Is Forced Autostop Bad for the Hybrid Battery?

Question obviously based on my IMA battery failure

I'm just trying to figure what can shorten a hybrid's battery life. One possibility is forced autostops may do to the automotive electrical system what frequent reboots do to a computer - increase the chance of damage from a power surge. I don't know what the chance of a power surge doing harm is - it might be very small.

Other factors would be to keep the hybrid in a garage to avoid extreme temperatures when possible, extended hill climbing (esp. Hondas), frequent stop-and-go traffic.

61.5mpg lifetime - 82mpg in recent months

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The Insight electric motor is not being replaced - it's the MCM and BCM units that are supposed to protect the battery unit that is my concern. I seriously doubt those units would function well from a power surge.

My theory is somehow the MCM and BCM units failed - ruining the batteries. So far, I have not explaination aside from "natural death" - which I think is just a euphenism for nobody knows.

61.5mpg lifetime - 82mpg in recent months

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"fanatic" is what the lazy call the dedicated

Chuck, what is the advantage of a forced auto stop? Ive heard of people doing it , but what does it do? Thanks. Dean

Clubford00,

I don't know if this is mainly Honda hybrid drivers, but some will do a forced autostop at intersections if it does not work. If the engine is not warmed up, has the defroster on, the A/C in certain modes, autostop does not work. The exception may be the 2006 HCH.

When I'm caught in freeway gridlock, eventually autostop does not work, so I've done forced autostop (FAS). There are other circumstance I don't use it such as coasting downhill (dubious practice as the fuel line is automatically cut off without loss of power steering so why FAS?).

61.5mpg lifetime - 82mpg in recent months

Best Run >
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"fanatic" is what the lazy call the dedicated

Again, this seems to be a missed point - the IMA electric motor is not being replaced and is not part of the problem.

61.5mpg lifetime - 82mpg in recent months

Best Run >
www.cleanmpg.com

"fanatic" is what the lazy call the dedicated

Power surges (such as might be experienced when you turn a car on and the charging system brings the voltage up) would be tolerable for a car's electronics. They are designed to run within a wide range of voltages and anything that could 'surge' on the 12v bus would be fine, unless somehow power was leaking from the HV pack, but that's another story.

What might cause some deterioration to the battery is high current, although you'd have the check the specs... Starting would be a big pulse, but not sustained, so you'd think it wouldn't be too bad, but it's hard to say how the D cells react. Remember, if only 1 of them goes your pack is probably close to useless.

2001 Prius Photos       2005 Prius Photos
'97 Prius Simulation Prius inner workings

Can you get any of the failed parts back? If so and you have the schematics, you could open them up and/or 'bench' test them. But speculation based upon "it broke" is not going to be very useful.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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One last thing, _IF_ you think that some way of operating the car caused the failure, you MUST, as soon as you get it back, repeat that behavior on the way home and for the next week. If you can 'operate' the car into failure in a couple of days, find out while you can still say, "It broke." The repair will be under warrantee and you will know whether or not you can operate it so it breaks.

If it doesn't break within a week, then you know it is pretty bullet proof and have a happy.

Bob "smoke escaped" Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.