So I just recently purchased a new 2009 HCH - car is about two weeks old. This morning I got up early to drop someone off at the airport and when I got home I mistakenly left the headlights on. Two hours later when I was ready to leave for work, the battery was dead and both the IMA and engine lights were on. Needing to get to work, I jumpstarted the HCH from our other car using jumper cables. My HCH started but the IMA and engine lights were both still on and my battery charge gauge was at zero. I drove to my office (about a 30 minute commute) and the recharge gauge never moved even when the breaks were applied. When I arrived, I turned off the car and tried to restart but no dice: it wouldn't restart and both lights are still on.

So what do I do? Does draining the battery by leaving the lights on ruin the 12V battery? Do I need to do something special to get my HCH back on track or does this require a dealer visit? I know very little about the inner workings of the hybrid engine so if anyone can offer any guidance it would be greatly appreciated! Thanks!

 

I think there is a mention of this in the manual re jump-start! Disconnect one of the engine battery cables for a few sec. and this may make it re-calibrate! I have never had this issue, so hopefully someone that has responds. Do you have Honda's road side assistance? Hal

 

Well, if anyone reads this post and is interested, I took the car to the dealer after jump-starting it again and it turns out the battery was bad. They said that leaving the lights on didn't help things but it shouldn't have caused a complete failure like this. I had suspicions that the battery might not be 100% from the beginning as the charge level fluctuated wildly even on short rides but having never owned a hybrid I wasn't sure if this was out of the ordinary. Long story-short, the new battery is in and the car runs even better than before. Battery charge level is much more constant and I'm even seeing better MPG than I was previously.

 

I think you basically ran down the 12 volt battery, by leaving the lights on. It was likely not "bad" to begin with: they just have a very limitted reserve. Leave the headlights on for an hour, or the reading lights overnight, and it will be near death's door.

We've come close to killing ours twice, but revived it both times by overnight charging with a 6 amp auto-charger.

Clarification: By "auto-charger" I mean a charger that senses the state-of-charge of your battery. It is safe to leave these hooked up indefinitely: as the battery recovers the charger detects it's improving state-of-charge and reduces the current it's sending to the battery.

When I first saw our HCHII's 12 volt battery I was suprised at how tiny it was. I haven't checked the spec., but I suspect it's much lower capacity than our past Honda's batteries.

BTW, that wild fluctuation you're seeing (I assume in the in-dash display) is not in the 12 volt battery: that display is showing the state-of-charge of the big Integrated Motor Assist battery, and it's normal for it to go up and down.