Went and got a removed IPA that had the DC to DC converter in it and the harness etc. Overpaid but wanted it for the weekend.

Swapped in the DC DC converter and charging fine at 13.9v.

I'm very surprised that the one I had went bad like that.

Thanks for you help.

 

Glad to hear it!

 

I'm having this issue too but only when it starts up, it will go away after driving for some time or when I restart the car. So this is the DC to DC converter?

 

Asked and answered over a year ago:

https://www.greenhybrid.com/forums/f...tml#post267684

When your IMA battery has failed, 12V charging can be very unreliable. If your DC-DC converter fails, you will NEVER get any kind of consistent charging.

You need a replacement IMA battery.

 

Oh yes thats right. Speaking of which I have been meaning to ask you.

When I got a new 12v battery, the IMA system did significantly less recalibrations then with the previous ones, however after a days use, it went back to normal recalibration habits. Since honda systems keep the battery at a lower voltage over most cars, would charging the battery to a higher voltage actually do what it did when I got it new? That or maybe changing the DC converter. I dont know.

 

When you replaced the 12V, you wiped all volatile memory from all the computers including the battery control module, which likely resulted in a temporary reprieve from the "normal" recalibration due to the more substantial "recalibration" associated with completely wiping the car's record of the battery data.

Assuming the 12V battery was truly fully charged at the time of installation, there might also have been a brief decrease in demand for 12V charging - slightly less stress on the HV system overall.

Pure speculation on my part, but it's what comes to mind, and I wouldn't expect the above conditions to last more than 1-2 short drives before "normal" behavior returns.

 

I think your right in regards to the 12v being new and having a higher voltage, as I have disconnected the battery on numerous occasions only for it to make no noticable difference like what I had with a new battery. I will try an overnight charge of it. It definately lasted longer then two short drives and nearly the whole day.