Thread: Touring and camping. Do I run everything off 24v?

Where are you going to get your 24v from??

Yes you draw half the amps on 24v but you need two batteries rather than one to get the 24v - so the net use is the same. In general the number of watts to run an item on 12v is the same as 24v.

So a 100ah 12v battery can in theory 1200w of power. Two 100ah batteries wired to provide 24v provides 2400w of power but you are using two batteries - twice as much storage as the 12v system.

So if a fridge uses 60watts of power it will take twice as long to drain the batteries in the 24w system but you have twice as much storage - reduce the two 12v batteries to 50ah so making the total capacity the same as the 12v system 1200w and the fridge will run no longer on 24v than it did on 12v. You do not get something for nothing.

The main advantage in the 24v system is the lower amps in the wiring. But a fridge running on 12v will use the same amount of power in watts as running on 24v.

Clear as mud - not sure I follow all that lot.

Garry

Makes sense to me. as he said, you don't get something for nothing. Ohms law. Voltage down. amps up and vice versa.

12v for mine, most equipment and accessories in camping industry use 12v.

To increase capacity ,utilise more batteries connected in parallel

Dave

Damn it! I thought I was on to something there. Live and learn.

Riddle me this then...
I have read on this forum that 24v solar panels charging 12v batteries via a suitable controller is more efficient than 12v panels. Is there anything to this?

Originally Posted by alittlebitconcerned

Damn it! I thought I was on to something there. Live and learn.

Riddle me this then...
I have read on this forum that 24v solar panels charging 12v batteries via a suitable controller is more efficient than 12v panels. Is there anything to this?

The "suitable controller" is a MPPT (maximum power point tracking) type which can use smart electronics to vary the input voltage to maximise the output power. They are intrinsically more efficient than the older style regulators but dearer if you buy a reputable brand. Example:

GSL MPPT Solar Regulator Panel Charge 12A 12 24V System | eBay

And is it more efficient using 24v panels into a mppt because there is more maximum power to track compared to a 12v panel?

As stated, power consumption will be the same either way.

Sounds like you need to sell your explorer fridge and buy a couple of engels. Use one as a fridge and one as a freezer. Mine will still cycle on-off while maintaining -15.

Originally Posted by alittlebitconcerned

And is it more efficient using 24v panels into a mppt because there is more maximum power to track compared to a 12v panel?

Two 100W panels will produce exactly the same power regardless of being connected in series (24V nominal) or parallel (12V nom). The difference is the power lost in the wiring from the panels to the regulator (half as much on 24V) and the efficiency of the conversion from solar voltage to battery voltage. I don't know exactly how different the efficiency would be but perhaps a few % only. Getting the specs for the converter would be helpful.