BMS needed for Victron system?

bigroadadventure · Oct 11, 2019

I’m planning a 600ah/24V system right now. Everything will be Victron (batteries are Sinopoly though). I see conflicting opinions on using a BMS, especially with such a large battery bank (low voltage cutoff relay is a challenge). Do you think the Victron setup requires it? 2 multipluses, 2 charge controllers and a Venus.

I do plan to keep an 8s balancer connected to check cell voltages periodically.

gnubie · Oct 11, 2019

My opinion is that if you can access the cells in a battery use a BMS. It will keep the cells in check so that they don't drift which will limit your overall capacity, make sure they don't get over charged, make sure they don't get over discharged, protect from high discharge rates, monitor cell temperature (if it has that feature of course).

As good as Victron stuff is, it can't see what is going on inside a 3rd party battery. All it can do is watch the overall battery voltage and current, and if you have one fitted, the battery temperature.

bigroadadventure · Oct 11, 2019

gnubie said:
My opinion is that if you can access the cells in a battery use a BMS. It will keep the cells in check so that they don't drift which will limit your overall capacity, make sure they don't get over charged, make sure they don't get over discharged, protect from high discharge rates, monitor cell temperature (if it has that feature of course).

As good as Victron stuff is, it can't see what is going on inside a 3rd party battery. All it can do is watch the overall battery voltage and current, and if you have one fitted, the battery temperature.

how would you handle 200A with a BMS? Seems like an actuator is the best path if you have one.

gnubie · Oct 11, 2019

There are BMSes out there that will handle 200 amps directly. Take a look at all the usual places, aliexpress, ebay etc. The only question there is are they really capable of what their specs say. If the BMS can work with a relay or contactor that would be a really good option.

The lifepo4 I have has a BMS rated at and can actually do 320 amps for short periods with 175 continuous.

bigroadadventure · Oct 11, 2019

Yeah, I saw the latest one that Will reviewed, it looked pretty nice feature-wise. But the wiring itself seemed a little suspect - and I'm betting it will have the same MOSFET issue that the Victron battery protect has (can only flow one direction without risk of melting/fire).

I may get that one to start and just use it for monitoring cells, keeping the main electrical path clear to the two 3K Multiplus's. Thanks for the reply!

BMS needed for Victron system?

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