memory saver

[monoxide]

hey guys every once in a while i will go fishing and fall asleep watching a movie in the truck and my battery will die but not enough to erase my eq settings and all that on my headunit and i have to get a jump start and then take my battery out and charge it. is there a thing i can make/buy that i can hook up to my battery cables before i take my battery out and it will keep just enough voltage in the cables to keep my settings there till i put my battery back in. i would like to run dual batterys but i dont have the money to do that right now. so is there some thing i can make or buy that can do this?

[Wicks]

Something like this:

http://batterytender.com/motorcycle/battery-tender-junior-12v-at-0-75a.html

Any small 12V charger with some large alligator-type clips.

Could also get a 12V wall wort from Radioshack that had about 1A of current capacity. Cut off the plug and solder on some clips.

Just plug the charger in and clamp it on your battery terminals or at another location under the hood where they won't get disturbed and lose connection.

Swap out the battery and reconnect it before removing the charger.

Just make sure to keep the key in the vehicle off so the car's accessories don't try to draw from the little charger, just the headunit memory.

Hell, even two 6V flashlight batteries in series would work.

[Wicks]

On second thought, your battery is going to be a load on the system and will therefore draw some current from the charger.

So you'll have to make sure the charger is either current limited or that it can handle the draw.

Or make sure you swap the two very quickly.