Thought I'd start a new thread because I've not seen these symptoms specifically discussed below [some of my earlier queries on constant recal's over the past 4 months were mentioned in a couple of posts in the thread started by "giantquesadilla", located about a dozen below]. Sorry for the length .

The car now has 54K miles, with 20 months / 27K miles warranty to go on the IMA systems); up here in Canada, Honda gives us only 8 years or 130,000 km /80.7K miles warranty.

Recently set off on a 1500 mile round trip from Calgary AB to Puyallup WA. For the first 95 miles, got the usual six recal's; then they stopped; and never saw another one for the balance of the trip or the 30 or so miles of around-town driving since my return.

But now it seems the state-of-charge [SOC] has settled in around 4 or 5 "squares", out of the 8 that indicates (indirectly) full charge. Here's what happens going down a long 1 mile hill nearby that allows coasting with foot off the gas with an occasional tap or two on the brakes to stay within the 50 mph limit. If the SOC was 4 at the top of the hill, it will gradually go up to 7 or 8 by the bottom, showing the full 11 green bars of maximum charge rate. Then, I pull a U-turn and go back up; I get the full 11 white bars of motor assist, keeping the constant 50 mph limit, with the motor revving between 3000 and 3500 rpm. The SOC battery level gauge goes down from 8 to 7 to 6 to 5 at about 10-second intervals, all the while providing the expected full 11 white bars of IMA. But then, it runs out of steam (so to speak). At SOC 5, the 11 white assist bars quickly drop to 1 or 2, then darkness. There is no assist available from SOC 4 (or 3 or 2). If I give a quick "stab and hold" for a second or two on the gas pedal, I might see a single white bar flash for a fraction of a second. Once, when going up a steep hill, on my 1500 mile trip, I even ran out of white bars on SOC 6 [SOC 5 and below were dark], but I haven't been able to reproduce that one-time event.

To me, it seems that the only effective battery assist capacity I'm left with is from SOC 8 to SOC 6 (and maybe a little from SOC 5) IF the battery level gauge was at the max before I needed the IMA. Trouble is, 90% of the time, on flat terrain or around town, the SOC snoozes at 4 or 5. So essentially, I have maybe a second or two of available assist passing or merging into traffic.

Of course, with all this, I've never seen the IMA light come on, so the dealers won't touch it. (Thank you Honda 2010 recall software update).

I'm tempting fate, as I plan to drive round-trip to Montreal (5,000 miles, partly in the USA). I can live with SOC 4 or 5 during the trip, but what is the ultimate IMA battery failure scenario ? If the IMA light comes on, and I drive to the nearest Honda dealer (which could be a couple of hundred miles) "as soon as possible", per the Owner's Manual, how long will the DC-to-DC converter off the high voltage NiMH battery be able to keep the lead-acid 12v battery charged ? If that fails, do I lose steering, brakes or ignition ?

Thanks in advance for all comments.

 

Disconnect neg. side of 12v battery (I then push on the brake pedal to drain the capacitors in the control module. Reconnect after a minute or two. Start the engine. Your SOC should show zero bars. Just let it idle for several minutes until SOC shows all bars (full charge). This may take several minutes. Now the IMA and the battery will perform like they are supposed to. Whenever you get "funny" symptoms again, repeat the process. Ever since the dealer updated my computer, I've had to do this. It's as though over time the computer gets confused, giving the exact symptoms you describe.

 

Thanks for the tip, merlotgoat. However, as I've still got 15 months warranty on the IMA battery, I'd rather not touch the system, as it will probably generate a code that would allow the dealer to invalidate the warranty. If I was past warranty, I'd certainly try your method.

What I really want is a recipe to kill the battery; the sooner the better, so that we can advertise the car for sale with a new battery (paperwork to prove) and a clean conscience.

There's a 1/2 mile long hill nearby that I go up/down most times I'm out, just to make the IMA work (ie. how many seconds @ 50 mph from full charge (top to bottom of hill) to no assist available [even at 5 or 6 SOC] (about 2/3 back up the hill).

One thing for sure; this is the first and last Honda product we'll ever have. Too bad though, as we like the car, and it gets great mileage (when it's on long highway trips, and therefore mostly not using the IMA).

I've had Honda Canada head office tell me that a new battery is $8 grand, so its replacement exceeds the car's value in a year or so.

 

I did my own battery replacement about a year ago. Got a refurbished unit from Milehybrid Automotive out of Denver. Total cost was about $1800, $300 of which was shipping. They don't reuse "good" cells, but instead replace all cells with new ones. You can save some money and get just a one year warranty, or pay a little more and get the 3 year warranty. The battery has worked well so far. The only issue I'm having is the same symptoms you are having. When I force a recalibration as I described, everything works well for a few months or approx. 1000 miles, then it gets funky again, so I just do a reset. It's weird--if you just disconnect the 12v battery for a few seconds and reconnect it, the recalibration works differently, usually starting out with 2 bars and then jumps up to full charge after a minute or so. But when I disconnect, hold my foot on the brake pedal for about a minute and then reconnect, when I start the car, there are no bars showing at all and it takes a lot longer to charge, and it does so more gradually, rather than jumping up to full charge from 3 bars. I blame the computer program for the problems. The battery is fine.
As far as getting your IMA light to turn on, you can force it by removing the back seat (back), then remove the metal battery panel, disconnect the thin wire wiring harness from the battery (not the main high voltage harness with the thick wires) and then start the car. The IMA will come on and stay on, even after you reconnect the wiring harness (low voltage one (with the thin wires). The dealer would never detect the cause.

 

You are a real piece of work....You want to kill a good battery, have someone else pay for it all so you can advertise the car for sale with a new battery. I would guess that you are involved in lawsuits or, at the least, threaten businesses with them for something that is not their fault.

I guess morals were never your strong suit......

 

There's a lot of misinfo here. You do NOT want to reset your 12v battery. All you are doing is resetting the state of charge so the car no longer understands how weak your battery is. You have a REAL problem if your car is recalibrating and it likely IS your IMA battery. The car is trying to alert the fault and then your advice is to lobotomize it so it forgets that the battery is going bad. Both C2 and MerlotGoat both have failing IMA batteries and no amount of disconnecting the 12v battery is going to fix it. It will actually make it worse as it will operate at a lower state of charge and closer to weak cell dropout, compounding your problems when you reset the 12v battery when the IMA battery is in a low voltage state.