Ideal Diode between Solar Panel and Battery
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- čas přidán 21. 08. 2024
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There's only 20mA of current back feeding from the battery into the solar panel at night, but this ideal diode eliminates that.
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You didn't measure the voltage drop across the ideal diode.
It will be the on resistance of the mosfets multiplied by the current.
@@JulianIlett I would still like to see what that turned out to be in your setup as you did not mention the device characteristics and even if you had, the implimentation could have some impact.
@@JulianIlett Yeahbut, who's to say it isn't just as bad as the first one you tried?
@@JulianIlett R(on)? On a data sheet sure. But who just blindly trusts that?
Yes, that voltage drop while charging is the most important thing to measure. Surely the whole purpose of an "ideal" diode is its much lower forward voltage drop than a conventional one. Any conventional diode, even a Schottky, will have a low enough reverse leakage to be of no consequence in this application.
"A few years ago I bought a whole set of these Ideal Diodes" Postbag: #76 (Nov 24, 2016) pretty much 5 years there.
On the brightside, at least that board with the LTC4359 is still available.
Was it really 5 years? Tempus fugit :)
haha yea I'm the same way, buy some modules just because I'm curious about them and want to test, and never end up deploying them. I definitely appreciate the fact check 👍
Finally something I know a lot about! The FETs are in reverse series. And have been doubled up. This way you guarantee that the body diodes never conduct either forward or backward. Therefore, the system only conducts when the gates are driven by the controller which is a glorified opamp with some bells and whistles.
If you're interested, LT also do an ideal diode full bridge rectifier which is really neat
I have a board with an LTC4352 and paralleled MOSFETs which I have never soldered up - maybe now is the time?
Hi, it would be cool if you could Help me out as i have a hard time understanding. Every FET has a body diode. So ist conducts in the opposite Direction compared to the Direction it is steerable. If i put two in reverse series, it seems to me that the current has to cross a body diode in one of them at least right?
@@knopfkrieger the body diode is just a parallel diode inside the body of the FET. It's an unfortunate downside of the design of FETs. As long as you can pump enough charge into the gate, with many FETs you can put them in backwards, so flipping around the drain and source. So yes, absolutely, reverse series works and is quite common, particularly with N channel.
Personally I used it to protect a battery and fuel cell which were hybridised in parallel, both of which don't like uncontrolled back feeding. This required a bidirectional break in the current, like a relay would provide but I needed high frequency (kHz). FETs only provide one way breaks due to this body diode. Unless you put two in reverse series then job is good if you can tolerate the reverse leakage through the side of course
So i use the mosfet the "wrong" way round normally and in the event of a reverse current the "right" direction working of the FET Kicks in and protects as you would expect with 0 gate source voltage ?
@@knopfkrieger you should look up the design of an "ideal diode" which uses a FET and is sort of what you're describing. Yes it can absolutely be used in this way. Like everything it depends on the FET and the circuit you choose. Sometimes it may take too long for the gate to charge/discharge in this design so it becomes dangerous, depending on the use case. So you often see a charge pump to speed up the reaction time and make it more decisive
Did you manage to check if the diode losses are less than the previous diode test ? It would be interesting to know this detail. Thank you for all the info contained in your video 🙏
Usually in a Ideal Diode is 0.02V
Thank you so much for this video! Was searching high and low, this is just what I needed.
This is certainly worthwhile, especially in environments where panels may not be sitting idle for most of an average 24-hour period. I've forgotten which panels are attached to the shed, but if I assume a 3A input current, the MOSFETs should burn about 10mA worth of current at ~28V (about 0.25W). This is half the reverse current that Julian observed when his panels were dark, but it would only reach this level at a 3A charging current so most of the time the losses will be even less.
yay let make a go fund me for a shed latch :)
One of these days a seagull may open his shed 😃
There is no point bothering if the loss is only 20mA. It's hard to validate buying anything to offset that tiny loss, it's so small of a loss that it's practically meaningless. And then when you buy more components to try to offset it, now you have many more points of potential failure in the circuit, it's generally not a good idea.
roughly 5WHr but I am highly suspicious of my math.
But it goes against the whole concept of letting Amps from the batteries to the panels, when it's supposed to go the other way. It's simply a bad mpp design that accept this do happen. So stoping this behaviour are only the right thing to do 👌
I used a LTC4357 in my MPPT charge controller design, works a treat although the IC itself is quite costly.
Remember kids, always wire your large lithium battery directly to an IC that can short circuit. You wouldn't want a high interrupt current fuse to block your exciting arc explosion of 5000-1000A!
Couple of years ago I've asked on one of your videos if you can try charging some lithium batteries, directly from solar panel as long as the panel voltage fits the battery voltage, like an 18v panel with a 21V open circuit voltage charging 5 series li-ion battery. Now I see you are finally thinking at doing that.
Sounds dangerous. Lithium is not a toy!
@@mrtechie6810 Not as dangerous as having an open fire in the house, yet we did it for thousands of years.😄
@@CANTON76A well, no one stops you then. Hope you live alone though!
mosfets are back to back to point the body diodes of each parallel mosfet pair, into each other, in order to block all conduction thru body diodes . then the mosfets become a true switch that can be operated by a current flow direction sensing circuit, to create the pseudo ideal diode
If the sources of back-to-back high efficiency trenchfet NPN Mosfets are on the high side, it is mysterious to me how the device is generating a full gate activation charge, like Source(+) + 12V.
Diode Ladder? Seems it would have to steal a little current while in forward mode to do this.
@@GnuReligion good point. i think it would need a separate supply line (P+ or P-, depending on low/high side arrangement), fed into a buck&boost circuit that can accept power from a large range of voltages and always achieve proper gate voltage . so in this way it would be kind of a pseudo ideal diode , in spirit/function...
maybe as you say there's some clever power sipping method such as blanking the mosfets for minute periods to sip power into a capacitor. this algorithm would need to adapt to the pack voltage and seems complex, and technically speaking would interfere with the end goal of the device in the first place ...
@@yeliab814 The way I do this at home, to make a circular battery pack (dynamically leaving the weakest cell out), is with Cockcroft-Walton multipliers. One can semi-isolate a reservoir charge grounded on each mosfet source. Takes a lot of caps. If they are doing something similar here, a lot of little caps would be the giveaway. Gotta wonder if this ideal diode will work down to 3V?
try the forward voltage on the green board with a higher voltage, the batteries (especially loaded with that bulb) might not be enough to turn on the FETs. If the board was only mean to use the body diodes there would be no need for the rest of the components. That said it probably wouldn't work in your application anyway, because once the FETs are turned on they will stay on with the battery voltage
What's odd about that green board is that none of the components has any connection to ground. Last time I looked at it, I came to the conclusion that it can't possibly work (other than being a diode). Perhaps it warrants another look :)
@@JulianIlett what is the part number on the fets? is it p-channel or n-channel?
75NF75 which I believe is N channel.
@@JulianIlett then the schematic shoudl be soemthing like this: i.stack.imgur.com/a4mNC.png
@@JulianIlett then look for a P+ connection rather than ground, no?
What do LEDs and solar cells have in common?
When you apply a voltage, they light up, but some in IR light.
If you shine light on then these generate electricity, but LEDs are not very efficient.
Wot's this business of putting wires _through_ holes? It's been years since I've seen that, all the stuff from the cheapie Chinese eBay sellers seem to come with wires soldered across the holes rather than through them.
Anyway, I'm glad you're now doing most of your solar and crytypocurrentsea experimenting in the shed, well away from the house. After seeing the most recent video from your fellow countryman and CZcamsr Mark Fixes Stuff about his house burning down, I feel like it's a good safety measure keeping this stuff outside of the house. I don't doubt the stuff you make, but I do sometimes worry that those cheapie Chinese eBay parts have one too many corners cut, or if they just decide to swap out copper for aluminium in the wires or connectors but don't downrate it accordingly.
Genius!
Ooh I deal diodes are fun, I am using them for my "Buffer Charge Distributor" which is just a 12v SLA battery acting as a DC online UPS that can be used for regerative discharge usage on my hobby charger. The only issue I am running into connecting all the DC-DC modules together is that EVERYONE uses negative current shunts 😛 we need to put a ban on them!!!
nice video going to order some of that 1 it really works good
6:58 Windows detected the solder iron was removed! :-)
I made a circuit and used a cap and a 1N4001 and had no problems, swop the diode and the cap go's pop instantly. I also had an led on to little resistance and the cap could be popping cause I doubled the resistance. Ima newb and don't get it, I think I put a 1N4007 in and popped two caps.
Hey! You rejected the green module as 'just a diode' by showing the voltage drop across it, but you never did that with the red one! OK you showed it was not getting hot, but it would have been interesting to see just how 'ideal' it is.
I'll take another look at the green module in due course, but I suspect it's 'fake'.
Nice idea there. Great video.
A simple sunlight sensor or a timer + a relay could automatically disconnect those solar panels from your system at night.
I would rewire my automatic night light to a relay for cost savings.
Any chance you could do a quick video on how the LTC4359 Ideal Diode works? I've never seen that board before.
a photo sensor and a relay would have far less insertion losses
I think The mosfet on your LTC4359 are back to back , this is the only way to use this little board as a load switch (indeed it's not the goal that your 're looking for )
With my little additional waiaaaaaaaaaaaaa😂😂
cool, wouldnt just a 1n400x in series with the + on the panel do the same?
6:36 "...minimum drama..." I gave up trying to use ~50 watt class soldering irons for such large soldering tasks, and I bought a Weller soldering gun )with 260 or 200 watts), just like my dad has had since 50+ years ago. Much easier. Cheers.
I'm still using mine from 1966 - wouldn't be without it....
I thought most / if not all solar panels had reverse protection diodes in the panels already ?
Thanks
Add a SZBK07 buck converter or similar and you charge whatever battery you want
those ideal wire strippers are great but you don't want to drop them off a ten foot ladder to concrete floor
Most of those Battery Checker modules like you have will attempt to balance the cells at the current voltage with a 5 - 20 mA drain, unless they never populated the resistors on your model.
Whats your advice to set 6 panels each 100w
Julian!!
Too hot to put a curve in? The hotter the insulation is, the softer it gets!
This is the best way to mine crypto! All solar!
Any schematic for this ideal diode? Component list?
You didn't show us the voltage drop across your "ideal" diode. Otherwise, what was the point of the video?
Schematic, MOSFET type numbers, principal of operation?
And what shall it be the voltage drop across the ideal diode??? It seldom is what the data sheets say...!!!......I usually use Schottky diodes but
now I'm curious if a change should be better....!!!
Nice. One thing I noticed, the heatshrink on the negative of the solar input didn't look shrunk to me. Might just be the camera angle or my crappy resolution. :)
Or could just be my 18V heat gun in a cold office :)
Please just hook up a real mppt solar charge controller rather than rigging everything
Well you're no fun.
One of the problems with the Ryobi is the tip you are using is a tiny conical tip, do they have any large 5mm+ tips?
Can you provide a link to this board?
Hi Julian, would this work for a 12v lead acid battery also? Keep up the good work 🤙🏼🇦🇺
don't charge controllers prevent this ? or only the high end ones ?
@9:50 so what is the Vdrops on that module with high current flowing through it? Thanks.
when i tried to solder xt90 it melted :(
interesting.
👍
How did you get the mpp to let amp seap out the wrong way anyhow? ☺️
Why not use a Shottkey?
is there not a diode already fitted to the panel??
There might be a reverse voltage diode, but forward diodes are not common. One panel will put out 10 amps, at 0.7V diode drop the diode will burn 7 watts.
The panel will have bypass diodes, but not a series diode.
Which pays more. Ant mining or back-feeding the grid?
Antmining (with the right machine) ~ 20p/kWh
Grid export ~ 5p/kWh.
You can get different prices when you backfeed the grid and there are different efficiencies with miners. So the simplest answer is if mining without solar is profitable then it is probably more profitable to mine than to backfeed the grid.
A lot of people have solar that can not backfeed the grid so any extra power goes to waist. If you pump that waist into a miner it makes you money instead of doing nothing.
This allows you to put up enough solar for the winter but then mine with the extra unused power in the summer.
@@JulianIlett thank you
what happened to other 2 Ideal Diodes? You didn't Test it and Start to explain mining 😄😆
What are you mining with the l3+ is it the doge litecoin combo mining
I mine into the Prohashing pool. It switches between Litecoin, Digibyte and a number of others automatically, whichever is most profitable. I can choose to get paid in any of 100 or so coins, or a mix of coins, and I can set the percentage mix.
doesnt your bms have built in blocking diodes?
No. If it did you wouldn't be able to discharge the battery at all.
I need that multimeter from Ryobi !!
Don't think you can buy them anymore
@@joshuabest100 Ya I already started looking. I only want it for the branding lol
That reminds me - I have a Parkside (Lidl) multimeter in a box somewhere. I need to do a review on it.
Irony when searching for the meter two results were to your videos
Can u test the first "ideal diode" at 12V pls? Any better?
Ya, I wonder what the specs say about that first one. Just like the ideal diode he used, it will have a minimum voltage and it has only likely 4-6V in his first test set up.
The voltage drop of most diodes is about 0.6v no mater what voltage you run it at. That is a smaller percentage of 12v so it is more efficient at higher voltages. But it is still going to be about a drop of 0.6v
@@ecospider5 A MOSFET acts as a very low impedance resistor when switched on. The forward voltage drop will be dependant on the current but will be very low even at high amperage. These circuits try to be an 'ideal diode' i.e. zero ohms forward and open circuit reverse and without any forward bias voltage drop. HTH.
One thing to watch out for with ideal diodes is that many are not suitable for reverse polarity protection.
Instead of spending hours showing how four solder joints are soldered, you should rather use a circuit diagram to explain what is happening here.
weren't these the things described as anti-anti-irrigation devices?
That's the one :)
I have some 60 cell solar panels for a 28v LIFEPO4 battery bank (yet to come), and was thinking like you said do I need a mppt charge controller, well I don't personally think so as the voltages are so close. The problem is when I do a Web search everyone says you need mppt with two panels? My batteries are expensive an I cannot risk them being damaged. Any thoughts anyone... Thanks
You'd certainly need a solar charge controller (specifically one with a DC/DC converter) if you put two 60-cell panels in series. But even if your panels are in parallel, you need a way to prevent the batteries being overcharged. My 60-cell panel has an open circuit voltage of up to 36V (when it's cold). That corresponds to 4.5V per cell for an 8-cell pack (more if they're out of balance). My Antminer will switch on when the pack voltage reaches an upper threshold (and off at a lower threshold) which will prevent overcharge and over discharge.
@@JulianIlett surely the bms will handle that? Thanks for the input.
Ps my battery will be 320ah and used daily running various loads. I have a load more panels to wire in parallel to increase the current. I also have an active ballencer I could use.
I've come to the conclusion the BMS doesn't so much 'manage' the battery as protect it. The upper cutoff voltage is very high (3.75V) and the lower cutoff voltage is really low (2.18V). Although some BMS's let you alter the thresholds (video on that coming soon).
@@hunter00047 I didn't see a BMS in use....is it hiding?
Ohh, F***! Another soldering video.
I thought the same when I watched it back. So no soldering in the next couple of videos :)
#BanBitcoin
To ban Bitcoin, you'd have to ban the internet!
@@JulianIlett #BanBanningBitcoin
I think you mean ban sociopaths. Like the massive Chinese bitcoin mining operations running on coal and diesel. Mining on solar is perfectly fine. Although yes, there are newer cryptocurrencies that do a better job of keeping rich people from ruining things for everyone
@@JulianIlett
ACTUALLY, I really don't.
That is some deluded libertarianism.
@@alakani
Not at all, ACTUALLY all energy has a cost including solar, this idea that it is emission free is just silly.
The eBay listing claimed that a 12 AWG wire could handle 41 amps?! That may be yet another eBay listing lie. The US National Electrical Code allows only 20A in 12 AWG house wiring. That's AC RMS, of course, but I can't think why DC would be that much different. For 40A, you need 8 AWG.
I did actually learn this "the hard way". Molten cable insulation and molten xt60.
Kept adding solar panels without beefing up the wiring. House not burned down luckily.
Code is based on multi core wiring embedded in structures and typically involves at least 50% derating over free air conditions, 12awg single core is rated 34A. Having said that I'd certainly be looking at something beefier.
@@Steve_Coates Good to know. Thanks!