20w coleman solar panel
Hello, I have just purchased a 20w coleman solar panel and a charge controller. I was wondering if there are some things i should know before i chuck this on the roof? Im going to just screw it to ...
Forum Discussion
Let’s say you want to off-road and depend solely on your solar panel.
Well, there is nothing mystical here, at full power (full sun) you solar panel will deliver 20 watts or about 1 .6 amps. So if you run your water pump at 3 amps for 5 minutes I will take about 10 minute to recharge.
Let’s say you have four hours a day of full sun and at total of 3 hours of partial sun, such as shade and early or late in the day sun, at only 10 watts from your solar panel. Then you will have generated 4 x 20 = 80 watts hours plus 3 x 10 =30 watts hours for a total of 110 watts hours of sun power that day. This is not very much power.
The question is what are you going to do with this power. In an idea world you could run a 25 watt light for about 4 hours or your 36 watt water pump for 3 hours etc.
Unfortunately theory hit the cold light of reality and other factors come into play.
• The systems are only about 80% efficient so you really have only about 90 watts hours to play with.
• You are dependent on tomorrow’s sun to make up for this evening usage.
• You may have various phantom loads that draw power that you have to account for.
On the plus side, if your water pump start and stops totals 1 hr of time and your total lamp usage is about two hours you, are within your limit and you battery will be recharged; if the next day is sunny.
The question in your case is whether it is worth the effort to mount the system or not. Keep in mind that a shady camp spot will cut into you solar output, unless you can move the panel into the sun during the day.
Some battery dependent people buy a bigger solar panel and switch to LED replacement lamps.
When my wife and I are battery bound for a few days we drag out the camping lanterns and othet gear to minimize our battery load until we can get shore power.
Well, there is nothing mystical here, at full power (full sun) you solar panel will deliver 20 watts or about 1 .6 amps. So if you run your water pump at 3 amps for 5 minutes I will take about 10 minute to recharge.
Let’s say you have four hours a day of full sun and at total of 3 hours of partial sun, such as shade and early or late in the day sun, at only 10 watts from your solar panel. Then you will have generated 4 x 20 = 80 watts hours plus 3 x 10 =30 watts hours for a total of 110 watts hours of sun power that day. This is not very much power.
The question is what are you going to do with this power. In an idea world you could run a 25 watt light for about 4 hours or your 36 watt water pump for 3 hours etc.
Unfortunately theory hit the cold light of reality and other factors come into play.
• The systems are only about 80% efficient so you really have only about 90 watts hours to play with.
• You are dependent on tomorrow’s sun to make up for this evening usage.
• You may have various phantom loads that draw power that you have to account for.
On the plus side, if your water pump start and stops totals 1 hr of time and your total lamp usage is about two hours you, are within your limit and you battery will be recharged; if the next day is sunny.
The question in your case is whether it is worth the effort to mount the system or not. Keep in mind that a shady camp spot will cut into you solar output, unless you can move the panel into the sun during the day.
Some battery dependent people buy a bigger solar panel and switch to LED replacement lamps.
When my wife and I are battery bound for a few days we drag out the camping lanterns and othet gear to minimize our battery load until we can get shore power.
