Hi, we are getting ready to add Lifepo4 batteries to our critical load solar system. I will be using 4, 280ah cells in series and 16 of these connected in parallel to make a 48 volt battery of about 1120ah. Is it best to just connect the cells that are in series together at the + on the first, and the - on the last and use one 300 amp BMS? Or, I’ve seen pictures the parallel connections at every cell, wouldn’t a setup like that make it necessary to have a BMS connected to each cell, not just to each group of cells? I’m trying to make it as simple and dependable as possible since I am not always there to correct issues. Suggestions are greatly appreciated. That’s about it. the dog
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That is a big battery system. What type of cells are they?
No, do not connect them all to the + on the first battery and - on the last battery as you will have cell balancing issues. You will want to connect all the strings of batteries to a common high current battery bus and make sure the cable length is the same for all battery strings.
Victron make a great DC bus called the Victron lynx. Victron also make the Victron Distributor which has fuse protection - I would highly recommend you have fuse protection on each string of batteries.
We haven’t purchased yet, but we are looking at new Eve 280ah cells. I appreciate your input. That’s exactly what I needed to know. So the Victron Distributor also has a fuse and is it also the BMS for the entire unit? We have 4 60amp charge controllers with a 10kw inverter that can charge at 100amps from the utility, but we have it set to 20amps so the solar will do most of the work right now.
I just want to say thank you for all your help with all the questions I’ve asked, I now am producing about 100kw a day on my systems and by the end of the year hope to have it up to 150kw a day with the addition of 2 more systems. That’s about it. the dog
Yes! I’ve been reading their site. Using this I would set up each set of 16 (48v) batteries as it’s own battery, then use this to connect all 4 batteries together and use an individual BMS for each battery, am I reading it right? Thanks. the dog
@the_uglydog yes that is correct. You would use the victron distributor to connect all 4 (groups) of batteries together. Each group will need it’s own BMS.
The Victron Distributor has fuses which you need and it can supply data to the BMS for the entire unit when used in conjunction with the Victron shunt.
“The Lynx shunt can send via the VE.CAN bus battery monitoring information to a GX device (Cerbo GX) or to a third party CANbus monitoring system, such as a NMEA2000.”
Read this for the full details…
https://www.victronenergy.com/live/dc_distribution
I would recommend you save your time and energy and use a professional battery system such as the PylonTech US2000 which already has a BMS and is configured to work directly with the Victron system using the common CANbus interface.
The PylonTech batteries also have a 10 year warranty and will save you a lot of hassle.
https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom
Yes, it would sure be simpler, but the difference in cost is what has been keeping me more focused on buying the individual cells. But I’ll research more today. Thanks. By the way I meant our system is producing 100kwh/day not 100kw/day. Dogs don’t always get it right… That’s about it. the dog