hi to all.. I have got myself a well used static caravan.
I am in need of advise about solar power. my idea is to have a 100 watt solar panel running through a charge controller then into a nice big leisure battery (maby 2 connected in parallel). the problem is I don't want to use a 240volt power inverter as I want all the things I need to run on 12 volt (you can get 12 volt tv, kettle, lights and toaster etc.) is the solar panel going to be able to cope with all the things I want it to? is it only powerful enough to power something silly like a table lamp? I am quite clued up on car electrics but I don't know if I am underestimating the power of solar..
hi to all.. I have got myself a well used static caravan.
I am in need of advise about solar power. my idea is to have a 100 watt solar panel running through a charge controller then into a nice big leisure battery (maby 2 connected in parallel). the problem is I don't want to use a 240volt power inverter as I want all the things I need to run on 12 volt (you can get 12 volt tv, kettle, lights and toaster etc.) is the solar panel going to be able to cope with all the things I want it to? is it only powerful enough to power something silly like a table lamp? I am quite clued up on car electrics but I don't know if I am underestimating the power of solar..
If you multiply each appliance power by the length of time you will use it for each day and sum the results, then divide total usage by the length of time the sun shines strongly each day you'll get a rough measure of needed solar power.
There is no yes or no answer here as there are too many variables. The battery will power the appliances and the solar panel will recharge the battery.
Whether the panel can fully recharge the battery depends on how much sun is available, how long its available, how much power is taken from the battery, the resistance of the wiring between the panel, charge controller !nd the battery, and the quality of the charge controller, some can waste as much as 50%.
Heating anything using 12V is effectively a no no. It takes about 130W to heat a litre of water in an efficient kettle. Assuming a certain amount of loss you would be looking at about an hour of good light directly on to the panel (optimal positioning) and a rule of thumb is you get about 3.5 times the rated output in W per day on an annual basis. Any heating should be done using gas if you do not have ehu and that also goes for fridges if you have absorption type.
As an aside it is probably better to split the loads across two batteries with one covering essentials such as lights and possibly water pump and heating ignition, the other for non essentials such as TV, laptop, phone/tablet recharging. Some controllers will then let you prioritise the charge to the primary battery and only charge the secondary battery when primary one is fully charged (other settings are sometimes available such as 50/50 split of the charge). This would prevent the batteries 'fighting' which is the problem with any multi battery system (electric cars have complex computerised monitoring and charging to stop this happening).
My advice would be to use gas as much as possible and make sure any devices are as energy efficient as possible (small TV, LED lighting, tablet computer instead of desktop or large laptop etc).
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Topic: solar power
