question

babeny2001 avatar image

Is there any workaround to run a Victron system with dead batteries?

Hello, I think after two years batteries are gone. It was set up and configured by company for my father, but was not monitored or serviced either. After he noticed often low voltage alarm he asked me for help, as the company is not reachable anymore.

There are 10x panels (AS-6P30-260W),
BlueSolar Charger MPPT 150/70 firmware 1.46
MultiPlus 48/3000/35-50 firmware 4.30

4x 12V victron 110Ah Gel batteries (in series)


I've studied something, purchased cables updated firmware, installed venusOS on raspberry, changed to ESS (before there was some Hub system - preventing feeding to grid - no allowed in my country) but still voltage drops very quickly and almost 90% usage is from AC grid even on sunny day, though usual load is between 200-600Watts, so I suspect inverter shuts down due low voltage very often.

I've read in this forum system is not able to run without batteries (he do no want to invest in new batteries anymore) question is, is it possible to set it up that way it will use as much solar power as possible even with such "dead" batteries, if yes what is the best configuration.

Or is Multi 48/3000 capable running with smaller voltage e.g. 12V or 24 ? I could try to isolate broken battery and try to set it up with remaining good ones, or maybe use spare 12V car battery if it's necessary for system to run


ESSVenus OSbattery system voltagelow battery warning
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6 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @babeny2001

I'm sorry but there is no workaround for defective batteries.

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JohnC avatar image
JohnC answered ·

I wouldn't give up on 2yo batts immediately either, unless you know they've been abused.

But your issues could be coming from several places, and we can't tell from here without much more information. If your VenusOS is linked to VRM, might it be possible for you to post screenshots of the relevant widgets over 24 hours?

(Say) VEBus A/V, Solar A/V, Grid input. Same day, so we can cross-reference to see what's happening..

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here are data from 2 separate days 10th september an 1st december , both sunny days, I think changes in voltage are too fast, but I'm more IT than electrician so maybe my assumptions are wrong but I think it has to do with batteries, also PV yield is simply small for 10x265W array, but load was also small overall, but in cases it was more than 1K it simply keeps down always.


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Hi babeny,

Amerisloar AS-6P30-260w

Solar yield looks low, esp for good sun.

10 panels seem to have been wired 2 series, 5 parallel. Suspect most of the array fuses have blown.


@klim8skeptic how did you work that out?

PV voltage of around 70v indicates 2 panel series strings.

PV current peaks at 12a, something bad there. Could be floppy/limp battery, or could be blown fuses.

Ah. Right. Thank you.

Tom avatar image
Tom answered ·

The multiplus requires battery to start up. You can hook up any size 48 volt battery to get it to turn on to use shore or generator power with the hybrid off. Or you can just bypass the AC through the multiplus all together.

Solar is totally different. An mppt is not an alternator or generator. It does not output regulated power so you need batteries to regulate that dc power.

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eiremos avatar image
eiremos answered ·

Hy ,

I also have this kind of batteries , 200AH and exceptionnaly pull more than 250w in one hour . i think those batteries are not adapted for working long period without sun and not being well recharged , but they can help to work has "buffers", meaning unload your electricity bill , particularly in sunny days . For example if you have a venus OS , you could work in ESS mode "optimised with battery life" , with in winter time a minimum SOC=90% and in summer you could go up to SOC=70% . in ESS mode you can also limit the charge and the discharging power , meaning that you work within fixed and reasonnable limits (ruled by the battery constructor , its capacity and age) to load and unload your battery with some experiments , meanwhile the extra power from the sun goes direct to the actual loads , consumption in realtime .

There is some nice victron litterature , easy to find that talk about ESS and its basics (free to download and called "ESS Design & installation manual") , were in FAQ you could find some questions and answers has :


"Is power from MPPT used to power the loads when feedback is disabled?" ,

"Yes. ESS will reduce grid usage to a minimum, preferably to 0W, with or without feed-in enabled...

...In Keep Batteries charged mode...There is a known issue
when using “Keep batteries charged” mode that can result in less production from the MPPT...

This only occurs when DVCC is disabled, and the “Feed-in
excess solar charger power” setting disabled"



I do not know any solution to make work a 48v multiplus in 24 or 12v , without any other expensive materials .

Hope this helps you , at least a little bit , to not feel alone in the so long way to energy independance , in a free world .


Thank-you

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@babeny2001 i suspect that the batteries have been deeply discharged for extended periods of time and because there are no battery balances in this 4 battery series bank, some of the batteries gradually got undercharged. They may be able to be recovered using a Victron battery charger or another 12v charger dedicated to trying to recover the battery.

JohnC avatar image
JohnC answered ·

Thanks for the screenshots, they do help.

I read at least one very sick batt(s), with a standing V of the string at ~44V and unable to accept much charge. This will mean the good ones will be experiencing overvoltage and will die eventually too. A multimeter across each batt will find the offender(s).

You'll need to replace it, and if you do that with a foreign fill-in, consider reducing the solar target V's to a Storage mode setting of, say, 53V. That way the solar won't push them too hard, and you could reduce or turn off any load completely. Ie. Just use them as a buffer. DVCC could help with doing this too, just in a different way.

The alarms should go away, but you could reset those downwards too if you want.

The solar perhaps a separate issue, maybe you've lost some strings? They're not really set up optimally for poor light anyway, and you could consider setting them up in 3x series strings and orphaning a panel. If you found a dud panel that would be a no-brainer.

But come back..

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babeny2001 avatar image
babeny2001 answered ·

guys, thanks for feedback

I've spent today with measurements around, today was sunny, but days before not.
Morning
1 - 12.89 V
2 - 12.9 V
3 - 10.4V !
4 - 8.7 V !

noon

1- 14.4
2 - 14.7
3 - 14.5
4 - 13.39

evening
1- 12.79
2 - 12.84
3 - 12.75
4 - 12.40

from this at least last one is bad and maybe the 3rd starts to be.
Also I've measured current with clamp multimeter all 4 wires from the roof (2 strings) (before fuse box) and as others wrote already it seems one string is dead, next step will be to analyze cables on the roof and measure each panel separately, but this will be little bit more difficult due access and set up load for each panel, I have to think about this first.

The goal is now to set up ESS that way it will first take care of loads and then the battery (use them as buffer) , I've turned DVCC on, set SOC little bit higher but all the energy now goes to batteries - problem is SOC indicated 85% but SOC on BMV says 99.6%, I don't have BMV connected to venus, so system works with 85 value, I do not know how to sync these two. I'll try to keep charging batteries for few days until there is 100% and then see if DVCC will serve the loads only.

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