Dead Battery (for starting the car)

[PHEV Newbie]

I accidentally left my lights on and drained the 12v battery overnight. When I went to my car in the morning the dome lights wouldn’t go on and the car wouldn’t start. I connected a jumper cable to the car just like I would do for any other car and was able to start the car and charge up the 12v. Does anyone know a way to “jump” the car from the 17kw battery? That one still had a full charge but a couldn’t use it to get the car started. I guess it’s good that it was protected from my stupidity that caused the 12v to drain.

I'm surprised the lights didn't shut off on their own, even if they're turned on but that's good to know. Anyway, I just keep one of those compact Lithium ion car starters (mine is Anker brand) in my trunk. They have plenty of power to crank an ICE engine so just powering the electronics to turn on the Clarity should be a piece of cake.

 

[RickSE]

I installed fog lights and have them wired independently so they don’t shut off. I’m rethinking that strategy. I have a Duracell battery from Costco that we use to charge phones when we go camping. It can also be used to jump start a car so that’s what I used. The car started easily with the unit. I hadn’t left the car plugged in overnight since I usually just charge it at work. My first thought was to plug the car in, but since the battery was dead I couldn’t open the charging door. One of those weird little catch 22s with a car like this. At least I could open the hood to jump it!

 

[jorgie393]

....My first thought was to plug the car in, but since the battery was dead I couldn’t open the charging door. One of those weird little catch 22s with a car like this. At least I could open the hood to jump it!

In the driver’s footwell, next to the fuse box, is a manual handle that when pulled opens the charging port door. [ I assume] It’s meant to be a backup for situations like this (or if the electric actuator dies). [Of course, I am not 100% sure the 12V system powers up when the charger is plugged in even if the 12v battery is dead, though I would expect so. ]

 

[DucRider]

In the driver’s footwell, next to the fuse box, is a manual handle that when pulled opens the charging port door. [ I assume] It’s meant to be a backup for situations like this (or if the electric actuator dies). [Of course, I am not 100% sure the 12V system powers up when the charger is plugged in even if the 12v battery is dead, though I would expect so. ]

With the 12v battery dead/disconnected, there is no communication with the EVSE and no power will be provided to the car.

"Hi! I'm an EVSE!"
"Well hello there - I'm an EV!"
"I can provide 32 amps of power. Interested?"
"Yes! Send it on down!"

All EV's require power to the electronics that manage charging before any juice flows to the car. I think the Ioniq may allow the power from the HV traction battery to be used under some circumstances, but don't know of any other examples that don't rely exclusively on the 12v battery.

 

[ozy]

I own a 2005 Prius, in addition to this Clarity, and I have been plagued by 12V battery issues (as have thousands of other Prius owners). The problem being that the 12V battery has to keep up with a lot of activities in the car even when the car is off ie: various things that run even after your turn the car off. When the battery is new it turns to do a good job doing this. Over time, the battery degrades, or sulfates (not sure what causes it) and at this point even leaving a cabin light on for a night will kill the car. As the battery gets even older it will die for minor things such as inadvertantly turning on the headlights, radio or AC in accessory mode. Yesterday, I literally saw it die in front of my eyes because my son turned on the AC in accessory mode. I have taken it to several mechanics who confirm that this happens to hybrid cars that do not have a starter (not sure why). Eventually I bought a little jump start device (about the size of large cell phone) and now use that to jump the battery as needed. Not sure if this is related whatsoever to the OP's original problem but definitely been there, done that.

 

[Gary Bartlett]

Eventually I bought a little jump start device (about the size of large cell phone) and now use that to jump the battery as needed.

Ozy, what jump starter device did you get? I'm interest to buy one after my 12V battery died on me after a two week trip away.

As the jump starter only needs to apply enough charge to power up the electronics (the HV battery actually starts the car) I'm thinking it doesn't need to be a high power jump starter.

Wondering whether a supercap jump starter would be good for this. Anyone have any recommendations?


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[LegoZ]

All EV's require power to the electronics that manage charging before any juice flows to the car. I think the Ioniq may allow the power from the HV traction battery to be used under some circumstances, but don't know of any other examples that don't rely exclusively on the 12v battery.

I know in my wife's Niro Hybrid (Not PHEV) the 12v battery is a Lion subpack, there is a system that protects the 12v subpack if it is accidentally depleted.


I believe the Ioniq uses the same system

 

[LegoZ]

Also with all factory equipment I think everything shuts off (lights) eventually. I know when I lock the car and precondition it with me in there I cannot turn on the map or any interior lighting.

 

[BBski]

I have a 2020 touring. After the third time I had to have it jumped in the first 6 months, I decided to replace the 12v with one from Costco. No issues until this week. Used the car Thurs-Sunday. Got home, plugged it in. Went to use it Wed night and it was dead, had to jump start it.

So frustrating that I have to carry a jump starter in my car.

Anyone get any solution to this?

 

[Landshark]

Anyone get any solution to this?

You need to identify what is causing the battery to discharge is such a short amount of time. There’s a small chance that the first battery was defective or improperly maintained and failed prematurely. There’s an even smaller chance that the second battery is also defective. It’s possible, just not likely.

What you’re experiencing is not normal.

 

[Teslawannabe]

Did you come to any understanding why the battery went dead?

I have a 2020 touring. After the third time I had to have it jumped in the first 6 months, I decided to replace the 12v with one from Costco. No issues until this week. Used the car Thurs-Sunday. Got home, plugged it in. Went to use it Wed night and it was dead, had to jump start it.

So frustrating that I have to carry a jump starter in my car.

Anyone get any solution to this?

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