fitting inverter to battery bank

[happy campers]

hi, havent been on here much lately as we've been getting our camper, Wolfie, all sorted these last few months

all we've got left to do now is attach the solar panels and the inverter to the battery bank, but the more we read on the net, the more problematic it sounds!

we have 2 x 100 watt solar panels, linked to each other.....a 5000/10,000 pure sine inverter and a battery bank that has a 300 Ah battery,plus a 65Ah and an 85Ah all connected together....we managed that bit lol! havent been able to work out which wattage cable should be used to attach inverter to battery bank ....ie 50mm? 20mm?

however, when we've looked on tinternet how to connect the inverter, it talks about isolation switches, shunts, using 250watt in-line fuses, and scary warnings that inverters are renowned for starting fires if all these other things arent used :danger: or is it just scaremongering to make people pay someone to fit them??

also is the standard cable that came attached to the solar panels, the ones with the crocodile clips attached, ok to be attached to the battery bank? it also has a regulator attached

surely some of you guys have fitted these and have managed to live to tell the tale lol!! so any help would be really appreciated.....the simpler you can explain it, the better :cheers:

 

[Deleted member 3011]

a 5000/10,000 pure sine inverter

This IS the scary bit. 5000Watt (presumably) is about 500Amps flowing around the cabling and that needs some fairly careful consideration to ensure that the whole system is properly protected against overloads and shorts. Also a

a 300 Ah battery,plus a 65Ah and an 85Ah all connected together

all connected together again raises major problems of getting voltage drops to an absolute minimum and having the cables arranged to make sure the batteries share the load properly - as much as such disparate battery capacities allow.

we managed that bit lol!

Hmmmm!

Then there is

also is the standard cable that came attached to the solar panels, the ones with the crocodile clips attached, ok to be attached to the battery bank? it also has a regulator attached

which has singular and plural conflicts that make it hard to work out whether you have one regulator or two - but disregarding that, this sort of setup really needs something more sophisticated than crocodile clips to hook it together on a permanent basis.. Perhaps it is one of those portable folding panel setups, so there is one regulator and indeed has crocodile clips. If this is going to be a permanent situation, I would suggest pulling the regulator off the back of the panel and mounting it adjacent to your batteries to avoid high voltage drops along the usually skinny cables causing chronic undercharging of the batteries.

Regardless of the details, you already have the required information about what sort of protection IS required and I doubt whether any responsible person is going to advise you to completely ignore standard safe procedures for hooking up such a large inverter to a strange battery setup.

Then again, if you are only going to power a 40Watt TV and a couple of phone chargers, why the huge inverter - or is there a decimal point missing or extra zero in there somewhere.

If you ever do use the full capabilities of that inverter, the batteries will be just about dead flat in 15 minutes, although more likely, the inverter will trip out because of undervoltage in seconds to minutes depending how good your cabling is.

 

[AndyC]

Regardless of the details, you already have the required information about what sort of protection IS required and I doubt whether any responsible person is going to advise you to completely ignore standard safe procedures for hooking up such a large inverter to a strange battery setup.

Quite so! Personally I would not be happy to give any advice about connecting up such a system without actually seeing it...

What I would say to the OP is that whatever you do, fit an appropriately rated isolator switch to the main +ve cable supplying the inverter. I've seen a few cases where large inverters have caught fire and the owners have had no way to shut off the supply to them. Fusing doesn't help in this case, as the size of fuse needed (over 500A) may not blow under certain fault conditions that would be sufficient to start a fire.

AndyC