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.
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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.