Backfeed the battery??

[Bluecoupe]

I noticed when I connected up my battery charger that my negative lead is slightly rusted. I want to disconnect it and clean them up, but I don't want the computers to lose their minds. An old GM trick is to hook up a 9 V battery to a cigarette plug and plug that in to the lighter outlet. This way the CPU's still have 5V when you disconnect the main battery leads, and you don't lose the info stored in them.
Anyone tried this with a Viper?

[Steve M]

Nothing will lose its mind if you disconnect the battery - if it is disconnected for long enough, the readiness tests will all reset and require some driving around to show complete, and you might have to do a window relearn (roll them all the way down and hold for 5 seconds, then all the way up and hold for 5 seconds). Things like fuel trims will all relearn with a little driving around.

If it is the original battery, I'd consider replacing it.

[Viper vince]

I have thought about this and I would connect another battery under the hood. Then disconnect the battery like you would jump it.

[Steve M]

I have thought about this and I would connect another battery under the hood. Then disconnect the battery like you would jump it.

Just keep in mind that when you go to disconnect the wires in the back, they will still be live, so any contact with metal will cause a nice spark show.

[Bluecoupe]

Just keep in mind that when you go to disconnect the wires in the back, they will still be live, so any contact with metal will cause a nice spark show.

Yep, that is why a 9 V, not enough current to spark, if anything shorts out, but enough to keep the EPROMS happy. Definately do not want to hook a second auto battery in parallel, you may do some unplanned welding!

It is not the original battery, it is a Diehard. I suspect what happened is that some rain water got up on the negative terminal when I brought her home last June from Augusta, Ga. I went throught the worst thunderstorm/gulleywasher I have ever seen in Vicksburg, Ms (at least the GPS said Vickburg was out there, I couldn't see 50' out the windshield). Some water got up there and caused some surface rusting. The + terminal is looking good, a quick clean and a light coat of grease and the negative will be good to go.

[FrgMstr]

I have had my battery unhooked for multiple days without issue multiple times. Don't sweat it.

[ViperTony]

I think you're looking for something like this: http://www.amazon.com/CTA-Computer-Memory-Saver/dp/B000GKD5Q0?tag=5336612429-20

[Bluecoupe]

I have had my battery unhooked for multiple days without issue multiple times. Don't sweat it.


I think you're looking for something like this: http://www.amazon.com/CTA-Computer-Memory-Saver/dp/B000GKD5Q0?tag=5336612429-20

Yep, that looks like mine, but I got the parts from radio shack about 1991.

[Steve-Indy]

I have used the device shown in ViperTony's link on Gen II and Gen III Vipers successfully when removeng the car's battery. I believe mine was purchased at Radio Shack several years ago.

[67PLY]

It won't work if your cig lighter is powered on and off with the key. Key off-no joy. I've always used the device that plugs into the OBD-2 port, as it is direct line to electrical system, key-on or key-off.

Joe B

[Troublemaker]

I would parallel, but I would try to get the same voltage with only a couple of amps if I was going to do this. Honestly trying to get the car to relearn to idle was the hardest part after the battery went dead for a month, it took me about 20 minutes. It was something like keep feathering the throttle until it caught enough to idle, let it sit for 10 minutes like that, then turn the AC on and do it again. I don't know if 9 volts is enough of a voltage reference, that's above my head.

[Steve-Indy]

As JonB ususlly notes..."the year matters".

Gen I and II Vipers have "live" cigarette lighters with ignition off. On Gen IV Vipers, BOTH lighter sockets are dead with ignition off...can't check Gen III as it's off site.

[SSGNRDZ_28]

One option would be to adapt a (12 power supply / transformer or battery) into an SAE-2 Pin connector that mounts up to the battery tender harness. Instead of a battery tender, connect a power source.

http://batterytender.com/ring-terminal-harness.html

This harness is able to be permanently mounted to the battery leads via the ring terminals. This would also work with the hard mounted DSE battery tender connector.

If this is done please insulate the positive terminal to prevent it from shorting anywhere on the chassis or negative terminal.