Battery Drain on Long Hill/Mtn Climb

The RPM increase is simply the computer letting the engine run higher on its power curve to compensate for the reduced traction motor output.

These are neat cars with fascinating software operating systems imo.

 

Tom, the thing to watch for is lack of power once you get down to 1 bar on the battery display. If you find that you are unable to maintain speed, then that indicates a potential problem with the gas engine. I have seen two cases around here, with people that commute to Los Alamos, where clogged intake or clogged exhaust for the engine has caused a significant driveability problem going uphill. The hallmark of such an issue is battery SoC falling to 30% (yes, it does happen!)

 

I am having that very issue. Decreased power on prolonged climbs and when traction battery is 1 bar (runs rough too when that happens). The car runs awesome and smooth on the flats with intermittent power struggles during acceleration. Are you talking about clogged intake or exhaust valves? Code free too, on Techstream. Would a seafoam soak help that or any other ideas?

 

NO. SeaFoam is mostly "snake oil" and can actually cause more trouble that it fixes in some circumstances.
On the off chance that you have clogged injectors, a double dose of a good cleaner in the gas might help.
Berrymans B12 Chemtool and Gumout are good. Seafoam is NOT.

What about engine maintenance items recommended in the manual ??
Things like throttle body cleaning, air filters, EGR cleaning and maybe even plugs if over 50K miles.

Are there no warning lights ON when this happens ??
A code scan might show something anyway.

 

Thanks for your help, Sam. I cleaned the throttle body about 6,000 miles ago and it still looks spic and span. Plugs have 6,000 miles on them too. There are no codes, pending or active, showing on my Techstream even with a driving test. No warning lights either. It happens so infrequently (mostly on a long hill) that I wasn't too concerned. I'm stumped. I'll give the high dose Berryman's a try. Thanks again.

 

If Techstream is 100% compatible with Toyota hybrids, you might be in a serious pickle.....................
because that kind of problem requires the services of a "real" mechanic and they are hard to find these days.

And one more comment: You have to get the raw power to climb the hill from SOMEWHERE.
If the HV battery is depleted, then ALL of that power must come from the engine and rev'ing higher to accomplish that likely really is NOT a sign of anything being wrong.

 

Got nothing to do with the engine the main power plant the hybrid battery is in stage 1 of failure.

With no power contribution from the hybrid battery its a 90 horsepower go kart so you keep pressing the gas pedal harder to make up for it like it’s a magic car and then the engine is balls out. To no avail.

Hundreds of posts about failed g2 battery’s.

It begins to fail pretty fast after that.

 

Sounds like the battery is losing capacity due to imbalance and age.

I agree. No harm in running some B12 or something through it, but I don't think it'll make a lot of difference. Watch the battery indicator on the MFD to see if it's going up and down quickly. With your car's age, that would not be a surprise.

 

Maybe, maybe not.
If the charge in the battery happens to be rather low at the start of the climb, and the rest of the charge is depleted before you crest the hill, then the engine has EVERYTHING do do with it.
The engine by itself isn't very powerful.
Noticing a loss of power in this situation might be perfectly normal.
Then it might not.

Given only the evidence in these few text messages, YOU have no way to really know if the battery is failing or not.
But that never seems to stop you from pronouncing a verdict.

 

With Techstream, or a ScanGauge or phone app with the right PIDs, you can watch the horsepower being demanded of the engine and MGs. You might have to look up the conversion from kilowatts to HP, or just do all your thinking in one or the other.

If you're in a flat-out haul and the engine is producing a lot less than its rated HP, there could be a problem. Otherwise, you know, you're just climbing a big hill, and it does what it does.

For my own data points, I found out that Afton Mountain with my sister driving is just a more-than-70-HP proposition (limit of the Gen 1's engine), but same mountain with the Gen 3's larger engine (and me driving) was within the engine's max output, so the battery even got charged some on the way up.

If the combination of the grade and speed is greater than the engine capacity, you will be using battery charge the whole way, until the battery gets below about 40% actual SoC (shown on the dash as no bars), at which point the ECU will say "all right, not doing that anymore", and you will find yourself completing the climb at the speed that actually matches the engine's capacity.