Comments on: CAN A 18W SOLAR PANEL CHARGE TWO CAR BATTERIES? I AM PLANNING GOING SOLAR, THANKS? http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/ blog Thu, 09 Feb 2012 01:51:38 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: MT C http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/comment-page-1/#comment-656 MT C Tue, 09 Feb 2010 12:06:12 +0000 http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/#comment-656 In short you need to read ratings and ask manufactures. There are lots of ways to figure power using current, voltage and resistance. The voltage has to be around 14 to 15 volts to charge a 12 volt battery and if you only have, say, less than one amp available, it could take days/weeks/more to charge the batteries. On the surface without knowing details, it doesn't sound feasible and if it is, functionality should be considered, if the battery will be discharged in four hours and it takes two days to charge it, is that really something you want. You need to seriously investigate the system you are planning to build/use. MT C In short you need to read ratings and ask manufactures. There are lots of ways to figure power using current, voltage and resistance. The voltage has to be around 14 to 15 volts to charge a 12 volt battery and if you only have, say, less than one amp available, it could take days/weeks/more to charge the batteries. On the surface without knowing details, it doesn’t sound feasible and if it is, functionality should be considered, if the battery will be discharged in four hours and it takes two days to charge it, is that really something you want. You need to seriously investigate the system you are planning to build/use.

MT C

]]> By: Chance C http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/comment-page-1/#comment-655 Chance C Tue, 09 Feb 2010 11:25:13 +0000 http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/#comment-655 why dont you just let your car charge the batteries??? why dont you just let your car charge the batteries???

]]> By: Keith http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/comment-page-1/#comment-654 Keith Tue, 09 Feb 2010 10:35:37 +0000 http://sludgie.net/276/can-a-18w-solar-panel-charge-two-car-batteries-i-am-planning-going-solar-thanks/#comment-654 The car batteries will charge fine but slow, if the panels output is over the 12.5v that car batteries usually sit at. Also, the panels voltage output may get loaded down by the car batteries and not get charged. Cars charging systems usually put out 14.1 to 14.4v to keep the battery charged. The 800 watt power inverter may be basically worthless with only 18w going into it. The car batteries will charge fine but slow, if the panels output is over the 12.5v that car batteries usually sit at. Also, the panels voltage output may get loaded down by the car batteries and not get charged. Cars charging systems usually put out 14.1 to 14.4v to keep the battery charged. The 800 watt power inverter may be basically worthless with only 18w going into it.

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