Should I pre-charge Inverter after turning off the battery

[Nightguest]

Heyoh!

I've got a question regarding when to pre-charge a 48v inverter.
My solar system is happily working now, it's got an SOK 48/100 connected to a Multiplus-ii 48/5000 and a Cerbo GX, and prior to turning it on the first time I did use a pre-charge resistor (50W/33R) and it worked like a charm.

However, at the time that I was putting the system together, I forgot about the VE Can to Can Bus cable for the battery to the Cerbo GX. Now, the cable is finally on it's way and I do want to plug it in, however, here is where I come across a situation that I am unfamiliar with.

Per the SOK manual, I need to turn off all loads (MPPT, Inverter, etc), then turn the battery off, and finally turn the BMS off. After that, I can connect the communication cables, and then turn the system back on.

My question(s) would be:
- Given that connecting the cables takes a few seconds, do I need to go through the whole pre-charge process again?
- If it is possible to answer, does anyone know approximately how long it takes for a capacitor to discharge to the point where the pre-charge is needed?
All I know is that the capacitor discharge rate is an exponential one, so it loses a lot fast, but then never hits 0, so I'm curious to know at what point they would need to be pre-charged or they will spark to hell and back again!

I hope that the question is understandable, I find it hard to explain in general so I'm sorry if it;'s a bit fluffy!

 

[MiSh]

Is there some reason you don't want to use the automatic pre-charge resister built into the SOK 48v battery?

Disregard. I see Current Connected now has a manual pre-charge for some reason. Maybe for the newer stripped down SOK battery?

 

[Nightguest]

Is there some reason you don't want to use the automatic pre-charge resister built into the SOK 48v battery?

Honestly speaking, I forgot about it.

When I put the system together the first time, I specifically wanted to use the resistor method as I felt a bit uneasy with the pre-charge circuit (that was purely in my own head, I just like to have things in my hands, so to speak).

However now that I've used this system a bit, I know it's not wired badly, etc, yeah that's perfect! So thanks so much for the reminder of that feature!

That said, I am still rather curious about the general question, is it generally recommended to always pre-charge after turning the system off (properly off), even if it's for say a minute, or is the process needed only if you have everything off for a longer period?

 

[rodrick]

Any time you restart the system its probably a good idea to just pre charge to be safe