Newbie AIO inverter questions

[ArtieKendall]

I just received my EG4 3000 AIO and a couple EG4 LL2 batteries (48v 100ah), and I have some newbie questions.

I've seen about a dozen videos warning that you need a pre-charge resistor because of the capacitors in inverters. I've seen even more saying to be sure everything is disconnected and/or turned off from your inverter before you start connecting stuff to it.

But I haven't seen any videos discussing the logical sum of these warnings, namely that even when everything is disconnected, your inverter might still be holding a charge in its capacitors. I did see a Will Prowse video showing that in some AIO inverters, the disconnected PV inputs had a high voltage on them from somewhere else in the unit.

So it makes sense to me that along with disconnecting the battery, AC, and PV inputs before I work on the inverter, I also want to discharge the capacitors.

Question 1: How do I discharge the capacitors safely? Can I just put a resistor across the AC out for a few seconds, the way you put a resistor in line with the battery to pre-charge?

Question 2: My batteries arrived with around 50% SOC. Can I connect my AIO to the batteries and the AC-in and start charging them, with no solar and no load, until they're at 100%?

Thanks for any help.

 

[DIYrich]

Resistor across dc. Assuming you connect the batteries in a safe way, you can charge them without solar and load.

 

[ArtieKendall]

Resistor across dc. Assuming you connect the batteries in a safe way, you can charge them without solar and load.

Thanks for the response, but I'm not sure what you mean by "across dc." The battery inputs?

 

[DIYrich]

Thanks for the response, but I'm not sure what you mean by "across dc." The battery inputs?

Yes. Battery connection of inverter.

 

[Skypower]

Temporarily in place of the switch just before you close the circuit.

 

[ArtieKendall]

Yes. Battery connection of inverter.

Thanks. It's really hard to reach in the EG43000; they have them about two inches behind a plastic shield. But I guess I could use the contacts on the circuit breaker I'll put between the battery and the inverter.

 

[Skypower]

Thanks. It's really hard to reach in the EG43000; they have them about two inches behind a plastic shield. But I guess I could use the contacts on the circuit breaker I'll put between the battery and the inverter.

You use the resistor at the external DC battery breaker that is separate from the inverter. Once you got the Inverter closed up you really shouldn’t need to go in there again. Note that some purchased batteries have a resistor built in. See Will video about pre charging and read up about your battery. Don’t mess with putting anything on the VP input’s except voltage appropriate rated DC breakers in an area within a few feet of the inverter(and you never have to pre charge PV. Just to be clear.

 

[ArtieKendall]

You use the resistor at the external DC battery breaker that is separate from the inverter. Once you got the Inverter closed up you really shouldn’t need to go in there again. Note that some purchased batteries have a resistor built in. See Will video about pre charging and read up about your battery. Don’t mess with putting anything on the VP input’s except voltage appropriate rated DC breakers in an area within a few feet of the inverter(and you never have to pre charge PV. Just to be clear.

I think you misunderstood my question. I'm not asking about precharging the inverter, I'm asking about discharging it. The scenario is I am new to this and I only have a few hours a day to work on it, so I will be taking small steps. First I want to get my batteries charged up, so I'll connect the batteries and AC input first. Later on, I'll connect the AC out (just to power strip) so I can power my fridge and stuff. And some time after that, I'll attach the PV wires. When I do that, I want to be sure that there is no voltage on the PV inputs, which according to Will's video can easily happen, even though it's not supposed to. So I want to not only disconnect the batteries and AC input, but discharge the capacitors before I connect the PV wires.

 

[Skypower]

My bad. You got this.
With time they self discharge, but it’s always safe to take steps to discharge and check, especially if you’re on time constraints.