12 volt battery needs charging - why?

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WAM

Active member
Joined
Jun 23, 2011
Messages
26
Location
San Jose
At my one year service/battery check, it was noted on the Leaf multi-check form that the 12 volt battery needs a recharge.
The service advisor made no mention of it when I picked up the car and I didn't see this "issue" until I got home.
Why would the 12 volt battery need a recharge if the car is driven "normally"?
Surely, leaving my iPod connected to the USB port all the time can't be draining the 12 volt battery THAT much, can it?
I don't have any other aftermarket accessories connected.
I do have very low mileage (4600 in one year) and I understand the 12 volt battery charges ONLY when the car is being driven.
It's also parked in a garage so the solar panel is not likely to add much charge to the battery.
Statistics from the Nissan 12v battery test printout;
RESULTS
NEEDS CHARGE
VOLTAGE 12.31v
MEASURED 409 CCA
RATED 55824
TEMPERATURE 61
STATE OF HEALTH
(Graph shows midpoint between bad and good)
TEST CODE
BAT 53C DFQ HXM 3J2
 
If you drive very little and keep your car plugged in, you could be affected by a Leaf "bug" when it drains 12V battery considerably while plugged in, but not charging, and short trips do not make it up for the lost energy.

WAM said:
At my one year service/battery check, it was noted on the Leaf multi-check form that the 12 volt battery needs a recharge.
The service advisor made no mention of it when I picked up the car and I didn't see this "issue" until I got home.
Why would the 12 volt battery need a recharge if the car is driven "normally"?
Surely, leaving my iPod connected to the USB port all the time can't be draining the 12 volt battery THAT much, can it?
I don't have any other aftermarket accessories connected.
I do have very low mileage (4600 in one year) and I understand the 12 volt battery charges ONLY when the car is being driven.
It's also parked in a garage so the solar panel is not likely to add much charge to the battery.
Statistics from the Nissan 12v battery test printout;
RESULTS
NEEDS CHARGE
VOLTAGE 12.31v
MEASURED 409 CCA
RATED 55824
TEMPERATURE 61
STATE OF HEALTH
(Graph shows midpoint between bad and good)
TEST CODE
BAT 53C DFQ HXM 3J2
 
I generally charge 2-3 times a week (overnight using charge timer) and don't keep the charge plug connected to the car unless I don't have to drive anywhere that day.
I do keep the plug connected almost daily during the colder months so I can pre-heat using charger power before driving off.
I charge to 80% most of the time.
 
Those are test results from a midtronics battery tester used in dealerships

the results can be variable depending on the accuracy of the info punched into the tester

12.31v is a tad low
put it on a trickle charger (the 12v battery)
 
Those battery tester results are also based on an ICE vehicle, where the voltage and CCA are extremely important for starting the vehicle. However, the LEAF battery is more like for "standby" use, float charged just for the accessories and computers. I don't think it will ever see that 13.8 volt charge an alternator typical puts out, so I would expect to always see the LEAF 12 volt battery read slightly lower than an ICE car. The good part is that it should last much longer, since the charging and draining cycles are much milder than in an ICE vehicle, IMO.
 
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