question

Hi. I'm not sure what the BMV is supposed to be able to do to revive their dead batt/bms. Nor it seems do they, aside from vague references and 'buy our mppt charger'.

Even on their own forum - http://renogy.boards.net/thread/291/renogy-100ah-li-batteries

There's a link there though that might help explain what you're up against: https://batteryuniversity.com/learn/article/low_voltage_cut_off

I'd expect a 'real' BMS to protect from this situation in the first place.

I'm guessing here, but might be worth to try:

-cell voltages are probably too low to charge with 'normal charging current' (this would damage them)

-battery protects itself from that

-try applying 10-11 volt at 0,1 A from an adjustable power supply and see if it does something, could try even lower voltage, we don't know how the Renogy BMS determines to connect again.

You need a charger like a NOCO to unlock it. I picked up a NOCO Genius last week just in case I did something similar. -Bill

I know I am not supposed to ask questions within the question (seems an odd way to do it), but before I continue down this road of trying to wake up the battery, is this even safe at this point? It has been in BMS for probably at least 5-6 weeks is my guess. Would prefer to not have a battery explode in my face.

Thank you for the replies

I did call Renogy. They said I need to use the BMV-712 to reactivate it and to contact Victron, hence why I am here, because unless I missed something this is really the only way to get support from Victron. I see no US support number.

Have you tried connecting another battery to it in parallel, ie, jumpstart it? I’ve had a few LFP batteries go into low voltage protection and this revived them.

You might also try to adjust the MPPT to a lower voltage/amperage such as 11V/1A and see if that will restart it.

There isn’t anything magical a certain device does to reset it, it just has to take a small charge and get above its low voltage cutoff point. It’s entirely possible that the cells or bms was damaged, in which case the battery would be toast.

From the Renogy maual. Maybe worth pointing this out to Renogy and ask what they mean by it.

"The BMS will protect and shut the battery down (0V) when it is over-discharged or short circuited. In these rare cases the user will need to activate the battery using an external device that has lithium battery activation feature. If the Lithium batteries voltage shows 0V the battery is not defective but in its protection setting. Please contact our Tech Support team at 909-287-7100 for any questions about the BMS."