Jump starter reanimates dead Leaf!

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Wavebender

Well-known member
Joined
Apr 7, 2021
Messages
70
Location
Boise ID USA
My wife was two blocks from home when her Leaf battery died and immobilized the car. She called road service and the flatbed arrived, but since the car could not be driven she wondered how the driver would get the car up the incline onto the ramp. He attached a small lithium-ion jump starter from Wall-Mart to the starter battery and the car came to life! He drove it up the ramp, delivered it to our driveway, then drove it into our garage where our 30-amp charge port is. He says he does this all the time.

How is this possible?
 
My theory is though while driving the available voltage dropped below the minimum requirements 2 things happened. First when available voltage dropped it also dropped the 12 volt battery voltage down below needed requirements to maintain memory data, contactor low voltage and various low voltage modules. 2nd after sitting with no drain the high voltage battery was able to slightly recover simply due to the composite material of the cells. When Tow Truck Driver applied 12 volts to the 12 volt battery (low voltage battery) the various modules powered up and contactors closed for the high voltage battery allowing the vehicle to propel itself briefly. Probably not worded to manufactures specs (lol) but this is basically what happened. Often when an ICE vehicles alterantor fails and the driver contiunes on the vehicle shuts down completed draining the 12 volt battery. After car sits for a little awhile with no drain the car will actually restart as the battery had time to recover somewhat. I hope this makes sense to you.
Thanks,
MacsVoltage
 
I have small 3 pound 20Ah Li-Ion portable battery I carry in my car in case my 12V battery goes kaput. It has USB B and C (C for charging it and powering a USB C device). It has battery clips for jumping a car. I have started a Pathfinder twice and a completely dead Rav4 yesterday and it only dropped 7%. It only keeps power on the jumpers for 5S so I had to start 4-5 times before I realized I had to hold the accelerator at 2000 RPM to keep the car running. I have charged a large tablet with it (that took 50% of it). Li-Ion packs a lot of power!
 
My theory is though while driving the available voltage dropped below the minimum requirements 2 things happened. First when available voltage dropped it also dropped the 12 volt battery voltage down below needed requirements to maintain memory data, contactor low voltage and various low voltage modules. 2nd after sitting with no drain the high voltage battery was able to slightly recover simply due to the composite material of the cells. When Tow Truck Driver applied 12 volts to the 12 volt battery (low voltage battery) the various modules powered up and contactors closed for the high voltage battery allowing the vehicle to propel itself briefly. Probably not worded to manufactures specs (lol) but this is basically what happened. Often when an ICE vehicles alterantor fails and the driver contiunes on the vehicle shuts down completed draining the 12 volt battery. After car sits for a little awhile with no drain the car will actually restart as the battery had time to recover somewhat. I hope this makes sense to you.
Thanks,
MacsVoltage
Sounds perfectly plausible to me, thank you!
 
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