Alkaline
Solar Wizard
OP is your BMS still working?
What would happen if a 100/50 MPPT failed and sent 100/50 to an FLA battery?
Why do these BMS have a 4 series limit? Given enough voltage anything will conduct, its just a matter of how much it can withstand. 17v was after they noticed the problem, once current flows voltage would be pulled down from VOC of 93v.Nope it should burn up and no longer allow power to go in our out of the unit. But if burns up and allows power to flow in/out then its a badly designed unit.
To do a nice, scientific destructive test on the (?five?) commonly purchased batteries could run over $5000 never mind a protected open area and paying fire support to limit liability.would be great if Will purposely tried to destroy one of these batteries to see what the BMS limits are as far as over voltage
I think Will has the funds to do it and the video would easily recoup the costs, he's destroyed much more than 5k in teardowns.To do a nice, scientific destructive test on the (?five?) commonly purchased batteries could run over $5000 never mind a protected open area and paying fire support to limit liability.
I think you hit the nail on the head. Everything has a point of failure. If you exceed the limits, it will break.@HighTechLab anything else you want to add to this? Or disagree with?
Yikes, quite a lot of bad information in this thread. Where should I start. First off, the sok is not special, even UL listed batteries for medical/military application will still be destroyed by high voltage. There is a limit to any OVD circuit. I don't think sok or any company should be responsible for this. There is over voltage protection within the working voltage range of the battery, and a fet based BMS accomplishes this well.
In marine application, alternator regulator failure leading to high voltage has destroyed any battery on the market. Battleborn, valence, sok etc.
Even if you use a fortress battery, simpliphi or discover battery (top of the line lifepo4), they will all be destroyed by high voltage, and I personally don't think it's fair to honor these warranty claims.
The individual should be responsible for these types of failures. I've had over voltage from transformer based chargers and I've destroyed BMS in the process. Did I blame the company? Absolutely not. It was MY fault, and no one else. Using these batteries can only be done in the way they are designed to be used. If you use cheap mppt and it fails, that's on the user. Not the company.
Not sure what else they could do, FETs tend fail short there is no way to guarantee they fail open, there are two in series so both have to fail however you have many in parallel and any set of two can fail and cause current to pass.While improvement is always good, and I am urging SOK to make their BMS fail in a safe manner instead of unsafe, I can't fault them for the issue at hand, because it took very severe abuse and didn't burn the OP's rig to the ground.
There is some bms use with lead acid but I know basically nothing.the only one with traditional batteries)
Nothing stopping someone from using a BMS with lead acid, I have never seen it, most rely on their solar controller to not accidentally pass high voltage to battery.There is some bms use with lead acid but I know basically nothing.
A simple voltage regulator device would do it- use the output to trigger a higher voltage/amp relay
A great way to put it!Part of the challenge in designing a safety disconnect is we don't even have a reliable characterization of rate of voltage rise when SCC shorts PV to battery. I'm not sure it even can be reliably described. I believe the current best theory is SCC shorts PV to battery through working BMS. Battery sinks current to hold PV voltage to battery, until voltage rises to BMS cutoff. Battery line voltage than quickly spikes to PV Voc, fries BMS, which brings the unprotected battery online again, which goes back to holding PV voltage to battery, rising slowly or not so slowly until the cells overpressure and vent.
Excellent video, this is the kind of tests I want to see, would love to see an over current one as well .
I'm not sure how to pull this one off. I have 2* 8v / 225A power supplies, I could put them in series but I think 225a is not enough. In parallel @ 450a is much better, but with only 8v to work with, it gets tricky trying to push 14v @ 450a (6.3kw)Excellent video, this is the kind of tests I want to see, would love to see an over current one as well .