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pegi avatar image
pegi asked

REC-BMS for Victron / Multiplus 24/3000 / Control Load busbar

Hi,

I'm pretty new to LiFeYPO4 (coming from normal batteries) and I want to build a Victron system using Winston LiFeYPO4 batteries with REC SI BMS for Victron. I intend to build a 2p8s system which is connected to the BMS.

REC BMS communicates with Victron via CAN and CCGX will be configured with DVCC to let the BMS decide the whole charging thing.

My issue is regarding the LOAD:

In all Lithium Victron diagrams (e.g. here) a Smart Battery Protect is used to switch loads on and of. SBP is controlled by VE-BUS BMS via the load disconnect signal. But with REC-BMS I have no clue to accieve this...

Is it possible to use the alarm relay of CCGX? REC BMS also has an optocoupler but the manual says this is only for charging...

My questions are:

Is it correct that in case of undervoltage the inverter of the MPII is switche off via CAN?

Has anybody an idea how to switch of all 24/12v loads in a Victron environment using REC BMS for Victron?

Any ideas appreciated.

Thanks
Peter

Multiplus-IIBMSCCGX Color Controllow battery warningdischarge level
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2 Answers
nebulight avatar image
nebulight answered ·

I'm not sure about the 24v BMS from REC, but the 12V active has two relays and two optocouplers which can be used for what you want. I'd use one of the optocouplers to drive the Smart Battery Protect in Lithium Mode (type C on the battery protect). It will work the same was as the ve.bus BMS except with the optocoupler, you'll need two wires to the BP since it'll just be a closed loop.

EDIT: It looks like the bigger units only have a "charge" optocoupler. You might want to reach out to REC to see if that can be reprogrammed.

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pegi avatar image
pegi answered ·

You are right. The 12V active version for 4 cells would have all I would need. But unfortunately the REC SI BMS for more than 4 cells has only one charge optocoupler as you correctly stated with your addendum.

My post was a little bit delayed (it was not approved by Victron) and meanwhile I was in touch with REC too.

They confirmed that pin 4/5 of the „internal relay“ can be programmed as a Load Control but only on a “battery“ level, not on a cell level. This may cause a cell damage.

And additionally: what do I do if I want to control a BuckBoost too? Ist it possible to disable the BuckBoost via CCGX?

Meanwhile I believe that choosing a different BMS would be better. I already had a closer look to Lipro from ecs-online.org. They do support Modbus and maybe there is a solution for a CCGX integration out there?

Regards, Peter

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nebulight avatar image nebulight commented ·

I think REC is the go to BMS for connection with Victron gear. Another option would have a cheaper cell monitor/bms (in addition to the REC) that has the ability to shut off loads; have that be the only function of that BMS. I have been playing around with an Electrodacus SBMS0. While it has no CAN communication, it can go up to 8s with up to 4 optocouplers to program how you see fit. While it is pretty basic in it's function, it's a pretty solid unit and I've been pretty impressed by it for the cost. It would be a great option for non-victron equipment DIYers.

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luckybeanz avatar image luckybeanz commented ·

I'm busy setting up a rec bms with 2p16s config using a cerbo gx and a multiplus ii. I found this thread interesting and wondering if there are any updates.. I know one can use a contactor for the bms to cut off loads/charging, but I'd rather try have the bms just control the multiplus via can and the cerbo. Still early days configuring it, but keen to hear what route you went down.

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