HI everyone,
I have 2x 12V Rolls 5000 flooded batteries 337Ah, 250/100 MPPT and Multiplus II 24/3000
Once upon a time when I had no inverter, my charging settings in the MPPT were working flawlessly, as I was using “Adaptive” mode charging and tail current option, set to 8Amps. The charging always kept running until the tail current is reached in Absorption mode and the SG, which I monitor regularly was at perfect levels according to batts’ temperature.
So far so good, but since I installed the Multiplus and cerbo, the charging, governed by the controller when the Multi is OFF (I do and want to keep it off most of the time) had begun to do wierd things, like:
During Bulk state (no “External control”, but Bulk, i.e. the charger is “in charge”) it behaves normal, reaches the Absorption voltage and goes into Absorption state - fine.
Absorption state however terminates a few minutes after going into that state when the current is 20A or more, far far away from the set tail current in the MPPT.
I tried removing the tail current option - no change. I set “Fixed time” for the absorption mode and set the time to 6 hours - no change again! The charger goes into Float mode a few minutes after Absorption has started. Even the shunt is telling the batteries are 85 or 90% charged, but the controller doesn’t care - it goes and stays in Float.
What could be the issue with this denial of the controller to stay in Absorption state?
Did you set the same charge values in the Multiplus through VE.Configure?
If the Multiplus is off, do you turn the Cerbo off as well? You could try disconnecting the MPPT from the Cerbo and see if that solves your problem. It should fall back on the MPPT settings and not use the GX settings.
Thank you Skipper!
No I don’t turn the Cerbo GX off when the Multi is off. (Multi is off all the time in the recent weeks).
But I didn’t know that the Cerbo “memorizes” the settings from the multi.
I can’t turn off the cerbo as I use it hourly to make monitoring.
The settings are the same but this doesn’t matter, because the tail current setting is the one that is crucial here. Multi doesn’t have it, it offers only “Absorption time” parameter to control the absorption duration. So I need the controller’s settings to be obeyed, i.e. the Tail current setting, in order to charge meaningfully my batteries.
Nope, it’s not enabled. Otherwise, I wouldn’t expect the controller to obey its own settings.
Only the shunt is on, maybe I should configure something there too? The tail current in the shunt is configured to percentage equal to a higher level of Ah, compared to the controller’s settings, as adviced here:
Yes in that case I’m not sure how to achieve your goal. Do you turn off the Multi via the software switch in VRM? If physical, maybe disconnecting the CAN bus cable does the trick?
Another settings you could check (maybe only useful for DVCC, but you can try):
Did you set the shunt as the battery monitor and hide the Multiplus in system settings?
Sorry for the delay.
The Multi is off all the time. I need it once every 2-3 months.
Yes, it’s off by the soft switch, but even if the controller is “reading” its settings, it would not make scence as the controller exits the charging cycle in 15-20-25 mins, but the maximum abs. time in the Multi is 6 hours.
If this is what you’re talking about, I think it’s as you suggest. But is it not just for the visible sensors in the Remote console rather about the actual data pulling from the controller? I’ve paired the MPPT to a battery sense module long time before the Multi appearance in the system.
