12V battery issue

mrmcg · 09-26-2011, 05:40 PM

I have a 2001 CVT Insight. I started the car yesterday, it barely turned over but it started, turned the lights on and they were very dim. I had similar issues lately and assumed it would charge as I drove, but I probably need a new 12V battery. I grabbed a jumper pack before I left the house just in case.
as I drove away I noticed the Battery and Brake indicator lights were on. Lights did not get brighter, about two miles down the road instrument panel went black and the radio shut off, I turned around and headed home, soon the transmission would not shift up, something started beeping, and the engine stalled. All this time the IMA battery showed a full charge. I hooked up the jumper pack rested the hood on it, car started right up and pack had enough power to get me home with incident. So, I may have a bad 12V battery but I am wondering why it didn't charge while driving? As I understand it, these cars don't have alternators, so I am not sure how the 12V charging takes place. I have not gotten it to a service station yet to check the codes (although the check engine light came on after it stalled)
Thanks for any help.

Willie Williford · 09-26-2011, 07:23 PM

There are hundereds of posts here at ICN about the problems of having a weak 12V battery in the system. Ground straps, weak cells in the 12V is something to investigate. Charge your 12V battery and do a load test. That will tell you the true condition.
Your 12V charging comes from dc converter. Dim lights and the battery indicator are the best indication that you have a weak 12V battery.
HTH
TMK there is no code for a weak or bad 12V battery.
Willie

Wocketman · 11-03-2011, 07:17 PM

So...what does it mean if the 12V battery was recently replaced (6mo ago), and it keeps going dead although the IMA battery seems ok? Bad DC-DC converter?

Eli · 11-03-2011, 08:27 PM

I've never heard of a DC-DC converter failing, though I'm sure it's possible.

More likely that it's a ground strap issue. If the DC-DC wasn't functioning, the red 12V battery light would be on.

Wocketman · 11-03-2011, 08:59 PM

Thanks! I'm going to look at a 2000 gen 1 tomorrow morning that supposedly is not charging the 12V batt. The engine & IMA batt were replaced about 30k ago, the body has about 200k on it. I've wanted a gen 1 Insight forever...this may be the one.

My current ride is a 91 CRX-HF that I've averaged 60mpg with this summer (best tank 65mpg). I use every hypermiling trick in the book, so now I want to see what I can do with a Gen 1 Insight...

Wocketman · 11-04-2011, 10:20 PM

Ok, so I spent some time looking a very neglected and cosmetically challenged Gen 1 today in Maine. Full of dirt, straw, missing the rocker panel plastic on the driver's side, dented bumpers, etc. Not driven for over six months. Oh well. Apparently the engine has only 30k on it and the IMA batt was replace a couple years ago.

The 12V battery was dead. Sure enough, the upper engine-chassis grounding strap was completely corroded severed. Finding something so obvious got my hopes up.

I put in another battery from a Honda VX that happened to fit, only the terminals were backwards and I wasn't paying attention...so got the horn reverse-polarity alarm but not before the main 80A fuse blew. So I went to the nearest Carquest and got a new fuse (and a grounding strap).

With fuse and strap mounted (and battery wired the right way), she started right up. No charge showing on the IMA battery. After a few minutes there were a few charging bars showing and the IMA started to show some bars as well. However, the voltage of the 12V batt did not go up (not charging).

Tried to drive but it wouldn't go into gear. Discovered that the clutch fluid reservior was empty. So, back to the Carquest for fluid and after filling that and pumping the clutch, she started allowing shifting.

So I got my first chance to drive a Gen 1 Insight. Unfortunately, the speedo only read zero and the charging/assist displays showed nothing. What is weird is that even though the charging display had stopped showing charging, the IMA batt continued to "fill up" and eventually showed a full charge. No assist, and the 12V batt continued to be depleted. CEL was on, ABS, 12V batt light flickering, etc. Not a pretty display of warnings. Forgot my code reader so couldn't check those.

So, one can drive the car (with no assist) until the 12V battery goes dead.

Gave a deposit, but I have until Wednes to decided if I want to buy it or not. I'm not sure I want to get too deep into a technical project over my head...are there any potentially simple fixes for what I'm seeing (aside from the already replaced grounding strap)? Did I F-up the ECU with the reversed polarity before the main fuse blew?

The current owner (whose mom is the original owner and drove the car without an oil change until the engine seized, that's why it has a newish engine now) was amazed that I found the broken ground strap.

Should I run away?