Thor Forums - View Single Post - Lithium Batteries and Factory Charge Controller

Jumbo Mug · 10-02-2020, 09:25 PM

Quote:

Originally Posted by DavidEM

Mike:

Your solar installation sounds good but with one big problem and a couple of questions and some possible problems:

The problem:

The beefier 8 gauge wire you installed is only good to 80 amps and the fuse/breaker protecting it should be no bigger than that value. Also the amps from the controller can be as high as 110, so you need #4 wire to carry that much current and stay within the breaker's rating. It will also help with voltage drop which will probably be too high for best results with the
8 gauge wire.

The questions:

I am a little confused about your statement that parallel wiring of the panels increases the voltage. I think you meant series wiring increases the voltage.

In one place you say 1320 watts of panels (a huge amount btw) and in another you say 33 watts each and in another 330 watts. I am sure you meant 330 watts each. If that is correct then those are usually 24V nominal panels and their Voc the maximum voltage that they can produce is about 34. If you wired them all in series then that is 128 volts which is ok for the charge controller but requires high voltage wiring techniques which I doubt you have. I am not sure that is a real safety problem but it doesn't meet electrical codes. At the very least put some tape over the panel input connections to the controller to keep prying fingers away.

Also the maximum current output of the controller that might be expected is 1320/12=110 amps, a little more than the Victron's rating. You will only see this current when the batteries are very low requiring low voltage and high current to charge them.

I am attaching a short article about How Solar Controllers Work which covers most of these issues.

David

Hi David,

You’re right I meant series not parallel. The 330w panels are vmp 34.6v and imp 9.55a (details here: https://www.solar-electric.com/rec-s...-module.html); 33 was a typo.

I’ll look into the wiring but I’m sure 4 gauge won’t work because NAWS told me the biggest the Victron will take is 6. Just looked and the 8 gauge is rated for 600v.

I’ll call NAWS on Monday and go over the wiring and breaker but they spec’ed the breaker at 150a and also ask about the high voltage wiring to mentioned.

Thanks for the input.

Mike