All Honda IMA systems can be disabled and configured such that the IMA motor and DC-DC converter will charge the 12V in a reduced operating range. For the HCH2, it's about 1500-3500 rpm.

The disabling will throw a continuous IMA and check engine light that will prohibit you from passing emissions if that's a criterion in your area.

It's best to have a cigarette lighter voltmeter, so you can keep an eye on your 12V health.

http://www.prolongima.com/hch/removal/bypass.html has instructions in their tech resources section for Insight and HCH1. For HCH2, you merely need to flip the pack switch off.

Steve

 

Is there any difference between turning off the IMA switch on a HCHII versus just driving with bad IMA battery?

The IMA light and check engine light will be on in both cases, and the sluggish start and reduced mpg will also be there in both cases. But at least the 12v charging seems to still be fine with my bad IMA battery.

 

I can't tell if you're quoting something or asking a question and then answering it. I'm going to answer the question.

Yes. A few.

With a bad IMA battery, you get limited operation, mostly normal 12V charging and more forced regens - which adversely impact mileage.

With a bypassed IMA battery, you get no IMA operation, 12V charging in a limited rpm range and NO regens.

Per previous, IMA and CEL illuminate in both cases. If your state requires no CEL to pass inspection, you will fail.

With bypass, you will ALWAYS be 20hp short on power. With bad IMA battery, you will be 20hp short on power most of the time.

A bypassed IMA battery typically gives BETTER mileage than one giving excessive recalibrations (several per day).

Highway mpg for bypassed vs. FULLY FUNCTIONAL IMA is about the same as the IMA system does almost nothing at highway speeds unless you're dealing with a lot of elevation changes where the IMA system has something to do at highway speeds.

 

Thanks S Keith! Since the weather's been warmer (I'm in Maryland), I've had no IMA light or CEL and still getting 41 mpg. So I think I'll keep driving it as is instead of turning off the IMA and fighting the 12V charging battle.

I have a 2006 HCHII with 194k miles. The first IMA battery failed at 88k and Honda went halfsies on the replacement (warranty ended at 80k). Then in the class action settlement, I got the other $1500 back. Then at 188k, I got IMA light, CEL, and flaky performance (goes up to 8 bars in a few seconds if charging and then can drop to 3 bars in a few seconds if assisting). Had it checked by dealer and it coded as needing IMA battery replacement, but considering the mileage, I just kept driving. Looking into a grid charger to get past the next emissions test if the lights come back in the fall.

Thanks for all your great answers on this forum.

 

If you're willing to pull the pack, you can build a grid charger for less than $50 and a discharger for maybe $10 more along with some cheap electrical bits and pieces (crimp connectors, old extension cords, etc.). If you're willing to invest another $50, you can add a PWM controller and run the car fan (charge with pack in car).

Hybrid Automotive sells the most economical charger/discharger option out there. He's in the process of enabling the ability to cycle your battery (charge and discharge) to programmed levels and # of cycles. You're looking at closer to $500 for everything you need, BUT it's a turnkey solution from a reliable supplier.

The bar behavior you describe is likely recalibration triggered by some weak subpacks (excessive voltage drop). Yours is behaving much like mine did before I started messing with things. Right now, I have a crap pack that has several subpacks with excessive self-discharge (most common cause for imbalance). I just grid charged it for about 30 hours, and it's performing GREAT even with A/C use here in AZ. Yes, it will deteriorate, but another round of deep discharge (basically to zero) and then grid charging will restore a lot of capacity and give it another "wind."

Good luck!

Steve

 

Quick question:
I have a HCH2 with just over 200k miles. IMA Light has been on for last 20k miles. It has excessive recalibrations while driving and I average 34mpg. Should I contintue to drive with a failing battery or do I flip the switch and disable the IMA system? Will everything still work when I disable the system?

 

Flip the master off and see for yourself. Your mileage will likely improve a bit during stop and go due to elimination of forced regen and your highway mileage should improve notably.

You will NOT charge the 12V at idle or high rpm. The red battery light will illuminate when 12V charging is not happening. It should go out after a few seconds when you are between 1500 and 3500rpm.

Something like these:

http://www.amazon.com/s/ref=nb_sb_ss...er%2Caps%2C187

will give you confidence in your 12V battery.

I would also recommend a 12V upgrade to a 51R from a 151R. Much higher capacity.

Grid charging/discharging your pack may restore it to full function. DIY version in my signature.

 

Thanks for the info! I will flip the switch within the next week and see how it goes. Will I need to charge the battery manually ever? or will simply driving the car everyday provide enough charging? I read somewhere to switch to a deep cycle battery and throw a trickle charger overnight

 

You could throw a 12V charger on it weekly if you want, but switching to a higher capacity 51R will give you way more margin and should make it unnecessary.

Those 12V cigarette lighter monitors are cheap, and you have the two 12V ports for installation. I have them in all 4 of my Hondas.

Lots of stop and go driving with excessive idling could run the battery down, but that's worst case.

You'll likely be fine in any case as long as the 12V light is out most of the time.

Steve

 

I already ordered the 12V cigarette lighter monitors amazon prime haha thanks for all the information! Would getting a optima d34 battery be a better option then the 151r? I read its easy to make a 34 battery fit in the civics. Ill keep you updated as well!