Too hot to park van in sun for solar..

[AussieMick]

Having done a lengthy trip to central Australia I have noticed a few things about my solar setup.
I have a 150w panel permanently mounted on my roof and a 150w blanket. My battery is a 120ah agm deep cycle.
My fridge is a 80 litre dometic.
In temperatures up to 25c I can park in the sun and permanent panel will keep battery charged ok. No problems.
BUT when its really hot and interior of van gets up to 35c and higher the fridge runs almost continuously trying to get temperature inside down to set temperature.
I cant park in the sun as this makes van interior even hotter so permanent panel is not outputting. I now have to rely on my 150w blanket which in ideal conditions can add 6 to 8 amps(120w_140w) to battery but fridge compressor is using 4 to 5 (60w)of those so only small amount going back to charge battery. This means it takes a long time to recharge battery and some days can only get to 80percent or so.
If the night stays hot then fridge cycles more often and by morning I can be down to 50 percent. If day is going to be hot again same situation as above again. What if cloudy and raining next day, almost nothing back to battery.
This showed me that even though my setup copes with temperate conditions when it gets really hot for longer periods I have to do a bit of juggling to keep battery charged enough.
I guess my solution is another battery and another portable panel so van can be in shade and portable panels in the sun.
Anyone got any thoughts on this as a solution.

 

[Ads_Essex]

I guess my solution is another battery and another portable panel so van can be in shade and portable panels in the sun.

I’m not as well clued up as others, but I think you’ve hit the nail on the head that additional batteries are required.

 

[benp1]

Presumably you're away from your van and leaving it locked up?

Otherwise you could just leave the windows/doors open and the inside wouldn't heat up as much?

Alternatively, would putting covers/thermal blinds on the windows help with the internal temperature?

 

[VanDamMan]

Hi... I use 2 x 150 panels ( but have space to store ) each panel rated at 8.54 amp and just got an extra battery in a box to piggyback of leisure battery on solar...my next project is to buy a trailer and hang the panels when on location it’s a purely mobile setup with lots of flexibility ..

 

[bootsam]

Covers and thermal blinds on inside will help a small amount (less than people think). But what people dont realise is that eventually the curtains/blinds/etc will heat up themselves and become radiators. You've merely exchanged one form of energy (radiative) to another (conductive/convective). The energy has still gotten in. The reflective ones work best (obviously). It is better to stop the energy getting in in the first place, so external covers would work better in hot climes like Aus.

Alas theres little to prevent the energy being conducted through the body panels and then internally it again becomes a radiator. Insulation will help slow it down, but it will still get in. Open windows will help keep the temps manageable but then weve shoved external covers over the windows and have blocked them.

Its a tricky balance but if you can stop the energy from entering in the first place, its easier to manage than if you've allowed the energy in and are trying to dissipate it. Cross flow vent works better. I'd park in shade and have the slidey door open so inside is circa same as ambient. Closed doors will just have the heat building up with nowhere to go.

Park in shade, but I guess theres not much of that in Aus. Good luck.

 

[CAB]

Hi... I use 2 x 150 panels ( but have space to store ) each panel rated at 8.54 amp and just got an extra battery in a box to piggyback of leisure battery on solar...my next project is to buy a trailer and hang the panels when on location it’s a purely mobile setup with lots of flexibility ..

View attachment 85199View attachment 85200

That’s the ticket! Panels on a trailer, just like Mark Watney in the film, The Martian

 

[bootsam]

Ventilating the fridges coil at the rear would help too in hot climes when your van is warmer inside than outside. The coil rejects its heat into the air, so having an increased airchange rate here would help. I've surveyed some air cooled chillers before and noticed that to get better performance the facilities manager and the maintenance guys jerry rigged a hose to spray water on it. I DO NOT RECOMMEND THIS. Legionella playground.

 

[CAB]

Ventilating the fridges coil at the rear would help too in hot climes when your van is warmer inside than outside. The coil rejects its heat into the air, so having an increased airchange rate here would help. I've surveyed some air cooled chillers before and noticed that to get better performance the facilities manager and the maintenance guys jerry rigged a hose to spray water on it. I DO NOT RECOMMEND THIS. Legionella playground.

Surely it's only still water that's a Legionella risk? Like windscreen wash water without a detergent.

But probably just me talking nonsense as usual

 

[bootsam]

Generally its warmish water at around 45°C where the germs breed, then vapour and spray gets in the air, you breath it and die. Horribly too by all accounts. Just to cheer everyone up.

 

[VanDamMan]

That’s the ticket! Panels on a trailer, just like Mark Watney in the film, The Martian

Cool...so someone beat me too it .......

 

[rover220]

additional batteries are all well and good but if you are using more ah than you can replace then you are on a hiding to nothing regardless.

 

[Cymro]

A bit OTT, but one of these on your roof?!



MaxX Air Fan Deluxe Tinted Remote Controlled Vent with Rain Cover (400 x 400mm) - J43709

 

[JSJQ]

I have a similar camper and fridge but with a portable 200watt solar panel. It’s a bit of a nuisance to transport as it lives on the floor when travelling. It keeps the battery charged for ten days plus with the van parked in the shade in the summer. I found what has made a big difference is an awning along the fridge side attached via sail track. I‘m also considering mounting a switched fan behind the fridge. We have just returned from a trip to outback Queensland and tried, when possible, to park the camper with the fridge side facing north or south. The majority of the heat came through the sides and the lifting roof.

 

[AussieMick]

I parked in the shade when possible with silver thermal blinds in the front windows and black out curtains closed, left sliding windows open a couple of inches.
If safe even put roof up and opened all top vents. Still the interior got to 35 to 40 degrees.
This causes fridge to run almost continuously which draws a lot of the power my solar panel was putting back into the battery.

I have a small 12v computer fan blowing on the compressor of fridge and we even put a foam mat in front of the fridge door.
During the day the van itself absorbs heat and at night takes ages to cool down especially if temperature at night is around 30 degrees .
This was causing my battery to be at around 50 percent by morning so my existing setup just coped, luckily every day was sunny so solar could put back power to battery but as compressor was running so much this took all day.

Now l am back in cooler weather my solar system copes easily and battery is kept charged quickly as fridge cycles infrequently.

I have been off the grid for 4+ weeks so system worked but l had to use solar blanket whenever possible to supplement fixed panel. Normally l don't have to worry about battery charge as fixed panel keeps it topped up.

 

[AussieMick]

Hi JSJQ , funny you mentioned a sail track and awning that's what we thought might help so l think l might fit one on fridge side of van , have you fitted one and did it help?

 

[JSJQ]

Yes we have and yes it helped. The track is fitted with 3m double sided tape which has held in strong, summer seaside winds. The awning (just a light plastic tarp really) is attached to ground pegs with elastic straps. Easy to fit and remove.

 

[Mud Digger]

Generally its warmish water at around 45°C where the germs breed, then vapour and spray gets in the air, you breath it and die. Horribly too by all accounts. Just to cheer everyone up.

hiya its lower than that
45°C is above hand hot (43 is H H )
its between 20°C - 60 °C
below 20 it's there but don't breed

remember to flush your shower heads when returning from holiday - that cough might not be from the plane - its when you shower getting home .

 

[boxelder]

The efficiency of panels drops by up to 25% once temps above 25deg C. This won't help

 

[AussieMick]

The only problem with adding more portable panels is that you cant leave them lying out in the sun and leave your van to go bushwalking, riding etc because some bast##d may pinch them.
My redarc blanket was not cheap.
Thinking of buying a cheap solar blanket to try to see what output it has and could use in parallel when around van or by itself when I'm not around.

 

[AussieMick]

Hi... I use 2 x 150 panels ( but have space to store ) each panel rated at 8.54 amp and just got an extra battery in a box to piggyback of leisure battery on solar...my next project is to buy a trailer and hang the panels when on location it’s a purely mobile setup with lots of flexibility ..

View attachment 85199View attachment 85200

Hi Mr VanDamMan, I may have to do something similar. Do you have an Anderson plug or similar and then connect this battery in parallel to your leisure battery and charge it via alternator and solar or is it a stand alone setup. I have no room to fit another battery permanently inside the vehicle but could connect this up and move it out of the way when needed.
Did you have to match it exactly to your leisure battery eg 120ah agm to 120ah agm.
Or can you mix 120ah agm to say 80ah agm. Thanks Mick