Environmental factors will likely increase charge time.
How long to charge 12v battery with 100w solar panel.
The first thing you have to do it to compute for the ampere rating of the solar panel by following the equation below.
How long to charge 12v battery with 100 watt solar panel.
Let s say you want to compute for the average charging time of a system with a 12v battery with 50 ah capacity and a 15 watts solar panel.
10 watt 18 volt solar panel charging a 12v 10 amp hour lead acid battery 120 wh from 50 full to full time 60wh x 2 10 watts 12 hours.
To get the most effective charging by a solar panel you have to maximize the amount of current by keeping the board pointed directly to the sun.
Some quick rules for estimation.
In most cases a solar panel that produces 1 amp of current takes 5 8 hours or more depending on the size of a battery.