12V battery BCI Size?

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A Google search says it's a 151R - http://myimiev.com/forum/viewtopic.php?t=2789

I bought a Miata AGM battery because I was familiar ith them, they're AGM and it was cheaper than the flooded replacement. Installed it in one of the cars about 2 years ago. It's not as tall as the OE battery, but I cut a piece of 2 X 6 the size of the battery to sit it on and it installed with the factory hold down clamps - Quick and easy install

Don
 
THX Don- My dad dutifully disconnected mom's original i-MiEV battery before putting the car into hibernation for 4 months, but without a 12V float it self-discharged down to 4 volts!
 
Same thing happened to us - The car was stored for about 6 months without a trickle charger and the OE battery was toast. The other car, driven regularly still has the 6 year old OE battery going strong. If you plan to store an older car for a month or more, a maintenance charger is a must

Don
 
. . . . but a flooded lead acid battery in a lithium powered car just seems so . . . . Twentieth Century :lol:

Don
 
Don said:
. . . . but a flooded lead acid battery in a lithium powered car just seems so . . . . Twentieth Century :lol:

Don
That would be great if they could find a dc to dc converter robust enough to power all the controls and accessories without a lead acid battery. Obviously it would have to be powered up from the traction battery 24/7.
 
ed5000 said:
That would be great if they could find a dc to dc converter robust enough to power all the controls and accessories without a lead acid battery. Obviously it would have to be powered up from the traction battery 24/7.
In actuality, that's exactly what's happening - Nothing 'runs off the 12 volt battery' while you're driving the car. It's just there to get it started. The DC to DC converter is quite robust (capable of 70 amps output, IIRC) and it can and does power every 12 volt accessory with plenty left over to recharge the 12 volt battery if it's ever in need of a charge

Don
 
151R is the size you need. After 6 years of ownership (7 year old battery/car), my 12 volt battery finally gave out. Just replaced it this morning with this:

https://shop.advanceautoparts.com/p/autocraft-gold-battery-group-size-151r-340-cca-151r/10081210-P?navigationPath=L1*14920%7CL2*15000%7CL3*15597

Car came right back to life, although I lost my trip odometers and radio presets as I expected. The original battery was at 2 volts, having sat through some wild temperature swings for about a month. Trying to charge it, my charger would do a check and error out with "shorted cell", and all the higher the resting voltage would go was 11.2 volts.

Definitely going to be investing in solar maintainers.
 
This must be the month for 2012 model year batteries to die. (Obtained my 2012 in February, 2013
Mine cratered over the last week. 10.6 volts (still could get ready light to come on) to now 8.4 volts and nothing happens.
Can I put a battery charger on it to get the voltage high enough to start the car? The manual indicates that cables must be disconnected to charge the battery. Is that true or can it be charged safely while still connected.
Interstate seems to have the correct group size replacement.
Stay charged my friend.
 
In your case i would not recommend that you try to charge the Aux battery and start your car, nor try to charge the pack until you get a new 12V Aux.

The damage that can result with trying to operate the car with a defective Aux power supply is very expensive.
 
151R is the correct group size. Changed my lifeless original (2012) battery today for a new Interstate flooded lead acid.
Getting the positive connection disconnected was tricky since there is not much slack in that cable.
All is good.
Stay charged my friend.
 
I *finally* got around to replacing the battery in our second car today. The OEM one was 7+ years old and had never shown any signs of getting weak, but I prefer to change things before they cause me problems. Used a Miata AGM again like I did in the first car 3 or 4 years ago. Ordered from Battery Mart for $107.95 with free shipping. Comes fully charged, sealed, maintenance-free and with a one year warranty

To it's credit, the OEM 151R served very well, considering I never added water to it . . . . and it was still working fine when I removed it

So now after 7+ years, both cars have required the same amount of 'maintenance.' One set of tires for each, one set of wiper blades for each, one battery . . . . and, that's about it. First really nice day, I think I'll drain and refill the transmissions. Really can't think of much else to pamper them with. Amazing cars, especially when you consider many hundreds of 3, 5, 7 or 10 mile trips are just about the worst kind of service you can subject any automobile to. We have other cars which rely on trickle chargers to be ready to go because they are so seldom driven. State Farm is making a mint off us insuring cars which seldom leave the garage

Don
 
Big shout out :D to members of this forum for emphasizing the need to monitor the health of aging auxiliary batteries. Used a conductance tester to determine that our factory installed (December 2011) Yuasa battery was degraded by use, time, and temperature fluctuation. The vehicle never exhibited any symptoms of 12v battery degradation over the 7+ years of service life, and we hope to enjoy a similar trouble free and extended period of service from the replacement Bosch 151R.

Many thanks!

 
Hi,

does anybody know if it's possible to charge the main battery, but in parallel remove the 12V battery ?

In fact, I would like to charge the 12V battery with an external charger (this charger has several modes, impulse and low currant to bring older batteries to better condition)

Thanks for advice ;)
 
I am so tempted to try out this LiFe 12-v aux lead replacement:

https://www.batteryspace.com/lifepo4-battery-12v-9ah-108wh-18a-rate-with-led-indicator-replace-sla-12v-7ah-lighter-weight-and-higher-capacity----un38-3-passed.aspx

While the spec specifically says "Must use LiFePO4 charging circuit. Do not use Lead Acid charger to charge this battery"; I am wondering if it's just to cover disclosure.

My thinking is that there is a built-in BMS with single cell as well as pack monitoring. It looks like this is what inside, including info on the BMS which is called PCB:

https://www.batteryspace.com/Plastic-Enclosure-151.2-x-65.5-x-95.5-mm.aspx

I am more concerned about keeping this 12-v LiFe pack at high SOC, due to the dc/dc charging it at 14.2v; so perhaps the LiFe can be parallel to a 12-v SLA.
 
But why-- Because it weighs less? That is too little useless a benefit for the risk of failure.

The price for this little UPS battery is the same as the full-sized lead acid in the miev. Plus it is way undersized for the current loads of a running car with headlights ON.

The chemistry requires a different charging procedure, so a new charrger from the 12V converter output to the LiFePO4 is needed.

Sure it has an internal BMS, but all lithium packs do (unless is was a diy). A BMS is not a charrger, it provides a cutoff mechanism to try to prevent pack damage.
 
Hi PBUI19,

Can this battery be charged at below freezing temperatures?
Does it freeze where you are?

Lithium Titanate batteries can be charged below freezing, will likely be on the market before the end of the year.

Thanks and good health, Weogo


pbui19 said:
I am so tempted to try out this LiFe 12-v aux lead replacement:
 
I happen to have a couple of those UPS 7A LiFe lying around unused, and no I would not pay the extra $ just to get them.

It just bugs me that the EV manufacturers are still using lead for the aux, and in particular Mistu because of the potential harm to the charger/inverter. In general, EVs are so "advance" with minimum maintenance and there is this consumable lead acid battery. The iMiev 12v really should last a lot longer than normal ICE usage, given the benign load and operating condition. But that's what I thought about the Prius 12v aux as well. Lead just sux. I haven't gotten my Tesla yet, but if Tesla also has lead 12v, that's just sad.

Does any one know the max current drawn from the 12v aux ? I vaguely recall Joes measured just under 10A. Ideally, by reducing the dc/dc charger voltage from 14.4v to 13.5v, (which gives 13.5/4-cell = 3.375v/cell) , these LiFe should be happy for a long time.

I am in northern CA and it rarely goes below freezing. I don't think these LiFe can handle low temperature and am doubtful if the BMS even monitor temperature.
 
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