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Re: Bricked

Posted: Thu May 09, 2019 4:52 am
by spazzman90
LOL regarding the model 3 as a 'better' 12 volt management system.

In short, there is no 12 Volt management system. It is always running, and it uses a lot of power especially in temps lower than 50 degrees ambient. The car would never survive a month parked in cooler temps by itself. It loses 5% per day, just sitting. One of the more annoying aspects of Tesla ownership. Bolt, Spark EV, Kia Soul EV, even Leaf. I can leave sit for a couple weeks and the traction battery doesn't lose anything, and the car is generally ready to go. One more thing. Lose 12 Volts in anything but a Tesla, and you can use your jump pack and go. Lose 12 Volts in your Tesla, and it gets super annoying really quick.

-Jeff

Re: Bricked

Posted: Sun May 12, 2019 9:38 pm
by mrdrmorgan
iwatson wrote:Although I guess I understand your issue, a month is a long time to leave any car. The Bolt certainly has the possibility of a work around for your unique situation. The Bolt has the ability to be remote started from an app on your phone. On a long trip as you describe, you could start your car up once or twice a week and let it run for 10-15 minutes, which should keep the 12v system charged.

Once started the car will run for 20 minutes and shut-off automatically, but I'm not suggesting you let it rip until it shuts off automatically. If memory serves you can only initiate two (2) remote starts under this condition. However if you remotely start it, then remotely shut it down after 10-15 minutes, you may be able to get the multiple start ups that your situation requires.

If you decide to test this out, please report your findings, as there may be others that fall into this unique operating condition.

This may sound "dumb' BUT, understanding that the 12 volt AGM battery can go dead if the car is parked and not used for long periods of time and no 110 VAC is available for a trickle charger, why not just disconnect the negative battery cable when you leave and reconnect it when you return?

Re: Bricked

Posted: Mon May 13, 2019 12:37 am
by YamanoteMaui
Yes, silly me, thinking that large high voltage full charged battery was sufficient to keep by Bolt going!

Re: Bricked

Posted: Mon May 13, 2019 2:10 am
by mrdrmorgan
YamanoteMaui wrote:Yes, silly me, thinking that large high voltage full charged battery was sufficient to keep by Bolt going!

With the ignition turned off and the key FOB removed from the car, I am wondering if the 12-volt battery charging function is also powered down and the HV battery does not charge the 12-volt AGM battery. I say this because whenever I use my AGM 12-volt battery charger, the display shows the 12-volt battery in both of my Spark EVs only have a 50% charge. However, Some functions must remain powered up. Otherwise, the key FOB, Onstar, etc. would not work.

Re: Bricked

Posted: Thu May 16, 2019 2:20 am
by SparkEVPilot
mrdrmorgan wrote:
YamanoteMaui wrote:Yes, silly me, thinking that large high voltage full charged battery was sufficient to keep by Bolt going!

With the ignition turned off and the key FOB removed from the car, I am wondering if the 12-volt battery charging function is also powered down and the HV battery does not charge the 12-volt AGM battery. I say this because whenever I use my AGM 12-volt battery charger, the display shows the 12-volt battery in both of my Spark EVs only have a 50% charge. However, Some functions must remain powered up. Otherwise, the key FOB, Onstar, etc. would not work.

In another post I made on this forum, I reported that the 12 volt AGM battery appears to be trickle-charged when the car is plugged in and, when the car is powered up, the HV battery then provides the main charging of the 12 volt battery.

Re: Bricked

Posted: Fri May 24, 2019 5:17 pm
by SparkE
I read a *very long* post by a GM-certified tech (probably copy-pasted from the service manual) a while back that described the behavior for keeping the 12V battery charged. Basically, if plugged in to an EVSE, the voltage of the 12V battery is checked fairly often (?12 hours?). If not plugged in, it is check every few days (?3 days? 4 days?). And (IMHO) the gateway (limit) voltages are way too low (?12.2V? ?12.4V?). And the 12V battery is also 'checked' and charged while driving the Bolt.

So :

(1) If the Bolt was parked for a long period of time on the dealer lot (or on a train or semi), your 12V battery got hosed and is borderline bad - good enough for day-to-day, but ... in very few days of no use it will go bad. Especially if it was in 'transport mode' and the dealer didn't transition it to 'customer mode' when it was received.

(2) IIRC, the 'battery check' functionality only kicks in if you have >40% main (propulsion) charge.

(3) If you are going to be away for a long period of time and can't leave the car plugged in, pop the hood and unplug the 12V battery. *ALL* modern vehicles (including ICE vehicles) have software running *ALL THE TIME*, which drains the 12V battery so they need to be charged or disconnected during long absences.

(4) I ran into this problem with a friend's LEAF, which was only left parked 4 days - because the 'keep me charged' logic in the older LEAFs was absolutely horrid. This isn't a problem only with the Bolt, and is actually a problem with any modern vehicle (as I already said above). An 'iffy' 12V battery will not stay charged for long periods - I always disconnect the battery in *all* of my vehicles if I am going to be away for more than 7-8 days. (It also thwarts thieves from stealing the car.)

Re: Bricked

Posted: Sun Jun 30, 2019 6:42 pm
by psyflyjohn
If I was leaving a car unattended for a month at a time, I would have a solar trickle charger inside my windshield. I'd find one that desulphates as well as maintains a small trickle. Upon arrival, the 12v battery would be in better condition than when parked a month ago...