The only role for this battery is to start my Cummins QSB 380. Charge on the big start battery is maintained from the main bus with an old Blue Sea ACR. The engine alternator is regulated with a Balmar 614 and is wired directly to the main bus bar.
Which Epoch batteries did you end up with, this with the original or V2 firmware? I might be choosing soon.
Mine are the V2 version, updated to the latest V2.7 firmware before install.
No problems so far. Install went smoothly, everything powered up as expected, Victron comms seem to "just work" so far. I've had the inverter forced to "inverter only" mode since yesterday to let things cycle a bit and also did a little load testing yesterday evening. So far everything seems to be performing great. Right now I'm using the Epoch BMS as the battery monitor. The Smartshunt is still wired into the system, but I need to re-route the power cable for it after the install, so it's not powered on right now.
The VRM data comes from the Cerbo GX, which gets data from the Epoch BMS, the Multiplus inverter/charger, the MPPT solar chargers, plus a couple of temperature sensors and such. The DC-DC chargers will also feed data to the Cerbo (and VRM) when I put those in this week, so I'll also have data on how much power is coming from the engine alternators. The Smartshunt will also feed battery data when I power it back up, but I'm not sure if it'll give me anything useful beyond what the Epoch BMS is already providing. If I find it doesn't then I might re-purpose the Smartshunt as a load meter somewhere at some point.
The BMS also has a current measuring shunt in it. I'm not sure what logic it uses to derive SOC though. From the video Barking_Sands linked earlier it appears that the 2 track pretty closely in most cases.
It takes a good 6 to 10 cycles to get these in balance. As a matter of fact its not unusual to have cell overvolt on the first 1 or 2 charges. I did mine on the bench prior to installing but you can just cycle them as is. You don't need to do big discharges ,but I'd recomend dropping to an soc of 89% or less so it initiates another bulk and absorption phase.
That's what I figured, I was just surprised not to see an indication of balancing in the app as others have mentioned that it shows which cells the balancer is working on. I haven't gotten a cell overvolt warning, although looking at where the high cell is on one of the batteries I must be close to the threshold.
On mine it does reflect both batteries for the high/low cell voltages. If it shows P00 that's the master battery, P01 is the first slave.
Hmmm. I am NOT seeing that on my screen. P01 is the only one. Unless those two cells are the ones the most out of balance. I will have to take a look once back at the boat.
Yes it will just show highest and lowest in either battery.could be from same pack or different.
Sorry my response got botched - was commenting that the picture cables look undersized. Probably just the photograph.
The cables in my setup currently are 1/0, fused at 250A. With the rest of the currently installed equipment that's adequate. About the only way to blow that fuse would be to run the inverter at max load, turn on a few DC loads, and then run the windlass without any charging being supplied so all of the current comes from the batteries.
I would say battery 1 is hugely out of balance, and battery 2 is a good bit out, but I can't see the 1st cell voltage.
This is a great example of what leads to unexpected BMS disconnects while charging. Cell 3 is at 3.666 volts and should be about to trigger a BMS disconnect. Yet cell 1 still has a ways to go before it's fully charged, and cells 2 and 4 are kind of in the middle. The pack voltage is 14.2V and any chargers set to manufacturer's specs will still be charging at full output. Then POW, the BMS disconnects because cell 3 is over voltage. If there were an Allow to Charge signal, it would have deactivated when cell 3 reached full charge at around 3.6V, and further charging would be blocked. It's then up to the balancer to bleed off charge from Cell 3 and/or add charge to Cell 1.
That looks like shunt setting?
These are the MPPT Victron solar panel settings.
As long as you can select bms control, the mppt should also follow the 14.2/13.5 settings in bms.
Well hell! You are correct. Work keeps getting in the way of me posting things here!
It means it will follow the published CVL of the BMS. Which is the same 14.2 absorption and 13.5 float that the Cerbo and multiplus sees.Well hell! You are correct. Work keeps getting in the way of me posting things here!
Thanks for catching that!
Hmmm. Know that I am looking at this. With the BMS control on yes, that could mean the smart shunt is running the show?
The Ancor technical data for the cable I'm using (105* C insulation rating) lists 285 amps for 1/0, 242 if in an engine space. That's assuming free air or a pair of cables together. The main cables aren't bundled anywhere in my setup, so they're within their ratings. Plus, achieving a continuous load of 200+ amps is rather challenging in my current setup.
Agreed. I'm going to let these cycle a bit daily through the week and see if they get closer. The difference between highest and lowest cells on the second battery is about half of what is shown for the first (my mistake on the bad screenshot).
