15 minutes (indoor) with deep sleep in between and battery lasts for 1.5~2 years. The supercap hereby covers the current peaks during WLAN connection until complete discharge of the battery. The setup is very simple as it does not require any voltage stabilizer. Thanks for all your great videos!
Thank you for sharing your project. A good use for such a cap because these batteries have a high internal resistance.
Thank you, very good video. I have seen before people using the balanced board with super caps as a car battery replacement, however I would worry about it going flat between engine starts.
Because they are hyped they provide good titles for CZcams videos ;-) But, as you say, probably not a good board.
I wish a car company would produce a super-cap gas (or diesel) hybrid. Have just a large enough super-cap bank to accelerate the car up to highway speeds several times and provide a place to dump energy during regenerative breaking. This would allow a car to use a small, light, and more fuel efficient engine. Hauling around an engine that can produce 200hp seems silly when it only takes about 30hp to drive down the highway.
A friend of mine had the idea for a car that used supercaps to start the engine. She then thought if it could be extended to accelerate the car to highway speed and it turns out the capacitance required is something silly like 3F at 450V.
I am sure we will see many new concepts in cars over the next few years. This development just started (compared to the long history of combustion engines)
Wonderful presentation as always. You're a valuable asset to the community and to the world at large.
😂😂 Presentation
Thank you for your nice words!
As always - Extremely effective video, typically Swiss. Thank you for the noble work of sharing your knowledge.
My pleasure!
Great video! There are different classes of supercaps, some for low power consumption, low current leakage and long time duration, keeping an RTC for example. These are not made for high current consumption. Other classes are for the opposite, can support high current, but have a huge current leakage and will last less time. Neither are the best option to keep a higher consumption device for a long time.
Thank you for the additional information!
Awesome lesson Adreas! Thanks a lot for your class!
My pleasure!
Hype is the pit of science. Anyway, interesting video. Thanks.
I agree.
Very timely work - I needed to hear some one else to make sure I was not missing something
Glad I was the one ;-)
Please check lithium-titanate batteries (LTO). They can fill the gap between batteries and SuperCap. Advantages:
- high current charge and discharge (~10C)
- temperature range (charge/discharge): -50..65 °C
- >20000 cycles (80% DOD)
- safe, can't burn/explode like normal Li-batteries
I compare them with LiFePo4 batteries where the low charging temperature is an advantage. Its disadvantage is the 2.4 volts where I did not see a standard charging/protection board so far.
Hi Andreas,
I would like to add three things to the "lessons learnt" section - from my own experience:
1) Supercaps are not created equal. You have the high-current types ("Maxwell") that have a high self-discharge, but very low ESR, allowing complete charge + discharge in ~ 20 second
2) On the other end, you have the "Sanyo" types - moderate-high ESR, but very low self-discharge. Useful for memory-backups.
3) Often for ESP32 or IoT projects, neither of the above is "just right" --> I came across a "best of both worlds" part made by a company called CapXX (now owned by Murata) that does a decent compromise between the two. It is in the "Goldilocks-zone" when it comes to IoT projects.
Adding to the leasons learnt
1. They are very sensitive to temperature and voltage, hence a slight over charging or using it at elevated temperatures can significantly reduce the life.
Thank you for your additions and your experiences!
In my company we have some applications for Ultracaps:
-Windturbine Pitch System Backup. A Box the size of 1..2 bottle crate stores the energy to turn back a blade at power failure once. Monitoring the capacitance by charge/discharge a little is much easier that with batteries and the last 20 years.
-Fast Frequency Response for a few seconds until diesel gensets start up.
-1MW for 1s UPS power to protect a whole factory or car paintshop.
-Storage to provide virtual inertia.
-Once my colleages charged up some caps with the wrong polarity. Because we do not give it to customer projects, but they are still working, electrified a kickscooter with 10x3000F cells. It drives approx. 1 km, which is good to travel between office and workshop. At the moment its charged for hours with a small buck converter from a small 24V power supply, but i have qick charging solution in mind...
Nice toys you have at work. 1MW. Incredible! These are perfect applications for supercaps. Our projects, however, are very different.
If you connect your scooter to one of your wind turbines it probably would charge faster, too ;-)
Very good summary of super capacitors. As I discovered from the FAD buoy which I took apart, video on my channel, super capacitors do have a use powering devices in some applications.
Reliability is one of them and no loss of capacity. The buoy is very much a sealed for life device.
The fish locating echo sounder is very high current when operating although for short bursts.
I've yet to use it in a project and it came with a great solar panel. Would make an incredible solar garden light.
The capacitor still has a charge in it from around 1½ years ago which I thought was incredible.
Good quality capacitor but rather expensive and large.
Indeed, it would make a exclusive garden light!. I wonder why they used a super cap in this design because the temperature variations are not too big and I would assume that the device will not last forever. But obviously they trusted this tech more than the batteries and they had enough space...
BTW: I see that you also are a bicycle enthusiast! I gave up with measuring power when I bought my new bike and ordered one with a built-in sensor. They came down in price.
@@AndreasSpiess I'm a bit obsessed with my automatic shifting bicycles and the power meters. Always developing the code for the shifting, currently switching to an external EEPROM.
The power meter is currently providing quite successful but depends what you want out of it. It will never achieve 1% accuracy but has mostly been + - 5W of my Garmin pedals for a ride average so good enough for me. Just about to receive some costume HX711 boards for it with 116Hz sample rate.
Nice video, I was used them in my final thesis to get higher amps for miliseconds. It worked though, as you mentioned it’s not the best for small and tiny electronics.
Thank you for sharing your experience!
Perfect spanish translation. Felicitaciones!!! Saludos, Carlos, Buenos Aires.
The translation is done by Luciana, an Argentinean lady...
Hi Andreas,
Thanks for the video and the time that went into putting this together.
It is a nice comprehensive comparison between the two energy storage mediums.
The caps are good for pulse duty as you said, like providing high current for a short time.
Car audio systems which are very high powered are a good subject.
One may for instance need 10 - 30 times the output current available of the alternator only briefly.
But, as the lead acid battery chemistry is not capable of supplying that kind of current, the caps are perfect.
The maths you did confirms my suspicion, because I am too lazy to do the math myself, that the energy density ratio of the two storage devices is quite high.
And a chemical storage device is still the best, especially if it has to be portable.
The better the batteries, the bigger the issues with the chemistry though.
That is the trade off.
Anyhow, your video as always goes down well with a Sunday beverage.
Kind regards,
South Africa
I hope you are well because we do not get good news from your region ;-) I thought that car batteries have to be able to supply quite a lot of current to crank the engine. At least more than my audio system needs. Since I am no more young, there are for sure much higher powered systems available than mine...
I found an usage for them: I built an UPS for my 4 servers on Raspberry Pi 4. The power supply supported by 8 x 500F super caps giving 5.4V - when 230V is gone, the voltage on these caps can keep 5A for more than 1 minute until it goes to 4.9V - this 60 seconds is more than enough to send "sudo poweroff" command to all servers. One issue: the caps are continuously leaking the current - even when fully charged - up to 0.5A from the power supply - so lots of energy is lost. On top of that: they discharge must faster the first 1V than the next 1V - but this would require boost converter - another power hungry device.
After few months I decided to trash them (the caps - not the servers).
I once made a video where I used a much smaller cap for the same purpose. But only one Raspberry, of course.
@@AndreasSpiess I know, I saw, it pushed me to do it on a bigger scale so thank you
Good and well-founded answer. Thank you for the video.👍🏻
Glad it was helpful!
Well done video. If you look into LTO batteries, they are like a hybrid between a battery and supercap, can charge/discharge quickly and high currents, but have lot more capacity and less voltage drop.
AFAIK they use chemical changes to store energy. So I would count them as batteries. They have their advantages, but their voltage (2.4 volt) is not ideal for our projects. They are probably the best choice for low temperature projects. Unfortunately I did not find standard modules for 2.4V charging or protection.
Useful information and a good reminder of the differences between capacitors and batteries.
Thank you!
Thank you Andreas for this great presentation! As always very well explained and well researched.
Thank you! You are really very active in SOTA Portable Radio ;-)
@@AndreasSpiess Yes, I like to do SOTA, but not right now, with this terrible weather ;)
To me, SOTA combines several great things, like technology and outdoors. And there are several summits in your vicinity that you could probably reach directly by foot. Not like me, who lives in the city.
Your channel is a fascinating source of inspirations!
So far I only tried it once with a colleague. We made two summits in one day. Maybe next summer. Too many priorities...
@@AndreasSpiess Cool! Like you, I did a long ham break before I discovered SOTA.
Have fun and best 73, Stephan
Thanks for all the informative videos i've learned a lot, danke schön Andreas!
You are welcome!
About 30 years ago, I (a software engineer) was working on a project intended for schools. We wanted a way to retain a small amount of settings (tens of bytes) in RAM when mains power was turned off. That was outside of school hours, but also 3 months of summer vacation. I think EEPROM or flash were considered too expensive. They didn't want the hassle of a removable battery. They probably didn't want the expense of a charging circuit for a rechargeable battery (which would also have to be removable, since the product would need to last many years). The hardware engineer suggested a large capacitor (multiple Farads). Alas, the project got canceled before we could see whether the capacitor would work.
Soper caps probably would not have been a good choice neither because of their rather high leakage current. They are good for relatively short-term storage. The pack with standard caps would have been rather big and expensive, I assume...
I've done the same thought experiment with my Arduino projects some time ago as well.. the 5.5V supercaps would be perfect to replace the USB supply.. but a runtime of only a few hours or a day made it quite clear that there's no real way around LiIon cells any time soon.
Thank you for sharing your experience!
Wow, I've had all those questions myself. This addressed all of them plus a few I didn't think of.
Glad the content was useful for you!
Thx for bringing the hype back to ground level,.. very informative!
You are welcome!
Well done again Andreas! But it is sometimes like if someone like beef and someone only chicken! People that play with capacitors might disagree..... I agree with your statement and conclusion - for Arduino or ESP projects. Thank you again!
You are welcome. That is why I try to focus on use cases. Good or bad mostly are attached to what you want ;-)
Thank you for the overview.
You are welcome!
I could imagine super caps being used for those deep sleep sensors with solar panels (like you said), but for locations that you really heckin' don't wanna revisit often, since the caps don't suffer from charge/discharge cycles. Maybe a satellite in space or on the moon, for example.
I do not know if they are used in satellites. But a few properties of the super caps seem to be ideal for that purpose.
Andreas, what was the electronic load you were using to plot overtime the voltage and current.
What software and what microprocessor where you're using to do that you electronic load test????
I seen something in the description of the electronic load test but when I click on the link nothing happens.
Could you give us a more description of what you used?????
Maybe you try the link again. I replaced it (and make sure you do not use an ad-blocker)
TY Andreas! This was just the video I needed; we have boilers on the rooftoops here, I want to power a setup for reading the temp. Coupled with a smart switch inside my home for powering it, using supercaps might be a good solution instead of li-ion; I thought, thanks for filling out the gaps !
With lots of sun super caps are probably a good solution because you do not have to store a lot of power.
@@AndreasSpiess Since I'm planning to use this also on rainy and cloudy days (even more then sunny ones) photovoltics makes less sense to me, I will piggyback boiler power to charge the caps using a smart switch inside my house. Im currently testing the project using li-ion; Ordered the components before U published this video :) But I'll update here if I have news
Well, almost finished the project (again much inspiration from this video); However looks like the setup holds up much less time then I expected. I might have a current leaking "back" to the dc-dc that charges the the caps. should I add a diode between the Buck and the caps @9:39 ?
These do pair well for lithium batteries in solar setups, you will need a separate balancer for your caps and it will end up being 2 caps in series for every lithium cell you have. But they can do wonders for helping your setup handle the higher starting current demands for some applications.
I'll use this in RV's where weight is a concern, and yes, you will need 2 active balancers, which anymore giving the quality issues in lithium cells is almost a must anyway.
Indeed, they are perfect if you need high initial currents.
This was a video I was waiting for. Silly enough I was using a booster / buck converter and didn't think of using a booster and putting everything parallel ...
not always the first idea is the best. I also started with a buck-boost converter...
Extremely informative video, sir!
Glad you think so!
Very informative video! Last 2 year I made non-stop solar machines, windowsill size. To bridge the night en cloudy weather I store the solarenergy of the 5V 60mA solarpanel in a 50F 3V supercap. One pendulum is running non-stop for 672 days on 20 micro Ampere (incl. the LCD daycounter). To convert the solar voltage to the supercap I use only a 3V low power voltage regulator. My experience with buck boosters is that they have a high start- and own power use. My advice: With less than 0.1mA use, a 50F supercap can deliver non stop power for a very, very long time, when charged by a small solarpanel. We did enter the micro- and nanoWatt era.
Thank you for sharing your experience. Seems to be a good project!
What voltage regulator did you use? I have a similar project to this, I Only want to power something that uses about 20uA. Also what supercap did you use?
@@elpechos The voltage regulator is a 3 pin 3V LP2950 low self power use. As supercap I use a 50F 3V one, charged with a 5V 60mA solarpanel.
@@Bertoaus Thanks for that
Very interesting. I was wondering how to use this for esp32 cameras with motion sensor project, to connect to lora wan for monitoring. Cameras outdoors in winter, far enough away from building that ac power is an issue
You can do your calculations on how big the capacitor has to be and if you do not find a solution with batteries (LiFePO4 batteries can be discharged down to -20C)
Speaking of simple circuits, what would use for detecting presence of 12v DC with an ESP32? I have considered optocoupler and voltage divider with resistors.
A voltage divider is enough.
Interesting video, and clear explanation. Any electronic technician working before the digital era knew that high voltage "paper and oil" capacitors of several uF of capacity could maintain their dangerous voltage/charge/energy even for years, and that it was necessary to provide a parallel resistor to discharge them (resistance that during operation also served to balance the voltage in series configurations). An old high voltage capacitor "paper and oil", can be assimilated to a supercapacitor (the Coulomb is the measure of stored energy), only that in this case it would be necessary a DC DC step down converter to stabilize the voltage (of course, it is a theoretical speech, because involving high voltage creates many more complications). I agree that it is risky to compare batteries and capacitors, since the uses in which both can be used are few. In those cases, however, the capacitor could be the winner.
As you describe, each technology has its use cases where they "shine".
Andreas, good video! But I still think that makers could benefit from using supercapacitors a lot (not in all projects of course).
I use a 1.5 F supercapacitor to power my "Wireless solar-powered sensor node" (basically, it is a thermometer) for almost 48 hours. It sends readings each minute (each 3 min when discharged below some level). Also, when using a bare AVR microcontroller we have quite a wide voltage range (1.8V - 5V).
I can share a link if you are interested in reading about the project (the previous comment was deleted, maybe due to the link in it).
Interesting! You have to send the link via Facebook messenger or twitter. CZcams deletes links :-(
@@AndreasSpiess, I've sent it via FB. It also can get easily googled by the name "Wireless solar-powered sensor node".
I worked in a shop that did a project that involved putting super caps in a city bus. I wish I could say it was a success but it wasn't. That was ten years ago. Hopefully, the current crop of caps are better suited for such an application. Anything to cut down on diesel smoke is worth a try.
Maybe you were ahead of time 10 years ago. Here they at least start to replace diesel buses with electrical ones. They produce much less noise (and have many more advantages). Supercaps will be an exception in this application, I think.
One more car application for super capacitors I've seen mentioned: Ability to charge from a near dead car battery and store enough energy to start the car (a smaller gas engine based car). Without having to pre-charge the super capacitor, the way you have to keep the backup battery pack charged.
This is for sure possible. But probably a quite expensive solution compared with a standard Li-Ion booster.
And both are far more expensive than a pair of standard jumper cables. Perfectly suitable for the very occasional (once every few years) that they would normally be needed.
If you are repeatedly having to jump start your car, it is much better to repair it's charging system.
Very interesting and thank you for the understandable explanations.
Have a project that we need to detect power failures/drops. We need to run the 3/4g modem and the mcu for a number of minutes after power failure detected.
Do you have a project using super caps that can achieve this?
I once made a video where I used supercaps to power a Raspberry for a safe shutdown.
@@AndreasSpiess OK, I'll look through your back catalogue.
Thanks for the response
Thank you for a useful and informative video! I have been wondering about supercaps for a while now, and you hit upon all of the relevant points that I've been mulling over. You did miss one point, however, how quickly they can be recharged. Perhaps you didn't miss it per se, but rather framed it in the context of the "electric car" and thus missed some useful "temporary storage" uses in other applications.
As stated in the intro this video is focused on small projects. Making videos means to say "no" to most things. Otherwise the video would become very long ;-)
@@AndreasSpiess Right, but that is one of the great benefits they have over batteries.
Great video!
However, also consider the Low duty cycle use case . turn the circuit completely off for long periods of time and then turn it on. for example, suppose we want to turn the circuit off for one week and then turn it on for one minute, take a measurement and then turn it off again for another week. Now the only thing we need to worry about is a timer that can turn the circuit on and off, the amount of power such a timer would take, and the leakage of the Super capacitor. There are very low power 555 timers with built-in counters. Hooked to a MOSFET We can easily switch our circuit on and off with a long dirty cycle.
Unfortunately, the Supercaps have a relatively high leakage current (compared to their capacity. So I am not sure if they are a good choice for long-term projects.
@@AndreasSpiess The leakage current will stabilize after 24 hours. After which it is minuscule.
Yes you will need to measure the residual Energy left in the capacitor after a time that depends on the application (a week? a year? I don't know.).
As an experiment, I charged a capacitor on my desk and let it sit for a week.
It still has voltage you can measure. The voltage is much lower, typically around half to 1 V.
Still, it may be enough for the application: depending upon how much energy is required and over what period of time.
It all depends on the application. The CSS555 is a micropower version of the popular 555 timer IC. It
features an operating current under 5µA. Using a long duty cycle should
enable the buck boost to be turned off while the super cap leaks. I have
a super cap that registered 0.3V after a year of sitting. IT is a 5.5V
4.0F cap (cheap and unremarkable). It contains 0.3*4F= 1.2 joules of
energy (after a year of sitting). With 5 of these things, you could get
1.5 v, even after a year (and they are not very big). Not much, power, I
grant you, but not zero either. A next generation rfid
tag has a power consumption of 700 nA at 1.5 V. (1 uW).
I have manage to build a weather station with just 2 supercaps of 5F (1.8€ each) and a mini solar panel of 0.6W. It runs without sun about 80 hours! It wakes up every 15 minutes to take the measures and send it with a NRF24L01 module to a gateway inside the house.
It works pretty well. You don't have to worry about battery supervisors, over-charge, over-discharge, heating, low temperatures...
I use an arduino pro mini without led/regulator, a boost to 5V and a LDO. With that I can use the charge of the caps from 2.7V to 5V. Even with weak sun it charges in minutes and survives about 3 days of no sun at all. Everything cheap and simple.
Cool project!
@@AndreasSpiess By the way, great channel and great work! I'm learning a lot, from practical tricks to the most technical topics. A nest of insane new ideas for a hobbitst :-)
I'm new on all this electronics stuff since my times at the university long time ago, and I find this amazing and somehow much more available and powerful than before for a hobbist. And cheaper.
And happy to see that the open source philosophy is also spreading here!
@@gosdeCarrer You are right. I always say that I live in a "land of milk and honey" compared with when I was young (in the 1980s)
Thanks for the info.
My pleasure!
Well you are wrong ☺️. Skeleton Technology has made super Cap configurations that for the same volume of a 10 KWh battery they deliver 100KWh with supercaps. Technology is evolving
Good to know. Let's hope that I am wrong and technology is faster.
What is the preferred solution if I want to have a 12v capacitor bank: Use Boot Converter (2.7V caps in parallel) or balancing/load managent (2.7V caps in series) ?
2.7 volts is quite low and would create a lot of current if boosted to 12 volts. So maybe a few caps in series and a boost converter is a better strategy. But all depends on your needs. For a constant voltage you anyway need a boost converter as it showed in the video.
The link in the description mentioned at 1:43 is missing, although I would really prefer to watch something made by you about it, as I really like how you explain stuff.
A video that I´d also love to watch would be one discussing alternatives, if any, to retrofit old hardware where electrolytic and tantalum caps are starting to leak and fail, as it is difficult to decide which would be the best reliable alternatives with the current cap technologies.
Thanks for the video!
1. Thank you. I added the link.
2. I am not in vintage electronics. But if I watch such videos (Mr Carlson's Lab, for example) They usually exchange all old electrolytical caps with quality brand new ones. Usually without measuring them.
The Art of Electronics at least the second addition had a section on capacitor types and their trade offs. Since modern electrolytic are smaller sometimes you can gut the aluminum cans and restuff them with better spec's parts than original if you stick to good brands from professional distributers. Some purists want to keep as close to original as possible for esthetics. I guess it depends on if you want to repair it or restore it to original performance and reliability.
i looked into using supercapacitors for powering a esp32 running from a coin cell. i came to conclusion its simpler and easier to get a lipo or li battery - the esr you'd need for esp32 is quite low, which means there arent any nice and compact ones you can find. ... supercapacitors are very good for pulsed power applications , my little 12V 20F capacitor bank effectively can put out like 1.5 kW pulses for about 1 or 2 seconds with 100W or less of input accumulating energy. ........ in the future if we get all graphene supercapacitors it might begin to be feasible as a alternative to batteries as in theory you should be able to store incredible amounts of energy in them.
Thank you for sharing your experience. And I am sure we will get a lot of innovation in energy storage over the next years. It is needed...
I am actually designing a project using energy harvesting and chose a 3 V, 15F supercap because I felt like it would be adapted for the charge-discharge scenario of my energy harvester IC fed by a solar cell. Not to mention my application, an ambient condition sensor, is very low-powered.
I think this is a perfect match!
Thank you, Professor.
You are welcome!
What’s the fancy load tester with graphing you are using?
Now I added a link in the description...
Thank your for the video. Is it really true, that super capacitors do not wear out? I have heard that they have charge cycles as batteries, but or course lasting a much higher amount of these.
Theoretically, they should last forever as other caps which are charged and discharged a million times per second (at one Megahertz). But you are right, I also saw max cycle numbers which were probably not relevant for most projects because they were very high.
Like the bus, think Switzerland also used gyro busses in the 60’ who else than professional watch makers would do that. :-)
Indeed. A mechanical storage is very close to a mechanical watch. If the bus would have used a spring to store energy it would have been exactly like the watches…
finally a video on capacitors i can finally understand how they work
Glad the video was helpful!
Great video! Thanks 😀
Glad you liked it! 73.
La descarga de los condensadores se realiza de forma diferente a más baterías. A medida que se descargan va bajando volt. 12, 11, 10, 9, 8.
En cambio la pila, mantiene sus volt Si hasta el final.
Saludos
You are right
Always love your vids this one especialy. Missing highlighting the practical problem of over charging voltage, as they are extremely sensitive for over voltage ,even just a little will destroy the supercap and will make them leak.Many people that have a weather station from Davis have suffered from this problem.just 0,5 volt over a long period will kill the super cap,the solution was 2 caps in series,just take a higher capacitor value . I took me 3 replacements of the original before I found a artikel about over voltage ,and after that I never had a leak capacitor again.
I agree with the overvoltage and I thought I mentioned it. This is why you also need this "balancing" circuit which also have a protection built-in
@@AndreasSpiess - you certainly did mention it, but viewers might feel it came across as a "side comment" or "in passing", rather than something critical.
Mentioned at 3:28 then about needing balance and OV protect between 8:13 to 8;35
Hey Andrea, do you think if electrical appliances were built with tantalum caps ... they would last longer ??
I do not know. But I know that tantalums are expensive...
Thanks for the great video!
Thanks for the explanation and comparison. What about Li-Ion capacitors, how do they compare?
I do not know. I never had such parts on my bench.
9:40 .... I was actually thinking of this for a solar powered clock in my work's lunchroom... I have the caps, I have the clock... One cap, fully charged, will run the clock for about 23 hours... I just need to see if the solar cell can keep the cap full whenever the room is occupied (the lights go off when it is empty)...
My big problem is that, Christmas Day & New Years Day my work is closed and empty, and the lights will stay off... For around (????) 24 ish hours...?
I'll get around to it someday...
I assume you would need to dimension the cap accordingly. Like the batteries in a solar powered outside project...
If you have a device that varies in its current draw, such as occasional high-current event, supercaps can help keep those high-current events from batteries, which hate that kind of use. As you said, supercaps would be great for a hybrid car, because they don't wear as much as batteries.
What you stated that capacitors undergo no chemical change is largely true, but electrolytic capacitors do store charge in their electrolyte. Electrolytic capacitors can develop a voltage even after being apparently discharged, which is quite a dangerous thing in high-voltage work. Sadly, electrolytic capacitors will be the failure point of most things that use them.
I agree with all your comments.
@@AndreasSpiess , well, I am flattered. Thank you.
I am curious if this use case is possible with super capacitors: it charges up using a solar panel, boots up an esp32, sends out sensor data, then turns off fully again (not deep sleep). This could run a long time without an ageing battery.
This is possible. I did it for my "Amazon Dash Button" project. The only question is: How to switch the MCU on (I used a mechanical switch)
Thanks Andreas, I'm hoping for a supercap boost in my next e-car in Canada.
I read that the Tesla Roadster aims for 1.2 sec from 0-60miles/h. I do not know if they use supercaps...
What about use in conjunktion with lithium for surge protection
I do not understand what you mean :-(
Can you show if we can use supercaps in power supplies like linear psu or switching psu?
There we use normal caps because the frequencies are higher (linear: 100 or 120 Hz and switching kHz to MHz) and we do not need extensive capacities.
Thank you for shedding light on the truth through all the hype !
You are welcome!
Hi, try this experiment: Charge a supercap to 2.7V; then wait a little while (maybe 10 minutes or so) and measure voltage again (no load). The self-discharge will have reduced the voltage. You can then compute an 'equivalent resistor' -- which I have found to be about 123K ohms. This is too much self-discharge in my opinion. Just too much leakage for anything but short-term; 1 day is just not practical, as you discuss. Perhaps a few minutes.
I did a similar experiment when I connected the buck converter to a 330k resistor. My supercap did not discharge as fast as yours (or it was bigger). But I agree: I would not propose to use them for long-term storage.
Great job. Thank you. 73s
You are welcome! 73
They are also pretty great for undersized power supplies, charge slowly and use them when a lot of relays has to be turned on at the same time.
I am thinking about using them for a emergency jump start box. Since they can push a lot of current and have a low energy density a handy crank or charging from a "dead" battery would be possible.
@The Southern Cross but why should I spend 100€ when I could do it more expensive myself by buying capacitors costing more than a small box, overengineer the rest and add stuff due to featurecreep that I'll never use.
If you are sure that your engine starts reliably fast, super caps are a good idea. Otherwise batteries are still needed. AFAIK they use super caps for lorry starter because they need a lot of current... Maybe good for my Harley (two cylinders, 1700cc needs a lot of torque to start), too
@@AndreasSpiess off topic but I'm always impressed how often you answer to comments under your videos.
I've seen year's ago a video here on CZcams where someone only had a 6ah battery (somewhere in that range) and a few big caps as replacement for the original battery. The small battery was only there to Keep the caps charged. It even seemed the vehicles started better with that bit of extra current. So it is definitely possible to make a jump start box with them.
I don't know if lorries have them but it would really make sense
You are right, I try to answer to all comments because I like the conversation with my viewers an I learned a lot with it!
I see maybe another application for home solar application when switching from the solar inverter to the grid (for partial offgrid setup). During this switching, electrical microcut can occured and you can loose your internet internet connexion for example. So maybe such supercapacitors can be used to overcome these microcuts during few ms for devices such as intenet box, wifi router, raspberry PI, etc...
Good idea!
SMA uses large capacitors to do daytime backup without batteries. They're not supercaps, however, just large high voltage electrolytics.
Excellent video. One of the hyped uses of super capacitors in weight, where they are lighter than batteries for the same capacity. Still not so useful in small projects, with the possible exception of airborne projects.
I never compared the weight of supercaps with batteries. So good to know.
There are some storage controllers with a backup battery made from supercaps.
I'm using two supercaps in series to power a CMOS based clock if there is a power failure. The clock runs more than 1 hour with the caps.
In some cases supercaps are fine :-)
Nice project! I also used such a setup to safely power-down a Raspberry at power failure.
As you said in the video, a supercapacitor and a small solar panel will do the job. Well I live in the Benelux. I have 2 panels in parallel which in summer give me a peak output of around 140 Watt. Yesterday at around 1pm I measured a 0,066A (shorted terminals) which leads to around 1 Watt of output. 1/140th of it's capacity. If we then use a smaller 5W panel and do the same math we are not going to get there I am afraid. There is a reason why I decouple all garden lights of their small panels here in the beginning of October and use a small dc/dc to charge them with the bigger panels.
You are right. LEDs are not low power devices (micro amperes). BTW: I once made a video where I did all the necessary calculations for year-round solar projets
So, warum Andreas, bringt Tesla nicht einige wenige
Supercaps zusätzlich zu den Akkus in die
Konfiguration?
Könnten sie doch wie du sagst, die allgegenwätigen
Beschleunigung/Bremsungs Zyklen auffangen?
Ich weiss es nicht. Ich vermute dass sie so viele Batterien parallel haben dass sie mit den hohen Strömen umgehen können. Supercaps brauchen immer auch Kosten und Platz. Vielleicht sind grössere Batterien wichtiger als Supercaps.
What I am currently looking at trying with my EV project is using the SCs ability to dump a lot of current in a short period of time to create my own 'ludicrous mode'; battery charges the SC bank, SC bank pours current into the motors.
I hope you will be successful!
In lymens terms i think the more pressure on the caps plates the higher the charge rate they hold, Lto cells are a happy medium very temperature robust and 30000 cycles but we still dont reach the energy density of of li cells
Absolutely love the mini hand and glove.
AFAIK LTOs change their chemical structure and I would count them into batteries. But maybe I am wrong.
They might be useful for driving an ESP off of a tiny solar cell during sunlight or overcast days. You could use a solar cell that outputs only a few mA of current in those conditions, and still be able to power the ESP's required >100mA for under a minute.
They might also be useful for a non-stable power source. Like a solar cell that may get shade occasionally, or something that generates power from movement.
did you practically try to charge a supercap from solar? just asking...
I agree. They are good for relatively short-term energy storage in general.
Usualy people who does not know what they are talking about are asking this question.
Great video as ussual 👍
Now all should know ;-)
Very good job.👏
Thank you!
Supercaps are very handy, though, for maintaining power on an RPi on an unexpected power supply loss, long enough for a clean OS shutdown.
I agree and I even made a video about it in the past...
@@AndreasSpiess ....and it was very clever, thanks Andreas.
also since they have very low internal resistance and thus can deliver very high amounts of current, they are also suitable for making a portable spot welder or if u just want to make things glow red hot
True. But be aware that these applications need a lot of energy. I assume the caps are discharged quite rapidly and have to be charged if they are not huge.
yes for the second one that is true, but if u use a decently sized super cap bank i think it should be sufficient for a spot welder also i think these can also be used to power the xenon flash lamps in flash lamp pumped lasers
Parts just arrived, 2x30F 2.7V seem to pack quite a punch (fried some wires when shortened accidently). BUT I just noticed that Aliexpress Boost converters tend to have high minimum input voltage! at least 2V.
The one you supplied has no tech spec on the product page; Anyone have a lead for a Low voltage boost converter capable of utilizing more juice out of the 2.7 Parallel caps?
The typical energy harvesting chips are made to start at very low voltages.
Can these thin legs and balancing board handle the current of a car jump starter for a bigger diesel ?
I do not know. But I saw that someone advertised supercaps to jump start lorries
Extremely useful video, I’m using super capacitors I’m my project in Brazil
Thank you for your feedback!
How about use with high voltage solar system to store then charge a low voltage battery bank? I have a 300v270uf cap. that will hold some butt kicking power.
Maybe needed if you only use small batteries which cannot support the full current of the solar panels.
If they find a way to eliminate internal leakage ... then the only remaining problem is volume. If volume is no issue, than they would be a better option for a lot of storage problems like a home battery and the heavy charge discharge applications.
That would be ideal especially for EV's when charging and of course the charging stations. Especially the charging station could benefit from storing when on standard power lines not designed for the heavy load of charging EV's.
I agree that there are many potential applications. Most of them involving high current/power. I tried to keep the focus of this video to small projects.
@@AndreasSpiess I am interested in battery and capacitor technology for a long time now. And they have been swinging the holy grail of battery technology carrot for the last decade with hollow promises and fake or dodgy "new" discovery startups for me to trust anything that pops up now. So my hope has basically switched a bit from battery to capacitor. And with the leakage solved also small projects would benefit 😉
I recall a teacher saying that a 1 Farad capacitor would be as large as a telephone box (UK)! 40 years later and they are clearly much, much, smaller.
Definitively! Also a few other things became smaller during this time. Just my belly became bigger ;-)
As you suggested, the big breakthrough would be to be able to use higher voltages with supercaps. Battery voltage is limited by the chemistry used, while capacitors have no such theoretical limits, although they do ofcourse have practical limits, but it remains conceivable that some day the current practical limits could be overcome.
The other technology you have not addressed is the use of flywheels (or even springs) to store electrical energy; although neither of these would probably currently be practical for micro-projects.
I have seen a "rechargeable" batteryless radio that used a spring and a generator.
@@NiHaoMike64 radios can be such low power that no battery capacitor or any other power source is required. The antenna and ground is enough.
Hfil66, capacitors have very defined limits. Higher voltage means thicker dielectric which means lower capacitance. You could put 2 in series as noted, but by definition at half the capacitance. Note supercapacitors can be battery like and limited by their chemical changes used to store energy.
@@1boobtube Does that not assume that the dielectric of the material remains constant, that the breakdown voltage of the material remains constant, and that the surface area of the electrodes remains constant. If all these things remain constant, then the only way to allow for a greater voltage is to increase the thickness of the insulator.
The earliest capacitors would only have an air gap between flat plates, and this ofcourse meant they had to have a significant space between the plates, and thus very low capacitance. We have come a long way since then.
I agree with the mechanical storage. Another interesting concept (also not for small projects) is this one: czcams.com/video/itbwXMMkBQw/video.html