The engine battery has probably been dead from the day it was installed. The IMA normally starts the car, but when it is low it uses the engine bat. Hopefully that corrects your problem.

 

I'm 99% sure the IMA does NOT start the engine. I left my hazard lights on overnight in my driveway because I was planning to put the car in the garage but forgot, and in the morning the car wouldn't unlock with the key fob, the hazard lights were off, and it wouldn't start.

After getting it jump started, the alarm started blaring because the car alarm hadn't been disabled when I used my key to unlock the door directly. With the car running I clicked the unlock on my key fob and the alarm went off.

This was a very standard jump start experience--and it was the wimpy 12V battery in the engine compartment that was dead and needed a jump start, because my IMA was 90% charged when I finally got the car started with the help of AAA. By the way, the nice AAA guy said to turn my headlights to the on position because sometimes jump starting the 12V battery can blow a fuse because this car uses so little juice.

 

Yes, the IMA battery turns the electric motor to turn the crankshaft to start the gas engine. Instead of the gas engine's starter, which uses the regular 12V battery. This is the normal situation, and is why it starts so quickly, and why you don't hear the regular starter kick in. If the IMA battery is very low on juice, or (more likely) if it's very cold outside, then the 12V battery and the regular starter will be used to start the gas engine.

What I'm not certain of is this: IF your 12V battery is DEAD, will the IMA battery start the gas engine? I think not. If my guess is correct, this may be what you experienced. Either that, or it was too cold for the IMA battery to be used to start the car, so it attempted to use the regular starter, but alas, you have a dead 12V battery. So nothing happened.

 

Folks,

While this car is a Hybrid, it is mainly designed around the components of a regular car and is designed to function 100% like a regular car if any of the IMA system fails. So if the main battery is dead, I don't think the engine mangement systems gets any jiuce and the car cannot be started, even if the IMA motor and battery coud do it.

I also did some poking around in the service manual about this issue, and it would have to be either a (1) faulty wire or 12V battery, (2) a failure of the DC-DC converter that is supposed to keep the battery and the rest of the car's 12 V accessories powered, or (3) a current leak that is discharging the battery. The dealer should be able to troubleshoot this easily even if it is intermittent.

Note that there is no conventional alternator in this car.

BTW, isn't the DC-DC converter a recall item for some '06 cars?

Hope the OP can get this fixed -- it seems like an easy one. Also he is right that once a conventional battery gets drained 5 or 6 times, it will never work right...

Dobe

 

I have 2005 Hybrid Accord. The meter on the dashboard only shows 4 bars for the battery, it used to show 6. The car was outside in cold weather for 2 months. The charging and assist bars on the panel don't always display the mode the car is in. Help, anyone?