When is a charge controller needed ?

groar · 08-12-09, 04:45 PM

I haven't found cheap/free 2nd hand solar panels yet, but thanks to Gascort I'm thinking about building my own... then I'm imagining where to put put these cells and so how to design the shape of the panels...

One question I have : when is a charge controller needed ?

My current cases are :

a 1.5W panel connected to the car's battery, itself connected to the alternator.
the old car battery in the trunk is connected to a 13W solar panel and this feeds my GPS navigator, a rear view camera and occasionally a computer.

I think that in both cases, the panels are too weak to damage the 50Ah 12V batteries. From which wattage does a charge controller is needed ?

Denis.

08-12-09, 04:45 PM	#1
groar X-Frenchy: very Join Date: Sep 2008 Location: Toulouse, France Posts: 153 Thanks: 0 Thanked 2 Times in 2 Posts	When is a charge controller needed ? I haven't found cheap/free 2nd hand solar panels yet, but thanks to Gascort I'm thinking about building my own... then I'm imagining where to put put these cells and so how to design the shape of the panels... One question I have : when is a charge controller needed ? My current cases are : a 1.5W panel connected to the car's battery, itself connected to the alternator. the old car battery in the trunk is connected to a 13W solar panel and this feeds my GPS navigator, a rear view camera and occasionally a computer. I think that in both cases, the panels are too weak to damage the 50Ah 12V batteries. From which wattage does a charge controller is needed ? Denis. __________________ Earth absorbs 1.8 t CO2/head/yr, while a French generates 6.2 t CO2/yr To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. kg saved 06/08-08/09: 1816.9+382.9 (ecodriving / 1420mi not driven) = 2199.8 To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. (2.66 kg/l diesel) kg saved by 3kWc photo-voltaic solar panels : 187 kg/yr To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. (59.1 g/kWh) Radioactive wastes saved by 3kWc photo-voltaic solar panels : Long life (>100,000 years) : 2.85 g/yr (0.9 mg/kWh) Short life (<300 years) : 31.7 g/yr (10.0 mg/kWh) Based upon "official" French figures...