timthecarguy Report post Posted February 13, 2015 Most RVers are buying solar systems that are not doing what they want or expect. If you are buying a 10 or 150 watt solar system and are running lead acid or agm batteries, the push back or resistance from your battery makes the charging from your panels almost nothing. If you are going to spend the money and you are going to count on the power for boondocking make sure you get something that is going to work. One thing for sure solar is not cheap but a good system pays for itself. Get a good system and you will be happier and further ahead. I have been researching lithium batteries and they are way better and well worth the money. Tim Share this post Link to post Share on other sites
desertdeals69 Report post Posted February 28, 2015 If considering solar I would start with a minimum of 600 watts and a MPPT controller which is 98% efficient. With good sunlight mine will charge at 40 amps. Share this post Link to post Share on other sites
sergeantsue Report post Posted July 17, 2015 Is there a truly definitive technical article on this? This "Push back" resistance is understandable, but how does one measure that? I am not sure of the efficiency of our system, or how much it is actually charging our batteries. I have a 180 watt Astropower panel and a Trace C40, 40 amp controller for 12/24/48 VDC and four lead acid batteries that are five years old, but show no sign of failing (they are on battery conditioner when we are not on the road). Switching to LED lights appears to have really helped. Share this post Link to post Share on other sites
dickandlois Report post Posted July 17, 2015 The internal resistance of all batteries changes as they age. This link will offer some insight into this issue and covers a number of different battery chemistries. http://batteryuniversity.com/learn/article/rising_internal_resistance Rich. Share this post Link to post Share on other sites
