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ondra asked

ESS mode ignores BMS BMZ ESS-X control

I would like to ask if it is normal that ESS mode ignores BMS control from BMZ ESS X battery. Configuration 3 x MPII, 3 x BMZ ESS-X, MPPT 250/85, Fronius Symo and AC OUT1, Cebo. All devices have the latest version of FW. Unfortunately even if the BMS battery sends a parameter - CCL = 0A:

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so the batteries are still charging. The charger is set according to the manual for BMZ = Absobrtion time = 1. Unfortunately = Absobrtion time is never one hour, even 7 hours at a time.

1615370332097.png

Status code # 3 should appear in ESS mode: BMS disabled charging, I've never seen it with BMZ ESS X in ESS mode. I run another 4 similar systems with BMZ ESS X and I have also never seen status code # 3: BMS disabled charging.

I'm worried about the batteries, about the safety of operation. I think I overcharge them this way and they could be damaged. Please tell me if this behavior is normal (the battery is not overcharging) or if it is an error. Thanks Ondra



Multiplus-IIESSBMS
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2 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Ondra

first: absorbtion time, etc. is not used when using a CANbus controlled battery, the battery controls charging.

in this case 'absorbtion' means that the charge voltage is reached, and Bulk that it is below target voltage.

second: because ESS is continuously charging / discharging the battery, the system will just keep the target voltage of 61,5 volt, otherwise the battery would stop charging, and a little later charge again.

So as long as CVL is respected, there is no problem and your battery is not overcharged.

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ondra avatar image ondra commented ·

Hi @Daniël Boekel (Victron Energy Staff)

Thank you for the explanation. I'll be calmer right away :-) Maybe this explanation could be part of the ESS manual or the VE Configure setup manual for BMZ batteries (https://www.victronenergy.com/live/battery_compatibility:bmz_ess). There would be fewer similar questions.


Ondra

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ondra avatar image ondra commented ·

Hi @Daniël Boekel (Victron Energy Staff)

Unfortunately, it has now happened several times that the battery has been overcharged - see the picture below - CAN-bus BMS battery warning High voltage.

1617437732705.png

Data from MPPT, here you can see the maximum battery voltage of 61.98 V, while the maximum is 61.5

1617437749354.png


So I don't think battery charge control is working properly. I have found that this only happens when DC-coupled PV - feed in excess is enabled and the battery is 100% charged.

I use MPPT 250/85 connected via VE.Can. The battery is connected via BMS Can. See settings:

1617437776937.png


Thank you for your reaction, or for recommending something else to try to avoid overcharging. Ondra


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vicens avatar image
vicens answered ·

Quita la compensacion de temperatura del mppt. A 0.

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