Safely Charging Any Battery With Your Variable Power Supply.
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- čas přidán 23. 07. 2024
- I recently made a video where I showed how I'm able to use my Variable DC power supply
to charge a variety of different batteries, and why it doesn't matter how high I set the voltage, so long as I set my current down low enough. If you already know what the ideal charge voltage should be, there is no point in using a higher than ideal charge voltage, but
since many of us may find ourselves in situations where we don't know what the ideal charge voltage should be, and we don't want to guess and possibly damage our batteries. Lowering the current assures us we will not damage our batteries no matter what voltage we use,.
The only down side to applying a higher than ideal charge voltage to your battery, is that your battery will have a non stop current being applied to it even after it reaches its full charged state.
At a low current setting it's not going to create an explosion, but it would be wasted energy and cause your battery to fall short of its normal life expectancy.
In this video I also talked about reversing the polarity to batteries that would not take in any charge current just to jump start them for a very short time interval, but I'd like to add it would be dangerous to do this for more than a few seconds, and it should only be done while cautiously observing the current flow into your batteries. Once you see the current starting to flow, I suggest shitching the the leads from your power supply back to the correct charge polarity to see if the battery will start to accept a charge. Sometimes I repeat this step a few times.
Well you are describing is exactly how automotive battery charging systems are designed to work and due to the nature of lead acid battery cells it works well in that application. You explained the theory behind it very well.
GREAT video, yes you ARE absolutely correct…. It is possible to recharge a battery using a variable charger. Just use good common sense and caution. We did and still do this all the time. Just match the rated voltage on the battery and go low on the amperage. Most important… check it and the cables every few minutes and make sure they are NOT getting hot. I NEVER leave batteries that I am charging unattended.
Thank you VERY much for this fantastic well done video. 😀
Also, we used to OVER charge CRT’s (cathode Ray tubes) that’s the main vacuum tube in which the picture is displayed
on an old style TV tube for a few seconds to burn corrosion off the electrodes and hopefully regenerate the picture a bit. This is done with equipment specifically designed for this… NOT with a variable charger. 😊
I had a B&K picture tube rejuvinator, but gave it away not long after the flat screen TVs took over the market. There were a couple times my rejuvinator did more harm than good, but other times they really helped.
Great job explaining battery charge methods. The Ni-mh and Ni-cad tend to grow crystals that effectively short the battery and the sudden high current and or reverse charge will often blow those crystals away. Usually it is a short term fix though. I have done it literally hundreds of times over the years.
Thanks Steve, I think your right about this kind of fix being short term. Perhaps One exception is when you buy new battery that needs a small jump start before the charger it's designed to be used with can do its job.. I've even done this with car batteries, but once they are that stage where this is necessary I don't expect them to last much longer.
Indeed, a "dead" 12V battery can be brought back to life with a high voltage like 30V and a few mA for a few seconds.
In fact, some chargers specially for AGM / Gel Acid batteries, when the batteries are fully drained or not used for a while,
the charger use at the beginning a very high voltage and low current, and from the moment the battery responds and begin charging, the voltage begins to drop, and the current raise to approx 1/10 of the battery capacity. This is controlled by a microcontroller.
Per example a 12V 7Ah battery, will then be charged with a maximum of 700mA.
If the chargecurrent on AGM / Gel Acid batteries is to high, they produce a lot of Sulfur odor (like rotten eggs or matchsticks).
Back in the old days i tried to charge a 7Ah AGM battery with a oldstyle battery charger (linear 12V 4A) and after half hour,
the whole room had this Sulfur odor, and i saw that the battery already expanded (swollen) a little and felt very hot, it was time to pull the plug :-)
After that, i always use the thumb rule of charging at max 1/10 of the battery capacity, 700mA for 7Ah, 1,4A for a 14Ah battery etc....
And if the maximum charge current can't be adjusted, a 55W Halogen car light bulb in series with the charger leads will do the job.
Thanks Bjom V
Valuable information, I appreciate the 1/10 current of Ah for charging lead acid. It’s safe and effective.
Don’t hesitate to provide viewers with your valuable knowledge.
Greetings from Saudi Arabia.
@@__-hh3gt Thank you
@@BjornV78what is the rule of charging for Lipo batteries? I got some 3.7 v 22ah batteries and just wanna set proper values in my vaeiable dc power supply
thank you for this video. it's exactly what I needed to know. need to charge a ni-cd and my expensive charger has a blown mos-fet
THANK YOU FOR THE EDUCATION
haha right when you said it was from a cell phone I got flashbacks to my mom's old 90's cell phone. The big gray block one lol.
To charge a dead LiPo battery that won't charge, connect it to the charger (the blue charger in your video) and select NiCd (lead acid battery setting) and set the amps to the lowest option (0.1). CHarge for 10 minutes, then charge like normal under the LiPo setting.
This technique of high voltage low amperage I use it a lot especially when trying to bring back an extremely old dead dead battery most of the time the voltage sag so the battery never experience any damage. It's surprising how these new technical guys do not know of this technique it's like their discovering new all over again.
There is a simple explonation, they make automatic chargers, and we live in capitalism, why teach someone how to revive a battery when they can replace it? Also, i had to teach a few students as a car mechanic, while it's not dangerous if you know what you are doin, it can produce explosive gasses if you don't pay attention, not a sigle one of them understood after explaining 4 times why, thogh my boss told me to let them do it, they forgot about the battery and we had to shut off power for the whole building and ventilate 4 floors.
If I understand it correctly, I think it boils down to Ohm's law. Voltage is what drives current through a resistor. If we assume that the resistance of the battery and the cables at any given point in time is constant, the only remaining variable is the voltage. The higher the voltage, the more current will flow. The only way the power supply can actually limit the current is by ignoring your voltage setting and dropping it down.
I also read you can leave most modern NiMH cells in the charger if(!) the current is low enough. It's called trickle charging. There's a catalyst in the cell that will recombine the oxygen which normally forms when the cell is full. That reaction, however, creates heat, and the catalyst can only handle so much at once. Hence the need to keep the current low. If you overwhelm the catalyst, bad things may happen. It may be why some devices still use these cells instead of LiPos. If charging time isn't an issue, you can keep the charging circuit really simple (read: cheap).
Yes the voltage drives the current through the resistance.
Ohms law the first thing I've ever learned in instrumentation and still use it everyday
good info
Any thoughts on restoring 24v ridged battery’s. I have 8 of them and they are not made anymore.
This very interesting. May I ask for the link to the previous video you mention in this video?
Sorry but I've replaced the first video with this one.
Thanks, Dave. That's why I like the Blue ESR Meter because it can test the ESR of batteries.
I can't find that other video. What happened to it?
Hi Robert. After reading some of the comments under my first video, I thought it best to remove it out of concern that someone might blow up their batteries if I was misunderstood. Thanks for the reminder about the battery testing function of the Blue ESR meter.
@@GrantsPassTVRepair Oh, ok. I stopped smoking and started vaping several years ago. And many times people would ask for recommendations for a sub-ohm meter to check their vaping coils with.
I always told them to buy a Blue ESR Meter since ESR meters are designed to read sub-ohm values, plus they will be able to test the ESR of their batteries and also test E-caps if they ever need to. But I changed the cables in mine with some good coax cable and I don't use the cheap clips that come with it.
@@robertcalkjr.8325 My only complaint about my blue ESR meter is that it would often turn on by itself without me pressing the power button, so I installed a second switch to stop that from happening. BTW the newest blue ESR 2 talks to you. czcams.com/video/g2jSE0WSIwY/video.html
This is true. If you use 10 % of the batteries capacity you won't damage a Ni-cd but it will take a long time. Check out battery charging techniques for more on this.
What current should I set to charge a lipo battery 3.7v 22000mah?
U said that the voltage drops bcse of the battery's own internal resistance right? So can I 'gess' the battery internal resistance doing that? I have a lot of batteries cells, so Could I compare them doimg this test to see which ones has the higer internal resistance?
I made the mistake of leaving my lithium 24V battery switch on after storing my boat and came back after a few weeks and the battery was dead. Is it possible to jump start or recharge the battery using a product like this? How long would it typically take to recharge if possible?
I'm surprised your lab bench switching power supply doesn't read amperage. I think people didn't understand you, because they don't get the difference between voltage and amperage haha awesome video!
Your probably right about the confusion. My variable power supply is able to measure amperage, but it requires that I flip a switch to do so. Some of them will display both current and voltage at the same time.
@@GrantsPassTVRepair oh okay. That's pretty cool 😉 also, this video was needed. Yes there's other videos about charging a battery like this. But, this video right here is what should be in every other video on this, but you're the only one. I was watching it like "thank you! Someone explained this in an easy helpful way!" Haha Hope you get a ton of views and likes!
Yes, I believe that you're onto something here, SMP. It reminds me of the folks you run into at auto parts stores who firmly believe that a physically larger 12 VDC auto storage battery will damage the circuitry in a vehicle that came from the factory with a physically smaller battery. I've tried to explain to some of them that 12 VDC is 12 VDC -- regardless of the physical size of the battery -- and, just as importantly, that the benefit of a "larger" bank of saturated lead acid battery cells is that it should be capable of reliably handling a larger current load, but most of them remain convinced that a physically larger storage battery always means more current will magically flow through any given circuit...which, naturally, leads to more power/heat. Considering that most of these people don't know what a carburetor is, I've given up on trying to teach basic Ohm's Law to these folks.
Thanks for the info, I think if you dropped references like links, people would stop the criticism.
I think you're probably right about that. Thanks for the tip.
I have a 20V DeWalt battery pack that is sitting at 13V. And I can’t get it to pull any current from my power supply. What do you recommend I try to do?
i have the PSU set to 20V 1A.
I'm guessing the DeWalt battery may have some internal charging circuitry built in to it, which may prevent the charger from charging the battery if it senses there's a problem with the battery, such as not having any voltage in the battery at all. If it were mine. I'd probably try to charge the battery from the output side of the battery, which bypasses the charging circuitry, but I'd also raise the charging voltage using a variable power supply, and monitor how much current it draws with an amp meter, so you don't over do it and end up blowing up your battery.
Great video but my
Question for you is how do you check the state of charge ? Like you level of charge in the battery
To the best of my knowledge a voltage drop test under load is the best way to test a battery. Here is a video where I talk about this. czcams.com/video/TQenKo9AFfQ/video.html
the reason I ask
Is I had a battery for a rc car that was 14.8 v i charged it to 15 volts . But what. It was put an a rc car bms said the charge was at 22 per cent capacity . It then charged its to 100% capacity and was about 17 volts
I have long time discharged 18650 LG cells. Visually in perfect condition, voltage is under 0.0500v
Can I try to shock them with 12v 5a dc charger for few seconds?
I did try to connect them to healthy cell and voltage go up to 3v but fast go back when disconnected ...
I'm not sure if it's okay, but I've often done this when a battery doesn't take a charge. Is your battery not charging up when using the ideal charge rate for this battery?
@@GrantsPassTVRepair I did try with 12v 5A dc charger
First I started with few seconds after that but there was no change (cid is ok not blown up)
So i left it for 30s 1 min for few times, now it shows 0.8v 1v but that's it. I'm not sure how long i cant leave it on 12v dc power supply ...
Sadly i dont have power supply as you so with this dc power adapter I'm blind what I do :)
@@donmarkon I've done many experiments like your doing when I've had batteries that would not take a charge, and what I learned is some batteries are to far gone to regenerate, or they may come back to life, and only have a fraction of their amp hour capacity as they should. As you probably know there's always a risk of damaging the battery or causing it to explode if you overcharge a battery, Much like yourself I take a few calculated risks now and then, but I would not feel comfortable advising you on this one, except to say be careful.
@@GrantsPassTVRepair Understood :)
Thank you
can this desulfate a car battery ?
But what I do I charge each cell separatly and it works great also
If the AC power fails when using a DC power supply to charge a battery, will the DC power supply be damaged due to the the battery sending voltage to the unpowered DC power supply? The manual for my low cost DC power supply says that damage can occur in this situation.
Since I haven't seen the power supply circuit design in which you speak I don't know, but It sounds unlikly that an interruption in the AC input power going to the DC power supply would damage the unit just because it had no AC input. I've never seen anything like this occur.
A diode would prevent the battery feeding back into the power supply during a power outage, if I'm thinking correctly.
With this theory, could I use a 84v lithium charger for a moment to revive a 48v battery pack if I turn the dial to 1 amp? The 48v battery typically is charged with its 54v 2amp charger but its been drained to 49.8v and no longer recognizes the charger.
I've had some success reviving batteries in this manner. Sometimes the batteries are to far gone to restore, but as far as the safety factor goes it's probably best I don't advise you since I can't see your set up, and I don't know if your charger has a direct connection to the battery your wanting to charge, or if your battery has any kind of internal regulation circuitry as found in some makita drill batteries.
@@GrantsPassTVRepair Thanks for your response. I went ahead and purchased a 60v dc power supply and thanks to amazon it will be here by 8am but it's a 48v battery with bms from an electric scooter and its discharged to 49.8. Nearly a brand new scooter, I think my son ran it dead and ten turned the power on one more time to get more. Anyhow, appreciate the response, I reckon I could have saved some cash and tried it.
So... if 30V battery is charged by dropped voltage of 13V - does that mean I can technically charge 5V AA battery full with 2,3V 100mA charger if I let it sit long enough?
naaah, the charging significantly *discharged* it to 2,3V lol
How can a laptop battery be charged using a DC bench power supply? Doesn't have to be fully charged, but maybe 1/2 to 3/4 for Laptop test purposes. Thanks
The power supply you use to charge the battery in the laptop computer will need to have an output voltage above the stated voltage of the battery used in the laptop by at least 1 volt, but unless you have a variable current output on your bench power supply like the one I show in this video the only way to regulate your current going into your battery is through a current regulator or a high wattage resistor. The problem with using a resistor to regulate current is that it will get extremely hot. Naturally you will need a plug that fits your computer charging port, and you will need to match the correct polarity on your plug of you can end up causing your battery to explode, and possibly damage your computer.
@@GrantsPassTVRepair thanks for the answer. Some bench power supplies have variable current output but would have to look at which ones are best. Also thought of making a short cable to connect to a working Laptop to a good battery to charge it.
this guy is a chemist under electrician's disguise!
This works because of the current-limiting action of the power supply. The power supply reduces the voltage automatically to keep the current at the 10mA limit you set.
If the supply had no current limiting, and the voltage is significantly higher than the battery, then damage will likely occur. So it is important to note, this method can only be done with a current limited supply!
I agree, It would be possible to use a voltage regulator or a resistor to drop your current, but doing so is would generate a great deal of heat.
I can't seem to find the original video
I removed it to make sure no one misses the point on the importance of current regulation.
Darn I have five of these 12volt agm batteries that are dead. Picked up a bench adjustable power supply to test this with just this weekend.
My bench power supply has max output volts to 17V
And 2A
Im trying to charge a 12V car batt lead acid
When i connect the psu to batt the psu drops to 11.5 V??? And fluctuating (11.1V-12v)
And amp fluctuate (0.00 to 2.99)
What is wrong here?
It sounds like your power supply can't deliver as much current as your battery is attempting to consume, so it's overloading the power supply and causing a drop in power.
@@GrantsPassTVRepair yes its a puny mobile repair powersupply. make sense. Thanks. Ill stop charging it now. So far it was able to charge from 11.2 to 11.5 volts in 8 hours. So i need a bigger power supply.
Do you think i can use a ac adapter from my laptop to do this? That ac adaptor has an output of DC 19V and 4.5 Amps. If yes do i connect it straight. All i need is one start ofmy car and i then plan to take car on a 1 hour ride and that will charge up the battery. So all i need is 1 self from this depleted battery. Any help will be appreciated.
So, the main thing about charging a battery with higher voltage is, it doesn't kill it, as long as the battery don't go higher then the intended charge voltage, for 12v a healthy 100% charge is ~12.9v normaly when charging it can go up to 14.3v which is normal however, as you connect the power supply and the battery is on low voltage ( 9 or under that) the voltage on your power supply will drop significantly so to charge it you need higher, even up to 30v could be used, however as the voltage inside the battery go higher the overall voltage drop will be lower, if a 12v battery goes down to 6v and you put a 20v and don't pay any attention to it it could go above 15v at which poin most 12v battery start producing explosive gasses. So yes you can charge a battery with higher voltage, and yes it could explode if you leave it on for too long, however at low current it could take days or even weeks to become explosive.
I was not able to understand everything you said.
I know from experience batteries produce an explosive hydrogen gas as they charge, That's why people who live off grid on solar energy are encouraged to keep their battery banks in a area that has ventelation on the roof of the container they are kept inside. Aside from the hydrogen gas danger, the other danger from overcharging is to much pressure inside the battery can cause it to explode. I don't believe this should ever be a problem if your current is kept very low,
@@GrantsPassTVRepair Okay i read back on what i said, it's realy caothic sorry kinda lost my point there. In base what i wanted to say is, if the current is kept low it could still produce hydrogen, if it's hooked for too long to high voltage, however the current will tell you how fast it will happen, and as i said at low current it could take weeks or months. and it's indicated by the overall voltage on the battery while charging, if you start charging a battery the voltage will slowly rise as the battery charges, if it reach a point like a 12v battery charge 13.5-14.5v above that, it usaly produces hydrogen and could be dangerous. but on low current, it would probably sit there for weeks or months if it's a big battery, and it has to sit there, charging in an airtight, locked room to explode. If you don't actively try to achive an explosion it probably won't happen, but saying that it's not dangerous, is not right since if you don't know how to set the volt-current ratio it could take months to charge or explode in the wrong hands. But i think you could probably fine tune it as it fully charged to stay under that 14.5 volts.
@@studioreaper9646 Unless you are using a smart charger which monitors the battery and adjusts the charge rate according to the batteries needs, I would not leave any battery on a charger continuously day after day for weeks at a time as it could cause unnecessary wear on the battery, but as long as your current is set low enough I don't see the likelyhood of an explosion. ...I remember taking apart an uninterrupable power supply which contained a 12 volt gel cell battery, and a regulated charger which continually put out a charge voltage of 13.8 volts no matter what the charge rate of the battery was. Even though batteries don't consume much current at that voltage after they are fully charged, at 13.8 volts they do consume a little power around the clock, but apparently the designer of the uninterruptable power supply concluded it wasn't enough to be an issue. ....I think short term charging using a higher than suggested voltage is fine for short term charging, but to create an explosion takes heat, and if your current is set low enough the heat produced can be so small I don't believe it's likely to be a problem.
@@GrantsPassTVRepair Yeah smart chargers are mutch safer. Also that 13.8 volt is pretty mutch optimal to keep a battery charged. Also fun fact smart chargers don't operate on the voltage they actualy put out, they usaly have higher voltage, using square sign waves peaking at around 25 volts periodicaly ceasing and restarting the charge on high frequency , connected to a capacitor to even it out, meaning the charging is ceased 45% of the time to achive 13.8v under no load and under heavy load it could turn it up to 25volts although the actual output voltage is never shown since it's set up so the battery would stay on 13,8 or lower as the voltage drops under the load.
@@studioreaper9646 Sorry but I could only understand half of what you said here.
Cant see why you would do that. If you limit the current its not going to charge any faster with a higher voltage. Its just going to drop the excess voltage x current (power) in the charger circuit instead.
Yes I agree. A low current charge could take much longer to charge up a battery, but sometimes you may not know what the ideal charge current or voltages should be, so I was just demonstrating one possible approach in a situation where you're left to guess.
@@GrantsPassTVRepair Yes I understand that , pick a low charging current if you dont know, but what is the point of the higher voltage if you are limiting the current anyway? If you dont know the fully charged voltage of the battery then you probably shouldnt be trying to charge it anyway. In other words just pick a charging voltage slightly higher than your target voltage. It makes no difference to the final result in charging time if you are current limiting and you arent wasting power with a large voltage drop either..
@@mrgriggs5815 Since many of us may find ourselves in situations where we don't know what the ideal charge voltage should be, and we don't feel safe to guess and possibly damage our batteries, lowering the current assures us we will not damage our batteries no matter what voltage we use,. Other than for this reason you are correct. There is no point to use a higher than necessary voltage if you know what the voltage should be.
@@GrantsPassTVRepair i appreciate the video and the discussion as i am trying to learn everything i can at the moment about electricity. if i can ask, in what situation would one not know the the target charging voltage? i was huge into rc about 8 years ago and ran all lipo but occasionally i would run across a person with one of those cheap/weak nimh 8 cell battery, and my high end charger could charge four at a time so i ended up charging everyone's stuff in the field for them but i had to google the suggested current......i realize i approached my problem from a different angle, but would my example be a time you would just crank the volts to 30v but limit the current to .500a? granted i was in the field so we wanted a quick charge, and in the shop it can sit on the charger all day if needed. just curious? thanks
@@jasonbrown467 Sometimes t needed to charge up devices that did not come with a charger, and not knowing the ideal charge rate this technique came in handy.
This guy agrees: czcams.com/video/NcH-TwXJPmU/video.html
Thanks for squelching my anxiety.
🤔Now can this machine bring a Lithium-ion wheelchair battery back and other kinds of batteries to be able to bring the battery up let it start taking a charger the rest of the way?Because what going on with the battery is 🫣it's way too low for the charger to read to even start up charging it right now!And these two battery's are not even a year old yet . She wasn't really using her wheelchair that much and Definitely Not Keeping them charged up like she should have to keep them taking a good charger.
Wait back up explain it a little slower If you could give some visual cues on paper might help also. Me Not enough smart for variables.😂 I could never figure out why everything just kept catching fire 😳
just watched a similar tutorial and he sets his current at 5A to charge his battery and doesn't explain how to work out how much current to set the bench power supply depending on battery capacity. Seemed wrong to me and deffo not enough and correct info for people learning.
The matter is very simple, I don't know why so much drama and ignorance of the facts. Each type and model of battery has a prescribed excellent maximum voltage at which it is considered fully charged!
That's why, on your power source, limit the max charging voltage and set a limit for the current according to the capacity parameter, for example C/10, or even less! It can't hurt even less! And that is that.
E.g. for a 3.6v LiOn battery, the ideal voltage is 4.3V, current e.g. 500mA
For example, a classic lead-acid battery 64Ah (600A), Umax=14.4v (normal charging) Imax=6.4A, or less, if it has been discharged a lot below 10.5v and has been standing for a long time. The topic is too broad to mention all the details... And that's it. When the maximum voltage is reached, it switches to the constant voltage regime, the current drops to 0, most often it stays at the order of 100-200 mA...etc...
I don't know why you would set the voltage without limitation????? Why?????? What you are doing is dangerous!!!
Did you watch this whole video? I was not encouraging anyone to keep their battery charging on a continuous basis with the battery voltage above it's suggested charge voltage. I mentioned that doing so was a bad idea and potentially dangerous. I was simply explaining a technique I've been using for years, when i needed to charge a battery of an unknown amp hour capacity, and I did so by keeping the current down low enough, that I could walk away for a while, and still charge my battery without the fear of damaging the battery from excessive heat. Listen to 1:12 of this video.
@@GrantsPassTVRepair You don't need to know the capacity of the battery, but you certainly know its working voltage!!!! It can be 1.2v 3.6v 6v 9v 12v 24v 48v for example. It does not matter. If you know what type of battery you are charging, whether it is Li-ion, lead acid, agm lead acid, gel... you also know how to determine the final voltage! If you don't know the capacity, then you just put the current as low as possible, we agree on that, but it can clearly be assumed if you know the type and see what size it is.