Solar Fridge

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Last week at Horseshoe Canyon in Canyonlands the 80 watt panels were putting out 82 watts at noon with sun directly overhead - about 85F.
During the day the fridge was on about 50% of the time (32 watts), Netbook (30 watts), and radio on most of the day. Panels were replacing or supplying most or all of that load.
During the night just the fridge was on the batteries- but soon as the sun was up the panels are trickle charging my batteries before I am up.
 
I'm following this set-up with great interest. I have a dual batter set up with house deep cycle but not having to worry about it for a few days parked would be great. I'm looking at possible fitting a Pop top to my 80 (think westy style) and a solar panel on one of those would be a snap.
 
Puma Draw

The fridge and inverter/netbook draws are handled easily by the panels, but airing up Greg's and my tires - eight 315's tires might be taxing my batteries more than anticipated. Greg did not have time to wire in his Puma. The routine in Moab is airing up daily. Some days the alternator and panels do not have time before camp to fully charge the batteries before nightfall. A bit of a timing issue

Not sure what a BJ74 alternator puts out - a guess is 40 amps . Truck still starts fine in the morning. Interesting the Puma pulls so much power out of the two batteries using it a lot.
 
Not quite, BJ74 30A (24V), BJ60 55A (12V)... cold. It only gets worse from there

Alternator.webp
 
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Fantom said:
.......nice, well what do you expect, the trucks were built to be simple, reliable and all mechanical, none of this fancy electric stuff :D
Click to expand...

Exactly, all the alt. is expected to do is charge the batteries, run the heater, a couple of headlights and windshield wipers.
 
I now suspect my inverter is the cause of my problem? I disconnected it today and things look closer than normal.
 
I'm pretty sure my Inverter is the cause of most of my electrical drain gremlins, as I recall some mention that it draws power even when it's not on. I tried switching it on to charge some camera batteries while I had my Puma running and was airing up, and all I heard was *BEEEEEP* as it's warning system told me to pound sand instead.
Even the fridge warning light goes on when the Puma is running, that thing sucks a lot of power, but works great.
 
Inverter does not like momentary low voltage

What is happening is before I start the truck I have full battery charge with inverter on for the netbook - I start the engine in the morning and battery voltage drrops to 23 volts for a few seconds - then the inverter low voltage alarm sounds - turn off the inverter - alarm stops - wait a minute untill the voltage regulator tells the batteries need charge - voltage climbs to 27 v to 29 V - turn inverter back on - no low voltage alarm. From my bad memory the starter draws 4.6 kW, which is 192 amps at 24 volts - no wonder the voltage drops for a few seconds

I think I will put a 24 v solinoid in the inverter/PUMA ciruit so I can remotely control the inverter connection before and after engine starts.

Any thoughts ?

PS I checked my inverter ( 900 watt mil spec unit) - it draws no power when turned off, but the 24v/12v converter does draw power and I have relayed that to ignition on only. On long sits that 24v/12v converter will depete the battery

http://www.voltageconverters.com/itemdesc.asp?ic=ML900-24
 
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Long Sit Test

I wanted to do a long sit test of the solar fridge (without any external power).
The engine has not been started for 10 days and last Thursday I turned the fridge on (May 24).
Today June 1 -- 8 days latter - I checked the battery, which measured 27.2 v.

So the battery (x2) has been kept at full charge while powering the fridge, over a week of overcast and little sun.
It looks like the solar panels can keep things running indefinitely, or at least until the batteries croak of old age - perpetual cold beverages even during a power outage. :beer:

P1030559 (Medium).webp


P1030562 (Medium).webp
 
That's a great test! I would like to set up a panel for mine some day on a future roof rack.
 
Thanks mate!
 
My equipment is a relatively high tech setup with a Morningstar MPPT charge controller ( $210) and mono crystalline panels (2X 40 watts $140 each). Not that many that can charge 24 volt batteries.

Morningstar Corporation SunSaver MPPT

I paid $750 USD for my fridge in 2008.
 
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