Ugh, I think my 12V battery's dying

[Tideland Prius]

I parked at the grocery store today and listened to the radio for about 30 mins while waiting for my mum.

I then decided to go in so I go to IG-ON to wind up the window and I get the red triangle of death. I turn the car off, wind up my window and shut off my lights (it was dusk and the headlights were on in AUTO mode). I opened the door and got a "Key-in-ignition" chime despite the fact that my key was in the pocket.

Fiddled around and cycle'd and finally got it behaving again.

Came back to the car 5-10 mins later and loaded up the trunk. When I sat inside, I played with the headlight switch. The "taillight on" light was barely illuminating. Something can't be right. I turn the headlights to full on. They seem dim and the screen flickered. I pulled to flash the high beams, still dim and the radio shut off and turn itself on again.

Ugh... it was then I realised that the battery was running low so I decided to start the car while I can. Headlights went to full brightness, MFD brightened up a bit and the "taillight on" light came back to full intensity.

Servicing on Sat, I'll have them check the condition of the 12V battery.

[05 Solar Prius]

just had mine replaced. went to dealer and was told $175. it was under warranty so it was free. not stocked by every dealer so i would have them check if it is in before you go. Kragen is $89.00. is it under warr?

[richard schumacher]

The battery is dying because you're killing it. It's a small battery and can't run any accessories for more than a few minutes. If you want to run any accessories for more than five minutes leave the car ON and in Park and let it manage its own energy state, as it was designed to do. The only time you should not do this is when the car is inside a building or other completely enclosed space without no provision for exhaust removal, in which case you'll have to suffer without the radio, lights, and A/C.

[Winston]

I second what Richard says. Don't ever use your car battery for listening to the radio more than a couple minutes in any car. Your battery will last much longer.

[efusco]

Originally Posted by Winston

I second what Richard says. Don't ever use your car battery for listening to the radio more than a couple minutes in any car. Your battery will last much longer.

I disagree with you both. While the battery is not huge it's not exactly tiny either. The dimensions are relatively comparable to other small cars. I've routinely run my basic electronics for 15-30 minutes and my original battery lasted over 4 years.
We're not talking about a couple D-cell batteries and a high drain...very very little energy is required to run the radio in ACC mode and 30 minutes should be fine. The only reason Jon had any issues is b/c his battery is at the end of it's life cycle.

[mingoglia]

Originally Posted by efusco

I disagree with you both. While the battery is not huge it's not exactly tiny either. The dimensions are relatively comparable to other small cars. I've routinely run my basic electronics for 15-30 minutes and my original battery lasted over 4 years.
We're not talking about a couple D-cell batteries and a high drain...very very little energy is required to run the radio in ACC mode and 30 minutes should be fine. The only reason Jon had any issues is b/c his battery is at the end of it's life cycle.

I agree. However, with my Prius I tend to leave the vehicle on as was mentioned earlier. I don't do this because I'm afraid of the 12v battery giving up the ghost as much as I do it because sitting for relatively short periods of time the car is going to be on battery anyway so I figure I'd just let it do it's thing and as someone else put it allow the car to manage it's on power. Besides, In AZ it's nice to have the A/C running. Although I bought my '08 towards the end of the hot season last year I have had it in the low 100 degree weather and was pleasantly surprised how long the Prius will run on battery with the A/C on parked.

Mike

Mike

[Winston]

Four years is not very long for a car battery. My cheap oem batteries in other cars last 7-8 years. Car batteries are not made to be charged and discharged. That would be a "deep cycle" battery. Deep cycle batteries are constructed much different than a standard car battery. Plate dimensions, thickness, clearance from bottom of the battery case, etc.

Car batteries are happiest being fully charged all the time.

OTOH, it is not some sort of crisis if you partially discharge your battery periodically. However, it WILL decrease its life.

[mingoglia]

Originally Posted by Winston

Four years is not very long for a car battery. My cheap oem batteries in other cars last 7-8 years. Car batteries are not made to be charged and discharged. That would be a "deep cycle" battery. Deep cycle batteries are constructed much different than a standard car battery. Plate dimensions, thickness, clearance from bottom of the battery case, etc.

Car batteries are happiest being fully charged all the time.

OTOH, it is not some sort of crisis if you partially discharge your battery periodically. However, it WILL decrease its life.

You are correct about contrasting the difference between starting batteries and deep cycle batteries. However, 30 minutes of listening to the radio won't run down a battery in good condition enough to make this a problem.

I'm not sure what part of the country you're in but in parts that have extreme temperatures 3-4 years is doing pretty well. Heck 2 years here in Arizona where it's still 104F at 2am (and upwards of 120F during the day) is good.

[patsparks]

Quick run get a grain of salt.
Personally I don't mess about with batteries, if they go flat with little provocation they get replaced. No point having a $20,000 car if your stuck because of a $100 battery.

Different story if I leave a light on all night, I will recharge but if it goes flat or seems to be going flat with little draw, recycle time.

[dacarls]

My 6 month old new battery (2008 car) died - for no reason? Its totally dead. How to jump? Nothing works. The manual says pull off the fusebox cover - then a cover - presumably the little red one with a +. NO negative ground is obvious. Ground Anywhere? And has the main battery set also been discharged? Is it damaged? Where could all that voltage have gone?