Don
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Location: Biloxi MS

Re: Help with problems with the 12 v battery

Wed Jul 01, 2020 7:16 am

JoeS wrote:Anyone have any more suggestions for Casper?

How old is the 12 volt battery? iMiEV's are notorious for all sorts of problems associated with weak 12 volt batteries, as that battery runs every computer in the car. If the battery is more than 3 or 4 years old, swapping it for a new one would be my very first troubleshooting check, especially now that you know for sure your DC to DC converter is charging it properly

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2017 Chevy Volt Premier
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kiev
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Re: Help with problems with the 12 v battery

Wed Jul 01, 2020 10:00 am

smueller99au wrote:...
So, does anyone have any idea where I would find the connector between the OBC and the battery, and secondly where should I look on the circuit board for some kind of regulator circuit?

Many thanks for the help!!

Stephen
Copenhagen area, Denmark.


The 12V line connector to the battery is located directly on the "back" of the OBC, i.e. toward the front of the car. It is a black connector with a single blade terminal that is hard-mounted with a steel bracket to the OBC housing. i think it has a large gage white wire.

This is a picture of the connector disassembled, it was quite difficult to extract the terminal.

Image
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smueller99au
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Joined: Tue Sep 17, 2019 8:24 am
Location: Denmark

Re: Help with problems with the 12 v battery

Wed Jul 01, 2020 10:50 am

Hi Don.
Thanks for the reply. As I mentioned the battery is pretty new, as in within 6 months. I’ll go check if it has a date stamp on it to confirm though.

What I’m worried about is that the charger drives 14.8V!! This is why it’s shutting down. I managed to get it to drive today at 14.6 volts all the way home. But this morning it didn’t even think about charging. I never saw about 12.8V on the meter.

Are you sure it’s 12v battery related?

@kiev: thanks for the tip with the connector. I’ll see if there’s some corrosion on it.

Cheers
Stephen

smueller99au
Posts: 7
Joined: Tue Sep 17, 2019 8:24 am
Location: Denmark

Re: Help with problems with the 12 v battery

Thu Jul 02, 2020 11:02 am

A little update for you.
Battery is new - Exide Premium EA386 (UK:054TE). I just can't find the date stamp on it.

Found the right connector but haven't had a chance to pull it apart yet. I'll try that on the weekend.

I drove it 6 times today. The first 2 times the charger worked as it should. The 3rd time it failed so I immediately switched off and the on-Ready again. This fixed it. Same thing happened the next 2 times. Each time it failed (battery light actually never went out, then exclamation light comes on a few seconds later) a shut down and restart worked. Odd. But it indicates to me some kind of relay is faulty or storage circuit fault (capacitor?). If I can't find anything outside the OBC then I'll have to open it up and start replacing the blue caps on the 12V side.

Any other ideas?

Cheers.
Stephen.

smueller99au
Posts: 7
Joined: Tue Sep 17, 2019 8:24 am
Location: Denmark

Re: Help with problems with the 12 v battery

Mon Aug 03, 2020 12:08 pm

Further update. Problem is fixed. I went through all the connectors, earth wires, etc. as per the service manual and nothing seemed wrong. Did the diagnostics tests also as per the service manual but it passed everything. So, nothing more to do except replace the entire OBC.

Well, this sorted out the problem. No more error, charging voltage back to 14.4V again. Perfect.

I pulled the cover on the old charger but nothing looked 'smoked' on first visual inspection. Should I start by replacing all the capacitors? Or does someone have an idea where the output voltage is regulated from?

Cheers.
Stephen.

kiev
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Re: Help with problems with the 12 v battery

Mon Aug 03, 2020 4:44 pm

It's in the bottom side plenum of the OBC; the upper side is the HV battery charrger and the lower plenum is the DC/DC converter used to charge the LV Aux battery. There may be a photo posted in one of the threads here, but not sure exactly where just now.

found it posted by skylogger here:
viewtopic.php?f=23&t=4079&start=20#p36638
kiev = kenny's innovative electric vehicle

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