solar setup

[petery27]

HI

just in the process of building a day van/camper, currently have 240v hook up, 3x110ah batteries and running led lighting and a 75w 12v fridge, looking to add some solar but not wanting to blow loads of money on it. Really looking for something that will give sufficient charge to the batteries to allow me to run the fridge all the time and keep it cold overnight and charge a phone/lights on for a bit of time each night.

All based in a LWB Crafter van so have approx 3m plus width of the vehicle of space on the roof, first proper trip will be to le mans in June so 4/5days on a campsite with no hookup but i do have a petrol genny to top up with but its not a very sociable one so want to limit the use of it as much as possible.

what do people suggest as a complete kit?

[Scrump]

Dc to dc charger so the leisure batteries charge from the alternator (dc to dc charger is better than a split charge system).

Then add solar, if you want it to work in the winter then you can't get too much!. I have 200w feeding a mppt charger (mppt is better than pwm) and this trickle charges the start battery and bulk charges the leisure. I also have another 120w solar which I use to charge a power station (this is so I can power laptop etc outside the van).

This set up works for me with a few days off grid powering a fridge, lights etc. Can go indefinitely in the summer, whilst in the winter I may have to start the engine after a few days to top up the batteries (I have 2x110ah AGM leak sure batteries).

I hardly ever use EHU.

[petery27]

So something like this should be more than up to the job

https://uk.renogy.com/renogy-300-watts-solar-panel...

Or a pair of these for a more budget/flexible option

https://www.diy.com/departments/200w-12v-black-por...

[Scrump]

The renology does not appear to be able to charge the starter battery as well as the leisure batteries, otherwise looks good. I would not go for the flexible panels, go for the rigid ones.

I bought most of my kit from Photonic universe.

portable panels would not be my choice, fixed panels means they are always deployed.

Don’t forget a dc to dc charger, really useful when the sun doesn’t shine.

Edit:
My solar controller
https://www.photonicuniverse.com/en/catalog/full/6...

Remote display
https://www.photonicuniverse.com/en/catalog/full/6...

My 200w panel
https://www.photonicuniverse.com/en/catalog/full/1...

My dc to dc is from ctek.

Edited by Scrump on Thursday 11th April 11:17

[POIDH]

I have 1x 110ah battery and manage three nights off-power like that, with heater, fridge and lights....We do manage power carefully - in winter we turn the fridge off at night to off-set heater use. We do not have an invertor and only use 12v - so have an old tablet to watch films etc.

How many times will you need a full week+ off-grid?

We just go to campsites every other night or three and plugin.

We do not have solar, and currently I am not feeling the need for it.

[TwinKam]

POIDH said:

I have 1x 110ah battery and manage three nights off-power like that, with heater, fridge and lights....We do manage power carefully - in winter we turn the fridge off at night to off-set heater use. We do not have an invertor and only use 12v - so have an old tablet to watch films etc.

How many times will you need a full week+ off-grid?

We just go to campsites every other night or three and plugin.

We do not have solar, and currently I am not feeling the need for it.

What fridge do you have and what does it draw? OP states his is 75W...

[POIDH]

It is a Dometic 50l compressor - but would not be able to tell you what that draws. We are careful with it - it is not on coldest setting, keep door closed etc etc. We have only had the bus through the winter, so perhaps a hot day may massively increase the fridge energy draw. Plus our van drives each day, it does not sit on a site..

[Bootdog]

We have a 50L dometic also, and get just about 2 days from a 110Ah leisure battery in peak Summer. It wasn't quite enough to get us through the second evening, so I added 200W of rigid solar (an older 80W flexi had failed). The solar should also keep the leisure battery in better shape, and avoid running it flat. You could get away without it, but a light left on all day by accident killed our battery, and recharging off the engine takes forever, so solar was a better option.

[hidetheelephants]

POIDH said:

It is a Dometic 50l compressor - but would not be able to tell you what that draws. We are careful with it - it is not on coldest setting, keep door closed etc etc. We have only had the bus through the winter, so perhaps a hot day may massively increase the fridge energy draw. Plus our van drives each day, it does not sit on a site..

What compressor is it? The one on the old man's boat is a Danfoss BD35 and draws about 3 amps when running.

[TwinKam]

3 amps is about right but, as you say, that's only when it's running; the duty cycle will depend on various factors such as ambient temperature, desired fridge temp setting, and the fridge's insulation. I recommend a power consumption meter to ascertain what it is over a 24 hrs period.
I've made a thermal jacket for mine, it is in a tent so I take care to ensure it's not in the sun. and although it can go to -20°C I only run it as a fridge at +3°, and it generally works out less than 30%
Remember though that a lead acid battery can only give you half its amp hour rating.
If you're driving every every day you will be absolutely fine, every other day you should still be fine. Any longer than that and you'll need another battery or the solar option, I have a 120A panel and can camp indefinitely (given reasonable weather).