Running an electric cooler in my van on solar

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iwire said:
Ask kwired http://forums.mikeholt.com/showthread.php?t=175548&p=1736898#post1736898 ;)
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I didn't realize this was something for someone sitting in a vehicle all day. :p

Refrigerator powered from the grid is probably the cheapest cost for owning and maintaining and even cheaper when plugged into someone else's facility and using their energy, but not always convenient for something in a vehicle.
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Plus, my way is 'greener' because you actually drink the melted ice instead of pouring it into the ground. Remember all this if you ever see me walking around drinking water out of a Gatorade bottle wrapped bubble wrap secured by electrical tape.

Darn.....

I forgot about the tape. That's an additional cost I hadn't figured in.
 
mgookin said:
That would have to be a pretty remote jobsite to need ice to last 10 days.
Lunch time usually works for me.
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In Florida;) Some places at some times you may need to keep your lunch from freezing instead.

Keeping ice cold enough to prevent melting is one thing, but chilling other items with ice means those items are going to give up heat to the ice.
 
Another option that is along the same lines as Dereck's solution, is to use a sealed lead acid battery charged by a circuit that is only 'on with key'. That isolates the SLA from the vehicle's starting, lights and accessories (also called SLA) battery when the key is off. When the vehicle is started back up, the sealed battery gets charged along with the starting battery.

The above will work no matter if the sun is shining or not.
 
K8MHZ said:
Another option that is along the same lines as Dereck's solution, is to use a sealed lead acid battery charged by a circuit that is only 'on with key'. That isolates the SLA from the vehicle's starting, lights and accessories (also called SLA) battery when the key is off. When the vehicle is started back up, the sealed battery gets charged along with the starting battery.

The above will work no matter if the sun is shining or not.
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and there is fuel in the tank:)
 
K8MHZ said:
Shoe me the math.

Given a cost of $0.13 per kWh, how much electricity would it take to freeze all the rain that fell on a 100 x 60 foot flat roof, inclined at 5 degrees, collected in approximately 1/3 to 1/2 of a 946.35 ml plastic bottle at standard temperature and pressure?

:roll:
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About 0.31 cents per 1/2 liter to get it to frozen (right at melting temp) and about 0.34 cents per 1/2 liter to get to -10F (a good freezer temperature).

The roof really doesn't matter but that is about 3726.04 gal per inch of rain, if you want to drink rainwater. I used a COP 0f 2.5 for the freezer, and a starting temperature of 72F.
 
K8MHZ said:
Another option that is along the same lines as Dereck's solution, is to use a sealed lead acid battery charged by a circuit that is only 'on with key'. That isolates the SLA from the vehicle's starting, lights and accessories (also called SLA) battery when the key is off. When the vehicle is started back up, the sealed battery gets charged along with the starting battery.

The above will work no matter if the sun is shining or not.
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This is what I used to accomplish this:

http://www.amazon.com/Blue-Sea-Syst...&redirect=true&ref_=oh_aui_detailpage_o06_s00


It's called an "automatic charging relay". When it senses charging, it combines the batteries and both get charged. When not charging it isolates the batteries so you don't run down the starting battery. It differs from a "battery isolator" in that it doesn't use a diode. I checked on the "isolator" but found out that due to voltage drop across the diode that you never truly get a full charge.

I bought a motorcycle battery and put it behind the seat. I use it for my inverter. I don't keep a cooler cold with it but I suppose I could. Mainly for battery chargers and times when I may need to power something small temporarily.
 
Little Bill said:
This is what I used to accomplish this:

http://www.amazon.com/Blue-Sea-Syst...&redirect=true&ref_=oh_aui_detailpage_o06_s00


It's called an "automatic charging relay". When it senses charging, it combines the batteries and both get charged. When not charging it isolates the batteries so you don't run down the starting battery. It differs from a "battery isolator" in that it doesn't use a diode. I checked on the "isolator" but found out that due to voltage drop across the diode that you never truly get a full charge.

I bought a motorcycle battery and put it behind the seat. I use it for my inverter. I don't keep a cooler cold with it but I suppose I could. Mainly for battery chargers and times when I may need to power something small temporarily.
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Yeah, I forgot about that loss of .7 volts. Back in the day of external voltage regulators, the solution was simple, just move one wire to the battery side of the isolator. Probably not even possible now.
 
K8MHZ said:
Yeah, I forgot about that loss of .7 volts. Back in the day of external voltage regulators, the solution was simple, just move one wire to the battery side of the isolator. Probably not even possible now.
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These days you can achieve the same isolation using FETs or other active semiconductors and avoid most of that diode drop. Even if you just use a Schottky diode the drop could be as little as .2V.
 
I can't believe no one has given the obvious solution, the OP needs to buy a motor home with a full size frige and freezer.
 
kwired said:
Some of what has been discussed here can be found at motor home/camper dealers.
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the problem is, that we aren't combining info from other threads to solve this.
if we get the rats from sahib's thread, and put them on little treadmills......
along with a small wind turbine for when the car is moving.... and an
amphetamine dispenser that is enabled when the car stops moving, the
rat(s) can get cranked, spin the treatmill when the car isn't moving,
collapse in exhaustion when it is moving, and the wind turbine is powering
the refer, the OP can have a cold tasty beverage whenever he wants....

and having relocated the rats from the other thread, that problem goes away as well.
 
OP could move from Florida to Canada and have less problems keeping food or beverages cool.

Bob insists that ice is the cheapest way to go, and maybe is, but unless you go outside and pick it up off the ground it likely cost someone something to make it if done via man made refrigeration methods. If you purchase bagged ice every day all year around that is likely the most expensive way. If you only need ice limited number of times a year bagged ice is probably cheaper then owning and operating your own ice machine.

Depending on what kind of work is lined up for the summer months I may go through a lot of ice or I may hardly use any. Next couple of months I will be at a facility that has water cooler fountains, and refrigerators that won't be heavily used as it is in a school and only people there will be HVAC/construction/and maintenance people, and limited office staffing, so I probably don't even bring my own water jug like I may on many other summer time jobs - just happens to be the luck of the draw this time around. Other years I may have been on sites that don't even have tap water and you must bring your own water.
 
kwired said:
Bob insists that ice is the cheapest way to go, and maybe is, but unless you go outside and pick it up off the ground it likely cost someone something to make it if done via man made refrigeration methods. If you purchase bagged ice every day all year around that is likely the most expensive way. If you only need ice limited number of times a year bagged ice is probably cheaper then owning and operating your own ice machine.

Depending on what kind of work is lined up for the summer months I may go through a lot of ice or I may hardly use any. Next couple of months I will be at a facility that has water cooler fountains, and refrigerators that won't be heavily used as it is in a school and only people there will be HVAC/construction/and maintenance people, and limited office staffing, so I probably don't even bring my own water jug like I may on many other summer time jobs - just happens to be the luck of the draw this time around. Other years I may have been on sites that don't even have tap water and you must bring your own water.
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Are you on dope?
 
K8MHZ said:
No. Say it ain't so. How did you ever survive?

:lol:

You forgot to mention sites that have tap water that smells and tastes like public swimming pool water.
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You obviously don't know where I often work - swimming pool water would be welcome, try water that came from a well near 2500 head of cattle or pigs. Some might not want it even it if was tested safe or even purified right in front of them. I'd probably drink it as long as it don't have any harmful bacteria in the test. High nitrates - probably not good to drink it all the time, but once in a while isn't going to hurt you.
 
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