Throw a little conduit over your wires and voila! You have a portable 12-volt power source that you can easily keep at the requisite 12-volts as long as you have a steady supply of AA batteries. The project costs around $20 and only took an hour to build, including the trip to Harbor Freight and Radio Shack.

Power. We use it for so many things: communication, video, overtaking a small Third World nation. For this discussion, we will stick with electrical power. As racers we mostly use 12-volt power to run or recharge our different cameras, radios, transponders, data acquisition systems, etc. Sometimes at the track I have found I don’t have enough 12-volt receptacles to handle all the things I want to charge or, even worse, I don’t have enough vehicle battery afterward to start the motorhome when it is time to leave. But now, thanks to a little ingenuity, a few bucks, and some electrical engineering know-how, I have a solution for portable, renewable 12-volt power using AA batteries.

It turns out that eight AA batteries combined churn out 12-volts of power, the exact amount of power that run vehicle electronics. The good news is that AA batteries can be located anywhere and everywhere. Just look in your wife’s bedside table. She has a stash of these things … for the remote control, of course. Since these batteries are easy to locate and replace, it means that by building a small portable power system using eight AA batteries, you will never run out of juice and you can use it anywhere.

I originally came up with this concept while trying to set up a Racepak data logger system. The digital dashboard/lap timing system required 12-volt power to be turned on and it required a fair amount of laptop time to set up the system for a particular vehicle. I didn’t feel like climbing through the roll cage and squatting inside the racecar while balancing the laptop on my knees to get this done. I thought it would be easier to have a portable 12-volt power system on a table to power the unit up and I could take the time to get the system working while comfortably sitting in a chair. First I considered bringing in the battery from my wife’s car and setting it on the kitchen table to power the unit. Then I remembered I didn’t want to get divorced.

A Google search, $20 in parts, and trips to Radio Shack and Harbor Freight got me exactly what I needed to build a portable, renewable 12-volt power source to solve my problems. Radio Shack carries an inexpensive plastic eight-AA battery pack. I picked up some wire and a 12-volt extension cord from which to salvage a 12-volt receptacle. I spliced the wire from the receptacle and connected it to the battery pack with a 9-volt connection wire, which is nice because it is already color coded red and black, and you can’t connect it to the battery pack the wrong way.

Once I had the system built, I used a voltmeter to ensure that the voltage from the eight AA batteries was what Google told me it would be, and it was a perfect 12.99 volts. Most vehicle electronics require 10-15 volts to work. Because I added a 12-volt receptacle to the portable power source, then I could connect a multitude of devices to get power: GoPro camera, cell phone, transponder, or what I started the project for, a data logger. Once I had the little system built, I found all sorts of uses for it, like cellphone power while camping, and anytime the power goes down, I just need to replace the AA batteries.

I also found that by using a USB adapter, I can power a GoPro camera for much longer than the internal battery will allow, thanks to the external power. This is nice, especially when using a 32 gig SD card during a long endurance race. Once the race is over, I install eight more AA batteries and I am back in action with all the power I need. The only complaint about the system comes from my wife, since her household AA battery stash keeps getting mysteriously depleted. Oh well, she’ll live. Enjoy the power and I’ll see you at the track.

For this project, you will need a battery holder for eight AA batteries, which equals 12-volts, and the connecting wire. Radio Shack carries these items and they will only set you back about $7.
For this project, you will need a battery holder for eight AA batteries, which equals 12-volts, and the connecting wire. Radio Shack carries these items and they will only set you back about $7.
A trip to Harbor Freight will supply you with some solderless connectors, wire, a 12-volt extension cord (you will use the female end), and a bunch of AA batteries. Total cost: around $14.
A trip to Harbor Freight will supply you with some solderless connectors, wire, a 12-volt extension cord (you will use the female end), and a bunch of AA batteries. Total cost: around $14.
AA batteries are some of the most common and inexpensive batteries you will find. Because they are so common, they are the perfect battery to use in a portable power source. Eight of these together make 12-volts of power.
AA batteries are some of the most common and inexpensive batteries you will find. Because they are so common, they are the perfect battery to use in a portable power source. Eight of these together make 12-volts of power.
Here is your battery pack, filled with eight AA batteries, which will provide 12-volts of power. To connect power, a simple 9-volt battery connector will get the juice flowing.
Here is your battery pack, filled with eight AA batteries, which will provide 12-volts of power. To connect power, a simple 9-volt battery connector will get the juice flowing.
To make sure your battery pack is working to the correct voltage, use a voltmeter and check your readings. Here you can see we are getting a sweet 12.99 volts from our little portable battery pack. Most automotive electronics require between 10 to 15 volts to function.
To make sure your battery pack is working to the correct voltage, use a voltmeter and check your readings. Here you can see we are getting a sweet 12.99 volts from our little portable battery pack. Most automotive electronics require between 10 to 15 volts to function.
You will need to use the female end as a receptacle for your portable power source. A simple snip with some wire cutters is all it takes. You can save the male end for mating with an electronic device you want to connect to power later, for instance, a digital dashboard from a racecar.
You will need to use the female end as a receptacle for your portable power source. A simple snip with some wire cutters is all it takes. You can save the male end for mating with an electronic device you want to connect to power later, for instance, a digital dashboard from a racecar.
Instead of making a mess with a solder gun, press the easy button and just use a premade 9-volt battery harness to connect with the portable power source. The nice part is these wires are already correctly color coded red and black. The connector will ensure you don’t accidentally switch the polarity as you plug it in to your power source.
Instead of making a mess with a solder gun, press the easy button and just use a premade 9-volt battery harness to connect with the portable power source. The nice part is these wires are already correctly color coded red and black. The connector will ensure you don’t accidentally switch the polarity as you plug it in to your power source.
Once your 9-volt wire is connected to your battery pack, you can prepare to splice in your female 12-volt receptacle. This will allow you to easily connect any number of devices that can benefit from 12-volt power.
Once your 9-volt wire is connected to your battery pack, you can prepare to splice in your female 12-volt receptacle. This will allow you to easily connect any number of devices that can benefit from 12-volt power.
Using the continuity setting on your voltmeter, determine which wire on your receptacle is ground and which wire is power. Then you can use solderless crimp connectors to hook the receptacle to your 9-volt wires to ultimately connect to your eight-AA battery pack.
Using the continuity setting on your voltmeter, determine which wire on your receptacle is ground and which wire is power. Then you can use solderless crimp connectors to hook the receptacle to your 9-volt wires to ultimately connect to your eight-AA battery pack.
To do a quick check to ensure your portable power source is working, simply plug in a cellphone charger and see if things light up like they should. We have all run out of cellphone power at some point. Made for a lot less than some aftermarket portable power systems, this device works anywhere at any time.
To do a quick check to ensure your portable power source is working, simply plug in a cellphone charger and see if things light up like they should. We have all run out of cellphone power at some point. Made for a lot less than some aftermarket portable power systems, this device works anywhere at any time.
These little 12-volt USB converters are sitting on the counter of nearly every convenience store you go into (in your case, liquor store). Pick one up for less than $5 and make your portable power source even more versatile.
These little 12-volt USB converters are sitting on the counter of nearly every convenience store you go into (in your case, liquor store). Pick one up for less than $5 and make your portable power source even more versatile.
With the USB converter in my portable power source, I can charge a GoPro camera between sessions without depleting the battery on my racecar. You also can mount this system in a car during a long endurance race where you want that 32 gig SD card to cover the entire race, but the GoPro battery alone won’t last long enough.
With the USB converter in my portable power source, I can charge a GoPro camera between sessions without depleting the battery on my racecar. You also can mount this system in a car during a long endurance race where you want that 32 gig SD card to cover the entire race, but the GoPro battery alone won’t last long enough.
Here is the real reason I started this project, to provide juice to a digital dashboard Racepak data logger that requires a laptop to setup. I didn’t want to sit inside a racing seat for hours messing around with software on my laptop. I wanted to sit comfortably in my kitchen to do it, so I brought 12-volt power to my kitchen and was able to dial in the system easily.
Here is the real reason I started this project, to provide juice to a digital dashboard Racepak data logger that requires a laptop to setup. I didn’t want to sit inside a racing seat for hours messing around with software on my laptop. I wanted to sit comfortably in my kitchen to do it, so I brought 12-volt power to my kitchen and was able to dial in the system easily.
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Image courtesy of Rob Krider