Epoch 460 amp hour, 12 volt battery full charge protection 

Thanks bunches Ben And Andre. This now confirms the details many of us suspected. It also allows us to confidently configure our charging parameters to avoid these conditions the first time instead of figuring it out the hard way, lol. One other thing to consider that I have recently seen... In the victron inverter chargers it has been observed that when max voltage of 13.9 is set in the DVCC an occasional over reach in voltage has been seen. Over reach just long enough to see the 14.0 and trigger this event. Which makes sense because if set at 13.9 the current will taper down to below 3.5 amps for a while and if the voltage even touches 14 for the few seconds it triggers the event since the current threshold is already met. Of course when we set 13.9 in the DVCC that a pretty round number, It would be nice if we could set 13.92 and the Victron have very tight control. But I think it can be a bit lax at times. So I have accepted 13.8 for my use to steer well clear. Doing this also avoids the larger cell deviation that seems to occur above this range where the balancing cant really keep up. Also, set at 13.8 and the charge mosfet NOT disconnecting you will be essentially absorbing for some period of time, which will result in pretty much 100 capacity. Regarding this shut down, IMO there is nothin inherently wrong with this happening since of course it is overcharge protection. The problem lies in the way that we cruisers want to use them, with solar, alternator charging etc that requires a perfectly stable system. The main thing I would like to see is the charge mosfet lock out reengagement threshold raised. Again...thanks for your persistence and sharing of information.

Charge MOSFET needs to turn for discharge in single port BMS. The charge and discharge mosfets are in series, they use their body diodes to allow discharge through the charge MOSFET even though its off, the body diodes cannot handle much current so it just uses that to sense discharge then quickly turns charge mosfet back on to support full current, then turns back off again if it senses charge. This is why you see the charge MOSFET turn on as soon as you put a load on.

I. See identical behavior with SOK batteries, who seems tonhave similar balancing profiles. As I approach 3.4v per cell, things start to separate. A much slower finishing charge (or lower overall voltage) is needed to stop bms shut down. It seems passive balancing on big packs needs a ton of time or perfectly paired cells.

Great video, thanks for all the work in trying to help understand and mitigate the problem. Does your testing concern you at all, or do you think it’s manageable and /or possibly something they could fix somehow?

Hey Ben. It just dawned on me. You were doing this test at 14.2 as a target voltage. Very close to 14 which is part of the threshold for charge mosfet disconnect. So as it crossed 14 towards 14.2 the amps dropped to meet the other part of the parameter and shut off the charge mosfet. Given that you have the interrogation software and can see balancing, try the following experiment. Repeat the same experiment, but turn up the voltage to 14.6. You should blast past 14.0 while still taking a significant current. Well above 3.5 amps. You will likely get 14.3-14.5 volts in the end but you should be able to observe cell balancing above 14.0 with your interrogation tool. Granted at that high of voltage it may not keep up but you should be able to see if its still occurring. This would give some good feedback. I essentially did this a number of times and got cells in the 3.6x range with cell deviation never going above .050. But I did not have the interrogation tool to see if balancing was still active. Il will wager $1 balancing will be active above 14.0 😀

thanks for the video, been struggling with this same problem on an install, not been getting much help from epoch, despite calling multiple times over a few weeks time span, which is disappointing. they did say that balancing begins at 14.2 same as their 300ah v2 batteries. glad to see you've found its lower.

Interesting exploration. I have 2 Epoch 460’s in parallel, no Cerbo or DVCC, charging at a rather conservative 13.9 VDC, 13.4 Float & 13.25 Storage. Cell balancing so far, has been excellent (~ +/- 5 mV) & no alarms. I wonder if the DVCC / Multiplus Canbus interface is part of the problem? Maybe the KISS principle is worth adopting for these batteries?