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Whirring sound (from generator?) when breaking or accelerating

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1.9K views 12 replies 6 participants last post by  KenS  
#1 ·
No warning lights or difference in performance. I took it to a dealer who diagnosed it as a generator or drive motor problem. When I asked if this was the generator that charged the battery (it’s a PHEV) he said yes but he was just relaying what the mechanic told him.

My question is how safe is it to drive. Everyone within 100 miles is backed up and first appt is late next week and that assumes they get the part. Any other thoughts are appreciated.

A side note. I got the diagnosis from a Canadian dealer. I live and bought the car in the US but am currently visiting near the Canadian/US border. There are significant ”challenges” getting the part and getting it covered under warranty in Canada. If y’all have thoughts on this as well …..
 
#2 ·
No warning lights or difference in performance. I took it to a dealer who diagnosed it as a generator or drive motor problem. When I asked if this was the generator that charged the battery (it’s a PHEV) he said yes but he was just relaying what the mechanic told him.

My question is how safe is it to drive. Everyone within 100 miles is backed up and first appt is late next week and that assumes they get the part. Any other thoughts are appreciated.

A side note. I got the diagnosis from a Canadian dealer. I live and bought the car in the US but am currently visiting near the Canadian/US border. There are significant ”challenges” getting the part and getting it covered under warranty in Canada. If y’all have thoughts on this as well …..
Please reply with the year of Niro so we know for sure that it is a 2023 PHEV.
Generator does not work for me as charging is accomplished by the DC-DC converter.
It could possibly be the electric motor??
If possible, you will want to get any warranty completed in the US because of the significant challenge that you mention.
 
#4 ·
When I asked if this was the generator that charged the battery (it’s a PHEV) he said yes but he was just relaying what the mechanic told him.
There is no generator that charges the 12v battery. The only "generator" the car has is the EV motor when it's in regen mode while slowing the car. I doubt the mechanic said any such thing, and the service advisor probably said yes to get you to leave him alone. I agree that if it's not a "normal" or acceptable sound, it's a warranty issue, especially on a car that is only one model year old.
 
#6 ·
Incorrect, the HSG, the hybrid starter generator IS also a high voltage 3 phase alternator that can charge the hybrid battery. Because it is comparatively small and belt driven, it is very inefficient as a generator vs. the electric motor and is mainly used for vehicle starting, but can recover energy from the ICE to the hybrid battery when the clutches are disengaged and the EV motor is not spinning.
 
#7 ·
But that is assuming the ICE is running. I acknowledge that it is a generator, but it is not designed to charge the 12v battery because the ICE doesn't run steadily in a PHEV. In almost two months of ownership of my new PHEV, I've used about 1.5 gallons of gas. I go many, many days without the engine ever starting, so the HSG cannot be relied on to charge the 12v.
 
#13 ·
The difference between a motor and a generator (an alternating current generator is often called an alternator) is the wiring connections and whether power is running into or out of it. Such a device used both ways is properly called a motor-generator.

I used to run two or three generators in parallel, 2 megawatts each. Each one had a reverse power relay to take it off line if the power reversed, i.e., went into it instead of out. If the prime mover on one (diesel engine or steam turbine depending on the installation) failed it otherwise would motorize and possibly run that prime mover to destruction. The reverse power relays were tested often and required by law.