yahshoor said:
So, this frosty morning in Portland, I attempted to preheat as per usual - ten minutes of heater, followed by thirty minutes of defrost - but it didn't work at all. Furthermore, it took three tries to start the car and get it into Ready mode. The first two tries, I just got a ding and a 12v battery warning. This afternoon, I took the tester to the battery and found it at 13.04 volts. Not the 13.4 volts I had expected.
You do realize that the
J1772 plug needs to plugged into the car from a live
EVSE? I don't understand why it would take two tries to get your car going, especially after you had just run the heater/defrost which I believe also actuates the 12 dc-dc converter... ah, but the heater/defroster didn't work either.
Need to be careful of the conditions under which you are testing the 12v battery: leave the hood unlatched and in the morning before doing anything measure the battery across the terminals. Hopefully you read >12.5v. The reading you saw was probably shortly after the car had been running, as the dc-dc kicks up the voltage to 14.4vdc at around 65°F as soon as you start the car or whenever it is charging. As soon as you turn off the car (or unplug a
charger) it slowly decays down to an ideal of around 12.65v at 70°F. Again,
as measured across the battery and NOT the 12v outlet inside the car. As soon as you open the car door the incandescent interior lights put enough of a load on the battery to start drawing it down to below 12.5vdc unless it is quite new.
yahshoor said:
Should I disconnect the 12v battery and test again? Take it inside to charge it on the trickle
charger? Install a battery heater? I expect that the reason that I wasn't able to precondition the cabin was that my battery needs to be replaced (it has a 12/19 sticker on it)m or maybe that the extreme (lol, 0C or -1C) cold was keeping my battery from cranking out the amps necessary to start? I guess I'm asking you folks which thread I should read next.
The battery 'starting' current is negligible compared to turning a starter on an infernal combustion engine. It's usually enough to get the car into READY, at which time the dc-dc takes over. For peace of mind, can you run an
extension cord out to the car and put a small float charger across it overnight? It's too much trouble to remove the battery regularly, IMO.
What I have done with every 12v battery in all my cars is added a fused wire pigtail with Anderson connector on the end, and use that for plugging in a smart float
charger whenever I leave the car alone for more than a couple of days.
Oh, and you might check the calibration of your voltmeter - many of the cheaper ones can be off as much as 1/2-volt.
Finally, one of a number of threads about the 12v battery:
https://myimiev.com/forum/viewtopic.php?p=27166