Solar panel size question

I have exactly the same usage as you have listed with a 120 ah fullriver battery and the 100w panel i got off Derek Bester works a treat, providing you move the panel at least once during the day in qld you can get about 8 charge a day easy. I have camped for a week and it has kept the battery at around 12.5 volts, am thinking of adding another waeco for a drinks fridge, that will be stretching the friendship I think!

Not much in reserve for that rainy overcast day.
I have an 80w for a smaller 35l Waeco. No water pump.
I would go the 100w folding way if the 123w is too difficult..

At least 100w I would say. The bi-fold one that I bought fits nicely in the 4by, and keeps the battery topped up!

Bought it from ABR who advertise on this site. The GP-100.

Cheers

Brian

I have 130w locked to roof rack. Only runs 32 lt engel and shower. We move every 4-5 days.park with shade for good part of each day and have never missed a beat - in northern Aust. Has also had no problem on 5 days of overcast/rain. Went oversize for simplicity.

Cheers
Chris

Mogul

If the Solar REGULATOR (that you WILL need) will not maintain the correct voltage and supply ALL the AMPS needed to the 'storage battery' then you will have a "small" or "under-size" problem.

The relevant 'numbers' listed, 80w or 123w, only indicate the Maximum Wattage available from a solar panel in PEAK operating conditions, not in AVERAGE or NORMAL camping conditions.

If the Solar panel is too small in Amps produced, then its simply too small and a complete pain in the, however if the panel is too large in Amps produced - the Solar REGULATOR will fix that !!

The 123w panel would be a Sharp - what "type" of panel is it ?
Some 'types' work more efficiently than others, the web site explains that, so it's not for me to tell you the difference :-))

Your 120ah Battery is, stated simply, only the "storage facility" of the solar system, it stores the 12v power produced by the solar panel, and as such is similar to a Dam or water supply, the larger the better and more reliable.

Some more "EFFICIENT" solar REGULATORS will run the fridge DIRECT from the SOLAR POWER actually produced, and will ALSO charge the battery, if there is an excess of solar power produced.
If there is NOT an excess of solar power then the same Solar REGULATOR will then allow all the Solar power to go DIRECT to the fridge and the 12v battery only has to supply the balance.
Eg: (numbers are ONLY for reference and not related to any fridge model mentioned) all 4 Amps produced @ solar panel will go to fridge and only ~1.5 Amps will be drawn from your battery - only while fridge is actually running.
When fridge turns off, all 5.5 Amps produced by the Solar panel will then recharge the 'lost' 1.5 Amps x 30 odd minutes the fridge was running, because it DID start running when it was @ 100% SoC capacity.

You (normally) will only need to use the stored 12v battery power at night, when the sun ain't shining and running your fridge and also maintaining the 120ah battery at a fully charged 'State of Charge' during the day
ONLY IF YOU GET THE SYSTEM SPECIFIED & WIRED CORRECTLY !!

Hi
I have run nearly the same set up that you have with 100w (2x50) for 2 weeks without any problems. Got them from Derek.

Cheers

Howard.

Thanks for all your replies.

I've just purchased a 123w Sharp panel and a 20amp Powertech regulater.