Solar and sla batteries.

[ShreddinPB]

Hey guys.. I am putting together some panels for my camp at burning man.. I have 2 home made bucket swamp coolers that take about 2.5Ah each.

I got 3 of these panels
http://www.amazon.com/gp/product/B00DCDQKII/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

and this charge controller
http://www.amazon.com/gp/product/B008I0IZ7O/ref=oh_details_o03_s00_i01?ie=UTF8&psc=1

I have a bunch of SLA batteries that I would like to use to store the energy gathered by the array. My question is, if the SLA batteries are not all the same Ah rating, is that bad?
I have 2x 7Ah, 2x9Ah, 2x12Ah and 1 x 17Ah. Can those all just be wired to parallel directly to the charge controller?
Can I then just hook that same parallel array to my swamp coolers?



If I can not use them like this.. I also have 2 55Ah SLA batteries.. can I do the same type of thing? those 2 in parallel with the charge controller and swamp coolers all plugged in at the same time?
thanks!

 

[John in CR]

Yes, you can parallel SLA batteries of the same voltage without issue.

Unless need power for something else, I'd just run the swamp coolers straight off the panels and do without batteries.

 

[ShreddinPB]

Yes, you can parallel SLA batteries of the same voltage without issue.

Unless need power for something else, I'd just run the swamp coolers straight off the panels and do without batteries.

So it doesnt matter that they are all different Ah ratings?

I want to have them all there so they can take a charge also. I have other electronics I can charge with the batteries also

 

[Hwy89]

For a temporary set up go ahead and parallel them but for long term use it is never a good idea to pair up mismatched batteries. What happens is that the current will find the battery with the lowest internal resistence and overcharge it while starving the rest if the bank. I go so far as buying sets with matched lot numbers and date codes for my solar storage.
Another idea that you might consider is to pair up like batteries into sets and rotate them through charge cycles.

 

[Hwy89]

Its not the greatest idea to connect those different voltage batteries together, you should be running a solenoid between them anyway

He never said the batteries were different voltages. Where did you get that from? Please elaborate on the purpose of putting a solenoid between parallel batteries.

 

[edcastrovalley]

I have done the same thing with flooded lead acid batteries with good results. It works very well. The batteries will maintain a voltage equalibrium and all be at the same voltage no matter their size (amphour capacity) by drawing more current for the larger batteries and less for the smaller ones. You only have to make sure the batteries all have the same voltage rating. When you first hook them up make sure the voltage is somewhat close to each other, say within a few tenths of a volt, other otherwise the stronger, higher voltage battery will send a high current to the lower voltage batteries overheating your battery wiring.