Hi all new guy here, i was looking in to getting some solar installed on my camper van just for powering laptop and charging phone etc.. nothing big. i have seen a 12v 20a panel which i was guessing would need a Solar Panel Charge Controller then connected to the leisure battery then a power inverter. has any one done this sort off thing before could give me advice and tips on the best way todo it etc.. would be great thanks guys
Solar power for campers
- Thread starter johnnyuk
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As long as it isn't over 80w I think you can connect it straight to the battery.
I'd be looking at a 60w one as a minimum really. I have been looking at doing this to my van for ages but never got around to it.
I'd be looking at a 60w one as a minimum really. I have been looking at doing this to my van for ages but never got around to it.
oh sorry i mean 20w not 20a. how do you decide what watt is best etc?
Will depend on the demand that is required of it and daylight hours.
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Will depend on the demand that is required of it and daylight hours.
I think 50-60W is a fair guide.
well it is just to charge a battery which i will run a power inverter so i can plug laptop and phone charger while the engine is stopped
But that doesn't answer the question 
You need to consider how much you will be taking out of the battery, for how long, how long between drives, etc. So if for example you expected to take 60W out for 2 hours a day (that's going to be around 10AH from a 12V battery), and you wanted the solar panel to keep the battery topped up over a long period, then you'd need at least 6 hours a day of bright sunshine to put that back with a 20W panel. Actually you would need considerably more to deal with the losses between what goes in and what you get out of a battery.
On the other hand, if you have (say) a 100AH battery, and tend not to be in one place for more than a couple of days, then you would find you'd cope with just the battery and recharging from the engine.
There again, if you are going to be using the computer all day, then that's a long more power than for 1/2 hour per day.
So work out what you will be taking out, how much you can supply just from battery capacity to be put back from the engine, and the difference is what you'll need from the panels - but multiply by something like 150%. Then work out how many hours/day of decent sunshine you are likely to get, divide the power you need by the hours, and that's the output you need from the panels. Apply a correction if the panels won't be directly facing the sun, and the end result is the size of the panels you'll need.
But sit down before doing this as you may well find it's "somewhat more" thatn you expected and the cost will go up accordingly.
You need to consider how much you will be taking out of the battery, for how long, how long between drives, etc. So if for example you expected to take 60W out for 2 hours a day (that's going to be around 10AH from a 12V battery), and you wanted the solar panel to keep the battery topped up over a long period, then you'd need at least 6 hours a day of bright sunshine to put that back with a 20W panel. Actually you would need considerably more to deal with the losses between what goes in and what you get out of a battery.
On the other hand, if you have (say) a 100AH battery, and tend not to be in one place for more than a couple of days, then you would find you'd cope with just the battery and recharging from the engine.
There again, if you are going to be using the computer all day, then that's a long more power than for 1/2 hour per day.
So work out what you will be taking out, how much you can supply just from battery capacity to be put back from the engine, and the difference is what you'll need from the panels - but multiply by something like 150%. Then work out how many hours/day of decent sunshine you are likely to get, divide the power you need by the hours, and that's the output you need from the panels. Apply a correction if the panels won't be directly facing the sun, and the end result is the size of the panels you'll need.
But sit down before doing this as you may well find it's "somewhat more" thatn you expected and the cost will go up accordingly.
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There are three ways to connect a solar panel.
1) No control just hope the battery does not over charge.
2) Simple control turns excess power into heat.
3) Complex control the voltage out of the panel is altered to extract max power an inverter is used to then feed this into the battery using a step charger system.
As the size of the panel increases both the need for careful control and the benefits of careful control also increase. Clearly a 10W solar panel does not warrant a complex charging system.
Pulse Width Modulation is the buzz word read here . The same device is used for wind chargers and solar panels.
It is normally considered over 10W you need some form of regulation. As to at what point it becomes worth using Pulse Width Modulation I am not sure. The point at which the solar panel starts putting power in the battery needs a lot less light with Pulse Width Modulation and also the power extracted from the panel is greater. So as one moves to more expensive panels the Pulse Width Modulation unit starts to pay for itself.
By time you have an inverter to lift volts to 230 and another to reduce it again to the 19 volts or what ever the laptop uses you are drawing around 10A from the battery so for one hour laptop use you need a solar panel of around 20W to replenish it. Clearly you want more than 1 hour as internal batteries will do that so looking at around 50W which are not cheap. So likely you will want a Pulse Width Modulation controller.
I looked into it all when my son lived on a boat. We decided we could buy a lot of diesel for the cost of the panels so although we fitted a 3kW inverter we did not go for the panels.
The small panels 1.5W and the like to stop battery discharging when not in use I think are a great idea. But the larger panels not so sure on. Maplin do a 40W for £80 complete with regulator that's around 2A charge with 10 hours per day average light enough for charger to work that would give around 1 hour of laptop use a day. For checking emails maybe good enough but not much else.
1) No control just hope the battery does not over charge.
2) Simple control turns excess power into heat.
3) Complex control the voltage out of the panel is altered to extract max power an inverter is used to then feed this into the battery using a step charger system.
As the size of the panel increases both the need for careful control and the benefits of careful control also increase. Clearly a 10W solar panel does not warrant a complex charging system.
Pulse Width Modulation is the buzz word read here . The same device is used for wind chargers and solar panels.
It is normally considered over 10W you need some form of regulation. As to at what point it becomes worth using Pulse Width Modulation I am not sure. The point at which the solar panel starts putting power in the battery needs a lot less light with Pulse Width Modulation and also the power extracted from the panel is greater. So as one moves to more expensive panels the Pulse Width Modulation unit starts to pay for itself.
By time you have an inverter to lift volts to 230 and another to reduce it again to the 19 volts or what ever the laptop uses you are drawing around 10A from the battery so for one hour laptop use you need a solar panel of around 20W to replenish it. Clearly you want more than 1 hour as internal batteries will do that so looking at around 50W which are not cheap. So likely you will want a Pulse Width Modulation controller.
I looked into it all when my son lived on a boat. We decided we could buy a lot of diesel for the cost of the panels so although we fitted a 3kW inverter we did not go for the panels.
The small panels 1.5W and the like to stop battery discharging when not in use I think are a great idea. But the larger panels not so sure on. Maplin do a 40W for £80 complete with regulator that's around 2A charge with 10 hours per day average light enough for charger to work that would give around 1 hour of laptop use a day. For checking emails maybe good enough but not much else.
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