Solar power on campervan

[Gini]

Hey guys we purchased a 270w solar panel and trying to figure out what kind of inverter, battery and so on we would require to run a 12 v fridge, about 60l and just usual laptop and mobile phone charging, maybe one day some LED lights in the ceiling.
Thanks for your interest and your help lovely people!

[EricL]

HI @Gini

It's great that you're getting fantastic gear for your van. Before we make any suggestions can you please post a picture of the brand and model of the solar panel? Any other details you can include such as the number of watts it produces would be very handy. Sometimes the manual of the panel makes a recommendation on which inverter works best with it. 

Can you also please include the voltage and wattage of each of the appliances you are planning to use.  

Let me tag our experienced members @MikeTNZ and @r23on for their recommendations on which inverter and battery to use.

We look forward to seeing the photos.

Eric

[MikeTNZ]

Hi @Gini,

Welcome along to Bunnings Workshop,

Given that you have a 270 Watt panel, you're more than likely going to need some sort of a Charge Controller to wire the

panel into, this controls (regulates) the output of the panel and makes life easier on both the battery and the panel.

Never connect a battery directly to a panel, some panels have an output of up to 35 VDC, this will seriously damage the battery!

There are two types of these available, the cheaper simple switching type and the more expensive (but better) MPPT type.

Please also be aware that some charge controllers will not work with Lead-Acid batteries and only work with Lithium-Iron batteries

because of the way the battery is charged.

Pretty much you can have as much battery capacity as you can afford, however you can add extra batteries down the track once the system is up and running, just remember that the batteries are always wired in parallel.

For your size of panel and the initial load you've mentioned, something like a 120 Ah battery or greater should do the trick.

Finally, the inverter, if you ever learn anything from me, don't ever buy a cheap inverter, yes you can pay thousands for one with all the bells and whistles, but stay away from the ones that aren't pure sine-wave or modified square-wave as they are often known.

Your sensitive electronics will thank you for it, the closer the output of the inverter is to a sine wave, the better off things will be.

The problem with fridges and other appliances that have motors in them is what is known as "in-rush current" when the appliance starts up,

this can be many times the normal run current of the motor, it's only for a second or so, but it still needs to be taken into account.

I would start at say 500 Watts as the bare minimum for your case, and possibly a 750 Watt inverter should suit your application.

If there's anything I've left out or if you have further questions, by all means, let me know.

I hope that this has been of some use to you.

Cheers,

Mike T.

[MitchellMc]

Many thanks for your comprehensive reply, @MikeTNZ. I trust @Gini really appreciates your knowledgeable input.

It appears something like this Projecta 900W Pure Sine Wave Inverter would be suitable.

Mitchell

[MikeTNZ]

@MitchellMc,

That would actually be damned near perfect for the application, with a bit of future-proofing as well.

You need to have a wee bit of "head-room" with inverters to ensure that you're not over-driving the input current vs the output current,

this is where a lot of people getting into solar fall short and load the thing up to levels that they aren't capable of delivering.

When this starts to happen, the output wave-shape becomes really distorted and abnormal.

If there is going to be a point of failure in a solar install it will normally be either batteries that aren't being charged correctly (as in boiling the cells dry by

excessive current) or the inverter is being over driven and expected to deliver current that it is not designed to.

This is why you need to have a decent charge controller on the panel feeding into the battery(s) and size the inverter correctly for the application.