Reply
Wed 28 Aug, 2013 01:59 pm
You might have seen my other post regarding battery consumption in another post, this expands on that somewhat but isn't required reading.
I'll explain the scenario. When we go camping we would like to power lights with deep cycle battery and charge cell phones, misc small stuff, maybe run a radio.
What I would like to know at what rate a 15watt solar panel (the inexpensive harbor freight ones inparticular) charges the 85ah deep cycle battery. I am leaning towards either increasing the recharge rate (more panels) or just buy another battery to cover the weekends use.
As a rule of thumb a panel rating of 15 watts delivers about 1 AH per hour of direct sunlight, so around 85 hours; however you lose around 30% in charging so make that 110 or so hours; so if you were wisely only discharging to 20% capacity, around 90 hours, let's say around 4 days, except the sun doesn't shine at night, so if you had 12 hours direct bright sunlight each day, around a week.
Based on the previous forum thread , I will use about 27% of my 85ah battery per evening. And based on 1ah per hour of recharging, I should theoretically add about 8 amp hour back per 15 watt panel (8-10 hours of sunlight).
So if I add 3 15 watt panels (45watts total) I should basically recharge it completely, correct?
Stumble It!
Tweet This
Bookmark on Delicious
Share on Facebook
Share on MySpace