lsquaredb
Posts: 2
Joined: Wed Jun 27, 2018 5:22 pm

First post and first problem (12V Battery Short)

Wed Jun 27, 2018 5:35 pm

Hi Everyone,

I bought a 2012 iMiev new, and have enjoyed looking at the forum from time to time. I finally got around to joining because I now have the first problem ever with the car. I was smelling rotten eggs on the way home tonight. I checked the 12V battery when I got home, and it was hot, smelly, and gurgling. I checked after dinner and it had cooled down and wasn't gurgling but the sides were bulging out. There are no warnings on the dash, and the car boots and drives with no difficulties. So is it just the battery is toast? In the morning, I going to check the voltages to make sure it's not a charger issue, and then try to find a replacement.

Leonard

JoeS
Site Moderator
Posts: 3574
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: First post and first problem

Wed Jun 27, 2018 6:55 pm

Hi Leonard, and welcome to the forum.

Two things come to mind with your 12v battery problem -

1. A shorted cell within the battery, the result being the dc-dc converter pumping loads of current into the other cells trying to bring them up. Result is heat generated by the good cells as well as the shorted cell, boiling off the battery fluid.

2. The output regulator of the dc-dc converter fails to do its job and a higher voltage is being fed directly to the battery, cooking all the cells. I haven't looked at the circuit so that's speculation.

I suspect the first.

Do NOT turn on the car. That battery is toast and I would simply take it out. Measure that battery voltage with everything disconnected: if the voltage is around 11.4v then the battery has a shorted cell (unless the other cells have now been damaged). Now, attach any usable 12v lead-acid battery to those car terminals (you can use jumper cables to a battery sitting on the ground, being VERY careful to insulate all exposed wiring so as not to short anything), put a voltmeter across those terminals and turn on the car. Hopefully it goes into READY, and that battery voltage should be somewhere around 14.4v when energized. If the voltage is way higher (like well over 15vdc), that would indicate a problem with the dc-dc converter.

Hopefully, all you need to do is simply replace the 12v battery and all will be well.

Good luck.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

PV1
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Location: Pittsburgh, PA
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Re: First post and first problem

Wed Jun 27, 2018 7:10 pm

Unless you noticed the lights on the car (dome, headlights) being exceptionally brighter than normal, I second a shorted cell in the 12 volt battery. Won't hurt (hopefully ;) ) to rule out proper charging voltage of around 14.4 volts while READY.

By the way, welcome.
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Thanks.

jray3
Posts: 1575
Joined: Tue Dec 06, 2011 1:05 am
Location: Tacoma area, WA
Contact: Website

Re: First post and first problem

Wed Jun 27, 2018 10:19 pm

Yep, I’ll vote for the shorted cell, a new BCI Group151R 12V battery oughtta fix it
2012 i-SE "MR BEAN" 94,000 miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh
1965 Karmann Ghia Cabriolet

lsquaredb
Posts: 2
Joined: Wed Jun 27, 2018 5:22 pm

Re: First post and first problem

Thu Jun 28, 2018 10:15 am

Thanks everybody. The old battery was showing 8.9V. I put in a new battery, and I'm getting 14.4V at the terminals with the car switched on. The car is fine now.

JoeS
Site Moderator
Posts: 3574
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: First post and first problem (12V Battery Short)

Thu Jun 28, 2018 12:17 pm

:D That was easy! (Whew!)

I moved this thread over to the Battery subforum and added a brief descriptor to the title so we could find it in the future.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

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