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2*400w Solar with 2*12v 260AH Batteries... is a SmartSolar MPPT 150/60 Tr the right choice?

I realize this is probably constantly asked, so apologies. I'm constructing my first solar system for my van and have two 400w Panels (data sheet here): https://www.tradezone.com.au//media/custom/upload/File-1582850469.pdf

I'm still working out whether to do series or parallel for the panels (depends on space as one will be covered by at least half, but should still have half showing and my understanding is that these panels will continue to work. So series will probably be the way to go.

And I'm purchasing two 260ah 12v batteries by Fullriver: http://www.fullriver.com/products/admin/upfile/DC260-12.pdf

I've done the calculator on the website here, and just wanted to make sure that the SmartSolar MPPT 150/60 Tr that is recommended is correct? As somewhere I read you're supposed to take the panels total watts divided by your batteries volts and plus on 25% to get size of the controller. Just want to double check this as spending money and don't want to purchase the incorrect controller for my system/damage my system haha!


Cheers!

MPPT Controllers
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maxxpwr answered ·

Hello, so it's best to work from your batteries backward, if you are using 2x 260ah batteries (connected in parralel?) then you need to be able to effectively charge 520ah, battery charging is most efficient when charged at 20% of rating total and not less than 10%, so at a bare minimum you must be able to reliably charge the batts at 52 amps to get a full charge, preferably 104 amps, which is why the calculator is throwing that charger at you. Now to get the 52 amps you need your panels will need to be sized accordingly, 52a x 14.4v is 748.8w, 800w of panels with 1 half shaded ain't going to cut it sorry, best practice is to oversize by 30% and that's for full sun applications so I'd go a full 50% for you so unless you can muster and additional 400w on top of what you've got, or plan to boost charge by mains or generator then your batts won't have anywhere near the life you want. Hope this helps

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