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Discussion Starter #1
Apparently, both 12V power plugs only supply power while the car is on or in RAP mode, which only lasts 10 minutes. I want to keep power to my Engel cooler while I'm at work for 10 hours occasionally. The cooler draws an average of 30W, which I calculate to be roughly 27 Ah for the duration I would need it to run with the car off. Does anyone forsee any problem with directly wiring a 12V accessory plug to the battery in the rear hatch area and using that to power the cooler?
 

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I don't know the capacity in Ah of the 12V battery, but assuming it is 250 Ah or greater you would only use about 10% or less for 30W / 10 hours. As long as the car does not get upset by this current draw when the car is off it should work, but I would try it one time over the weekend when you are going to be home all day as a 'dry run'.
 

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I don't know the capacity in Ah of the 12V battery, but assuming it is 250 Ah or greater you would only use about 10% or less for 30W / 10 hours.
250 Ah on a 12V battery would be 3 kWh. :rolleyes:

I had a surprisingly difficult time finding any specs for a Gen 2 Volt-compatible 12V battery, but this Gen 1-compatible battery one at Autozone specifies 60 Ah. http://www.autozone.com/ignition-tune-up-and-routine-maintenance/battery/duralast-platinum-battery/338292_537162_0

Sounds like a bad idea to me.
 

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Eric,

I believe the OP has a 12VDC compatible cooler so he would not necessarily require a DC to AC inverter.

But I would suggest the OP score a 12V battery jump pack as I think a flat 12V AGM is going to happen if the Volt is left powered off with the cooler sapping juice from the AGM all day in Arizona heat!;)
 

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I wouldn't draw down the 12V 50% on a regular basis (27Ah out of 60), but you might be able to get away with it for occasional use. You could also remote start the car twice during the day, which should top off the 12V (and cool the cabin / traction battery in crazy AZ heat).

More fun would be to get a 100W solar panel stored in the back hooked directly up to the cooler. When parked at work, pull the panel out and position (roof rack?) for optimal power. Actually, I think there are smaller panels (10-30W-ish?) that you could keep mounted inside the car and use to trickle charge the 12V while your cooler draws from it. Might actually work.
 

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Discussion Starter #7
Yeah, I have come to the same conclusion. I guess I'll just pick up a separate 12V AGM deep cycle battery to lug around with the cooler for the days I need it. Then I can recharge it once I get home again.
 

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Best possible solution would be to purchase an extra smaller AGM battery to run the cooler from. Then get a 12 volt relay that is powered on by the ignition to allow recharging of the extra battery. That way the main AGM battery is always at full charge, and the operation would be completely automatic and safe. The extra battery might be low enough profile so it will fit in the rear hatch storage area, which would make it a very neat and tidy installation.
 

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Yeah, I have come to the same conclusion. I guess I'll just pick up a separate 12V AGM deep cycle battery to lug around with the cooler for the days I need it. Then I can recharge it once I get home again.
Wow...just googled the Engel cooler website and I had no idea 12VDC coolers could be so expensive but this makes sense since they are actually are just tiny refrigerators!:eek:



Although also not very cheap, Yeti or Grizzly are a couple of cooler brands that supposedly will keep ice for 5 days (maybe less than 3 in Az temps:p). You also wouldn't have to lug a full sized 12V AGM around or worry about recharging it...
 

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Eric,

I believe the OP has a 12VDC compatible cooler so he would not necessarily require a DC to AC inverter.

But I would suggest the OP score a 12V battery jump pack as I think a flat 12V AGM is going to happen if the Volt is left powered off with the cooler sapping juice from the AGM all day in Arizona heat!;)
Hi Rich,

Correct. The wiring kit works quite well for DC applications as well though, you just connect some DC terminals to the end instead of an inverter :)

But like you and others point out, the real question is whether or not the 12V battery can handle the load for that duration of time without the Volt being powered on. Seems like the 12V battery is not large enough.
 

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Discussion Starter #11 (Edited)
I'm currently living in a 5th wheel during the week for work. I'm 25 miles from any ice of any significance. I have been trying the ice cooler method, but by the time I get enough ice in there to keep the 130-degree car temperatures at bay, there isn't much room left for all the produce I need to transport back home 180 miles away (and soggy produce is less than ideal as well). I even tried dry ice once, but even with a towel between it and the food, some of my veggies and fruit got frosty. So my options are to either drive back to my 5th wheel after a 10-hr work day, adding another 30 minutes of driving, and then drive 3 1/2 hours home, or to figure out how to power my Engel cooler while at work. I have also considered the solar panel option. A panel in my front windshield area may be possible. Too much dark tint everywhere else and leaving the panel outside the car isn't an option. I think I'll look into the solar panel idea a bit further.
 

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Yeah, I have come to the same conclusion.
Why not just leave the car turned ON? You'd have to put a rubber band around the button on the shifter to full the car into thinking it was NOT in Park, or it would turn off after 1 1/2 hrs or so. This would be a lot easier; you could lock it and nobody would know it was running, and the the 12v would be kept charged by the DC-DC converter. The measly .3kWh would be negligible for the traction battery.
 

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Why not just leave the car turned ON? You'd have to put a rubber band around the button on the shifter to full the car into thinking it was NOT in Park, or it would turn off after 1 1/2 hrs or so. This would be a lot easier; you could lock it and nobody would know it was running, and the the 12v would be kept charged by the DC-DC converter. The measly .3kWh would be negligible for the traction battery.
I have to agree especially since fuel is so damn cheap right now...

Yes, you would have to defeat this 2.5hr auto-off timer thru a simple rubber band or some 'other' method: Pushbutton Mods to Enable/Disable Triple-Honk Vehicle ON Warning and Auto-Off recall
 

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I'm currently living in a 5th wheel during the week for work. I'm 25 miles from any ice of any significance. I have been trying the ice cooler method, but by the time I get enough ice in there to keep the 130-degree car temperatures at bay, there isn't much room left for all the produce I need to transport back home 180 miles away (and soggy produce is less than ideal as well). I even tried dry ice once, but even with a towel between it and the food, some of my veggies and fruit got frosty. So my options are to either drive back to my 5th wheel after a 10-hr work day, adding another 30 minutes of driving, and then drive 3 1/2 hours home, or to figure out how to power my Engel cooler while at work. I have also considered the solar panel option. A panel in my front windshield area may be possible. Too much dark tint everywhere else and leaving the panel outside the car isn't an option. I think I'll look into the solar panel idea a bit further.
I could guess where you are for work, I've had my fair share of trips out there for work that are miles from the nearest fridge (or paved road, for that matter). ;)
 

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I'm currently living in a 5th wheel during the week for work. I'm 25 miles from any ice of any significance. I have been trying the ice cooler method, but by the time I get enough ice in there to keep the 130-degree car temperatures at bay, there isn't much room left for all the produce I need to transport back home 180 miles away (and soggy produce is less than ideal as well). I even tried dry ice once, but even with a towel between it and the food, some of my veggies and fruit got frosty. So my options are to either drive back to my 5th wheel after a 10-hr work day, adding another 30 minutes of driving, and then drive 3 1/2 hours home, or to figure out how to power my Engel cooler while at work. I have also considered the solar panel option. A panel in my front windshield area may be possible. Too much dark tint everywhere else and leaving the panel outside the car isn't an option. I think I'll look into the solar panel idea a bit further.

Instead of tapping into the car's power, how about adding some GoalZero accessories

http://www.goalzero.com

They have solar panels and lithium Ion battery power packs that are flexible and interoperate. So while driving you can charge the batteries with the car. While parked, you can setup an array of solar panels in your windshield and rear hatch (hopefully you have a VoltShelf), and then run the cooler off of the power pack and solar panels. I'm not sure whether there's enough power to last all day, but it seems like anything is better than nothing. These do get pricey as you go bigger and bigger. It's really designed for phones, tablets, laptops, etc.
 

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Discussion Starter #16 (Edited)
The measly .3kWh would be negligible for the traction battery.
It would be .3kWh plus whatever power the car used to keep all the systems up and running, battery cooling, etc. I would guess it would be closer to 7kWh in this desert heat. I'll give it a try this weekend and see how much power the car uses without anything plugged it.

Edit: Missed a decimal point there...
 

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It would be .3kWh plus whatever power the car used to keep all the systems up and running, battery cooling, etc. I would guess it would be closer to 7kWh in this desert heat. I'll give it a try this weekend and see how much power the car uses without anything plugged it.

Edit: Missed a decimal point there...
It make me wonder, is it more efficient to run the cooler in a hot car, or turn on the AC, burn some fuel if needed, and cool the car so the cooler doesn't have to work so hard to maintain temps?

Also, is it possible to get the entire car under shade to reduce that 130 degree in-the-sun temps? Maybe consider getting a car cover.
 

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I'll just add to the negative side - I tried this once with my old car with a (full size) lead acid battery.
Did the math and figured it would be ok for 8h - nope. Failed to start upon return.
Obviously an ICE needs more power to start, but the volt is also finicky sometimes on lower charge 12V.

What is work? No power there either? I'd be looking to plug the cooler into grid power if available.
 

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Discussion Starter #19
No power, no shade. We do have bottled water though. :D The Goal Zero looks interesting. Sure has a price tag though. Might just decide to pay the premium anyway just for the convenience.
 

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Related question - how well does the cooler work in such extreme heat?

Mine says it only works to about 40 degrees below ambient, IIRC.
That would only be 90 if it's 130 - nowhere near cold!
 
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