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 Topic: What size solar panel/battery
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12/7/2017 at 2:40pm
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Hello,
I am no expert here, but are you proposing to have the solar panel top up the car battery whilst you are on site and then charge everything from the car?
Or do you have a separate battery system in the trailer tent?
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12/7/2017 at 4:43pm
Location: N Wales
Outfit: Hymer Nova 590GL
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This is my setup. 150W roof mounted solar panel feeding 2x100 ah batteries. From this I can power all the vans requirements lights, water pump, central heating pump, radio, TV, chargers for iPads Kindles and phones. This set up can struggle end of October to end Feb ish when I say struggle the charge doesn't keep up with demand so batteries get flattened over several days. This time of year no issue batteries fully charged often before I get up. I don't even bother looking.
Making this practical for you. The battery get a decent sized battery 75ah or more. Think of it as the bucket where you keep your electricity. Secondly I said I have a 150w panel roof mounted. What I didn't say is roof mount a panel is very in efficient, so I would think that a 75W panel will be enough as long as it's pointed at the sun.
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12/7/2017 at 9:00pm
Location: West country
Outfit: Mondeo
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Not sure when you want to be away but output varies considerably from month to month.
This is the typical output in watt hours from a 1w peak panel for each month. You need to divide by the number of days.
You have calculated you want 165 watt hours per day. Worst month is Dec with only 20 watt hours per 1 watt panel so you need over 240 watts. You probably need a fair bit extra for system losses etc say 50% so a 360watt panel.
In April you have 103 watt hours so 3.3 per day. You only need a 50 watt panel +50% = 75 watts.
Jan 26
Feb 42
Mar 78
Apr 103
May 124
Jun 125
Jul 122
Aug 114
Sept 92
Oct 61
Nov 36
Dec 20
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12/7/2017 at 10:15pm
Location: West country
Outfit: Mondeo
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Don't forget, if you charge the battery at home you start with a full one and can return with an empty one. That gives you a bit extra, certainly enough for 1 day.
Also presumably the laptop and mobiles etc are charged at home first adding a little more bunce.
A 35A battery is 35 ampere hours at 12 volt. That is 35 x 12 = 420 watt hours. That should cover your 165 watt hours daily draw easily.
Those figures are for a commercial solar farm near Bristol with the panels angled but fixed. Of course, if you holiday in Margate, you will get many times more power as the sun will always be shining even when the rest of us have snow.
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