[Vwdiesel] solar auto chargers for travel use and of course happy holidays

[Roger Brown]

raymond greeley wrote:
> Hello all, I am planning to van camp most of january and think it wise i set 
> up a secondary electrical
> system (2nd 12 vt battery) that charges during auto operation. During 
> extended times when i am
> parked I was thinking that a solar charger would do the trick. My question 
> is, is there a level
> milliamp production that a panel should have to mostly charge this second 
> battery in 12 hrs.
> Also,, i would like it to be smaller as i plan to bicycle tour with it (to 
> charge lites, phone, camera,  etc.)
> alleletronics.com had individule moduals that i could string together to get 
> 12vlts + and of course
> harbor frt has premade options. thanks and happy holidays, ray

You would need to estimate the current draw of the various accessories and the time each is used to 
determine the amount of energy drawn from the battery.  To do so, multiply the draw of each item in 
amps by the number of hours run and add them up for a total Amp Hour (AH) figure.  Then reverse the 
calculations to determine how much current the solar panel needs to put out to charge the battery 
back up.  I think the rule of thumb is to add 40% to that for the recharging losses, so if you 
figure you need 10 AH for the accessories, you need 14 AH to recharge the battery, or 1.2 amps for 
12 hours for a rough estimate.  I think some of the solar panel web sites probably have better 
calculations accounting for sun angle and intensity changes during the day.

-- 
    Roger