Simple solar wiring questions

[Cubey]

I bought a 30A solar charger (the same on HF sells for $80) though I paid $32 on ebay for it, new. This will be going on a 200W (2x 100W panel) system so it's plenty large enough for my needs.

Question 1: I see that charge controllers have an output hookup for lights or whatever... but as I understand it, you don't even HAVE to use that hookup. You can just hook your 12v up directly to the battery and have everything work properly, correct?

Reviews I read on the controller on HF's site says you can't put more than 15W on the controller's "load" or it'll blow the controller. Since everything is already set up to run off of the batteries, I may as well leave that be and run the controller's battery connection to the batteries and run loads from the batteries directly as was originally intended.

I know it won't give the benefit of over-discharge protection but I can monitor that myself just fine by wiring in a digital volt meter.

My Class B van already has a complete 12v system with a house fuse panel that comes off of the house batteries (and a huge positive cable going to the Onan AJ 2.7KW generator.. a charging cable for when the generator is in use?).

Question 2: I also have a good working RV converter for 12v power and battery charging while on the grid. Will I need to separate the solar controller from the battery when I have my RV converter running? I would assume the controller should be okay having a charging current on the battery connection poles, but you never know.

A simple toggle switch would do the trick, but I'd have to be sure I flip it, if that's required to keep from blowing the controller.

[Ed-Sommers]

#1 Right
#2 No

My thoughts . . . . I believe that controller, as I remember from others posts, is just about worthless as it is not a three stage controller, for what it's worth.

A GOOD three stage, MPPT, controller in a small size is really not that much money, and you batteries will thank you for it.

Ed

[Cubey]

What's the diffference between what I bought and a MPPT controller?

For panels, I have my eye on USA made Renogy solar panels. They are $35 per panel higher than Korean made ones (which I have been told are the worst for quality) so maybe the Renogy ones will be higher quality.

Edit: I found this video (below) that seems to show that MPPT works better than PWM... .. No harm done, I'll just relist it on ebay since the seller does no returns, or keep it as an emergency spare if an MPPT one goes out on me while off the grid)

http://www.youtube.com/watch?v=4yvyoxzgdIc

[Cubey]

I think I am going to get a little fancy and install one of these between the panel and controller. I guess I could also install one between the battery and house fuse panel so I can see what kind of load I am pulling off of the batteries.

Digital LCD 60V 100A Balance Voltage Battery Power Analyzer Watt Meter Checker | eBay

The meter can be had for a few bucks less than that listing, but that listing shows it turned on.

(WindyNation on amazon wants $45 for the same thing.. and they are apparently selling for that.. LOL)

[jackfish]

Any meter without a shunt connection with not give an accurate reading of SOC.

[Cubey]

Originally Posted by jackfish

Any meter without a shunt connection with not give an accurate reading of SOC.

Shunts are cheap and easy to add in. What's SOC stand for?

[Dunner]

Battery State Of Charge.

https://www.google.com/search?client...iw=931&bih=548

A good read.

http://www.solar-electric.com/deep-c...ttery-faq.html

[Cubey]

Thanks. My batteries aren't the best.

One is a DieHard Group 27 I bought new in 2010 and barely ever used in the travel trailer I had. I pulled it (and the converter) before I sold it since I knew my van needed them.

The other is a cheap Wal-Mart (Group 24?) that was in the van when I got it, but a little bit newer.

I'll make due with them until they go bad.. then I may switch to Trojan 6V ones.

[Dunner]

Or... get some from Sam's or Costco and save a few $s.

[Cubey]

They won't be as good as Trojans.