If the drive batteries fail can you still drive the car gas engine only?

plumabob · 06-25-2009, 07:01 AM

n/t

JimboPalmer · 06-25-2009, 08:21 AM

As the traction battery starts the engine, you could never turn it on ever again, so it is not practical to consider it.

Why did you want to know?

donee · 06-25-2009, 09:38 AM

Hi Pluma...,

No. The transmission is in effect an electric torque converter, and the battery provides the leveling action (to use a plumbing term) between the generated electricty and the drive motor. If the battery fails, it could go high resistance, and and this might allow the voltage to be too spikey coming out of the generator. So, the Prius computers will just shut everything down. In effect the battery keeps the pipe from banging when the valves are turned off and on. And avoid breaking the pipes, the system is disabled if the battery developes a fault - to continue withthe plumbing analogy.

That being said, it rarely happens on cars on 100K miles. Its much more probable for a sticky throttle body and or running out of gas to cause the engine not to run. In which case its best to pull over the side of the road and NOT use the battery to cruise along.

auricchio · 06-25-2009, 11:59 PM

Actually, it's even a bit more extreme than what donee says.

The motor/generator is used to rotate the power-split device (PSD, aka transmission) to control power to the wheels. Since there are no gears nor clutch, electrical power is absolutely necessary for the vehicle to operate.

When the car is stopped and the engine continues to idle, the MG rotates the PSD "in reverse" so that the engine can continue turning, but no torque gets to the wheels.

DISCLAIMER: There are many here on PC who know this stuff way better than I.

V8Cobrakid · 06-26-2009, 12:23 AM

you guys pretty much covered it. in simple answers.. NO.. you can't drive the car with a failed battery. it is required to start the car, and rotate the car. and yes.. if it's tooo out of spec, the car will probably not turn on... (assuming that part)

plumabob · 06-26-2009, 05:40 AM

The reason I asked is that say you had an older prius and the Drive batteries went bad and you couldn't afford replacement at that time. I thought it would be nice just to use the gas engine until you could afford to do so. Doesn't sound like such a bad idea to me but if it is not possible then thats all it will remain...an idea.

Thanks!

qbee42 · 06-26-2009, 08:32 AM

Quote:

Originally Posted by plumabob

The reason I asked is that say you had an older prius and the Drive batteries went bad and you couldn't afford replacement at that time. I thought it would be nice just to use the gas engine until you could afford to do so. Doesn't sound like such a bad idea to me but if it is not possible then thats all it will remain...an idea.

Thanks!

It falls into the same category as driving a normal car with a failed automatic transmission. From a cost standpoint it could be handy if you are cash strapped, but it's not going to work.

Tom

06-25-2009, 07:01 AM	#1
plumabob Junior Member Join Date: Jun 2009 Location: NY Posts: 7 My Car: 2005 Prius Model: II Package: No Package Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	If the drive batteries fail can you still drive the car gas engine only? n/t

06-25-2009, 08:21 AM	#2
JimboPalmer Tsar of all the Rushers Join Date: Apr 2009 Location: Greenwood MS USA Posts: 378 My Car: 2009 Prius Model: N/A Package: #5 Thanks: 17 Thanked 66 Times in 53 Posts Friends: 3	Re: If the drive batteries fail can you still drive the car gas engine only? As the traction battery starts the engine, you could never turn it on ever again, so it is not practical to consider it. Why did you want to know?

06-25-2009, 09:38 AM	#3
donee Senior Member Join Date: Aug 2005 Location: Chicagoland Posts: 2,244 My Car: 2006 Prius Model: Package: #2 Thanks: 2 Thanked 54 Times in 47 Posts Friends: 0	Re: If the drive batteries fail can you still drive the car gas engine only? Hi Pluma..., No. The transmission is in effect an electric torque converter, and the battery provides the leveling action (to use a plumbing term) between the generated electricty and the drive motor. If the battery fails, it could go high resistance, and and this might allow the voltage to be too spikey coming out of the generator. So, the Prius computers will just shut everything down. In effect the battery keeps the pipe from banging when the valves are turned off and on. And avoid breaking the pipes, the system is disabled if the battery developes a fault - to continue withthe plumbing analogy. That being said, it rarely happens on cars on 100K miles. Its much more probable for a sticky throttle body and or running out of gas to cause the engine not to run. In which case its best to pull over the side of the road and NOT use the battery to cruise along.

06-25-2009, 11:59 PM	#4
auricchio Senior Member Join Date: Mar 2006 Location: Cambria, CA, USA Posts: 904 My Car: 2006 Prius Model: Package: #8 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: If the drive batteries fail can you still drive the car gas engine only? Actually, it's even a bit more extreme than what donee says. The motor/generator is used to rotate the power-split device (PSD, aka transmission) to control power to the wheels. Since there are no gears nor clutch, electrical power is absolutely necessary for the vehicle to operate. When the car is stopped and the engine continues to idle, the MG rotates the PSD "in reverse" so that the engine can continue turning, but no torque gets to the wheels. DISCLAIMER: There are many here on PC who know this stuff way better than I.

06-26-2009, 12:23 AM	#5
V8Cobrakid Senior Member Join Date: Jun 2004 Location: hell Posts: 2,894 My Car: 2004 Prius Model: N/A Package: #9 Thanks: 9 Thanked 18 Times in 18 Posts Friends: 5	Re: If the drive batteries fail can you still drive the car gas engine only? you guys pretty much covered it. in simple answers.. NO.. you can't drive the car with a failed battery. it is required to start the car, and rotate the car. and yes.. if it's tooo out of spec, the car will probably not turn on... (assuming that part)

06-26-2009, 05:40 AM	#6
plumabob Junior Member Join Date: Jun 2009 Location: NY Posts: 7 My Car: 2005 Prius Model: II Package: No Package Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: If the drive batteries fail can you still drive the car gas engine only? The reason I asked is that say you had an older prius and the Drive batteries went bad and you couldn't afford replacement at that time. I thought it would be nice just to use the gas engine until you could afford to do so. Doesn't sound like such a bad idea to me but if it is not possible then thats all it will remain...an idea. Thanks!

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