ODB2 car memory saver using Cigarette-lighter style power outlets - outlet reading 13.3v

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Dec 3, 2024
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Basic concept is when pulling a car battery to repalce or in my case to change an alternator, you use an ODB2 memory saver to give 12v power to car computer thru the ODB2 diagnostic port. Lots of more expensive devices that do this:

https://ezred.com/product/automotive-memory-saver/

Cheaper versions just supply the power thru another vehicles cig power connection OR use any other 12v source (like a one on a portable power bank charger). Im using this memory saver cable, known brand.

OBDII Memory Saver Cable - Schumacher Electric

Im using one of these Jackery Power Banks with cig-style power outlet.

Communication Device Musical instrument accessory Audio equipment Font Rectangle

Out of curiosity, I used a volt meter to test the "12v" power outlet and it reads 13.3 :^/

Is that a ifference I should be worried about? Some people use the battery that is removed from the vehicle to power the memory saver, and thats never exactly 12v either. But not really 13.3 either.

Sent email to manufacturer of the Schumacher device to see what they say. But I would expect they would play it safe and say only use with 12v. But exactly 12v?

;^)
 
Check the actual voltage at battery and compared the 2. You might have a voltage drop
Thanks for reply. Battery reads 12.6. The Schumacher support said the difference wont make a difference. But being its OBD/ECU related .....
 
since it sees 14v with alternator power that 13.3 is perfectly fine.

is it safe to change an alternator with a memory saver hooked up?
usually afaik its for changing the battery only.
 
I never understood the reason for this. The clock and radio presets aren't that hard to set and the ecu doesn't take that long to relearn.

Not difficult, but a hassle that can be avoided, especially given the number of settings in play.

"12V" electrical systems like "110V" wall outlets or "1.5V/9V" battery cells, and many other examples, are nominal figures.
 
Basic concept is when pulling a car battery to repalce or in my case to change an alternator, you use an ODB2 memory saver to give 12v power to car computer thru the ODB2 diagnostic port. Lots of more expensive devices that do this:

https://ezred.com/product/automotive-memory-saver/

Cheaper versions just supply the power thru another vehicles cig power connection OR use any other 12v source (like a one on a portable power bank charger). Im using this memory saver cable, known brand.

OBDII Memory Saver Cable - Schumacher Electric

Im using one of these Jackery Power Banks with cig-style power outlet.

Communication Device Musical instrument accessory Audio equipment Font Rectangle

Out of curiosity, I used a volt meter to test the "12v" power outlet and it reads 13.3 :^/

Is that a ifference I should be worried about? Some people use the battery that is removed from the vehicle to power the memory saver, and thats never exactly 12v either. But not really 13.3 either.

Sent email to manufacturer of the Schumacher device to see what they say. But I would expect they would play it safe and say only use with 12v. But exactly 12v?

;^
My saver uses a 9 volt battery I just clip on th the battery cables. 12 volts are not necessary for ECU memory.

 
The Jackery contains a lithium battery and the normal operating voltage of those is slightly higher than lead based batteries. It is a 12 volt nominal system; 13.2 volts is fine during operation.

Note that the alternator big wire is always energized and if you're on "memory save" and short the wire to ground during alternator work, the memory will be lost anyway and it is likely a fuse will blow.
 
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