If HV Battery Is Bad, Does That Affect Top Speed?

Could be the battery.
Could be the inverter.
Could be the inverter pump.
Could be the transmission (transaxle).
Could be a bad fan.

Could be...... lots of stuff.

Rather tahn guess you could:
- Bring your diagnostic tool and give it a scan.
- Find out if he already had it diagnosed at a dealer. Get a copy of the report
- Take it to an independent hybrid mechanic or dealer and get a pre-purchase inspection.

The real question is..... do you feel lucky?

 

The engine is designed to work with the electric side to provide full power. If the electric side isn't working (Eric listed most of them), the car will be severely underpowered. I've had my battery go out but only drove it around town to get back home and even getting to 35 mph was a lot of work for it.

 

$0 could be overpriced for this. If you lived in Oakland CA there is a mechanic I would trust, but I have not heard that the tri-cities are a hotbed of hybrid knowledge.

I suspect a mechanic would throw entire assemblies into the car until they found the right one or you ran out of money.

Where are you on the scale between novice and rocket scientist?

 

If you can get the error codes, or be able to read live data, that would be a helpful place to start.

I've brought many Prius back from the brink of death.

In fact today I am working on a Gen 1 that has been down for over 3 years. Slowly getting it up and running.
So far the cost is edging closer to $3,000

What year is this Prius?
Approximately how many miles?
Is it a base model, or does it have premium features?

I'd be happy to share some tips.

 

When the HV battery fails, the car will go into "Limp Mode". Barely enough speed to get to off a highway or dangerous situation and maybe enough to get to a place to service the car.

The way the power split device works has reliance on HV current available to counter-rotate the motor-generators to transfer ICE power to the wheels. Without sufficient current, the car is limping along.