Automotive

Charging car battery without a wall outlet

  • Last Updated:
  • May 16th, 2021 2:02 pm
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Sep 9, 2012
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Oakville, ON
What would MacGyver do? I’m thinking that even MacGyver would be stumped given OP’s requirements…
Deal Expert
Mar 23, 2004
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CanadianLurker wrote: What would MacGyver do? I’m thinking that even MacGyver would be stumped given OP’s requirements…
Buy bags of lemons, put like 16 of them in series, connect in parallel with car battery. Repeat as many times as necessary to charge battery.
Sr. Member
Feb 17, 2004
563 posts
249 upvotes
I'm calling OP out as a troll. Real car batteries have much more than 60Ah or 90Ah, more like 500-900CCA but nominal is still several hundred Ah. Unless they're talking power wheels Barbie car.

Truth is there is very little you can do for a car sitting in a barn with no electricity. Your option is to get a mini nuclear station or one of those Russian radioactive power plants they use in remote lighthouse locations.
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Feb 8, 2014
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Look for an outlet nearby and use that for charging. 100ft extension cords can be had for somewhat reasonable prices.
In fact in Rand McNally they wear hats on their feet and hamburgers eat people
Banned
Apr 28, 2021
36 posts
21 upvotes
mawzi wrote: Hi guys, I have my car parked in a garage with no access to electricity. I don't want to take the battery out of the car.

I'm looking for ideas to charge it periodically. Battery is 90AH. Ease of use and cost are a factor.

Thanks a lot.
Just drive the car for 20 minutes, park it and disconnect the negative terminal. Done! You are good until winter
Deal Guru
Jun 24, 2006
13383 posts
7646 upvotes
Hmmm, I never understand the need for this vs disconnecting the negative terminal.

My parents have a house in Arizona and are gone for 6 months a year. Every fall I go out to their house, disconnect the batteries to their vehicles. Every spring, the week before they come back, I go and re-connect the batteries, start the cars and go for a little drive. I have been doing this for many years, and never had one not start, and both vehicles still on the original batteries.
Deal Addict
Jun 14, 2008
4228 posts
3057 upvotes
Montreal
No such thing exist.

I've thought about how would I do it if I moved to a condo, and the only way I see is to have a large lithium jump starter with 12v output, plug a small inverter into that, then a battery maintainer into the inverter. Efficiency will be crap, but will charge battery without outlet. Or just an lithium power pack with built in 120v outlet, but those are expensive.
[OP]
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Jan 3, 2007
1161 posts
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Toronto
jzmtl wrote: No such thing exist.

I've thought about how would I do it if I moved to a condo, and the only way I see is to have a large lithium jump starter with 12v output, plug a small inverter into that, then a battery maintainer into the inverter. Efficiency will be crap, but will charge battery without outlet. Or just an lithium power pack with built in 120v outlet, but those are expensive.
I have used a spare car battery, and hooked a 12V to 110V inverter to it, and then a trickle charger connected to car battery. It appears to be working for like 20 mins, and then it shuts down.

Spare Battery > inverter > charger > Car battery

Like someone else said, probably too much loss from all the conversions to get a good charge.

My other solution was to buy one of the big lithium battery boosters that comes with 110v output, and connect a charger to it every couple of months to refill the car battery.

The problem is my car battery is very heavy, and tedious to remove/install. I'd rather keep it in the car, and disconnect the negative. I would charge it every 3 months, turn the car on, move it a couple of meters to prevent brakes from seizing, and for the sake of all the engine components/seals/hoses...
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Jul 26, 2008
958 posts
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Montreal
v82slo wrote: I'm calling OP out as a troll. Real car batteries have much more than 60Ah or 90Ah, more like 500-900CCA but nominal is still several hundred Ah. Unless they're talking power wheels Barbie car.

Truth is there is very little you can do for a car sitting in a barn with no electricity. Your option is to get a mini nuclear station or one of those Russian radioactive power plants they use in remote lighthouse locations.
I think OP is correct he if says his battery has 90Ah.

Amp Hour or C20 is an indicator of how much energy is stored in a battery. It is the energy a battery can deliver continuously for 20 hours at 80°F without falling below 10.5 volts.

In all the cars I have owned it seems the batteries only had the CCA rating, but that's not always the case as in this battery :

Image

check out this site its got a chart in the article that shows the Ah and CCA for a bunch of different batteries.

https://autocar-inspection.blogspot.com ... ttery.html
Deal Addict
Jun 14, 2008
4228 posts
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Montreal
mawzi wrote: I have used a spare car battery, and hooked a 12V to 110V inverter to it, and then a trickle charger connected to car battery. It appears to be working for like 20 mins, and then it shuts down.

Spare Battery > inverter > charger > Car battery

Like someone else said, probably too much loss from all the conversions to get a good charge.

My other solution was to buy one of the big lithium battery boosters that comes with 110v output, and connect a charger to it every couple of months to refill the car battery.

The problem is my car battery is very heavy, and tedious to remove/install. I'd rather keep it in the car, and disconnect the negative. I would charge it every 3 months, turn the car on, move it a couple of meters to prevent brakes from seizing, and for the sake of all the engine components/seals/hoses...
Probably battery voltage dropped below inverter's operating level.

But if you are willing to buy one, you can get these for as low as $150 now. https://www.amazon.ca/GOLABS-Portable-P ... B08NSYCZD4
Deal Expert
Jan 27, 2006
20709 posts
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Vancouver, BC
Covrig wrote: Just drive the car for 20 minutes, park it and disconnect the negative terminal. Done! You are good until winter
Disconnecting the negative terminal will do more than driving the car for 20 minutes. It has been shown that simply driving the car for a few minutes does little to charge the battery in modern cars. Maybe in your grandfather's day but not today.
Deal Expert
Jan 27, 2006
20709 posts
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Vancouver, BC
Gutty96 wrote: Hmmm, I never understand the need for this vs disconnecting the negative terminal.

My parents have a house in Arizona and are gone for 6 months a year. Every fall I go out to their house, disconnect the batteries to their vehicles. Every spring, the week before they come back, I go and re-connect the batteries, start the cars and go for a little drive. I have been doing this for many years, and never had one not start, and both vehicles still on the original batteries.
Most cars will drain a bit of power over time to keep settings in place. Some cars (especially those with dash cams and the like) will drain more from the battery than a car that is just stock. SO, disconnect the battery on some cars will make a world of different while others we are talking about a 50 mA drain which is pretty close to nothing.
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Nov 7, 2016
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Ontario
Pull the battery or lug a portable generator over there with a charger.
[OP]
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Jan 3, 2007
1161 posts
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Toronto
jzmtl wrote: Probably battery voltage dropped below inverter's operating level.

But if you are willing to buy one, you can get these for as low as $150 now. https://www.amazon.ca/GOLABS-Portable-P ... B08NSYCZD4
This is actually a good option. I wonder if I can trust its built in car charger, or I should connect its 110V outlet to my charger.
Deal Expert
Jan 27, 2006
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Vancouver, BC
mawzi wrote: This is actually a good option. I wonder if I can trust its built in car charger, or I should connect its 110V outlet to my charger.
Basically, it has a 63 Ah battery at 3.2V which isn't much once you convert it to 12V. I believe the built-in car charger is for your car to charge the device via the 12V access. port and not for the device to charge your car.
[OP]
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Jan 3, 2007
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Toronto
craftsman wrote: Basically, it has a 63 Ah battery at 3.2V which isn't much once you convert it to 12V. I believe the built-in car charger is for your car to charge the device via the 12V access. port and not for the device to charge your car.
I was being hopeful. They don't have a picture of the cable.
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Jun 12, 2007
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mawzi wrote: I have used a spare car battery, ...
If you already have a spare car battery, just rotate them around every few months and recharge the one that's removed from the car
Banned
Apr 28, 2021
36 posts
21 upvotes
craftsman wrote: Disconnecting the negative terminal will do more than driving the car for 20 minutes. It has been shown that simply driving the car for a few minutes does little to charge the battery in modern cars. Maybe in your grandfather's day but not today.
craftsman wrote: Most cars will drain a bit of power over time to keep settings in place. Some cars (especially those with dash cams and the like) will drain more from the battery than a car that is just stock. SO, disconnect the battery on some cars will make a world of different while others we are talking about a 50 mA drain which is pretty close to nothing.
Both me and Gutty96 say about disconnecting the negative terminal and you somehow keep at it that cars drain the battery to keep settings. How can it drain it if the battery is disconnected. And I'm saying to drive the car for 20 minutes before disconnecting the battery so it would be full, you're saying driving for a few minutes won't do much. 20 min vs few is a big difference.
Deal Expert
Jan 27, 2006
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Covrig wrote: Both me and Gutty96 say about disconnecting the negative terminal and you somehow keep at it that cars drain the battery to keep settings. How can it drain it if the battery is disconnected. And I'm saying to drive the car for 20 minutes before disconnecting the battery so it would be full, you're saying driving for a few minutes won't do much. 20 min vs few is a big difference.
Simple - read my statements again as you are taking both of my comments out of context. The first statement I made was in response to your statement about driving a car for 20 minutes to fully charge a battery which isn't going to happen as people have driven their cars for a hour or more trying to charge their battery fully and find that the battery still isn't full so what can 20 minutes do? Not much. As for 20 minutes vs a few minutes, that's all relative to what someone considers a long time. I consider a 20-minute drive a relatively short time when it comes to needing to charge a battery. Plus, the output of a standard alternator needs to be consistently over 2,000 to 2,500 RPM before it will generate enough power to even start charging the battery. Considering that most cars these days try to keep the RPM fairly low in order to save on gas, you need to drive that car fairly hard over those 20 minutes to even start charging the battery. Besides, where did you get the magic number of 20 minutes from anyways? I never mentioned anything about cars draining power from the battery when I responded to your comment so I don't know how you can you can connect my initial comment to you with that idea.

The second statement was in response to someone commenting that they disconnect the battery for 6 months of the year and why the battery was in decent shape afterwards. The statement I made was to add a bit of context to their statement.

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