Some Leaf owners have experienced the condition where the 12V battery was weak preventing
the Leaf from “starting”, requiring a jumper 12V battery. This problematic 12V battery condition
may occur if the Leaf has not been driven or connected to an EVSE for a number of days/weeks,
or when the 12V battery nears its end of life.
Obviously one can always connect an external 12V charger, but occasions may occur where an external
charging source is not available. Typically Leaf1 & Leaf2 charge the 12V battery while in the “run” mode
to 12.9/13.1 volts, which is not very effective when the 12V battery is weak or has prevented the Leaf
from “starting”. Although when the Leaf is initially started, the 12V battery is typically charged to about
14.2 volts for about a minute.
Under a unique condition, i.e. the windshield wipers being on, the Leaf’s 12V battery charges to about 14.2V
as long as the wipers are on. By using the wipers in the intermittent mode with delay being the longest,
the 12V charging voltage will be continuously at about 14.2V. With just one momentary activation
of the wipers, the 12V battery will be charged at about 14.2V for about one minute. So, leaving the
wipers on with longest delay will continuously charge the 12V battery to about 14.2V without
having the wipers fully on. It is unknown whether this Leaf function is documented in any Nissan info,
so some might consider it a software “easter-egg”.
After having posted this on MNL shortly after leasing my 2013 Leaf, I never really thought of a use
until today when 2013 Leaf had not been driven in over a week and the door button unlocking function
appeared to not function. After a few tries, the door unlocked and I was able to "start" the Leaf.
After remembering the feature I had discovered, I decided to leave the wipers in the delayed mode
as I drove for about 30 minutes to assure that the 12V battery received an adequate charge.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F