Pushing The Limits WILL Break Things! LiFePO4 Battery Overcharge Protection Limit

[@benssolarandbattery]

I always tell people not to rely on the BMS in place of proper charge and discharge settings. Thanks for sacrificing a battery and showing us why this is so important!!

[@BlackheartCharlie]

Marine electrician here with 30+ years experience in high-amp 12v systems. I am truly impressed with the amount of punishment that BMS took before failure. It would take a cascading chain of failures (and possibly some monumental stupidity) to wind up with a system configuration that would pump that kind of voltage into a 12v battery. Thanks for making this video!

[@dronetimes4861]

Thank you for demonstrating that to us. This was one of the most interesting videos I have watched on Lifepo4 systems, possibly ever. Your sacrifice of the SOK in the name of safety is greatly appreciated.

[@funNstuff]

LifePO4 don't explode. Swell and smoke, yes. Making sure you charge at the correct voltage is very important. Nice video showing the safety of LifePO4 and BMS systems

[@johnguilbert1349]

Excellent video. Keep the great content coming! Victron F'Yeah!

[@onthelake9554]

So a high dc voltage rated contactor or breaker with a voltage sensing controller would have prevented current flow. Maybe we need this protection on our systems as a backup to failed charge controllers , even high quality ones.

[@uwechristoph5627]

thank you for testing the BMS. What would happen, if you put 50 Volts only for milliseconds into the BMS ? So a user wouldn't recognize that the BMS is defective and 17 Volts would destroy the battery afterwards ?

[@bjtaudio]

Prob only that one smoking fet that is ruined, just replace it and bms may be ok, its odd it failed at only 50v for a 85v fet it may be the driver circuit that failed.

[@tunas66]

I've had 2 failed BMS's on my 206A SOK's The only thing charging them are 2 Growwatt 5k inverters I don't ever use but 55% on both Growatts. at a time otherwise they both run at 17% i'm just not unstanding why these BMS's keep going out?

[@PavolFilek]

I do not like BMS in my system. BMS is only to signal to my breaker to disconnect solar panels, or to signal my MPPT to go to 1 Amp, if my BMS is capable to balance at 1.5 Amps. Also at low voltage, my BMS have to signal my inverter/s to stop inverting, and to may DC/DC converters to disconnect also. And DC disconnect at 1 A / 1000 V is something easy, but to disconnect 1000 V / 18 A, is really tough job. I do not like BMS, that I call DIS-BMS, because system with such BMS is very unstable and unpredictable, and my system has to work without my intervention for 25 - 30 years, if I use my LFP or LTO battery within range, e.g. 15 - 25 *C, 0.25C for LFP or 1C for LTO.

[@_loki]

This sounds like a huge problem for 48v series connections. If the 1st battery goes into over voltage protection, it will have a relative 48v on the negative assuming a light or something is on and zero on the cell- side of the BMS. With the 50v pop you showed, doesn’t that mean ovp would not work in practice? Either that is a defective BMS, its 80v stats are wrong or something else is at play here?

[@theclearsounds3911]

If you have 4 batteries in series and one of them goes into overvoltage protection, the other batteries will subtract from the overall charging voltage, so you won't see anything too crazy across any one battery. If all of them go into overvoltage protection at once, then there might be an issue, but I don't see how that could possibly happen. If you start to get batteries shorting, then I can see a problem.

[@supashark72]

If they are 85v fets, why did they fail at a lower voltage????

[@_loki]

Exactly. Clearly a problem if a 12v battery sees 50v, but these are rated for 48v in series. In one unit goes into OVP they will see 50v+ as a normal and expected operating condition. Fully charged 48v is about 58v.

[@jakeandrules7724]

I was going to ask this as well. Why did they not hold up to closer to 85v? Id like to know. Sub par mosfets?

[@minwang102]

The IC burnt first, IC max working voltage at 40V,once IC burnt, it would also cause the MOS burnt..

[@_loki]

@@minwang102 This means that the BMS is not rated for 48V series then? I believe I read that these were 12/24/48 volt compatible. I guess it really doesn’t matter why it releases the smoke, if it dies switching 50v it can’t be 48v compatible.

[@minwang102]

@@_loki connect in series voltage & single battery voltage, 2 different things

[@davidpatrick1813]

When you dial up the voltage it is like tuning a guitar string up tighter and tighter and one is paying a lot of attention.

[@kennethalmond8922]

What a great video - thank you sir!

[@sarcotexas]

Thank you for sharing !!

[@caroman6761]

In my BMS are installed NoSmoker FET*s only ;-)

[@markohofmann5091]

Thx for doing this very interesting!!!

[@theheathkitshop2424]

What model is the HP Power supply?

[@blackz06]

What cells are in that battery, 100Ah prismatics?

[@nebulight]

So did the user in the video actually just hook up solar panels to the battery instead of a charge controller!? I’m out of the loop on this one.

[@HighTechLab]

Don't try getting in the loop, it's a nightmare. Anywho, they used a cheap charge controller that failed by shorting the solar directly to output. The brand name was furion. Not only did it cook their batteries it also cooked all of their 12 volt equipment that received extremely high voltage

[@Foxfried]

What type of a device can you put to stop overvoltage? All the fuses I have seen are rated for 250V or higher, they aren't going to stop 50v.

[@davestech6357]

A crowbar circuit that shorts at a specified voltage. Or sensing circuit that opens at a specific voltage.

[@themartinandersson]

@@davestech6357 Which one would believe should already be in the BMS! Clearly their "overcharge protection" is a shameful mockery.

[@davestech6357]

The fets in this application do blocking or pass through function, not bypass.

[@HighTechLab]

They always allow reverse current flow, only when turned on do they allow bidirectional flow

[@davestech6357]

@@HighTechLab Well your correct but that is called blocking too.

[@Mr1Spring]

I still do not get it, why should you not put multiple batteries in series if each of them are below 15V. Each BMS can handle easily more than eg 24V. If you put eg 100 batteries in series, each battery will still be within its own limits.

[@HighTechLab]

Because when one shuts down, it will breaking the voltage of the whole string.

[@Mr1Spring]

@@HighTechLab I still don't get it. If one battery in the strings fails open, each other battery remains still at 12V. And if one battery in the string fails short all the others still have 12V them.

[@Mr1Spring]

Accoding to your datasheet it should withstand 85V but it failed at 50V. Bad product!

[@Foxfried]

Well that guy claimed 17 volts caused it to burn up, clearly he wasn't telling the truth. Also this is the 4th or 5th case I have seen with the Furion causing issues like this.

[@MrLeesanders]

did not claim 17 v. clearly stated in excess of 90v. as controller failed

[@Foxfried]

@@MrLeesanders I was reading an online forum they said he claim 17v...

[@Foxfried]

@@MrLeesanders Have you contacted furion and showed them this video, I think they owe you a new battery.

[@MrLeesanders]

we are talking.

[@theclearsounds3911]

Here's the moral to the story. Keep these batteries and all your inverters and solar controllers far away from your house, in a shed. That way, when they turn into a fireworks show, your house won't burn down.

[@haxby2008]

Is this battery advertised as being suitable for 48v systems? If so, it clearly isn't!

[@ReizungV]

ddon't know your logic with this statement. But for this battery in a 48 volt system. 3/4 batteries would need to break at the same time for a single battery to experience this voltage. So i would say it is suitable for 48v system. Lead acid uses no BMS at all. it is still suitable for 48v systems.

[@jaygold4467]

This is the user fault. Not the battery.

[@rafaelbezerra8008]

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