Can you continue to drive with a bad Hybrid Battery?

My understanding is that you can continue to drive but the MPG will poor and also consider the engine is an atikinson cycle and it may not be appropriate to run it under load 100% of the time. I am NOT an engineer so it would be best to ask some of our other members whom are more experience than myself.

Relevant read:
Driving prius with bad battery | PriusChat (IMPORTANT NOTE: Reverse may not work as the battery sends reverse voltage to the motors to allow the car to go backyards, TLDR: Reverse gear is powered from battery)

 

• Nope the hybrid battery is used to start the car. Hybrid battery powers up the motor generator in the trans that in turn rotates the engine till it starts.

No hybrid battery no start. Car is a brick.

Keep reading the forum it has all the info you need. If you have a question just use the search forums link up top and search in the appropriate forum.

 

While true, the car will usually keep the engine running long enough for you to pull over, and may even be able to drive some distance at a very reduced speed.

 

whoopie!

 

I'm interpreting that as a sarcastic response to the post above it. It is, in fact, an important feature. I've had several cars suddenly die on the road, leaving me with no way to even get to a safe shoulder. An F150 with a bad spark plug wire. A Ford XL with a defective ground to the ECU. A Mazda RX7 that grenaded the rear differential, locking the rear tires at 65 MPH.

So it was comforting that when my hybrid battery developed a leak it was able to limp home in turtle mode.

 

So it depends on how bad is bad.

The battery is used to start the engine, so if it gets bad enough, eventually that isn't going to happen, and you're not going anywhere. (Whether the car will "keep the engine running" becomes a sort of academic question once it has no way to get the engine running.)

The reason for all the diversity in answers is that the car starts giving you trouble codes earlier than that, when the battery is just bad, not only when it's kaput. So you can keep driving around for a while.

It's hard to predict how long "a while" is. Generally, if you keep driving around, and then you get a loud bang and bad smells from the back of the car, you've just found out how long your "while" was.

 

There have been people who reset the failed high voltage battery code many times and continue driving for months. Some think they are driving on engine alone because the engine never shuts off, for example at stop signs and lights. That simply means the high voltage battery is so bad it won't take enough charge to allow a stop light shutdown. The car needs high voltage at all times when it is in Ready mode.

Nevertheless, you can get stranded because of a bad hv battery when you stop at a store and can't restart it.

At that point you are being towed and forced to buy a new hv battery on the spot. The good news is you usually get weeks to months of warnings that are impossible to miss.

 

First the dash warning lights come on and trouble codes are set. Clearing codes may or may not get the warning lights to turn off for a while.

Next the battery fan starts working overtime even on short trips, due to heat caused by imbalanced voltage between modules.

Eventually car will give up on the HV battery altogether and go into limp mode, which is only good for getting down the road a short distance. Turning engine off and clearing codes will get the car going again, but only until the next time it goes into limp mode.

 

Or there will be the eventual bang and bad smells followed by a walk home.

 

yup. Lots of posts of bangs and smoke with resetting the Ground Fault nag.

 

Ive been on this site 16 years. Bought my 07 new.

Back in the day idiots would run there G2's out of gas all the time and kill the Hybrid battery.
Lots of guys still on this site who know what I'm talking about. It was hilarious.

When your low on gas in a G2 First the gas gauge blinks...then when your almost dry it does a loud beep...nope they kept driving till the engine shut off but wait then like a magic carpet the car still drove...AWESOME... till the hybrid battery went dry. Not far...Then your done....
Its a 4000 lb brick.

In those days you had to tow it to the dealer and wait weeks till Toyota Corp sent that dealer a High Voltage Power supply and special charging harness to charge the Hybrid battery back up outboard. Engine wont start with a dead hybrid battery so it has to be out board charged.
It was $$$$$.

Your still screwed if you pull that now unless you happen to own a Hybrid Automotive charger and have the harness installed. But if you have that you know what time it is and would not do that idiocy anyway. Run out of gas stop the car.

That magic carpet car happened alot. Idiots trying to get the last drop out of the tank to get the best mileage. Nothing more frustrating then getting stuck behind a new G2 owner back in the day going 20 miles lower than the posted in those days.

That's a big contributing factor why there was so much Prius hate. At least for me lol....

 

The walk home is the worst part.

 

Depends how you feel about bad smells.