question

jorge-folgado avatar image
jorge-folgado asked

Sustain current too high?

Hello Victron fellows,


I have set some Li ion with Victron inverters, always for self consumption with PV inverters, but this one is cracking me up. This system consists in three 48V Multiplus II 3000/35 as a three phasic system, and an ESS assistant is set. The sustain voltage is 43V and cuttoff around 42V. The modules have a low SOH, but the system should work anyway. It charges and discharges correctly, up to the point where my BMS disables allow to discharge at around 48V, because there are low cells (it should discharge to less than 42V if it was good).

Then, Sustain mode is active and the current goes UP TO 90A. Of course when this happens the voltage raises quickly, the allow to discharge comes on again and it goes to Discharging mode. Repeating the process endlessly - Even without PV POWER, that means it consumes a lot of power.

My question is, why does it go up to 90A, since sustain mode should be 5A per unit and how can I solve this?

Thank you very much!

Multiplus-IIESScharge current limitcurrent limit
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4 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Jorge Folgado

I've sent you an email, we'd like to look in to this.

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diego quintero avatar image
diego quintero answered ·

I Have a similar problem, can you provide some guide?

I connected the batteries switch on Multiplus Victron, I have installed ESS too and then 15Amps was putted in the system, when I only allow 3 max in the configuration. In my system this can damage my batteries. After 10 min I switch everything off, because sustain mode was present and could not have control with ESS grid set point.

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sedlons avatar image
sedlons answered ·

Same problem here.

I have 3pcs of Multiplus 5000 48V with ESS and two wire BMS. Sustain voltage configured to 40V.

Around 47V is disabled discharge allow and immediately start charging with current > 80A. Sustain mode is left after pack voltage is over 50V.

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hjb avatar image
hjb answered ·

same problem here.

i use multiplus 2 GX with a ESS and configure the 2 channel BMS.

when the bms give the signal UVP, the multi begins to load with the max current. and it will never stop.

thats a proplem. is there any solution for this? i would, that the Multi go to the sustain Voltage with a max. 5 Ampere current and stop the charching at the sustain voltage level. Or go return to the normal use, when the UVP signal is loss.



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