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Ingo avatar image
Ingo asked

ESS slowly discharges my battery with Keep Batteries Charged

My system slowly discharges my managed battery over a couple of days even while the Keep Batteries Charged option is selected. Currently it's down to 94% and doesn't seem to stop any time soon. My PV Charger is out of commision (Panel Maintenance) so the only charge source is the Grid - which is fine.

Quattro/478

VenusGX/2.60

Freedomwon 10/8

SmartSolar 150/35/1.54

ESS/Keep Batteries Charged

No Power Assist or anything strange selected. Pure UPS at this point in time.

Any ideas why it would keep on discharging my battery? At some point I am going to need the capacity for grid failures.


venusgx-status.png

ESS
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4 Answers
seb71 avatar image
seb71 answered ·

Your Quattro inverter and other DC powered devices are discharging the battery, not ESS.

Is the charger enabled in Quattro? If yes, what are the settings?

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Ingo avatar image Ingo commented ·

You are correct, it's the Venus and Quattro itself. My charger is enabled and set to the battery manufacturer's specifications.

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Ingo

What parameters does the BMS send? (devices, BMS, Parameters)

You can also enable those values in a widget on VRM 'advanced' page

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Ingo avatar image Ingo commented ·

Hi @Daniël Boekel (Victron Energy Staff)

VRM id: 985dadcac66b

The below has been enabled on VRM portal. On the actual Venus Console there are a few more. I think the Freedom Lite batteries have one of the more comprehensive BMS' around.


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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Ingo

Your battery tells the system at what voltage to charge, and the system does just that: charge to 55.2 volt. I'ts the battery that tells the sytem the SOC, and that SOC is incorrect IMHO, you can see cells are at 3.45V / cell and that is 100% charged.

screenshot of BMS limits:

screenshot-2021-01-22-102352.png


So best to ask your battery supplier if this can be improved (or just don't worry about it now you know what is going on).


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Ingo avatar image Ingo commented ·

You are absolutely right @Daniël Boekel (Victron Energy Staff). I also just came back from a session getting the battery firmware updated to the latest. The vendor said we must give it a day or so to 'adjust' and it should eventually hover around 99.X% SOC and a slightly higher charge voltage. I will report back on Monday with the results.

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Ingo avatar image Ingo Ingo commented ·

Ok, this is more like it. With the updated firmware the voltage increased to 55.5V and the SOC toggles between 99% and 100%

So if anyone finds this post in future, please make sure that the battery manufacturer has loaded the latest firmware - it looks like my issue has been resolved.

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seb71 avatar image seb71 Ingo commented ·

You said it did the same thing with your old lead-acid battery (so without a BMS).

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Ingo avatar image Ingo seb71 commented ·

Yea, could be something unrelated to this issue.

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Robert Boerescu avatar image
Robert Boerescu answered ·

I have the same issue, I have keep battery charged selected but SOC has been drifting down ever since I set it, now at 83%. I have a smartshunt and generic lifepo4 without a smart BMS.drift.png


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derrick thomas avatar image derrick thomas commented ·
You appear to be in float with a voltage of 51. What are your charge settings in the inverter? Is dvcc enabled? What are the voltage/amperage settings in dvcc? With a voltage of 51 your SOC is going to keep dropping.
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Robert Boerescu avatar image Robert Boerescu derrick thomas commented ·

The battery is 15S and the recommended charging voltage on it says 54V. However I have been doing a lot of reading and listening to youtube videos on the subject and I decided to set the charging voltage to 52 and float to 51, similar with pylontec batteries. It has been working fine like this. I do not need a lot of capacity, this is only 100Ah, mostly for critical loads in case of power cut. The way I use it lately is to keep it charged. The only issue I see is that SOC goes down every day. Yesterday I set it to optimized with battery life and this morning charged again to 100%. Not sure what is causing to go down. DVCC is enabled.

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