hotponyshoes
Member
- Messages
- 6,411
- Location
- Somerset. Uk
I have fitted a fair few panels to stuff before but i'm working on a boat at the moment and this is not quite the same as normal..
Due to the mounting location I can fit a maximium of 2x50w panels.
About 1/3 of each panel is mounted under a radar arch (so in the shade)
I got a pair of ETFE (low profile, semi flexible type) as the research I did made me think these were less prone to suffering if partially shaded. Having got them sat in place and tested them I am very impressed.
Im measuering about 20v from each panel in the open and this is only dropping by .5v when installed under the shade. In fact, I can cover over half of the exposed panel and I still get 18.5v or so.
My original plan (I was expecting the shaded area to cause much more drop than this) was to wire both panels in series and send to a mppt/dc step-down charge controller.
After testing I don't think this is required and I think I can just connect the panels in parrallel (so i'm still ok if one fails) and run to a pwm controller.
The boat only has one battery (standard car type, 110ah or so)
I want to add a second battery that is completly indpendent as a back up.
I am planning to fit 2 isolators, one on each battery so I would only turn one on at the start of the day and then if i do happen to drain it I can turn it off and turn on the second.
I had planned to fit a solar charge controller with dual charging outputs and just randomly select a battery each trip so both of them get used/worn out evenly but I had forgotten about using the engine output to charge as well.
The actual question: I'm not sure if it's best to fit a twin output charge controller or fit a single output and send it to a battery designated as primary then fit a smart charge relay between the primary and reserve battery so the engine will charge both when that's running.
When not in use the only power drain will be an automatic bilge pump which (hopefully!) won't be running very often at all but I will need to choose one battery to connect this up to.
Due to the mounting location I can fit a maximium of 2x50w panels.
About 1/3 of each panel is mounted under a radar arch (so in the shade)
I got a pair of ETFE (low profile, semi flexible type) as the research I did made me think these were less prone to suffering if partially shaded. Having got them sat in place and tested them I am very impressed.
Im measuering about 20v from each panel in the open and this is only dropping by .5v when installed under the shade. In fact, I can cover over half of the exposed panel and I still get 18.5v or so.
My original plan (I was expecting the shaded area to cause much more drop than this) was to wire both panels in series and send to a mppt/dc step-down charge controller.
After testing I don't think this is required and I think I can just connect the panels in parrallel (so i'm still ok if one fails) and run to a pwm controller.
The boat only has one battery (standard car type, 110ah or so)
I want to add a second battery that is completly indpendent as a back up.
I am planning to fit 2 isolators, one on each battery so I would only turn one on at the start of the day and then if i do happen to drain it I can turn it off and turn on the second.
I had planned to fit a solar charge controller with dual charging outputs and just randomly select a battery each trip so both of them get used/worn out evenly but I had forgotten about using the engine output to charge as well.
The actual question: I'm not sure if it's best to fit a twin output charge controller or fit a single output and send it to a battery designated as primary then fit a smart charge relay between the primary and reserve battery so the engine will charge both when that's running.
When not in use the only power drain will be an automatic bilge pump which (hopefully!) won't be running very often at all but I will need to choose one battery to connect this up to.