Epoch 460 amp hour, 12 volt battery full charge protection
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- Опубліковано 10 вер 2024
- Andre Cormier of the Yacht Rigger and Ben Stein of Panbo have been working to understand the behavior of Epoch's new 460 amp hour, 12 volt, Victron Communicating battery. At least a contributing factor is the battery's full charge protection functionality. This video explores the protection and the battery's behavior when that protection is enabled.
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.
One other detail that makes me think 13.8 is a fine setpoint for absorption is that balancing begins at 3.35v per cell or 13.4v for the pack. So, from 13.4 to 13.8, the BMS can balance if needed. It's also interesting that balancing doesn't begin until cell delta reaches 50mv, so in practice I don't see balancing occur until about 13.6v for the pack. I am working on more analysis, but I suspect we may determine that charging any higher is going to require larger balance capabilities.
@@Panbo_Marine_Electronics Thats what I have roughly observed as well. Having that interrogation tool is fantastic. Do you know if thats something that can be purchased?
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.
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?
I think the issues are manageable. Essentially, if the battery is charged with an absorption voltage of 13.8 or 13.9 volts these issues are avoided. I'd like better documentation and clearer guidance from Epcoh, but overall the issues don't concern me too much. I'm working on an update about the batteries in general that will posted over at www.panbo.com shortly.
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.
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.
Kevin, the owner I think, is about the only guy over there that kinda knows what hes doing and is willing to help. The other customer service is basically worthless for tech support. They will point you to a facebook group run by just a random customer.
But bottom line....for this issue to even exist means they likely barely tested the battery at all. Because their recommended settings flat out wont work on a typical system.
In further conversations with Epoch I've learned that not only does balancing begin at 3.35 volts per cell or 13.4 volts for the pack, but it STOPS at 3.5 volts per cell or 14 volts for the pack. So, the out of balance issues it appears we are seeing when the batteries are pushed past 14 volts may not be an issue at all. However, the lack of clear documentation on this is an issue and hopefully one that will be addressed sooner rather later.
-Ben S.
I dont think the balancing stops at 14.0. If I had to guess, it stops there when the charge mosfet shuts down as the current drops to the parameters you noted. I have a video from one of my first tests with the dvcc voltage set at 14.6
I had already short cycled many times and was hitting 14.5 with 30 amps with a cell deviation or less than .050 without charge mosfet disconnect. I dont think id be able to get that high without balancing. I have that video set as private if anyone wants to view it for reference. I just didnt post it because it was just me babbling to myself..lol.
Likewise, thanks for making this video. I had to set the voltage limit in DVCC to 13.8V to prevent the high voltage alarms. I am very disappointed in this battery. They advertised it as a canbus / Victron compatible battery, which I guess is true, but my goal was to have a canbus battery not have to fiddle with settings. It seems obvious to me they never even tested this battery with DVCC using their own 14.6V setting programmed into the BMS. I sent an email to their support but received no response.
@@kennisbutnerjr3947 Their support is basically worthless. Essentially this is a RowPow battery. So its very good. Top of market quality in most ways. Epoch just sells them as a white labeled product. Clearly doesn't test them at all. And becomes a headache of a middle man IMO. Nobody there is truly a battery expert.
So for people like us who can recognize the issue and work around it...fine. But they must be getting tons of returns from normal consumers who simply use their recommended settings and wonder why the battery isnt working correctly.
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?
I think the biggest single issue is probably that you're charging at 13.9 volts absorption. That lower absorption voltage means you're not hitting the full charge protection disconnect nor are you hitting the voltage range where balance is disabled.
@@Panbo_Marine_Electronics
Exactly. No issues with a simpler system. (I am simply using a collection of Victron chargers and a custom CC/CV profile on a Magnum 120A charger. )
It is working very well and I am utilizing the majority of the batteries' capacity without nuisance alarms or BMS shutdowns. The cells are getting enough voltage to be balanced.
@@Panbo_Marine_Electronics That doesn't strike me as an 'issue' but a positive benefit. No unwelcome disconnects and the cells remain tightly balanced with good charge acceptance and more than adequate SOC.