House/solar battery opinions
My current battery space is 20"L x 14"w x 10"H Going solar, and want to packs as much AH in there as I can (reasonably). Currently looking at 250 - 300. Price is not THE deciding factor, unless ...
Forum Discussion
seraphim;
Hang in there. Understanding daily battery draws is trivial compared to understanding solar recharging.
This concept of how to connect panels/modules takes a while to grasp.
Here are two runs of the MS string calculator.
1. 102W 24V modules
2. 102W 12V modules
The modules I found are 102W, but one is 12V and the other is 24V. That is close enough for discussion.
Note the min Vmps for the 816W squares. I set the min temp to 15C to allow the extra 2W to work here.
With the 24V modules there is only one choice, 4 strings of 2 series modules each giving a 48V nominal system. Mouse over the 816 cell. The actual min Vmp is 53V+. If you size wire for 48V, you will always have adequate wiring for best Watts to arrive at the controller. There will always be losses no matter what size wire due to resistance. There are wire sizing websites to help choose wire size.
For the 12V modules there are two choices. You want the 2 strings of 4 series modules = 48V because you will always have 55V+ and 48V sized wiring will always be adequate. The other 4 x 2 array needs 24V wiring which will be larger and not necessary.
The final answer is that either 12V or 24V panels, or any Voltage, can be configured to achieve useful arrays. They do have to fit the roof real estate, though.
HTH;
John
Hang in there. Understanding daily battery draws is trivial compared to understanding solar recharging.
This concept of how to connect panels/modules takes a while to grasp.
Here are two runs of the MS string calculator.
1. 102W 24V modules
2. 102W 12V modules
The modules I found are 102W, but one is 12V and the other is 24V. That is close enough for discussion.
Note the min Vmps for the 816W squares. I set the min temp to 15C to allow the extra 2W to work here.
With the 24V modules there is only one choice, 4 strings of 2 series modules each giving a 48V nominal system. Mouse over the 816 cell. The actual min Vmp is 53V+. If you size wire for 48V, you will always have adequate wiring for best Watts to arrive at the controller. There will always be losses no matter what size wire due to resistance. There are wire sizing websites to help choose wire size.
For the 12V modules there are two choices. You want the 2 strings of 4 series modules = 48V because you will always have 55V+ and 48V sized wiring will always be adequate. The other 4 x 2 array needs 24V wiring which will be larger and not necessary.
The final answer is that either 12V or 24V panels, or any Voltage, can be configured to achieve useful arrays. They do have to fit the roof real estate, though.
HTH;
John
