Valence U-Charge RT series 24 volt BMS Question

[cwilken]

I was looking at some slightly used Valence U charge batteries that are missing the data cable to join two BMS together so they can balance. Does anyone know a way to buy this part or what the exact name of this cable is ? For Valence U-Chare RT Series U1-24RT

 

[cwilken]

I'm seeing a number of these on Ebay @24volt 20ah for a decent price.
These particular ones never had the BMS cabling coming out of them.
I would like to use four of these for a 48 volt system (2S2P)
1. Has anyone tried these in the 2S2P configuration as is? Can I just manage it with my Growatt unit?
2. Has anyone taken the top cap off to see how much BMS or battery management there is?
3. Has anyone taken one apart and put a third party BMS? There are some forums on the 12v system but not with units that never ever had BMS cabling coming out the ports)

 

[Gruffalo]

View attachment 60352
I'm seeing a number of these on Ebay @24volt 20ah for a decent price.
These particular ones never had the BMS cabling coming out of them.
I would like to use four of these for a 48 volt system (2S2P)
1. Has anyone tried these in the 2S2P configuration as is? Can I just manage it with my Growatt unit?
2. Has anyone taken the top cap off to see how much BMS or battery management there is?
3. Has anyone taken one apart and put a third party BMS? There are some forums on the 12v system but not with units that never ever had BMS cabling coming out the ports)

The BMS in those are excellent and I would not replace it. I imagine you could find the series cables somewhere. You will need them to connect these in series. They balance themselves with those cables so you wont need another external device for that. I would look for a user manual from the manufacturer for more details.

My limited understanding is that those cables will form a series between the batteries. You could then parallel them to another 48 v set using the termi als and some heavy gauge wire. Theoretically you could hook the parallel connection to only one of the battery terminals in each set and use the one negative and one positive external terminal for the charge/discharge hookup. However I may have to test that. (Have some 12v with cables in the mail)

 

[cwilken]

I downloaded the spec sheets from the manufacturer. They said they could be put in series up to 48 volts. They dont seem to connect with cables in series like the 12v models do. So I have had them connected 2S2P for a month now. I just have to keep my inverter from going down to close to their minimum capacity as if one BMS shuts down the whole battery system shuts down. I switch back to grid when I get within 1.5 volts of thier BMS shutoff value.