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12V battery capacity

Posted: Tue Aug 15, 2017 6:14 pm
by brotherjethro
Hi all,

Long time lurker, first post...

I've read a lot of threads which mention the supposed low capacity of the 12V battery. These threads cover a wide variety of topics, but seem to center on the idea that the 12V battery in the leaf is not meant for handling "normal" ICE car duties, such as starting an engine, etc.

I'm confused by this: The battery in my 2013 Leaf is a "51R" style lead acid battery, which is used in thousands (millions?) of ICE cars on the road today. As examples, my wife's 2017 Honda CR-V, and our older 2000 Honda CR-V both have an identical battery.

The battery in my 2013 Leaf advertises 500CCA on side, and I don't doubt it, as I have jump started many cars from our older CR-V.

What is the source of this idea that the 12V battery in the Leaf is so weak that it must be treated with special care? Is it the poor battery management firmware in the Leaf, which basically only charges at 13V?

As far as I can tell, the battery is perfectly normal, if a little small, and the only issue is that one needs to charge it manually occasionally to keep it topped off.

Re: 12V battery capacity

Posted: Tue Aug 15, 2017 8:33 pm
by LeftieBiker
You have misunderstood what you've read. The Leaf does indeed have a standard starting battery. The problems are, first and mainly, that the car doesn't always maintain the charge properly (especially with the 2013 leaf) and second, that a starting type battery isn't really appropriate for this kind of application - a deep cycle battery would be better. There were also quite a few defective batteries in the 2013 cars, from what I've read.

This really should have been posted in one of the existing topics. Maybe a Mod will move the thread there.

Re: 12V battery capacity

Posted: Tue Aug 15, 2017 9:22 pm
by brotherjethro
Okay, thanks for that. So if it's just a matter of battery management, I understand that. It does seem to be quite poor, but at least it can be supplemented manually.

Re: 12V battery capacity

Posted: Tue Aug 15, 2017 9:41 pm
by LeftieBiker
brotherjethro wrote:Okay, thanks for that. So if it's just a matter of battery management, I understand that. It does seem to be quite poor, but at least it can be supplemented manually.


Yes, although after doing that for three years and change, I can say with authority that it gets Old.

Re: 12V battery capacity

Posted: Tue Aug 15, 2017 11:10 pm
by Evoforce
And then there are some of us who have never had replacement batteries or put maintainers on them. I myself have (2) 2011 Leafs that still have original batteries in them. However, both are SL and have solar supplement.