Back up generator charging

Q&A and troubleshooting
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1

Hello all.

I have just installed a generator for the cloudy days to my system and was wondering if it was possible to charge the batteries any quicker?

The generator is generating about 2200w but the batteries are only charging 1700w. The generator is also capable of charging a lot more. I was wondering where the rest is going?
Is it how my multiplus can handle?
Is it the limit that my batteries can handle?
Is it possible to charge more?

I have the
multiplus 48-3000-35 inverter
Genergy greta sol generator.
2x Pylontech US3000C 48V 3,5 kWh batteries

Thanks in advance :slight_smile:

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2

Batteries ? Capacity and Type ?
Any Other Infos about your Components ?

3

Inverter chargers are about 80% efficient converting AC power (from generator) into DC power (to battery).
The inverter chargers also have a maximum DC output current (typically measured at 25°C). The inverter listed is 35ADC maximum. Into a 52V nominal battery, the maximum charging power will be around 52V×35A=1820W. As the charger circuit heats up, the output power will be reduced.
If more charging power is desired, one strategy is to add another Multiplus and configure it Charger Only. Its charging power would add in parallel to the main Multiplus, effectively doubling output.
My solution is to use an external AC charger, and run it from the generator. I use an EG4 Chargeverter (100ADC max.)
To get it “seen” in Venus, I feed its output through a SmartShunt configured as a power meter.

4

The batteries are Pylontech US3000C 48V 3,5 kWh. I have 2 of them. That’s it I think apart from the VE buss i think it’s called.

5

Is the Pylontech BMS selected as the ‘battery monitor’ or the Multi?

6

I see. My batteries are Pylontech US3000C 48V 3,5 kWh
so 48v x 35A = 1680W which is what I am charging.

7

The battery monitor is set on automatic

8

I see. So your solution is buying a separate inverter that’s changing the ac from the generator to dc?

9

Adding an MPII as a charger only is a method suggested several times by pro installers. It is more practical with the 230V Multiplus used in Europe, as its substantially cheaper than the 120V version generally used in the U.S.A. (where I live.) The 2nd MPII will integrate tightly into the rest of the ecosystem, making control and monitoring easier.
For my system, I use the EG4 Chargeverter GC. It can accept up to 5kW and charge at 100A. I use it at 4kW / 75A so it runs cooler. Since its “foreign” to the Victron ecosystem, a little extra work would be needed to monitor and control.

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At the moment, this system uses non-Victron inverters, so the discharge from the battery bus shows up as DC Loads. (The - load is actually the net charge current flowing to the battery.) The AC Charger on the left is monitored by a SmartShunt.

1 Like
10

Moved to it’s own topic