Dream Theater

Hi All,

Is there a way to change the battery where I don't have to reset the radio code
or have to go through all that revving the engine and driving 50 - 55mph for 30 miles smog check B.S.?

Thanks

flanders

Just connect a 12V power source to the terminals or the fusebox.

windhund116

If you have trickle charger, keep it connected to battery terminals, as you replace the battery. There is one of these things that hook to the OBDII port. You connect the other end to a cigarette lighter, on another car or 12VDC source to maintain power to the ECU.

Car Analogy

A lomg time ago, probably before many on this forum were born, I rigged up a simple gadget for this purpose. Using a single 9v battery, a radio shack battery connector, and some very large alligator clips (more like mini jumper cable clips).

Make sure the wire is long enough to reach both battery terminals, and make sure to get the polarity correct.

Even though the battery is only 9v, its enough to keep the radio and ecu going, as they only use 5v.

The problem with using a trickle charger is if its a smart charger, as soon as you disconnect the battery, it senses that and shuts itself off. You'd need a dumb charger that just supplies current no matter what.

You could also take an old power supply from some broken household appliance, one of those little black box transformers that plugs into an outlet, so long as it supplies something between say 9v-16v dc, and connect your alligator clips to that. That could also be used as a crude, dumb trickle charger, and could also be left connected to cars battery terminals to preserve ecu and radio settings long term when cars battery removed, longer than the 9v could ever do. Again, just make sure to get polarity correct.

flanders

That 9V battery wont be very happy when you reconnect the car battery again.

Dream Theater

Thanks everyone, I'll pick up a 12v power supply and give it a go.

Chuck S

You don't have the radio code? Little card came with the new card and it's often hand written on one of the booklets.


-- Chuck

cosmomiller

I always thought the cycling of the charger would screw it up. Once the battery is disconnected, the 12V source is gone and the charger (mine at least, 25 year old) would stop providing power as it does not detect a battery.

Sometimes when a battery voltage is very low and the charger will not operate, I have to link a good 12v battery to the dead battery to bring up the charge enough for the charger to operate.

hoobastnk90

couldn't you just hook up jumper cables to another battery while your disconnecting the old one?

windhund116

Yes, you are correct. Prolly safer to go to a dedicated unit that keeps power through the OBDII port. That way you don't lose connection to the car, while messing with the old & new batteries.