Mixing Seplos Pack sizes - possibly BMS

[fastknight]

I started with 2x Seplos 135Ah BMS v2 packs sometime ago - been workign great. I needed more capacity and wanted to consolidate space-wise so I purchased a 280Ah BMS v3 pack with cells and an additioncal 280Ah BMS v3 empty chasis. I was intending on moving the cells from my 2x 135Ah packs to the empty 280Ah and at same time standardise on BMS v3. I then realised my mistake as the cell sizes are obviously physically different sizes etc and can't be moved into the 280Ah case so just thinking through options.

Are there any options other than selling the 2x 135Ah units with BMS v2 and then just buying new 280Ah cells for my empty 280Ah case?

I'm using a rack so the deeper 280Ah units work better for me space wise than the 135Ah rack cases anyway hence why i started down this upgrade (both in Ah and BMS versions) - but just exploring any other viable options.

Thanks for any ideas. The overall system has been working great - my misunderstanding of how the packs are built up caused my screw up above. Leason learnt - still all feels a bit early adopter tech at times!

 

[DIYrich]

Are there any options other than selling the 2x 135Ah units with BMS v2 and then just buying new 280Ah cells for my empty 280Ah case?

1) Save the 280ah case for your next upgrade.
2) Sell the 280ah case.

 

[fastknight]

Can the 135Ah systems be used alongside the BMS v3 pack? I was of the understanding they were not compatabile on the 485 ports - can you connect both packs to the Inverter using two CANbus ports for example?

 

[houseofancients]

Can the 135Ah systems be used alongside the BMS v3 pack? I was of the understanding they were not compatabile on the 485 ports - can you connect both packs to the Inverter using two CANbus ports for example?

The V2/v1 and V3 will not be able to communicate to each other

 

[DIYrich]

Don't know if you can connect both. I would connect one, and let the other run in voltage mode.

 

[fastknight]

I can

Don't know if you can connect both. I would connect one, and let the other run in voltage mode.

I can't find any information on voltage mode. Is this something you specifically set somewhere in the BMS or just by not setting/connecting to CANbus or 485 it basically manages itself?

 

[houseofancients]

I can


I can't find any information on voltage mode. Is this something you specifically set somewhere in the BMS or just by not setting/connecting to CANbus or 485 it basically manages itself?

Voltage mode means running without any form of communication

 

[fastknight]

Voltage mode means running without any form of communication

Thanks for confirming - that may well be an option. I wasn't so keen on having the inverter running blind to the BMS but as a last resort its worth testing.

Its a shame Seplos went down this incompatibility path - I'm sure they have their reasons but it does seem to bring additional complexity to an already fragmented system.