How to Start on Dead Prius Battery

You can jump start the 12v battery, but if the HV battery is depleted, your Prius will not be able to start the engine. Charging a depleted HV battery requires a special charger that a dealer can access, but the HV battery can only get depleted if your engine cannot start (either due to mechanical problems or no gas) and you continually try to start the engine. Driving in EV mode when you run out of gas is not a good idea.

JeffD

 

You're telling me that you got that DANGEROUS MORONIC STUPID IDIOT CR*P advice from a dealer website?
If so, they must want to MEGA SCREW their customers, and sell them TWO NEW VEHICLES.

YOU NEVER EVER EVER EVER have both vehicles running at the same time - ***NEVER***!
With both vehicles running, the alternator(s)/12-volt-charging electronics FIGHT - often to the DEATH!!


It's best to disconnect the jumper cable first, before trying to start the dead car.
Next best is to TURN OFF the good car, THEN try to start the dead car.

Or, imho, get a jump pack on Amazon. They have protection circuits in them, to prevent the dead/target vehicle from trying to charge the jump-pack batteries, or to fight the jump pack electronics.

Or, get a jump pack, with a 12v dry cell, like the older Stanley jump packs, or the professional jump packs.

Imho, on a Gen4, just jump the battery using the battery terminals.
If your car blows up, tell me, send me the official police, court, and expert documentation, and I'll consider sending a condolence card.

Wow, just wow.
MORONS that are over SIX DECADES BEHIND in basic automotive knowledge.
Wow, they must have great service advisors and top notch mechanics - NOT!
And yes, even in the early 70's, there were warnings about having the two vehicles running at the same time, because of the possibility of alternator or electronic damage.

Btw, on a Prius, turning the car on, starts the high voltage/traction battery charging the 12volt battery. The engine does not have to be running.

As for any comments about new electronics/charging system, I'll get some Mustangs, Camaros, and Vettes that would love to have their running alternators blow the Prius' just turned-on electronics to the moon and back.
Heck, I haven't even mentioned the trucks, with their mega alternators.


You've got to ask yourself one question. Do I feel lucky? Well, do ya, punk?

Code:

https://www.youtube.com/watch?v=f5NJFNaL2Qg
Dirty Harry - "Do You Feel Lucky?" Clip Warner Bros.

 

Wow, just wow.
The above seems to be the official STUPID advice from Toyota.
My pony car and I are going to go around to all of the Toyota dealerships, and start blowing the crud out of Toyota electronics. If my car and I can't do it, then I could get super nasty, and get a vehicle with an older high output GM alternator. GM alternators have a very infamous history. For many decades.

 

that is true for the generations with the 12v in the back. if you deplete the hybrid battery, you can have a dealer charge it, buy a prolong charger, or build one yourself

 

Never, never use a Prius to jump another car. There is too much risk of expensive damage to the power electronics. You can jump your Prius from another car, but never attach the cables backwards as expensive bills will occur. As stated above having a jump battery is a good idea. It allows you to be a good Samaritan with little risk to your Prius.

JeffD

 

It's not a simple true/false. It's more complicated.

If your Prius 12v battery dies, you will not be able to boot the computers and close the contactors that make the big hybrid battery do its thing, and its thing includes starting the gas engine.

so... if your 12v battery is dead and your hybrid battery is NOT dead, then it is possible to jump the Prius and get it started.

If the 12v battery is dead and your hybrid battery is ALSO dead, don't bother. None of this will work. Tow to dealer.

 

Or, keep one of these in your "trunk" and get going in about a minute!

 

Reiterating Leadfoot's point, that will "get you going in about a minute' if your only problem is a discharged 12 volt battery.

It will not do squat for you if the battery that's dead is the 200 volt one.

 

i think the op is confused, but since he hasn't returned...

 

when you say 'node', do you mean the 'jump start terminal' you mention in your first post?

if so, it's probably because the battery is under the hood in gen4, and you don't need it. that would have been for gen2 and gen3

 

The basics are the 12v battery is not designed to and won't crank the engine on a hybrid. No matter how good it is.

The hybrid high voltage battery does the engine cranking at a much higher speed under direction of computers initiated with power from the 12v battery. It has to do this at startup and perhaps hundreds of times while you are driving. So it has to be powerful and resilient. A hybrid battery can sit idle for months and even a year and still crank the engine. A 12v battery can not.

As far as jump starting a drained 12v battery goes, Toyota does instruct how to do it from another car as you indicate. But this is dangerous if polarities are reversed even for a second. Normally reversed polarity will blow multiple fuses and fusible links, often resulting in a tow.

If you get a 12v car to car jump right, everything will be ok. But its recommended to use a lithium jump pack because their charge can last a year or more and they have reverse polarity protection built in. Any roadside service will use a jump pack. As a side benefit you can use the jump pack for other motorists instead of risking your hybrid.

 

Yay I get my own practice at this! Super psyched! ...Not!

Another driver in my family who shall remain nameless decided to leave the car in accessory mode for long enough to matter and ran down the 12v battery before abandoning the car in the airport parking lot and flying halfway across the country.

So tomorrow I get to go to the airport and jump the Prius, let it charge up so that [REDACTED] can drive home after the trip.

 

Just updating, the process worked fine. I used my ~20 year old AGM jump box on the underhood jump terminal, got the Prius into READY mode without drama, and then sat there for an hour while it charged its 12v battery.

[REDACTED] had no difficulty on the drive home a few hours later.

 

I did this once...in 1987 on a gasser car. Had to push it half a mile to the nearest "hill".to pop the clutch and get it to start up...in the summer heat in FL...... being eaten by mosquitoes...I learned a VERY valuable lesson that day. I never did it again. Had a buddy run out of gas once and his Dad got him a gas tank and made him walk the 2 miles back to his car....I learned from his lesson also. Good times. Sorry you had to do that...