Morning all, please assist. I have an og5.48 plus invertor. Running on 8 550w pannels and charging 4 off mecer M48100 baterries

I want to install an xstra og5.48 plus invertor only to use as a charging unit

Reason for this is that i want to add xstra 8 pannels

I dont need xstra output

I know the the charging output from the invertor just gets connected on the batteries where the master invertor is connected.

My consern is how does the idling invertor know when the bateries are full. No space to connect a com cable from new invertor to batteries

5 minutes ago, johans9 said:

My concern is how does the idling invertor know when the batteries are full.

Using a whole inverter just for solar charging seems a waste. Why not just use a stand alone Solar Charge Controller?

To answer your question, it relies on the voltage of the battery. Since the battery is LFP, it won't know how full it is until it's nearly full; then the battery voltage will suddenly shoot up. So the external charger is useful for pouring energy into the battery while it's not full. I used to do this before I had two inverters in parallel. I set the bulk/absorb battery voltage setting of the external charger just a little under than of the main inverter. That way they don't get confused near the end of the charge. The battery can't charge at high current at the end anyway, so it doesn't matter than only the main inverter charges the battery the last few percent.

Being plus models, you might add paralleling boards so that the inverters talk to each other. Plus/King models can do that; straight OG models can't (they're Axpert VM models). But if you're not using the output, it might get confused, and I don't see the point of the added expense. There is CAN bus messaging going on between paralleled inverters; I think that one of the things that they communicate is their battery voltage. Possibly also State of Charge. But I don't know if they use this information to improve the charging process.

@Coulomb hi. The thing is i have the inverter already, so to go and buy a charging unit will be a waist of money

If you have it, then you might as well parallel it and let the two inverters share the load. That is to say that your two Inverters have the paralleling Hardware already.
To just use it as a separate charger is a waste.
If you don't have the paralleling hardware, then do as Coulomb already suggested, set your "charging" Inverter to "USE/Manual" mode and manually set the bulk and float voltages to a value slightly lower than what the battery specs are.

@zsde hi thank you for the info

Is there a way that i can contact you

Dont always understand the info that you guys are giving me

My number

0828981953

You can parallel non-VM models of Axpert inverters to increase their power output. For example, two 5 kW inverters can act as a single 10 kW inverter. But to do that, you need some extra wiring and a another breaker, and two "paralleling kits":

If you already have these boards and cables (two sets are required), then it's probably worth considering the slight extra cost of paralleling them. But if not, just ignore this option, unless you find that you need more inverter power later on,