eirik avatar image
eirik asked

Charge control on MPPT / Venus GX; 0A not possible

In my boat I have a Venus GX, an MPPT 75/15, a Multiplus 1600/70/16, a BMV 712 hooked up to a 600Ah Winston LFP bank controlled by a REC BMS (not the Victron compatible version). To the MPPT I have connected 2x100 W solar panels.

I would like to be able to limit/stop charging by solar when I leave the boat for longer periods, (as I prefer to keep the batteries at a SOC below 70%), and have thus turned on DVCC, Limit Charging and set Max charging current to 0 A. The MPPT reports that it is Networked, Slave and ESS mode, but nevertheless produces 1A of current (BMS Controlled is turned off). If I increase the charge limit it works correctly (1A also yields, 1A, 2A yields to 2A, and so on, up to what the PVs produce). The fact that I can't stop charging completely (i.e. 0A) is a bit annoying, as it would be nice to have full control (which I don't have now). The Multiplus is, BTW, turned off (via the Venus), and is usually not hooked up to shore power. Any views, or intended fixes in a future firmware version?

MPPT ControllersVenus GX - VGXcharge current limit
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2 Answers
Mark avatar image
Mark answered ·

Probably not the answer your looking for, but if you have a SmartSolar MPPT or a Bluetooth dongle, you could easily use Victron Connect to switch the 'Charger Enabled' toggle to off...

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eirik avatar image
eirik answered ·

OK. I have made some discoveries, and the issue appears to be caused by the Multiplus being connected.

I first discovered that by turning on the inverter part of the Multiplus, the production from the BlueSolar MPPT remained at 1A, but the overall charge to the batteries was 0A, thus the MPPT produces exactly enough current to operate the Multiplus in standby mode (and I guess also for inverting if that this is taking place). But now the Multiplus needs to be left on, which I don't desire when I am away from the boat (and it will draw power during night).

I then disconnected the Multiplus from the Venus GX (VE Bus), and restarted the Venus. The current from the MPPT is now 0A, as desired. However, this not how I would like to have the system set up.

So obviously, the Venus GX (I believe) compensates for the fact that there is a Multiplus connected. The problem is that it disregards whether the Muliplus is it turned off or is in inverter mode. In other words, Victron has made the Venus smart, but not smart enough.

Ideally, either the following could be done. @Victron, would you consider any of these?

1) Use the information whether the Multiplus is in inverter mode or turned off to adjust the current from the MPPT.

2) Be able to turn off the MPPT charging via VRM (in the same ways as is possible via Bluetooth/VEDirect), cf. @Mark's answer.

3) Disregard (or have the option to) that there is a Multiplus attached.



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