Replace small 12v battery to regular one.

[LeftieBiker]

Leaf and many modern vehicles charge 12V battery to very optimal state of charge, around 80%.

Lead-acid batteries like to be at 100% state of charge, or as close to it as possible. 80% may be good for a lithium battery, but 80% on a LA battery will cause gradual but significant sulfation.

[arnis]

Correct. Though charging to this high state of charge results in excessive gassing (electrolyte loss - aka water boils out).
Salt deposition starts at around 60%.
Keeping charging voltage up to around 80% state of charge does not result in excessive gassing.
Ideal window is narrow though definitely doable.

[powersurge]

I don't seem to see the need to worry about the 12V battery. After 4+ years and 55K miles, my battery is perfectly happy with good voltage numbers. I don't see the 12v battery to be a "maintenance" concern for most drivers. Also, if you put the battery on a "battery tender", then you really will not have issues......

BUT....... You should open the battery and check the water level on the cells regularly... That will kill the Bat.

[arnis]

Only if cells can be opened. Valve regulated battery with 13.0V charging voltage will not let electrolyte to evaporate nor boil even in hot weather.

[LeftieBiker]

Only if cells can be opened. Valve regulated battery with 13.0V charging voltage will not let electrolyte to evaporate nor boil even in hot weather.

The North American Leaf 12 volt batteries use flooded cells that can (and should, annually) be opened.

[powersurge]

Only if cells can be opened. Valve regulated battery with 13.0V charging voltage will not let electrolyte to evaporate nor boil even in hot weather.

The only "sealed" 12v car batteries I have seen were the tiny GM with the little green sight glass (green when it was fully charged) in the 1970s.. All "NORMAL" 12 volts have either individual screw top plugs, or the have 2 sets of square covers that you pry open with a screwdriver...

Either way, you got to open up the plugs to clean the top of the battery and check the water levels every once in a while..

[powersurge]

Only if cells can be opened. Valve regulated battery with 13.0V charging voltage will not let electrolyte to evaporate nor boil even in hot weather.

..

The only "sealed" 12v car batteries I have seen were the tiny GM batteries with the little green sight glass (green when it was fully charged) in the 1970-80s.. All "NORMAL" 12 volts have either individual screw top plugs, or the have 2 sets of square covers that you pry open with a screwdriver...

Either way, you got to open up the plugs to clean the top of the battery and check the water levels every once in a while...

[GerryAZ]

AGM and VRLA (absorbed glass mat and valve-regulated lead acid) batteries are sealed, but have a pressure relief valve to release excess pressure if they are overcharged. If they are overcharged frequently, they eventually lose electrolyte and fail because there is no realistic way to refill them. They generally last much longer than conventional batteries if they are never overcharged.

[xsnapshot]

What is the amp hour capacity of the stock battery out of curiosity? The Optima YellowTop AGM direct drop in (same 51R) shows only 38ah. Would that satisfy the consensus that the leaf likes charging bigger batteries? I've seen some get creative and fit larger batteries in there....