Another Dead Leaf after Vacation Plugged In - Detailed Info

[HairyCairy]

I recently Left My 2011 Leaf plugged in for twenty one days.
I left with a SOC of two bars and set a charge timer to come on for one hour each day until I reached 80 percent. I also hooked up a battery tender to my twelve volt battery because I was parked in doors. I was a bit worried because after seven days I was no longer able to communicate with my leaf through car wings. I figured it was because it had not been started in a while and hopped for the best.
I got home after twenty one days. I unplugged the battery tender and powered up the Leaf. The SOC was at eighty. My car began to communicate with car wings as soon as I powered up, my suspicion was right.

 

[klapauzius]

Just to add another long term storage experience:

I was gone for over 6 weeks, left the Leaf unplugged and at 4 bars SOC. I did not disconnect the 12 V battery.

When I came back, everything worked just fine.

 

[GerryAZ]

The charging algorithm of the Leaf's DC-DC converter is ideal for the 12-volt battery. The charging voltage is about 14.0 to 14.5 volts for a little while after turning on the Leaf until the 12-volt battery reaches full charge. The charging voltage then drops to about 12.8 to 13.5 volts (depending on temperature) which is ideal for float-charging. The DC-DC converter functions the same way when L1, L2, or L3 charging starts and also when it automatically charges the 12-volt battery from the main pack every 5 days while the car sits unplugged. There is no need to disconnect the 12-volt battery when the car is parked.

If you really need to leave the EVSE connected to the car to charge the main pack while the car sits for an extended period of time, then you either need to set a timer to charge a few minutes every day or you need to use a battery tender. The car's electronic systems draw more power from the 12-volt battery when an EVSE is connected and the DC-DC converter will only charge the 12-volt battery when the main pack is actually charging so the 12-volt battery begins discharging as soon as charging of the main pack stops. Since the DC-DC converter will not turn on automatically every 5 days to charge the 12-volt battery if an EVSE is connected, the 12-volt battery will eventually become completely discharged.

Gerry

 

[garygid]

I believe that the 5-day timer gets reset each time the charging timer
activates, even if no actual charging is done.

Setting your charging timer to charge only ONCE a week should allow
the 5-day timer to charge the 12 volt battery once a week.

 

[Deleted member 3147]

I believe that the 5-day timer gets reset each time the charging timer
activates, even if no actual charging is done.

Setting your charging timer to charge only ONCE a week should allow
the 5-day timer to charge the 12 volt battery once a week.

The problem here is that with the EVSE connected, the Leaf's computers draw more current than if unconnected (per Phil/Ingineer). It's not clear that with the extra draw, once per week is enough. I'd play it safe and sets the timer for 2 days/week, maybe 30 minutes each. I'll still take a long time to get the traction battery to a high SOC.

 

[RegGuheert]

If anyone else has other reports of "experiments" of leaving their car plugged in for 8+ days please give the full details.

I don't yet have any data for the "plugged-in" case, but I have been taking some data for the unplugged case to use as a baseline. My data is taken manually on a LEAF which is driven intermittently, so I never know a priori how long the car will sit. Still, I think there is some useful data to be gleaned here.

I've been doing quite a bit of desulfating with my Battery Minder 1500 over the last year and the 12V battery in our MY2011 LEAF (which was assembled in June 2011) seems to be in quite good shape now. Yesterday I charged it to full with the Battery Minder and then disconnected it for about 12 hours before taking a reading (car and OBDII unplugged). The voltage was still at 12.85V after that amount of time. Water level in all six cells is just below the "Full" line.

The bottom line is that with proper charging, the nearly-six-year-old OEM 12V battery in our LEAF is currently in like-new condition.

It's too bad Nissan didn't manage to program their charging system to prevent the premature deaths of most of these batteries.

 

[jjeff]

It's too bad Nissan didn't manage to program their charging system to prevent the premature deaths of most of these batteries.

And while it would be much harder to implement this on an ICE vehicle where people don't normally plug them in, on a BEV incorporating some sort of 12v battery minder, preferably one with a desulfacation feature, would have been extremely easy. I mean people plug them in all the time and adding that feature couldn't cost that much, I know the standalone chargers I have with that feature were all under $50, some closer to $25. Maybe Nissan doesn't want the 12v battery to last forever? I guess people prematurely replacing their 12v battery could be a steady revenue stream for Nissan if people actually went back to the dealer for such things.....or maybe Nissan just doesn't care and figures the added cost of building something like this in the vehicle isn't cost effective :?
Personally I just pop the hood on my Leaf and hook up my standalone tenders with that feature every couple weeks for a day or two, I do it to my ICE vehicles also and knock on wood haven't had to replace a 12v battery since doing this regiment 5?? years ago.

 

[joeriv]

I have left my Leaf on a trickle charger whenever I travel for a week or more - longest 5 weeks with the traction battery at about 40%. The 12v battery after 3 years is like new (desulfation works!) when I check with a battery checker.