I just got my HAH yesterday, and I' getting about 33.5mpg so far. I'm pretty happy with that, since I only have about 120 miles on it.

One thing I don't understand is "when does assist come one?". Some times when I accelerate, it comes on fully, some times it comes on slightly, and sometimes it doesn't at all.

I would think that if I'm accelerating, that assist should light up all the way. I would think it would use assist prior to turing off "eco" mode.

Also - I usually have 3 or 4 bars on the Battery indicator. Once I got 5 bars. Is there a 6th? And what do you need to do to get it charged up that high!?

Yes there are 6 bars. Mine normally statys between 3-4. IMA assist varies with battery charge- more charge = more frequent, and earlier assist. The 6th bar will come on after a LOT of recharging- a lot of braking from speed.

IMA asist comes on to varying degrees, as you found out. Battery charge state, how hard you accelerate, how much incline, whether there is enough engine power (3 vs 6cyl) in that condition and gear. You can get IMA assist in 3cyl mode, if you are very gentle on the pedal or its a very gentle incline- if the computer thinks the IMA cannot handle, it goes straight to 6cyl.

Each generation of IMA is a little different- Insight vs Civic vs HAH. They get to play with keeping it in lean burn, we get to play with 3cyl mode. Perhaps someday there will be user-selectable preferences for how/when IMA comes on.

I have a question a little off the topic, but more related to the battery bars. My daily commute is pretty much 20 miles each way stop and go highway traffic. There have been a few times where the traffic is so congested I'm literally going about 5-10 miles per hour most of the way home. At the same time, I might be running the A/C. The battery bars have gone all the way down to 1 bar, and I get nervous so I turn off the A/C and try to get off the freeway and take a few streets just so that the assist comes on and the battery charges again. I am just wondering am I worrying for nothing? What would happen if I kept the A/C running and didn't engage the assist, and the battery bar goes below 1 bar? Would the car shut down? I am planning to call Honda to see if I can get an answer too, but thought I might find the answer here in the forum.


Thanks!!

No, the car won't shut down, that would be really problematic. When the battery display says "empty" the battery still has 20% of it's charge, so you won't completely kill the battery by draining it all the way down by using electric A/C. Your car should recharge the battery at that point, but I can't say for sure how it will go about doing that. It does need to have power available in the HV battery so that the 12v system can be charged from it.

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

Fear not.

The car will self-regulate by shutting off IMA and keeping it in 6cyl and recharging at every opportunity. I've seen my car stopped, running at idle with some recharge bars lit. It will also disable autostop if there is not enough energy in the 144v battery for several high-voltage starts. And beyond that, there's still the 12v starter, off the 12v battery.

I think most of that info is in the owners' manual, or somewhere on the Honda site. I don't recall where I read it, but it was a Honda source.

The AC compressor is electric and ICE driven according to Honda... haven't looked at the specifics of how that occurs. If the battery runs down the AC won't shut off- the engine will jsut stay on- its got to recharge the pack at that point, anyway.

Schwa and gonavy, thanks for those responses. I feel much better knowing my car won't shut off. It's only been once or twice that I've even seen the battery go down to 1 bar. I normally don't use the A/C very often anyways. I will definitely read up on the manual too.

Please tell us about that 12V starter.

Alan

There's nothing to tell. Its the normal starting system that every car has. Only its the 'backup' for us. All Honda hybrids have it. You can see the starter under the hood. The only thing missing from ours, I think, is the alternator- the 12v gets its recharge from the electric motor (really just a big alternator) and/or big battery- not sure which.