Battery dead after four days

GeoffM · 10-29-2004, 06:17 PM

I drove my Prius about 60 miles last Sunday and then went out of town until last night (Thursday). This morning, I jumped in the car, pressed the Start button, and nothing happened. No lights, no sounds, nothing. I opened the door to see if the interior light would go on but that didn't work either. Totally dead battery. No problem I thought, the car's parked in the garage and I have a small charger, so just hook it up, get it started and go. Not quite so fast...

Despite many things I've read here about needing minimal power to start a Prius with a dead battery, I didn't find that to be the case. My slow charger can put out about 8 amps and every time I pressed the brake pedal to try to start the car, the current draw went so high it pegged the meter on the charger and wouldn't start. So I walked to work and came back about four hours later to try again. By that time the battery had charged enought to start, and off I went.

Questions:

1. What would cause the battery to discharge so quickly? I checked all the interior lights and they were set to "door", so that shouldn't have caused the problem (and the doors were closed). My Prius is a 2005 BC with SKS, but the car was parked in my garage with the doors unlocked so you would think that SKS wouldn't be using much power. I don't have anything plugged into any of the power outlets. What else can I check?

2. What kind of power will it take to start a completely dead car? I know my slow charger can't do it, does anyone know what the starting current is for the car? Obviously the electric-assist brakes are using a bunch of current, just curious how small a charger or battery would get you going again.

Needless to say, I'm now incredibly concerned about taking this car to LaGuardia and parking it in the garage for more than a day or two when I go out of town. And not being able to even get the car in neutral without power means it could be really tricky to get a jump parked face-forward (as required) unless someone has really long cables. Even getting the back hatch open to try to access the battery directly from the rear won't be fun.

Any way you look at this this is not the car to end up with a dead battery, and it's too bad the computers don't work as hard to maintain the SOC on the 12v battery as they do the HV one.

Geoff

**efusco** · 10-29-2004, 06:30 PM

First I'd buy a rechargable 12v jump start kit. Mine has a built in safetly light and air pump that's convinient for adjusting tire pressures.

Next, you need to have the car checked at the dealer. There is something causeing a serious draw on your battery or your battery has been deeply discharged previously and is no longer capable of maintaining a charge for very long and needs replacement. This is NOT normal behavior. You addressed the obvious things (interior lights in particular).

I would not have expected your slow charger to be able to jump your car, but probably just 30min or so of charging the battery would have been enough. Some have even speculated that a couple of 6v lantern batteries would be adequate...I'm not so sure.

Another option that you can consider, but should NOT have to resort to, is a solar trickle charger you could leave your car on while parked (assuming you're in the sun) to keep the battery charged while you're away. But make the dealer thoroughly check first.

LungCookie · 10-29-2004, 06:59 PM

It's a real long shot, but have you checked for the dreaded "Penny Wedged In The Power Outlet" problem?

http://www.priuschat.com/forums/how-to-avo...d-a-vt3965.html

It would probably blow the fuse right away, but you never know.

bruceha_2000 · 10-29-2004, 09:55 PM

Geoff,
Is it remotely possible you left the car in ACC or IG-On? Maybe powered off then went to either of these modes to check something, listen to the radio, etc and forgot to power off when you left?

GeoffM · 10-29-2004, 10:06 PM

Quote:

Geoff,
Is it remotely possible you left the car in ACC or IG-On? Maybe powered off then went to either of these modes to check something, listen to the radio, etc and forgot to power off when you left?

Nope. Plus, SKS would have beeped at me and with the car parked in the garage there's no way I would have missed that.

Looks like I'll be taking Evan's advice and getting the car in to the dealer for a checkup. Arrghhh... 3-week-old Toyota's aren't supposed to be in the shop!!!

Geoff

**efusco** · 10-29-2004, 10:10 PM

Geoff,
The 3 week old thing is what makes me most suspicious that the dealership, at some point, did one of the things mentioned above and let the 12v discharge completely. Now it's not functioning up to snuff.

GeoffM · 10-29-2004, 10:14 PM

Quote:

Geoff,
The 3 week old thing is what makes me most suspicious that the dealership, at some point, did one of the things mentioned above and let the 12v discharge completely. Now it's not functioning up to snuff.

Perhaps, but wouldn't you think an 18-hour drive from MI to NY would have recharged the battery, no matter what the state of the initial charge?

Geoff

Frank Hudon · 10-29-2004, 11:14 PM

most modern automotive batterys don't ever recover from a complete discharge. The older lead acid batterys would but the new ones us a larger amout of antimony in the plates instead of lead and this is the problem. It creates a chemical barrier to the transfer of electrons. I could get more technical if you want but that is essentially the bottom line.

DaveinOlyWA · 10-30-2004, 12:52 AM

i agree with frank. a battery as small as the 12 volt battery in the Prius i would think would be very weak and not withstand many discharges.

as far as your trickle charger starting the car, that wont happen. 8 amps at 12 volts is 96 watts. that aint enough to do it. add the resistance of a dead battery and its gonna be worse. realize that power output isnt that cut and dried but it still gives you a general idea of what is needed. to jump a car with a dead battery, you are looking at various levels of charge ranging from roughly 150 amps for short duration charges to maybe 20 amps for 15 minutes of charge. keep in mind that temperature of the battery also plays a part too.

to boot an average computer can take up to 300 watts if you have an optical drive and multiple hard drives with a CRT monitor and computers use very little power when compared to nearly every appliance.

GeoffM · 10-30-2004, 10:42 AM

Quote:

i agree with frank. a battery as small as the 12 volt battery in the Prius i would think would be very weak and not withstand many discharges.

So it sounds like you're saying that my battery may have latent damage from over discharge through some event before I picked the car up, and if not, then it has some now because of what just happened? Disapponting to say the least if the battery is that easily damaged, and Toyota did nothing to prevent deep discharges.

Quote:

as far as your trickle charger starting the car, that wont happen. 8 amps at 12 volts is 96 watts. that aint enough to do it. add the resistance of a dead battery and its gonna be worse. realize that power output isnt that cut and dried but it still gives you a general idea of what is needed. to jump a car with a dead battery, you are looking at various levels of charge ranging from roughly 150 amps for short duration charges to maybe 20 amps for 15 minutes of charge. keep in mind that temperature of the battery also plays a part too.

Sure, to bring a dead battery back to life takes sustained power over some period of time, but if you look at some of the other threads on this board related to starting a Prius with a dead battery, it's very easy to get the impression that all it takes is enough current to activate the ECUs, the HV battery relays, and be on your way. Guess nobody really tried it, and as I found out, the brake system is what kills that theory.

Geoff

10-29-2004, 06:17 PM	#1
GeoffM Join Date: Aug 2004 Location: Long Island, NY Posts: 90 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Battery dead after four days I drove my Prius about 60 miles last Sunday and then went out of town until last night (Thursday). This morning, I jumped in the car, pressed the Start button, and nothing happened. No lights, no sounds, nothing. I opened the door to see if the interior light would go on but that didn't work either. Totally dead battery. No problem I thought, the car's parked in the garage and I have a small charger, so just hook it up, get it started and go. Not quite so fast... Despite many things I've read here about needing minimal power to start a Prius with a dead battery, I didn't find that to be the case. My slow charger can put out about 8 amps and every time I pressed the brake pedal to try to start the car, the current draw went so high it pegged the meter on the charger and wouldn't start. So I walked to work and came back about four hours later to try again. By that time the battery had charged enought to start, and off I went. Questions: 1. What would cause the battery to discharge so quickly? I checked all the interior lights and they were set to "door", so that shouldn't have caused the problem (and the doors were closed). My Prius is a 2005 BC with SKS, but the car was parked in my garage with the doors unlocked so you would think that SKS wouldn't be using much power. I don't have anything plugged into any of the power outlets. What else can I check? 2. What kind of power will it take to start a completely dead car? I know my slow charger can't do it, does anyone know what the starting current is for the car? Obviously the electric-assist brakes are using a bunch of current, just curious how small a charger or battery would get you going again. Needless to say, I'm now incredibly concerned about taking this car to LaGuardia and parking it in the garage for more than a day or two when I go out of town. And not being able to even get the car in neutral without power means it could be really tricky to get a jump parked face-forward (as required) unless someone has really long cables. Even getting the back hatch open to try to access the battery directly from the rear won't be fun. Any way you look at this this is not the car to end up with a dead battery, and it's too bad the computers don't work as hard to maintain the SOC on the 12v battery as they do the HV one. Geoff

10-29-2004, 06:30 PM	#2
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,231 My Car: 2004 Prius Model: Package: #9 Thanks: 49 Thanked 249 Times in 148 Posts Friends: 37	First I'd buy a rechargable 12v jump start kit. Mine has a built in safetly light and air pump that's convinient for adjusting tire pressures. Next, you need to have the car checked at the dealer. There is something causeing a serious draw on your battery or your battery has been deeply discharged previously and is no longer capable of maintaining a charge for very long and needs replacement. This is NOT normal behavior. You addressed the obvious things (interior lights in particular). I would not have expected your slow charger to be able to jump your car, but probably just 30min or so of charging the battery would have been enough. Some have even speculated that a couple of 6v lantern batteries would be adequate...I'm not so sure. Another option that you can consider, but should NOT have to resort to, is a solar trickle charger you could leave your car on while parked (assuming you're in the sun) to keep the battery charged while you're away. But make the dealer thoroughly check first. __________________ Evan E. Fusco, MD "It's a damn poor mind that can only think of one way to spell a word." -Andrew Jackson

10-30-2004, 12:52 AM	#9
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,378 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 24 Thanked 121 Times in 103 Posts Friends: 10	i agree with frank. a battery as small as the 12 volt battery in the Prius i would think would be very weak and not withstand many discharges. as far as your trickle charger starting the car, that wont happen. 8 amps at 12 volts is 96 watts. that aint enough to do it. add the resistance of a dead battery and its gonna be worse. realize that power output isnt that cut and dried but it still gives you a general idea of what is needed. to jump a car with a dead battery, you are looking at various levels of charge ranging from roughly 150 amps for short duration charges to maybe 20 amps for 15 minutes of charge. keep in mind that temperature of the battery also plays a part too. to boot an average computer can take up to 300 watts if you have an optical drive and multiple hard drives with a CRT monitor and computers use very little power when compared to nearly every appliance. __________________ My Blue 2010 : Last tank 541.9 @ 49.48 pump (56.7 MFD) 5.54 CPM, 21 MPH, Lifetime:5442.2 miles 56.5 MPG pump. (62.22 MFD) 4.72 CPM. Summer MPG 57.4 Winter: 49.5 My 2006 SPM: Last tank 376.6 miles @38.21 pump (40.8 MFD) 7.17 cpm winter mpg 49.64 summer mpg 53.41 lifetime: 42,563.5 miles 51.5 mpg pump (52.7 mpg MFD) 5.51 cpm My 2007 Zenn total "fuel cost" $166.58 on "about" 9599.7 miles. 1.74 cents per mile (granted i plug in for free at work!!) My Plate: DUALPWR (Dual Power)

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10-29-2004, 06:59 PM	#3
LungCookie Join Date: May 2004 Location: Minnesota Posts: 67 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	It's a real long shot, but have you checked for the dreaded "Penny Wedged In The Power Outlet" problem? http://www.priuschat.com/forums/how-to-avo...d-a-vt3965.html It would probably blow the fuse right away, but you never know.

10-29-2004, 09:55 PM	#4
bruceha_2000 Senior Member Join Date: Jan 2004 Location: South Burlington, VT Posts: 2,549 My Car: 2004 Prius Model: Package: #8 Thanks: 6 Thanked 17 Times in 16 Posts Friends: 1	Geoff, Is it remotely possible you left the car in ACC or IG-On? Maybe powered off then went to either of these modes to check something, listen to the radio, etc and forgot to power off when you left?

10-29-2004, 10:10 PM	#6
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,231 My Car: 2004 Prius Model: Package: #9 Thanks: 49 Thanked 249 Times in 148 Posts Friends: 37	Geoff, The 3 week old thing is what makes me most suspicious that the dealership, at some point, did one of the things mentioned above and let the 12v discharge completely. Now it's not functioning up to snuff.

10-29-2004, 11:14 PM	#8
Frank Hudon Senior Member Join Date: Jan 2004 Posts: 4,144 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	most modern automotive batterys don't ever recover from a complete discharge. The older lead acid batterys would but the new ones us a larger amout of antimony in the plates instead of lead and this is the problem. It creates a chemical barrier to the transfer of electrons. I could get more technical if you want but that is essentially the bottom line.