Hi! I'm setting up a power system for my camper so I can full time in it. My energy budget comes out to 500Wh per day, of which about half is needed off-peak/at night. I have a 80Ah 12V lead acid deep cycle on there now, so using the 50% discharge rule that's about 500Wh of usable storage. I'd prefer more but don't have room for anything more than a group 24 or 27 battery. I'm thinking I should oversize the panels so that they can still perform ok on overcast days or when camped in the forest, but have not been able to find much concrete information as far as what kind of factor is necessary for these situations.
1) Is there any way to improve battery capacity within a group 24/27 form factor by upgrading to lithium? To some extent I can shift usage by getting extra batteries for my devices and charge those when it's sunny, but it would be even better to have a 2 day energy supply built in to the camper to smooth out the curve.
2) Looking at panels, ebay has 32-cell flexible mono panels for about $95 and 36-cell panels for about $115. I was also considering unisolar panels because they are supposedly shade tolerant but I don't have the space for such a long panel (my area constraint is a 61"x85" surface plus a 52"x85" surface). Let's frame the problem this way: I want 500Wh on an overcast day or in a forest with mixed sun/shade. Which panel/converter combo would you choose to satisfy that requirement while minimizing cost?
There's a $475 kit on ebay with 400W in 36-cell panels, a barebones 30A controller, and an MC4 cable and 4-way splitter. Might this be up to the task, or are these panels not shade tolerant enough?
I'm an electrical engineer so I'm not afraid of tinkering if that gets me the best solution. I see some people have cut and rewired the unisolar panels so that is an option if that's the best way forward.
1) Is there any way to improve battery capacity within a group 24/27 form factor by upgrading to lithium? To some extent I can shift usage by getting extra batteries for my devices and charge those when it's sunny, but it would be even better to have a 2 day energy supply built in to the camper to smooth out the curve.
2) Looking at panels, ebay has 32-cell flexible mono panels for about $95 and 36-cell panels for about $115. I was also considering unisolar panels because they are supposedly shade tolerant but I don't have the space for such a long panel (my area constraint is a 61"x85" surface plus a 52"x85" surface). Let's frame the problem this way: I want 500Wh on an overcast day or in a forest with mixed sun/shade. Which panel/converter combo would you choose to satisfy that requirement while minimizing cost?
There's a $475 kit on ebay with 400W in 36-cell panels, a barebones 30A controller, and an MC4 cable and 4-way splitter. Might this be up to the task, or are these panels not shade tolerant enough?
I'm an electrical engineer so I'm not afraid of tinkering if that gets me the best solution. I see some people have cut and rewired the unisolar panels so that is an option if that's the best way forward.
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