VE Smart BMV712 and 2 MPPTs battery current difference

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jon-m asked Mar 19, '23

VE Smart BMV712 and 2 MPPTs battery current difference

We have:

1 BMV 712

1 MPPT 150/100

1 MPPT 100/20

With VE smart networking setup, the 100/20 only shows as receiving battery voltage from the BMV 712 whereas the 150/100 shows as receiving battery voltage and current,

Is this a limitation to the smaller controller or a problem with the network?

All firmware should be current based on Victron connect

I’ve tried removing and re-adding the network to the smaller controller with no difference

We are planning on adding 2 MPPT 100/50s shortly and wanted to validate things before we grow the network further

VE.Smart Network

3

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kevgermany ♦♦ commented · Mar 20, 2023 at 06:31 AM

Guessing here.

Smart networking is intended for small simple systems. I don't think it will work well when you add the extra MPPTs. Might be an idea to add a Cerbo and switch to VE Direct cabled network. The smart network must be disabled when you do.

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jon-m kevgermany ♦♦ commented · Mar 20, 2023 at 10:54 PM

Thanks,

My understanding was that the VE Smart device limit is 10 devices, so I was hoping that 5 (4*MPPT, 1*BMV) would still work

As we were hoping to leave cerbo/GX till next year’s updates

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jon-m commented · Mar 29, 2023 at 12:36 PM

Screen shots below from Victron connect

There are differences in what they show when selecting the VE smart network icon,

Image

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mkuiken answered · Apr 05, 2023 at 08:21 AM

Hi @Jon M ,

This is expected behavior.

When synchronised charging is active, one of the SmartSolars will take the lead in the chargecycle. This SmartSolar will use the current from the bmv to determine what the charge settings for the ongoing chargecycle need to be. The other SmartSolars will then simply follow those charge settings and have no need for the current from the bmv anymore.

In your case the "Wanderer" MPPT has apparently taken the lead (and is using the current from the bmv for this) and the other MPPT is just simply following what it is told to do.

Adding more SmartSolars to the VE.Smart network should not be any problem. The network might decide though that one of the newly added SmartSolars should take the lead instead of "Wanderer" MPPT. Also in that case, only that newly added SmartSolar will use the bmv current and "Wanderer" MPPT will stop using the bmv current.

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Modifications Space

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Answer 1 · 2023-03-21T06:45:18Z

kevgermany answered · Mar 21, 2023 at 06:45 AM

Please post screen shots of the two MPPTs (first page in Victron connect) and the battery settings page for both. Taken while the system is running. I'm a bit confused by you saying one controller is not receiving current from the BMV. They report current from internal readings, not values from the BMV.

If the system is wired and functioning correctly the following current equation applies.

MPPT1 + MPPT2 - loads = battery

Battery is reported by the BMV. Loads are not reported directly (needs a second meter(BMV)).

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Answer 2 · 2023-04-05T04:06:15Z

kevgermany answered · Apr 05, 2023 at 04:06 AM

Sorry, have only just seen your screen shots.

Looks good. Absorption voltage settings aren't quite the same, should be.

Difference in battery voltage on the one MPPT is very small. Might be due to current/resistance differences. Probably not worth worrying about. The MPPTs report what they see at their end of the cable. They don't report the BMV values.

BMV reports on battery and the MPPTs are reporting their individual values.

Looks like you have load on the system, but the solar is covering this and has good power to charge as well. Both MPPTs in same bulk state.

Try to get the batteries up to 100% reasonably often. It allows the BMV to synchronise properly and is good for the batteries.

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