12v chargers

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Wild stab in the dark but BMW is usually canbus controlled and switches them off after a defined time. Given that it's an electric vehicle I would assume that this is all the more important to restrict power drain when locked. You may therefore find you have no power to any of them. Sure an existing owner will confirm this though.
 
The one near the hatch is the most likely to stay on, if any. That's probably where you'd try to hook up the compressor if you had a flat or low tire.

Keep in mind that all of the electronics are run via the 12vdc circuits, but that small battery is only kept charged while actually hooked to external power, or while in the ready state. If the 12vdc battery gets flat, even if the main battery is full, you may be stuck, so you want to avoid a big load. I seem to remember the 12v outlets are limited to 120W, so watch what you plug into them, too.

There's an emergency feature that will charge the 12vdc battery if it is too low to allow 'normal' EVSE charging, which requires the computers to manage things...it will bring that battery up to a high enough charge, and then will switch to the normal charge process to then recharge the main batteries. Depending on how flat that 12vdc battery is, it could lengthen the overall recharging time by a fair amount.
 
The USB port seems continuously powered, or at least it's powered when I shut the car off and when I get back in. (I've left my phone there to charge a few time).

Of course, it might turn off a few minutes after I leave the car, and re-power when I unlock the car...
 
10-12 minutes after you leave the car (changes if you lock it), most everything shuts down that can be shut down. Things do reactivate when you unlock it. The 12vdc battery is more motorcycle sized and is 'normal' lead acid (might be AGM, but still lead acid based). The main batteries do NOT power the 12vdc power supply unless connected to an EVSE or you're in READY mode. "Extra" 12vdc loads could mean you will deadline your i3 and require hooking up the EVSE, even if the main battery is fine.
 
jadnashuanh said:
The 12vdc battery is more motorcycle sized and is 'normal' lead acid (might be AGM, but still lead acid based).

Any idea off hand what the spec of the battery is in Ah? I was trying to figure that out yesterday to assess how much power it could supply and for how long to run auxiliary bits and pieces.
 
It's only a 20AHr AGM battery, pn 61219321815. Since it doesn't' need to crank an engine, it is only used for (primarily) the computers, it doesn't need to be huge. www.realoem.com is a good source of parts lists/breakdowns for BMW vehicles.
 
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