12v battery issue

12V can cause all kind of gremlins I had a list of strange behavior and after a ne2 battery they are all gone

 

Prius 12V batteries are wimpy. Leaving the lights on or a door ajar for a few hours can kill an old one. Always lock the car; a long warning beep will remind you of most common battery draining boo-boos.

Try the no-tools self-test procedure:
PriusOnline.com • View topic - how to put 12V battery in sleeping mode?
If it reads less than 12.0V under load it's dying.

 

The Prius is a different type of car with a different type of 12V battery. The 12V battery on the Prius is only used to provide standby power and boot the systems. It never does any cranking. This means you don't see it failing. It gets closer, closer, and then gone before you really know that you have a problem. Also, as mentioned above, it's a small battery. It won't take much abuse from open doors and left on lights.

Tom

 

I have. Hot weather is particularly hard on lead acid batteries; I have had a few fail without warning when the ambient temps were high (>100°F). I also had a Ford Ranger that would go through batteries every 2 or 3 years, although my Ford Explorer battery lasted about 6 years before needing replacement.

 

Hi Dan,

This would be a good analogy if the little battery in the computer also energized the control circuitry and a relay that allowed AC power to flow to the computer's power supply...

Regarding a 12V battery dying with no warning, this happened on a 2002 Ford Taurus that I used to own. My wife was stranded at a local shopping center. I bought a new battery and installed it at the shopping center parking lot.

 

From reading the forum, I know all about the 12V battery issues (and from having seen the thing, I know it's wimpy) but it never dawned on me that in a "normal" car cranking slow is a good warning that the battery is nearing the end of its lifecycle. And since our cars do not use the 12V to crank the engine, we get no advance warning. Interesting. This explains why we get all those wierd issues when the voltage is dropping - had the 12V been starting the engine, it would have been very slow and been replaced long before the point of causing computer issues.

I had an Alfa that had similar issues - it wouldn't boot the fuel injection computer, or it would but would give sensor errors when the voltage was below the switching voltage for the transistors in the computer. It would even crank slowly but not run if the fuel injection computer wasn't switching in (obviously - no fuel).

 

$216 for a low amp battery is a real insult. $275 for DVD updates is a huge rip off. I understand factory parts are more expensive than aftermarket, but this ain't right.

Toyota needs to get this more in line with other cars.

 

I don't know the local Nissan dealer wanted $159 for my friend to buy a new battery for her Altima, Part only no installation or inspection. I agree that this seems high, but I don't think they are out of line when compared to everyone else is all I am saying. Its not like the dealer is volume selling batteries like Wal-mart at $60 each.

 

Some dealers charge as little as ~$130 for the battery at the parts counter. The battery is made in Japan and comes in very elaborate packaging (the box alone is probably worth $20... )

 

And the OEM battery gives the appearance of very high quality. My Optima Yellowtop works fine but looks crude in comparison.