Battery-back up??

[ozmdd]

OK... I use an ultralight battery when I race, and then run my OEM battery the rest of the time. So far, I've just used a pair of jumpers and a lot of caution when swapping batteries to avoid losing continuous power to the car.

Is there a way to provide battery backup via the 12V plug, or some other way to swap the batteries without losing battery backup? Someone even suggested removing the battery while the car is running, but I don't want to freak-out my ECU unnecessarily.

[nick.dollimount]

Is this just so you don't have to set your time? Or maybe the radio presets? Seems like a lot of trouble to go through just for that.

[ozmdd]

Thanks. Now, does anyone have USEFUL information?

[severous01]

first off....DO NOT UNPLUG BATTERY WHILE CAR IS RUNNING. you'll destroy the ecu. old school you could, because the whole setup was run off a cap, that was charged by the alternator, and a distributor that ran off the cam no matter what. now you have a distributorless engine, and timing is set thru computer.


a cheap way to fix ur problem, and it's very simple...is to get a jump box with a cig lighter adapter. and a jumper. just be careful cuz with your terminals still active.....and they're hangin in the air....

another option from jcwhitney.com is a 9v battery with a cig plug. it wont last long, but you have time to change out batt's with no problems.

[CTScott]

I would back feed it from the inside fuse panel. If you look at the pic below, the red female spade terminal (which is the constant power feed for my remote starter) is the easiest place to tap to constant +12. You can then tap ground at the ground bolt under the driver's kick panel. You could use a pair of 2 pin connectors (even a panel mount tubular power connector for super quick and easy connect/disconnect). For the temporary battery, you could use a tiny motorcycle or alarm panel battery.

http://i372.photobucket.com/albums/oo163/ctscott329/Misc%20Yaris/12VConstant.jpg

[ozmdd]

Perfect. I thought the 12V plug would work, but wasn't sure. I also figured the new distributor-less engines wouldn't like the battery to disappear. Great info!

[CTScott]

The cigarette lighter solutions will only work if you leave the key in the ACC position, when swapping the battery.

[ozmdd]

Makes sense. Didn't think of that. Again, you enlighten me!

[severous01]

ya....i'd forgotten about the acc thingy....

any way, it's just a 9v battery, pos connected to pos, and neg connected to neg, with a cig lighter adapter. easy, cheap, and can be acquired anywhere.....check your used and unused (any more) cellphone adapters. just strip and get a connector for 9v batteries at radioshack.