Getting more power from Solar

[Peterr]

What was the inverter supplying power to ??? A 1200w inverter will suck about 3Amps sitting there doing nothing!!!


More solar is always good, but less rain would help!!!

[Ern_Reeders]

What are you running off the inverter?

My experience has been that it's best to really try to get everything on 12v. Inverters are inefficient and luxury items.

Or is it just serving as your voltmeter?

In any case, there's a drain from the inverter even when you're not using it.

[Rowley]

The inverter is just for the 80lt Waeco fridge. So that's all the battery was running at the time, inverter and fridge.
My LED lights were running of a Waeco battery pack, which is too small a power source to run the fridge.

So the way I see it at the moment some of my options are...
1) Get bigger battery - 120aH.
2) 2nd Battery 100aH, run them parallel.
3) Bigger solar panels. eg 120w
4) Don't use inverter, wire the fridge via 6 pin fuse box. My fridge has the option of 12v Anderson plug, 12v cigarette connection or via inverter.

[Peterr]

Much more efficient to run the fridge direct off the 12V battery..

Your current battery and solar setup , given fair sun conditions, should keep the fridge going for days , but no sun will cause no fridge in a day!!

Either more solar or a small , 1Kva, gen set and charger to top the battery up is a good way to go ....

I run a 105 A/H battery , 240W of solar , and carry a small gen set just in case! That powers a 60L fridge , a 30L fridge , LED lights and a pump no worries if its sunny or not...

[robcaz]

A good rule of thumb to follow for best battery life is not to discharge your deep cycle battery below 50% capacity, so in fact you really only have 45 amp hours of use. http://www.campertrailers.org/wattsup14.jpg

It is best to run your fridge from 12volt when camping. It is hard calculating the power usage of a compressor fridge as there are so many factors involved such as the fridges size, the rated power consumption of the motor, the ambient temperature, where the fridge is placed, how many items at ambient temperature is placed in the fridge, the fridges preset temperature, to name a few.

The fridge will not run all the time, but runs & then turns off or cycles to keep the preset temperature. By using a Watts Up Meter I was able to see exactly what the draw of our 40 litre Engel fridge when run as a fridge http://www.campertrailers.org/fridge_draw.htm

The 80 litre Waeco motor power rating is 7.5 amps so even with a duty cycle of 50% the fridge will consume 3.75 amps every hour. The motors of smaller fridges use less power, 2.6 amps as with our 40 litre Engel above.

You can also see the Waeco's low battery cutoff of 11.8 volts (10% capacity) has taken the battery well below the recommended 12.2volts 50% capacity.

When setting up a 12volt system you need to allow for a couple of rainy days with now solar input. Collyn Rivers recommends batteries to be at full capacity just after lunch, so it is not necessarily more battery amp hours, it can also be more solar.

You will find Richard's solar spread sheet helpful http://www.campertrailers.org/solar_spreadsheet.htm