12v management??

PV1 said:

I had no problem after a week, but I don't know about 4-6 weeks. The issue with the i-MiEV is, if the 12 volt goes flat and can't start the car, you'll get the EV warning light and it can only be cleared with the programmer tool the dealers have (a few members here have it, too). Better safe than sorry.

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Drove across state (long day even with level 2) to have my car get its first inspection at a trusted dealer. My air bag sensor seemed to be malfunctioning. After a thorough inspection found I out a few unexpected things. (like two recalls? including rust coating needs to be done on my car and accidentally found the former owner's address still in my nav).

The sensor seemed to be malfuctioning because the 12 volt battery had become unbalanced. The service department rebalanced it and the car worked fine for a couple weeks until I drove with the radio going full blast, nav on and parked it for less than 4 minutes listening to the news. Sensor light is back on and I suspect the 12v.

Anyone else experience this? I wonder if I can upgrade the battery?

I didn't know the 12v could be "unbalanced"

I am thinking it may be something else.

Or, if you need a new battery, go to Advanced Auto (I think most do this for free) and have them check your battery for free.
If it is slightly low then replace it.
Which you would have to do at some point anyway, so no loss if that doesn't fix it.

I had the airbag light come on twice due to a faulty sensor (there was an early recall on that, but I guess my car wasn't covered under it), but they replaced the sensor under warranty.

While it's pretty rare, 12 volt batteries can come unbalanced (any battery chemistry with more than 1 cell has the potential), though instead of "balancing", the term used is "equalizing". Smart battery chargers have the option to equalize wet cell batteries.

Have you noticed any issues with dim lights or slow-rolling windows when not in READY? Obviously, 12 volt stuff won't be as energetic when the car's off, I mean REALLY dim or slow.

The first time my airbag light came on, I took it to the dealer for diagnosis. They ordered a sensor and cleared the light. A couple of weeks later after charging on a public level 2 with the radio and fan on (12 volt system gets power from the mains when charging), the light came back on. About a month later the sensor came in, so I had it replaced. No issues since. It was the front left impact sensor.

Depending on your skills, some members have installed lithium-ion 12 volt batteries.

A load test of the 12v battery will quickly show its true colors. I personally would replace it with a small AGM battery to eliminate the corrosive acid fumes under the hood. Hey, a 12v battery has six cells in series and, yes, they get unbalanced but it is invisible...

JoeS said:

I personally would replace it with a small AGM battery to eliminate the corrosive acid fumes under the hood.

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Would U1 be a good fit in there? At 35 to 39 Ah the capacity would be more than adequate.

Aerowhatt

Aerowhatt said:

Would U1 be a good fit in there? At 35 to 39 Ah the capacity would be more than adequate.

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Sorry, I haven't done my homework yet to identify the exact AGM (not Gel) battery to use. First is form factor and terminal positions for compatibility with the existing i-MiEV location. After that, in my case I wouldn't worry about capacity too much as I never sit there parked and playing the radio for a long time, so just about any capacity battery would work. I use the car daily, but if I were to go away for a few weeks I'd simply plug in a float charger and not worry about capacity loss. I've already permanently added small Anderson PowerPole connectors to each car's battery for use with either a charger or inverter.

Joe, What if one was to leave the car for say a Month (or a tad longer) for Winter.

I might have to do that if the Winter gets really bad like it did this past Jan-Feb here in Boston. I have my P-U for Winter driving.

Thought I would add this to this thread in case I forget

tigger19687 said:

Joe, What if one was to leave the car for say a Month (or a tad longer) for Winter. I might have to do that if the Winter gets really bad like it did this past Jan-Feb here in Boston. I have my P-U for Winter driving.

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Ah, Winter - especially if you have an unheated garage. That is a more-stressful environment for that 12v battery. In that situation I would definitely plug in a smart float charger such as a Battery Tender (now with high-efficiency California and Oregon versions :mrgreen: ):
http://www.batterytender.com/Chargers/Battery-Tender-Junior-High-Efficiency.html
I've also used many of these inexpensive float chargers with my Sparrow Optima batteries:
http://www.batteryspace.com/leadacidsmartcharger08afor12vleadacidbatterywith3stagesfloating.aspx

JoeS said:

tigger19687 said:

Joe, What if one was to leave the car for say a Month (or a tad longer) for Winter. I might have to do that if the Winter gets really bad like it did this past Jan-Feb here in Boston. I have my P-U for Winter driving.

Click to expand...

Ah, Winter - especially if you have an unheated garage. That is a more-stressful environment for that 12v battery. In that situation I would definitely plug in a smart float charger such as a Battery Tender (now with high-efficiency California and Oregon versions :mrgreen: ):
http://www.batterytender.com/Chargers/Battery-Tender-Junior-High-Efficiency.html
I've also used many of these inexpensive float chargers with my Sparrow Optima batteries:
http://www.batteryspace.com/leadacidsmartcharger08afor12vleadacidbatterywith3stagesfloating.aspx

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But should I leave it in the car or disconnect and bring inside or is it better to leave it in the car.

Is the EV battery ok to be left alone for a month if I took out the battery (if charged to say 90% before sitting) ?

No. Leave the 12 volt battery in the car and hooked up. Also the main lithium pack should be kept at 4-7 bars. Do not plug in the EVSE. No maintenance charge is needed on the main battery, we only need to keep a battery tender on the 12 volt battery.

As long as a lead battery is charged, it won't freeze during the winter.