Prius Main Battery Disconnect

AlexB · 12-03-2007, 09:05 PM

Dear Forum,
My name is Alex and I work for an autobody shop. We have a prius in that needs a new battery. The main battery was removed before we received the car on a trailer. The body is repaired and ready to go, but we are unfamiliar with hybrids. We have to drive the car to a toyota dealership for a new battery installation. Can we start the car and drive normally with only the gas engine? For future reference because i am interested, can you drive it without the electric assist? Will it function on reduced gas engine power or anything like that if you drive without the main battery? Will it still turn off at stop lights? Thanks alot.
-Alex

statultra · 12-03-2007, 09:08 PM

the main battery is used to power the electric motor to spin up the gasoline engine, there is no starter. Therefore you need the main battery hooked up in order to start the vehicle, it cannot be driven without it. If the charge is depleted below 40 % SOC the vehicle will not start.

its fairly easy to hook it up you know, unless your missing parts, if the case and everything is on the battery you can bolt it on and hook up the two wires and plug in the ECU, its fairly simple. The voltage is isolated as long as the battery case is not off.

If you cant install battery you will need a tow to the dealer

**efusco** · 12-03-2007, 09:16 PM

Judging by your unfamiliarity of how the Prius works I strongly discourage you from trying to install the new battery yourself. It's high voltage and though not a mechanically difficult task to accomplish if done wrong could lead to your death or serious damage to the car.

Just put it on a flat-bed and drive it to the dealer...they'll need to do some testing with their scan tool anyway and you can let them risk death instead of you!

hobbit · 12-03-2007, 10:21 PM

Now, hold on a sec. This is an excellent learning opportunity
for an independent, and we know how important that is. If you have
time, check out some of the training resources kicking around on
the net -- my slides, autoshop101, the Emergency Response guides
at Toyota... all of these can help you be both safe and confident
on hybrids, and I'd much rather see you grab this chance than just
give up and push it into Toyota's bay! [And believe us, there
are a few "hybrid qualified" guys over there you wouldn't want
muckin' around back there either -- you get all kinds, as in any
field.]
.
Where are you out of? This is making me wonder how convenient
it would be to stop by and make a new friend..
.
_H*

**efusco** · 12-03-2007, 10:53 PM

Quote:

Originally Posted by hobbit

Now, hold on a sec. This is an excellent learning opportunity
for an independent, and we know how important that is. If you have
time, check out some of the training resources kicking around on
the net -- my slides, autoshop101, the Emergency Response guides
at Toyota... all of these can help you be both safe and confident
on hybrids, and I'd much rather see you grab this chance than just
give up and push it into Toyota's bay! [And believe us, there
are a few "hybrid qualified" guys over there you wouldn't want
muckin' around back there either -- you get all kinds, as in any
field.]
.
Where are you out of? This is making me wonder how convenient
it would be to stop by and make a new friend..
.
_H*

Under Hobbit's tutalage I'd attempt an entire Prius disassembly!

patsparks · 12-04-2007, 07:20 AM

I'd have a go at it, as long as you don't touch an electrical contact there should be no problem.

qbee42 · 12-04-2007, 10:01 AM

Quote:

Originally Posted by efusco

Under Hobbit's tutalage I'd attempt an entire Prius disassembly!

The disassembly it the easy part. It's getting all the pieces back together that takes some doing, and no, having a few left over is not a good thing.

Tom

David Beale · 12-04-2007, 11:23 AM

Unless the battery is damaged somehow, it would be VERY difficult to get a shock from it. It's disconnected -inside- the metal box by a relay. The internal connection is made by a relay. Any short of either power lead to ground will shut it down. The relay is only closed if the onboard computers are happy when you try to start the car (foot on brake pedal, you press "ON").

Toyota didn't want mechanics to be getting shocks or electrocution. It's bad for business.

The duplex outlet on the wall is more dangerous!

DaveinOlyWA · 12-04-2007, 11:55 AM

gotta take it in... i thought you had to use scantool after battery replacement because car will recognize the change and have to be "calibrated" for the new battery...maybe wrong but i seem to remember...

where is galaxee when you need her ??

AlexB · 12-04-2007, 06:06 PM

Thanks, I guess we will probably just load it on a flatbed and take it to the dealer.

What happens in a prius if you are driving down the road, the gasoline engine on, and the main battery fails, doesnt charge, disconects, ect. Does the car just stop or is there some kind of "limp home" mode.

12-03-2007, 09:05 PM	#1
AlexB Junior Member Join Date: Dec 2007 Posts: 2 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Prius Main Battery Disconnect Dear Forum, My name is Alex and I work for an autobody shop. We have a prius in that needs a new battery. The main battery was removed before we received the car on a trailer. The body is repaired and ready to go, but we are unfamiliar with hybrids. We have to drive the car to a toyota dealership for a new battery installation. Can we start the car and drive normally with only the gas engine? For future reference because i am interested, can you drive it without the electric assist? Will it function on reduced gas engine power or anything like that if you drive without the main battery? Will it still turn off at stop lights? Thanks alot. -Alex

12-03-2007, 09:08 PM	#2
statultra uber-Senior Member Join Date: Dec 2005 Location: cape coral, FL Posts: 575 My Car: 2005 Prius Package: #9 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	the main battery is used to power the electric motor to spin up the gasoline engine, there is no starter. Therefore you need the main battery hooked up in order to start the vehicle, it cannot be driven without it. If the charge is depleted below 40 % SOC the vehicle will not start. its fairly easy to hook it up you know, unless your missing parts, if the case and everything is on the battery you can bolt it on and hook up the two wires and plug in the ECU, its fairly simple. The voltage is isolated as long as the battery case is not off. If you cant install battery you will need a tow to the dealer Last edited by statultra; 12-03-2007 at 09:12 PM.

12-04-2007, 06:06 PM	#10
AlexB Junior Member Join Date: Dec 2007 Posts: 2 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Thanks Thanks, I guess we will probably just load it on a flatbed and take it to the dealer. What happens in a prius if you are driving down the road, the gasoline engine on, and the main battery fails, doesnt charge, disconects, ect. Does the car just stop or is there some kind of "limp home" mode.

12-03-2007, 09:16 PM	#3
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,059 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 24	Judging by your unfamiliarity of how the Prius works I strongly discourage you from trying to install the new battery yourself. It's high voltage and though not a mechanically difficult task to accomplish if done wrong could lead to your death or serious damage to the car. Just put it on a flat-bed and drive it to the dealer...they'll need to do some testing with their scan tool anyway and you can let them risk death instead of you!

12-03-2007, 10:21 PM	#4
hobbit Senior Member Join Date: Mar 2005 Location: Bahstahn Posts: 2,957 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Now, hold on a sec. This is an excellent learning opportunity for an independent, and we know how important that is. If you have time, check out some of the training resources kicking around on the net -- my slides, autoshop101, the Emergency Response guides at Toyota... all of these can help you be both safe and confident on hybrids, and I'd much rather see you grab this chance than just give up and push it into Toyota's bay! [And believe us, there are a few "hybrid qualified" guys over there you wouldn't want muckin' around back there either -- you get all kinds, as in any field.] . Where are you out of? This is making me wonder how convenient it would be to stop by and make a new friend.. . _H*

12-04-2007, 07:20 AM	#6
patsparks Uneducated bird-brain Aussie Join Date: Jul 2007 Location: Adelaide South Australia Posts: 4,737 My Car: 2004 Prius Package: Base Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 16	I'd have a go at it, as long as you don't touch an electrical contact there should be no problem.

12-04-2007, 11:23 AM	#8
David Beale Senior Member Join Date: Jul 2006 Location: Edmonton Alberta Posts: 1,532 My Car: 2007 Prius Package: B Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Unless the battery is damaged somehow, it would be VERY difficult to get a shock from it. It's disconnected -inside- the metal box by a relay. The internal connection is made by a relay. Any short of either power lead to ground will shut it down. The relay is only closed if the onboard computers are happy when you try to start the car (foot on brake pedal, you press "ON"). Toyota didn't want mechanics to be getting shocks or electrocution. It's bad for business. The duplex outlet on the wall is more dangerous!

12-04-2007, 11:55 AM	#9
DaveinOlyWA Opps !! I Did it Again!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 9,544 My Car: 2006 Prius Package: #4 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 5	gotta take it in... i thought you had to use scantool after battery replacement because car will recognize the change and have to be "calibrated" for the new battery...maybe wrong but i seem to remember... where is galaxee when you need her ??