This is a common misunderstanding when reading the standard warranty book. And Honda is really to blame for not making it clearer. In the book under the heading "Battery", they are talking about the 12V battery under the hood, not the IMA battery. But most people when they read this section think it's about the IMA battery. Even dealers believe and tell people the IMA battery is pro-rated. No, it's the 12V battery that's pro-rated after 3 years, just like most other car batteries.

Just keep reading till you get to the VERY last page of the warranty book where it lists the specific hybrid-IMA warranties. It lists the states (including California) where it has a full 10yr/150K warranty.
In the rest of the states it is a full 8 yr/80k warranty.
No pro-rating in either case.

 

A three months ago, I had the IMA light go on just shy of 94,000 miles. Lute Riley Honda in Richardson Texas quoted me $6,500 to replace the battery pack, BCM and MCM units. I paid $450 and a rental car at commercial rate - Honda covered the rest. Heard horror stories of 1-2 months to get the battery - mine came back in nine days.

This is a 2000 5-speed Insight. The batteries and units are better, so I think another 150,000 miles (when the car gets to 250,000) is realistic. The new software does not allow the battery charge to get so low. I think the low point is now 40% - not 15% (someone verify please). Anyway, I had my 12-volt battery go dead 2-3 times. When it did, the hybrid battery pack also went dead (at least according to the display). This must have shortened the life.

What I'll do is never let the 12-volt battery go dead, and limit the assist boosts to 30 seconds. So far, my battery pack has not recaled.

 

That is a really good point. I also drive in ways that limit assist usage, hoping to prolong IMA battery life, I pay a slight mpg penalty, but figure it will be worth it in the long run.

Also, wrt driving the car on a dead IMA battery, with the Insights at least this is problematic (I don't know if the HCH's are similar but probably). There is no alternator in the Insight, it depends on the IMA system to charge the 12v battery, and the charging function is disabled by a dead IMA battery.

In the Insight forum there is a guy who recently reported trying to live without his IMA battery when it died. He lasted about 2 weeks before getting sick of charging his 12v battery every day. I think it died on him once and that was the last straw for him.

Here is the thread:

https://www.greenhybrid.com/discuss/...tery.5734.html

 

This is consistent with what I've observed in my 03 HCH. It begins charging the IMA off the engine at about the 50% depleted mark (could just as easily be 40% due to display error). Even with some 20 mile long up-hill climbs I've had, it never drained lower that 5-6 bars. At that level, even under modest to more-than-modest accelleration, the IMA did not assist. I almost have to floor it to get an assist. The car seems very protective of the IMA batteries, for lack of a better way to describe it.

 

Gosh, in my '04 CHC it would go down to one or two bars.
Now, on my '06 HCH, it never fills all the way or goes down all the way, pretty much stays near the middle mark all the time.

Jessica

 

To clarify, when discussing the low point 15% vs. 40%, what is meant is when the display reads zero, how much is actually left in the batteries. There is no way to measure that by observing the display.

I am not aware of NiMH's being harmed by going to zero however, the only reason I can think of are the voltage drop, and the cell variation, where some cells would be empty and other cells would force current through them, which is known to cause damage in NiMH's. So, to avoid those problems, the HCH leaves a reserve at the bottom.

Overcharging at the top is a definite NiMH killer, they cannot accept charge at high rates past about 80% full, so the HCH has a reserve at the top and will stop charging when the upper reserve is met. Again cell variation is a problem so the upper reserve point is likely to be lower than 80% when the meter shows a full battery.

So if your meter swings from full bars to zero bars, theoretically the battery only went from the upper reserve to the lower reserve point, figure less than half the rated capacity of the battery (6500mah on the HCH-I, don't know what it is on the HCH-II). So a 10% swing on the meter, is about a 5% swing in the actual battery capacity.

I recently discovered that the NiMH batteries that the HCH's use are rated for about 100k 5% swings, which compares very favorably with consumer NiMH batteries rated at 1000 full discharge cycles. Many small swings occur in normal driving. A naive calculation shows that 27 5% swings per day would yield 10 years of life. Accellerating gently from a stop to say 35 mph does not use 10% of my meter, although perhaps two of those would.

Course if I floor it and do a 0-65 leadfoot, I can use 30% of the meter in one go. :-)

I also used to have a problem with sustained hill climbing on my commute, if I camped in 5th gear, the display would drop to 4 bars every time before the charge cycle would start. My solution was simply to downshift. I don't think the CVT has this problem, although if you do have daily wild swings you could try 'S' (sport?) on hills to see if things improve.

 

There are some steep hills here in California that can drain your battery all the way down to 3 bars if you use the assist, and on the way up to Vegas as well.q

 

If what you're saying is accurate then my HCHII, at least, doesn't have the same reserve behavior on the Full end of the cycle and the Empty end of the cycle. The SOC gauge often goes to the top of the scale, i.e. it shows a full charge. Perhaps that means that the batteries are only 80% full. But then I'd expect the same to happen on the low end - the gauge should go to empty or near empty while there is a hidden reserve of 20% or 40% or whatever Honda chose. But in fact, the IMA has never allowed my charge to drop below four bars on the gauge. When it gets down to four bars the IMA refuses to provide any more assist and it often will force charging even when the engine is struggling up a steep slope. So, is it reasonable to think that Honda designed a hidden reserve on the top end but not on the bottom end?

I normally cycle between 100% charge and 40% charge every day because of the terrain - a steep climb up to my house. And sitting in my garage, the batteries are usually at 40% charge.

 

As best we understand it there is still a hidden reserve at each end of the meter. Reasons for why those last 4 bars remain are a mystery. My guess is that if you were to floor it up a steep sustained hill you could get at those last 4 bars, or at least a few of them. It may be a reserve for emergency accelleration. Sort of a visible reserve above the hidden one.

When you are coming up the hill, and get to the last 4 bars, try flooring it briefly and see if the assist comes on, it would be an interesting experiment. Other people here have reported getting below 4 bars, but rarely.

This is only opinion, but I don't want to be a fearmonger about pack swings either. I think fears of battery dying are overstated, even if you have large daily pack swings like I used to. And the warranty is excellent so we are taken care of nicely anyway.

 

I don't live in fear the battery pack will go in another 90,000 miles, but neither do I attempt to push the envelope.

My two recommendations is periodically check the 12-volt battery and avoid over using the assist with agressive driving.