Hey there,
If I am creating two separate 24V 230ah batteries using EVE cells and have two 8S JBD BMS, one in each battery, is it okay to combine the two 24V batteries to produce 48V? Is this problematic?
Hey there,
If I am creating two separate 24V 230ah batteries using EVE cells and have two 8S JBD BMS, one in each battery, is it okay to combine the two 24V batteries to produce 48V? Is this problematic?
So I'd be better off creating a 48v 230ah battery? And what happens if I want to make two of these (one in the future), then what do I do?
Just out of curiosity what is the big picture of what you are trying to do?And what happens if I want to make two of these (one in the future), then what do I do?
You can buddy pair the cells (2P16S) or buy another 16S BMS if you want redundancy. I have a 3P16S pack and think redundancy is overrated. But I have an $800 BMS so it is an economic issue for me......if I want to make two of these (one in the future), then what do I do?
I'm looking to make a future proof system and am working with 16 230ah EVE cells,Just out of curiosity what is the big picture of what you are trying to do?
Sounds like you built a couple 24V batteries and are looking to move up to 48V?
So a 8S2P BMS exists?You can buddy pair the cells (2P16S) or buy another 16S BMS if you want redundancy. I have a 3P16S pack and think redundancy is overrated. But I have an $800 BMS so it is an economic issue for me.
No, but a 16S BMS will see the buddy pairs as one cell so it will read a 2P16S pack the same as a 16S pack. The designation 2P is what the buddy pairs are. That is 16 pairs of 2. Each pair is wired in series with other pairs.So a 8S2P BMS exists?
So this would mean I would have two packages of 16 cells, each 48V 230AH, totalling 48v 460ah, correct?No, but a 16S BMS will see the buddy pairs as one cell so it will read a 2P16S pack the same as a 16S pack. The designation 2P is what the buddy pairs are. That is 16 pairs of 2. Each pair is wired in series with other pairs.
The same what will not apply? Voltage, kWhs or use of BMS?But the same will not apply....
Ahhh, I get it, the packs are in two cell couples, 32 total, that would be fine, but the whole goal is to keep the weight of each package less, as 144 lbs is too heavy.The same what will not apply? Voltage, kWhs or use of BMS?
To clarify, two packs of 16 cells is 32 cells and two packs of 8 cells is 16 cells. Yes the total kWhs of the first will be double the kWhs of the second. A 16S BMS will work for either scenerio depending how you wire them. I use the term pack to describe a group of cells in a configuration were there is a single negative and single positive terminal at the end of each pack.
Just to be clear, the original question was about two packs of 8 cells each with their own BMS.
A 16S BMS is the only thing that will keep all 16 cells balanced. It is possible to have two groups of eight cells connect into one 16S battery. The only tricky part will be the BMS wires and the bus bars when you want to separate those packs. But you would only have to remove one bolt if designed to accommodate that pack separation.Yes, two separate cases with 8 cells each at 24v, connected in series to make 48v, what kind of BMS will work for this?
So I can find a way to have loose wires that come out from the pack that join together to create the single 48v battery, that's an interesting thought, would it simply be the one cable that connects the + terminal from one battery to the - of the next? This and the BMS wires, how would I keep the BMS in one box and have it connect to the cells in the other enclosed box?A 16S BMS is the only thing that will keep all 16 cells balanced. It is possible to have two groups of eight cells connect into one 16S battery. The only tricky part will be the BMS wires and the bus bars when you want to separate those packs. But you would only have to remove one bolt if designed to accomodate that pack separation.
Long term 48 volt inverters are more plentiful and a better long term solution for your new house. For a low capacity portable pack 12 or 24 volts could work.
You are limited to the max amperage rating of one BMS when in series like that, 100A if I remember right. There also is the question of keeping cells balanced, might not be that easy when in series.Hey there,
If I am creating two separate 24V 230ah batteries using EVE cells and have two 8S JBD BMS, one in each battery, is it okay to combine the two 24V batteries to produce 48V? Is this problematic?
The risk of using two 24v BMS's in a 48v 16S battery array is the 24v BMS may be built with 40v breakdown MOSFET switches.
When one of the BMS's do shut down for low/high cell voltage, overcurrent, or over temp, that one open BMS MOSFET switch can be exposed to 55v or greater voltage which exceeds their MOSFET breakdown voltage rating.
Some 24v BMS are built with 80v to 100v MOSFET's but unless you are sure best not to risk it. You won't know you have a problem until one of the two BMS's actually shuts down. It can cause BMS to short out then damage battery cells
Yes, I will use a labeller to ensure that the batteries are labelled (Pack #1 Part #1, Pack #1 Part #2) etc.I would design them with a 16S BMS. They make connectors suitable for the set of BMS wires so you can disconnect them to separate the cases for travel. You just have to make sure the order is right and, if you make a 16S2P total configuration it would be prudent to avoid mixing up the 16S halves.