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Solar Panel(s)


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We are new to motor homing, so would appreciate some help.


Our motorhome is in storage so solar panel(s) to ensure that leisure and vehicle batteries are fully charged when we pick it up seems to be the way to go; but what options / suppliers / sizes / etc.


When driving with the fridge and sat nav on; the sat nav keeps shutting down as not enough current - so this means that the fridge is a heavy consumer of electricity (I assume). Does this mean that the fridge cannot be run from the solar panels to make the gas last longer when the sun is shining?


Can I just go with a single 100 watt and if it does not do the job, add another OR will I still be unable to power the fridge?


Explanation - The fridge has emptied our new 6kg cylinder in 3 long weekends away and I was looking to extend this.


At the moment we are limiting our electricity usage when away so as not to run out, but would prefer to be unlimited - so current usage is no guide. Next year would like to tour the continent without worrying about swapping gas bottles or electric hookups.


Thanks for your advice



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I would seriously suggest that there is something wrong with your MH on more than one count.


You say...


sgreensides1 - 2014-09-19 10:10 AM

When driving with the fridge and sat nav on; the sat nav keeps shutting down as not enough current - so this means that the fridge is a heavy consumer of electricity (I assume).


This says to me that there is something wrong with either the vehicle charging system or fridge wiring. The alternator should be able to easily cope with running the fridge and a sat nav. What happens if you turn the fridge off and run with headlights, wipers, heater blower, etc, etc?


Then your quote...


sgreensides1 - 2014-09-19 10:10 AM

The fridge has emptied our new 6kg cylinder in 3 long weekends away and I was looking to extend this.


suggests to me there is something wrong with your fridge or gas plumbing. For example we recently ran our fridge for 4 days, boiled the kettle numerous times for tea, cooked all meals and ran the heating for an hour a day and only dropped the level in a 13 kg cylinder by around 2 inches. ie used approx 1 kg of gas.


I would suggest you get your MH checked out by a professional for both charging and fridge/gas operation.



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Welcome to the Out&AboutLive forums, Steve.


The amount of 12-volt power used by a sat-nav is tiny. So, if your sat-nav is shutting down due to a shortage of 12-volt power, there is either something wrong with the power-supply ‘feeding’ the sat-nav or something wrong with the sat-nav itself. (It might help if you can say which make and model of sat-nav you have and how you know the cause of the device shutting down is lack of 12-volt power.) It’s near as dammit certain that the fridge’s 12-volt requirement is not impacting on the sat-nav. It might also help if you provided details of your motorhome (make, model and year of manufacture) in case there are known peculiarities.


As Keith says, a motorhome’s alternator must be capable of running all the normal ‘services’ (lights, wipers, etc.) associated with a vehicle that’s being driven as well as motorhome-related ancillaries like a fridge. A large fridge/freezer might need 8 Amps of 12-volt power (96 Watts) which is roughly equivalent to having the headlamps on, so its requirements (though significant) are not huge. I suspect that, if your motorhome’s alternator/charging-system is subnormal, you would have noticed this in other ways (like the motor failing to start) not merely the sat-nav shutting down.


A motorhome’s gas consumption will be directly related to the pattern of usage, the duration and the gas appliance(s) involved. It should be anticipated that a large-capacity fridge/freezer will use more gas than a small-capacity one and that more gas will be used in hot weather for fridge-cooling than in cold weather. Which make and model of fridge is fitted to your motorhome?


A full 6kg gas-cylinder holds about 12 litres of LPG. If your “long weekend” lasts (say) 60 hours, then your fridge would have been running on gas for 180 hours, equating to a gas usage of 1.6 litres per day. That’s an unusually high usage if gas is only being employed for the fridge, even if you had a very large fridge/freezer set to its maximum cooling setting. I used to work on a 1-litre per day gas consumption, but that included water-heating and some cooking. As Keith advises,it sounds like something is wrong.


As long as your motorhome is stored so that sunlight can reach the solar panel(s) that you have in mind to fit, it should be practicable to maintain the charge-state of the vehicle’s batteries. But the 12-volt electrical system of most motorhomes deliberately prevents a fridge being powered by 12-volts unless the motorhome’s engine is running. This restriction is to prevent the motorhome’s leisure-battery from being rapidly discharged.


While you should be able to avoid electric hook-ups if you have large-capacity batteries and a solar panel (or panels) I doubt that it’s going to be practicable to avoid powering your fridge from gas. The simplest approach to combating the ‘gas-bottle swapping abroad’ worry would be to fit a user-refillable gas-bottle. Examples are shown on the following link, but there are several alternatives



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