BMV712 with SmartSolar

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chrisryan43 asked Apr 15, '19

BMV712 with SmartSolar

I am charging my LFP battery bank from 3 x SmartSolar MPPT controllers (2 x 100/30, 1 x 75/15). They are all set to the standard LFP charge profile of Absorption: 14.2V for 6h and float voltage of 13.5V.

They all receive the same battery voltage information from the BMV712 yet they all go into float at vastly different times. The first of which is before the the BMV712 has reached 90% SOC. I am considering setting up a raspberry pi to act as a Venus Control which i think will give SOC information to the controllers. Is that correct and/or is there anything else i can do to get everything talking to each other better?

MPPT Controllers BMV Battery Monitor

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Modifications Space

Node Red Space

Answer 1 · 2019-04-18T13:45:41Z

Guy Stewart (Victron Community Manager) answered · Apr 18, 2019 at 01:45 PM

At this stage full synchronised charging with VE.direct MPPTs requires an external BMS that controls charge parameters, just a GX device is not enough. State of Charge will not have an effect, unless it is also an ESS system.

There is work in progress, and nearing a public beta that will allow SmartSolar controllers to communicate and synchronise charge stage.

I have personally been using these controllers unsynchronised for a long time already, and have found it hasn't made a difference to the batteries receiving a full and regular charge.

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chrisryan43 commented · Apr 18, 2019 at 04:44 PM

Thanks Guy, just to clarify that i have a BMS (for the LFP battery bank). I assume that will control charge parameters for the MPPT?

The biggest issue (for me at least) with this situation is that some controllers enter float mode far too early which may not have a detrimental effect on the battery but it does mean i am wasting precious solar energy.

Presumably the new firmware that you refer to will run on existing hardware?

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Answer 2 · 2022-11-21T06:29:02Z

tex260z answered · Nov 21, 2022 at 06:29 AM

Along the same lines.

I have an active balancer for a 4S 200 amp Hr LiFePO4 battery pack, said balancer has facilities for an activation switch, can anyone advise how I could used either my Bluesmart 75/15 MPPT regulator or the (networked) BMV712, to control the balancer?

I would like it to switch on when the battery is fully charged.

Any suggestion welcomed.

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Answer 3 · 2022-11-21T06:55:37Z

kevgermany answered · Nov 21, 2022 at 06:55 AM

@Tex260Z Look at the manual for the BMV. Section 4.2.2 gives all the relay settings.

You'll need to invert the relay, 11, then set the state of charge 16, 17.

The relay is intended as a switch, so if your balance function would pass significant current through the relay, use the internal relay to switch another relay the can handle the balancing current.

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