#98363  by Gingernutty
 Wed Aug 19, 2015 7:49 pm
Neddy wrote:"And if we had a choice at this time, would it be preferable to have 3 mppt controllers , or no mppt controllers?"

(1) Buy another MPPT controller giving them one each. This is the best option if one panel is tilted and one is not, or if one panel is more likely to be shaded than the other.

Thanks, Neville - any recommendations re brands?
 #98369  by Neddy
 Wed Aug 19, 2015 9:10 pm
Yes. Three discrete solar panels linked to three separate controllers, connected (in parallel) to the same battery.

MorningStar is perhaps the top brand, but their controllers do tend to be more expensive.

Chinese controllers are a bit of a lottery. Some are quite good, others absolute junk - and you can't tell the difference from the provided data.
 #98373  by Neddy
 Wed Aug 19, 2015 9:51 pm
Reputable solar controller brands are usually very conservatively rated and "20 amp" controllers would be all that you needed. If the controllers really did have a 20 amp limit, then it would be prudent for you to go up to a 30 amp model.

No fuses are required on the input side of such an install. Switches are optional, but nice to have.

That photo of 15 MorningStar controllers in parallel would be good to show your auto-electrician!
 #98415  by Gingernutty
 Thu Aug 20, 2015 6:25 pm
Thanks for all your advice, Neville. Our current thinking is to try and get the seller to allow us to return the 40a controller and get two 20a Tracer controllers instead, for the two new panels, and then each panel can have its own controller. Then we just need to instruct the auto-electrician how to wire it up.
 #98417  by Neddy
 Thu Aug 20, 2015 7:28 pm
Sounds good. Wiring up such a system is quite simple and you could do it all yourself if you wanted to.

A tentative suggestion. This could be "A Bridge Too Far" for you, but a really interesting thing would be to connect the output of each controller to the battery through an ammeter eg
http://www.aliexpress.com/item/DC-0-30A ... 63172.html
Three of these would cost very little and you could then see exactly what each individual panel was contributing at any time. What do you think?

 #98418  by Gingernutty
 Thu Aug 20, 2015 7:57 pm
We were thinking we would get the remotes for the Tracers, which I think would show us the amps, but it is a good idea to put something like that in for the old panel and controller. I am going to be quite curious now about how this all pans out. Hopefully it won't take us tooo long to get it in place. Thanks again for your advice.
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