06 HCH - main battery keeps dieing - any ideas?
 

Just bought a used HCH 06 a few weeks ago and the main battery went dead on me after not running it for a day or two. Just figured the battery need replacing so I picked up an autolite at the local kragen. Was working fine for a couple of weeks but after coming back from a 1 week vacation the [new] main battery was completely dead.

This is leading me to suspect that the battery is not the problem, but rather it's not being fully charged, or there's some sort of extra drain on it when the car is parked.

After jumping it and driving it around for 15 minutes it's still not holding a charge. It will start if you turn it off and back on immediately, but if you let it sit for a few minutes no go. I think this new battery is toast.

Outside of that the IMA system seems to be working fine. It charges well and the IMA battery seems to hold a charge well. As I understand it the HCH does not have a typical alternator, but rather uses the IMA system to charge the IMA and main batteries. It is certainly charging the IMA battery well as it seems to operate normally, so I assume there is no "alternator" problem, unless there is a problem in the system/circuitry that is responsible for charging the main battery. The vehicle had an after market shock sensor with a blinking led that I removed, but outside of that I don't see any visible premature drain when the car is parked other than the factory alarm light. When I was away on vacation I didn't even have the vehicle locked, so there wasn't even the alarm drain.

Any ideas on what the problem might be?

Thanks.

Re: 06 HCH - main battery keeps dieing - any ideas?
 

Visit a dealer... sounds like the DC-DC converter has gone belly up, though there should be some sort of fault code an trouble light associated with it.

Re: 06 HCH - main battery keeps dieing - any ideas?
 

The HCH II rarely uses the under hood battery to start the engine - it only uses the under hood battery and bendix starter if the IMA battery is too weak to turn the generator ( like in the autostop mode when driving ).

How many bars do you have in the charge indicator when you cut off the engine. It may be that you IMA battery is not charged enough. Drive about 4 miles in "S" instead of "D" ( below 45 mph ) to charge up the IMA battery. If you don't have at least 5 bars after doing this you IMA batteries are not holding their charge anymore or a fuse under the hood may be blown ( some will not leave any indication they are blown unless you look at it. Others cause the green D indicator to blink on and off when the car is in "D"rive.

This is my guess - your best bet is to get a Honda Hybrid Certified Mechanic to plug into the diagnostic port and see what the computer thinks is wrong. Many Honda mechanics are not Hybrid Certified. Many contributors of this forum and the 8thcivic.com forum know more than they do about the hybrid systems.

It might be the power converter - but if it is not working properly - your headlight will go dim(mer) when you are in autostop. The car battery does not power very much in the HCH II vehicles.

Good luck.

Re: 06 HCH - main battery keeps dieing - any ideas?
 

Thanks for the info.

Are you saying that when switching on the ignition from a cold start the IMA battery and generator is usually used to start the engine? If so, is this still the case if the main battery is dead?

I assume the interior lights, dash, door locks, etc. are all powered by the main battery since these are certainly all 12V DC, right? After driving about 15 mins this morning I turned off the engine, then started it right back up. Then turned it off again and tried loading the system by switching the lights on and then starting it, no go. After a few seconds with the lights on the whole dash went dead and that was the end of it.

I've read others say, and I believe I also experienced this, that after jumping the car w/ a dead main battery that the IMA battery shows near empty. But after driving a bit it will suddenly jump up to 80% plus, I believe after the system re-calibrates (the manual mentions this) it shows the actual charge level. To me this suggests that with a dead main battery it won't start, regardless of the charge in the IMA battery.

So I'm still leaning towards a problem with the main battery not charging, or being prematurely drained. Do you think I'm on the right track?

Re: 06 HCH - main battery keeps dieing - any ideas?
 

The 12v battery has to have enough power to flip the relays to the IMA batteries. - I would disconnect the battery from the car and charge it with an external charger for at least an hour and see if it starts that way.

I have no electrical hybrid manual to see how the 12v battery gets charged. I think it might be a fuse or the power converter. If the power converter has multiple outputs the one that goes to the battery might be bad. If it only has one you could not run the vehicle more than 20 minutes before it would run out of battery.

Re: 06 HCH - main battery keeps dieing - any ideas?
 

I think I can rule out the IMA battery and generator. I exchanged the main battery for a new one since it was only a few weeks old. Car started right up of course, and showed zero bars on the IMA battery. It went into a forced charge and I let it idle for 5-10 mins and it got up to about 2 bars. Then I did as you said and drove in "S" for about 10 mins. The charge got up to about 4-5 bars (~50%), then suddenly it jumped up to 100%.

It seems the IMA system calibrated itself and realized the IMA battery was at full charge. So based on this I think I can assume the IMA battery and generator are working properly.

I dropped it off at the dealership this morning and they said they'd run some diagnostics on it. The service tech said it would be $80 just to run the tests. I asked if the cost would be covered if it turned out to be a warranty issue with something in the IMA/emissions system since that is still under warranty (10/150K here in CA), and she claimed that it isn't related to the IMA system. I think she was thinking of the battery only, but based on the emissions parts list there's a bunch of stuff under IMA, such as the DC-DC Converter which seems suspect.

I'm hoping it turns out to be something covered under the IMA warranty. I'm also hoping the techs are competent enough to diagnose the problem correctly, rather than trial-error replacing components, esp. if they're not under warranty and come out of my pocket. We will see!

Re: 06 HCH - main battery keeps dieing - any ideas?
 

Just got a ring from the service tech, diagnosis: nothing wrong - no fault codes found. main battery voltage is fine and no parasitic draws. they claim they can not actually check that the main battery is being charged, that they can only check the voltage, which of course will be fine because it's a brand new battery.

They claim either:

a) battery was bad - seems unlikely to me as this happened to the original battery, and to the 3 week old autolite I got from kragen.

b) parking the car with empty (1-2 bars) IMA battery will drain the main battery - what?? has anyone ever heard of this? also seems unlikely as I normally park it with 70%+ battery level. plus once the IMA system re-calibrated after jumping it it shot up to 100%.

not very reassuring. a waste of $80?

Re: 06 HCH - main battery keeps dieing - any ideas?
 

I have a 06 hch ive replace my 12v battery it drains after recharge steering wheel gets hard and driver window doesn't lower no check engine light on besides red battery light on checked fuses there not blow . .help please

Re: 06 HCH - main battery keeps dieing - any ideas?
 

I have no codes jus a the red light battery on replaced with new and battery dies again steering wheel gets hard

Re: 06 HCH - main battery keeps dieing - any ideas?
 

You're 12V is not charging. There are a number of reasons for that. You need to have diagnostics done.