Mixing solar

Dirtpig wrote:
I don't think this cheap ZAMP controller has ability to adjust voltage setting for charging. I will remove it.

I have decided that I will buy a bit lower cost charge controller, still a blue sky 3 stage, but a PWM instead of mppt. Called an sc30. I also ordered a 2nd 140watt Kyocera panel. Identical to the one I already have. So I will have 280 watts. I chose the PWM because it was $150 cheaper and the research I read seemed to show that mppt wasn't as good with 17volt panels and may not be worth it.

Nice to see someone do there "homework" and make an informed choice.
Good job!! :B

You have a good plan.

I don't think this cheap ZAMP controller has ability to adjust voltage setting for charging. I will remove it.

I have decided that I will buy a bit lower cost charge controller, still a blue sky 3 stage, but a PWM instead of mppt. Called an sc30. I also ordered a 2nd 140watt Kyocera panel. Identical to the one I already have. So I will have 280 watts. I chose the PWM because it was $150 cheaper and the research I read seemed to show that mppt wasn't as good with 17volt panels and may not be worth it.

You can have as many separate charge controllers as you want. You would want them all set to roughly the same voltage parameters.
If you are hooking panels in parallel they need to have roughly the same Vmp. If you're hooking them in series they need to have roughly the same Imp.
I suspect you could put all of your in parallel on the new Blue Sky charge controller.

I guess I should point out a main concern for me going to extra panels is because I am over doubling batt capacity. I am moving from 2 group 24 12volts to 4 Trojan t105 6volts. Mainly for wintertime camping where this solar will be useless but I don't think 140 watt will do much for all this capacity even in summer?

Thanks for the replies. They put the little 20watt on top of the ac unit. So its not taking up space. My biggest concern is do these small panels rob charging potential from the big 140watt.. Smkettner making me feel better about using all 3 for a total of 220watts. I am also considering buying a second Kyocera 140 watt panel instead of all this Micky mousing with the 2 little ones. So regardless I should get rid of this puny 7amp no name controller and use the 30amp blue sky?

I would remove the 20 watt as it mostly just takes up space. If you must keep the little guy, all the 12v panels will play just fine together in parallel. May or may not add any power through an MPPT. Will not take away anything from the larger panels.

I have used multiple controllers on a bank. They worked fine as long as both were set to the same voltages.

As far as mixing panels on a MPPT controller, that 20w panel isn't enough power to worry about even messing with in my opinion. You really need to match up the panels on a MPPT controller because it has to find the sweet spot in the array voltage and mismatched panels make it hard for it to do it.

Not a solar expert by any means but have been reading up on it. Seems to me you can only have one controller feeding your battery bank--because the whole point is to manage the battery charging. Having 2 independent inputs seems like a good way to trash your batteries.

You could probably run all the panels, including the cheapo, into the good controller.