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johanneshovda avatar image
johanneshovda asked

Multiplus Trickle charge connection depletes the starter battery?

I have a Multiplus 24/3000/70-16 and a BMV702 set up in an RV with two separate battery banks (house + starter).

I noticed today that the AC input had failed, and the Multiplus depleted the house battery bank before entering low voltage shutdown at 24v (full charge is 28.7 volts). However, when I check the BMV702, the starter battery is also showing depleted at around 25 volts.

In VRM, I can see that the trends for both batteries follow eachother, which indicates to me that they are being paralleled for some reason.


Is the trickle charge connection (or the BMV702) somehow parallelling the battery banks??

MultiPlus Quattro Inverter ChargerBMV Battery Monitor
screen-shot-2019-07-29-at-83825-pm.png (165.2 KiB)
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jdubbayew avatar image jdubbayew commented ·

Joahnnes,

I am setting up my multiplus and Victron has little to no information on the trickle charge configuration.

Wondering if you will elaborate on how your have the trickle charge wiring configured.

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JohnC answered ·

Hi Johannes. I think what you're seeing there is just your starter battery V returning to a 'standing' state. A very healthy one too if they're Pb's. Under a trickle charge that would go higher, as you might normally see it, but without that a return to a standing V is expected.

Your SOC graph will be referring to your house bank, not the starter bank. If that's where the shunt is wired to.

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Eric M. avatar image
Eric M. answered ·

@johannes.hovda Did you ever figure this out? I'm having a similar issue and am trying to develop an understanding of how that connection is intended to work. @JohnC I don't really agree with your assessment, my findings indicate the trickle connection is constantly active and runs the risk of fully draining my starter.

Findings/question listed here:

https://community.victronenergy.com/questions/121332/multiplus-compact-consuming-from-starter-battery-t.html

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johanneshovda avatar image johanneshovda commented ·
No, I never did. But I just assumed I was wrong and everyone else was right, so I didn't look into it any further....
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Eric M. avatar image Eric M. johanneshovda commented ·
Well... +1 for don't think you're wrong! Unless I have a failed unit. Looking into installing a LVD or manual switch to engage on the rare times I actually plug onto the grid.
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