12V Battery Replacement Detailed
 

Well, I had a real adventure/education Friday (the 13th). I was stopped in a traffic jam in the middle of the city and car did not autostop. I turned it off to wait and in a few minutes when I went to start up, it did not start. Instead the IP flashed at a high rate continuously and there was a chattering sound like a relay coming from under the dash.
The noise, lights, and panic was very confusing...what is wrong? I noticed the SG said 9.5 volts, so I put it in park and got out to see it the terminals were tight. Nothing wrong. When I got back in the car, same light show. I was on a hill and in the middle of a jam, so I figured I could roll backwards and get out of traffic. Then I discovered that with the dead battery, I could not get it out of Park. Big trouble.
After 10 minutes of doing nothing, the battery built up enough charge to allow me to get it out of Park. I thanked The Lord. I rolled back off the road and got a jump from a guy and drove home no trouble.
(Continued)

Re: 12V Battery Replacement Detailed
 

The Honda replacement battery #151R is puny and costs $159. I instead bought an Interstate Megatron II #MT-51R for $95. OEM is 335 cca, Interstate is 500 cca.
THe case size is bigger, but it will fit in the HCH space fine, but the plastic tray has to go.
See the pictures attached to get an idea of how much bigger it is, and how it fits. I highly recommend this bigger battery.
I also submit this tale as a warning that if your 12v battery is 4 or 5 years old, you better get a new one asap. There was no warning at all that it was weak. And remember, do not put your HCH in Park if the battery is weak or dead, it can strand you helplessly.
GL

Re: 12V Battery Replacement Detailed
 

Hey John:
Thanks for your thread. Interesting! Is that Interstate 2" longer and the same width? H

Re: 12V Battery Replacement Detailed
 

Yes, thanks for the heads up and the photo of the new battery in situ. Glad no one was hurt....

Just an observation: if there was no warning at all prior to this adventure, is there a possibility that the DC/DC converter may have some sort of fault that is not making itself apparent?

Re: 12V Battery Replacement Detailed
 

I don't think there is anything wrong, other than the battery was just old, 07 OEM, and it charged up fine on the way home. It just wouldn't hold the charge.
Yes, the 51R is about 2" longer than the OEM, and the same width and height. I weighed the 151 at 21 lbs, and the 51 at 28 lbs.

It appears that the compartment will hold the 51R because that's what the non-hybrid Civic uses. Perhaps we could buy the tray, etc for a regular Civic and bolt in the bigger battery just like a normal Civic has. I haven't seen one to notice.

GL

Re: 12V Battery Replacement Detailed
 

I have a 06HCH2 and I maintain my 12v with a 2amp electronic battery charger. I watch the 12V on my scangauge for signs of weakness. Never gets below 12.5 V. H

Re: 12V Battery Replacement Detailed
 

The12v battery in this car behaves differently. Under typical conditions it uses very little power to do its job so it can deteriorate down to nothing and still start the car.


It can be hanging by a thread and give no indication.

A starting battery in regular will offer a clue, like slower cranking.

Re: 12V Battery Replacement Detailed
 

The 12V only starts the car when it is very cold or the pack is depleted for some reason. My HCH2 06 model has never started via the 12v starter. H

Re: 12V Battery Replacement Detailed
 

Yeah, that's what bugged me the most. Knowing that I had some 160 volts in the back seat and just because the ecu didn't see 12v, it wouldn't let me use them to start the car.
All the 12v battery does is power up the ECU and allow it to control the car's functions. When the 12v goes out, you lose everything, including the ability to get the car out of Park.
Honda should have provided a 12v tap off of the IMA battery for emergencies.

GL

Re: 12V Battery Replacement Detailed
 

Check that.......