Why the solar charger MPPT RS 450/100-Tr reducing current to charge the battery bank, when a generator input (e.g. 9,5A) is added via Quattro 48V/5000VA ?
It happens always, even when the battery voltage is low (48,5V) and a lot of current would be required to charge the battery bank 480Ah (6 x 12V 240Ah Victron AGM deep cycle batteries).
As soon as the generator is stopped the solar charger restores the current.
In MPPT settings the maximum charge current is set to 96A.
Dou you have 6 or 8 batteries? ;-)
Sorry, I have 8 batteries 12V 240Ah Victron AGM deep cycle, total 480Ah.
I would config the whole thing, that the generator stop at SOC 80-90% and let the Solarpanels do the rest.
I have tried in the winter (no sun or wind) to get the battery balanced with a generator but my MultiPlus-II was charging with only 35A and with 2,4l Bensin98 per hour it became quiet expensive.
Thank you very much for the hint!
Below are all settings.
NB! The battery bank locates in a room without heating. In this room the temperature fluctuates from -15C to +28C in summer.
Charging voltage in MPPT and Quattro is the same 57,6V at 25C + temperature compensation 4mV/Cell (24mV/℃ for 12V battery) = 96 mV/℃ for the 48V battery bank.
Both MPPT and Quattro have their own individual temperature sensors, however, both are slightly incorrect.
Temp. reading for MPPT is up to 1,5C higher than the actual temperature.
Temp. reading for Quattro is up to 1,5C lower than the actual temperature.
Respectively MPPT compensates less than Quattro. Therefore, most probably MPPT's factual absorption voltage is slightly lower than Quattro's absorption voltage.
In summary, it looks like I should increase MPPT base voltage 57,6V by 0,2 to 0,4V to equalize or set it to a bit higher level than Quattro's factual compensated absorption voltage.
Your advice is highly appreciated!
Hi @okelaa
I suspect this is very Voltage related. It appears that the mppt is backing off once it has reached Absorb, leaving the Quattro to dominate. This can happen in practice, despite the target settings for Abs (and Temp Comp) being identical. A pity your widget doesn't show V, so guessing somewhat.
To fix it, turn on DVCC so that they both see exactly the same V (maybe use the BMV's). Then drop the Quattro Abs setting slightly below that of the mppt. Over 48V, I find 0.1V enough for the mppt to assume priority, and the genset will back off first. Also make sure that the current limiting in DVCC isn't set where it too could cause undue limiting.
You mention this also happens at 48.5V, but that low a V can't happen with the charge current you're showing.
Thank you for most professional advice!
Here is the same chart V parameter added.
Following your instructions I set MPPT Absorption V slightly higher 57,7V and Quattro slightly lower 57,5V. So the current difference is 0,2V to see how it works. If all good, I'll reduce the difference to 0,1V.
I did set up DVCC as follows:
Moreover, I am not sure if it would be even better to set up the Smart Battery Sense for V and temp reading?
JohnC - You mention this also happens at 48.5V, but that low a V can't happen with the charge current you're showing.
Yes, perhaps I exaggerated. I'll be careful with further claims and back them up with objective data.
Look forward to hearing from you.
Kind regards,
Yeh, the V addtion tio the chart is what I expected. What you've done there with the DVCC should work fine.
