Don
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Location: Biloxi MS

Re: DC-DC Converter always on

Thu Sep 17, 2020 3:07 pm

veimi wrote:I feel better that it wasn't just my imagination now that it has been confirmed that charging the car does not always recharge the 12V battery.

If your 12 volt battery is in good shape, then it's always charged while the car is recharging. If the battery shows less than about 11 volts, many computerized chargers won't recognize it as a 12 volt battery and will fail to recharge it - I keep an old $30 6 amp analog battery charger on my shelf just for that purpose . . . . it will recharge any battery no matter how low the voltage is

One thing proven here many times over is . . . . when your 12 volt battery is near the end of it's useful life, an iMiEV will exhibit all sorts of very unusual problems. The factory battery at about 7 years of age has been the culprit more times than I can count. If you have to jump start your iMiEV for any reason, problems are just around the corner and you should probably make a trip to the store for a new battery if you do successfully get it running.

I've never had those problems, but I've never attempted to go much beyond 5 years or so before I preemptively changed out my 12 volt batteries in all 3 cars. I don't care for weird surprises . . . . and more than that, I hate to walk! :cry:

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon
2006 Itasca Navion Sprinter Motor Home

veimi
Posts: 105
Joined: Tue Jul 05, 2016 5:02 pm
Location: Toronto Canada

Re: DC-DC Converter always on

Thu Sep 17, 2020 4:58 pm

Don wrote:
veimi wrote:I feel better that it wasn't just my imagination now that it has been confirmed that charging the car does not always recharge the 12V battery.

If your 12 volt battery is in good shape, then it's always charged while the car is recharging.

Don

What do you do when you come out a few days after removing your dashcam and discover that when being removed the power wire to the camera accidentally had turned on your inside lights by brushing against the switch? Reading page 1-17 of the owner's manual would suggest that all one had to do was charge the car.

Don
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Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: DC-DC Converter always on

Thu Sep 17, 2020 5:37 pm

If you've left lights connected to your battery 'for a few days' then it's deader than dead and you're probably looking at buying a new battery, especially if it was a few years old to begin with. You could try recharging it with a Pulse Repair Technology battery charger and you might get it back up to 13 volts, but the damage has been done and it's very likely to give you more problems in the near future. Best case scenario, you destroyed most all of it's useful life by leaving it connected to a short (an unlit light bulb is effectively a short) for several days

If it was me, I'd bite the bullet and replace the battery - Lesson learned

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon
2006 Itasca Navion Sprinter Motor Home

yannd
Posts: 10
Joined: Wed Dec 18, 2019 2:16 pm

Re: DC-DC Converter always on

Mon Sep 28, 2020 12:02 pm

Anybody with more information on the original post on how to keep the DC-DC Converter ON without recharging the car or having the key turned ? Looking to have a constant charging of a secondary 12V Battery Bank (Connected with a controlled DC-DC Charger) Thanks !

yannd
Posts: 10
Joined: Wed Dec 18, 2019 2:16 pm

Re: DC-DC Converter always on

Tue Oct 20, 2020 8:20 am

Any way to reactivate this thread ?
Thanks :)

PV1
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Re: DC-DC Converter always on

Tue Oct 20, 2020 2:18 pm

I still have my doubts. For the DC-DC converter to work, high voltage has to be engaged for the whole car and the DC-DC itself needs an activation command from the EV-ECU. The car would physically be READY if the converter was active.

What would do the trick is figuring out a remote start system that can sense a low 12 volt battery and automatically “start” the car for 15 minutes.
"Bear" - 2012 Diamond White Pearl ES with QC
"Koorz" - 2012 Cool Silver Metallic ES with QC
"Photon" - 2017 Bolt EV LT in Orange with QC
Solar-powered since 10/10/2013

Life with Electric Vehicles: https://lbry.tv/@PV1

yannd
Posts: 10
Joined: Wed Dec 18, 2019 2:16 pm

Re: DC-DC Converter always on

Wed Oct 21, 2020 6:51 am

Could the remote transmitter be used to send a signal ? Maybe by modifying the charging timer command ?

Basically wondering if it would be easier to hack the software part or the hardware part...

For now plugging directly to the 400v pack with a second 12v DC-DC converter seems the fastest and easiest way, but also more dangerous and prone to other error codes if not done right by the mechanic (similar to the OBC bypass modification)

I'm sure other users would like to have an always live 12V from the traction pack with 600-800w...

PV1
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Re: DC-DC Converter always on

Wed Oct 21, 2020 9:55 am

The stock MiEV remote that handles charge timers and pre-conditioning won’t work. It can check the battery charge at any time when it’s near the car, but it requires the car being plugged in before it can activate the high voltage system. Maybe there’s a way to sniff the CANbus and see what command it sends to do that, and maybe sending that same command over OBDII and see what the car does. This is above my knowledge, though.
"Bear" - 2012 Diamond White Pearl ES with QC
"Koorz" - 2012 Cool Silver Metallic ES with QC
"Photon" - 2017 Bolt EV LT in Orange with QC
Solar-powered since 10/10/2013

Life with Electric Vehicles: https://lbry.tv/@PV1

kiev
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Location: The Heart o' Dixie
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Re: DC-DC Converter, commanded always on?

Thu Oct 22, 2020 8:49 pm

i opened one up and traced the harness, and it just may be possible to command the DCDC as a separate unit assuming you have a HV source. See the wiring and connector pinout in this thread,
viewtopic.php?f=23&t=4079&p=41781#p41781

There is no CAN buss, just a couple of discretes from the EV-ECU, don't know if they are sources or sinks yet.

[edit] Started a separate DCDC converter thread with pictures, schematics, etc
viewtopic.php?f=23&t=4737
kiev = kenny's innovative electric vehicle

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