Yes, you are right. But I would be able to replace a defective cell in an NKON battery within a minute. I assume (i don’t know really) that the busbars between the cells of the NKON are not welded as in most other batteries, but screwed as in my DIY battery. And the NKON battery is made of cells which are even sold to the public in smallest quantities. NKON has started as a cell wholesale bussiness.
Have a look at the many tests of LFP batteries in Youtube. Most are welded and even filled with some kind of plaster. You can’t do anything by yourself.
But anyhow: I would NEVER buy a battery without an active balancer.
if I go with 2 16kwh, I guess they will have a active balancing within each battery pack but just passive between them. I don’t know how big issue that is
I’m Just a little skeptical of the 250kg. 120kg is possible to handle.
The cells in a battery are connected in series, and therefore each cell can have a different voltage than the others. Two batteries connected in parallel, however, always have the same voltage. So there’s no need to equalize the voltages; physics takes care of that automatically.
You should connect the two batteries correctly with identical cables – the same length and gauge. And you should then connect the positive terminal of one battery and the negative terminal of the other to the MPII or the distribution block to prevent one battery from discharging more than the other due to different voltage drop in the cables.
Edit: You can find good videos for the integration of a battery with Seplos BMS into a Victron system, i.e. like that. It’s in German language, but you probably can get a translation. And here even a video from Andy from the OffgridGarage with two Seplos batteries in parallel connected to a Victron system.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
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The BMS in the SOK batteries is terrible. The SOK uses a generic, off-the-shelf BMS that they don’t control and it suffers the same cell voltage overshoot and annoying alarms that most of the generic rack-mount batteries suffer from. For instance, if you didn’t set a CVL in DVCC to 55.2V, the batteries would alarm with high cell voltages and eventually the customer would ask us to turn the alarms off or get better batteries. We didn’t sell SOK, but we removed a number of them.
Pytes, on the other hand, use their own BMS and it is plug-n-play compatible with Victron. It is a supported battery to Victron. Yes, there have been small annoyances that have been rapidly fixed with firmware updates, but since Pytes created their own BMS they can quickly rectify any issues. We do sell Pytes and use them in everything from large RV installations, off-grid homes & farms, and commercial vehicles. They are our go-to 48V battery.
