Expected life of aux 12v battery on 2015 Leaf 'S'?

We're the 2nd owners of a 2015 Nissan Leaf 'S' with about 36,000 miles.

Some questions:

• Is 3+ years about the expected life for the OEM battery? (my guess: yes)
• Does it really take a Nissan dealership with a Leaf certified tech to test the battery? (my guess: officially yes, but actually no)
• Can a typical auto repair location like Walmart's automotive or [fill-in-the-blank] do adequate testing of the 12v aux? (my guess: yes)
• Can I expect acceptable battery performance from a battery purchased at Sam's Club, Walmart, or [fill-in-the-blank]? $120 compared to $$$? (my guess: yes)
• ....
• Related issue that makes me suspect the OEM battery is 'fully depreciated' and ready to be replaced ...
  I intentionally had the flashers going for about 3-4 hours. That completely drained the 12v aux battery to the point the FOB wasn't recognized. I was expecting the 3+ hours of flashers to be a relatively trivial drain on the aux battery. Fortunately [?], a simple jumper cable assist got the Leaf back to operational condition. Was it a bad idea to user jumper cables?
  Other comments welcome.
• ...
• Suggestions Greatly Appreciated on cost effectively replacing the OEM aux 12v battery!
• Main Li-Ion battery has been relatively 'babied' for the 20 months and 22,000 miles we've owned it, with 12 health bars.
• Sorry if this has been asked before.

Changing the 12 volt battery on the Leaf is the same process as any other car. Any automotive place can test and replace the battery, just make sure the car is off while doing so. I would recommend an AGM style replacement battery. When I replaced my original battery, I got a Bosch AGM battery on sale from PEP Boys. The install was free, but I had to show them how to do it since they had never worked on a Leaf before.

The OEM battery is small so I am not surprised that you ran it down with the emergency flashers. Any place that tests conventional 12-volt car batteries can test it. The battery group size is 51R so you can get a replacement anywhere that sells car batteries.

When the OEM battery in my 2011 failed, I replaced it with an Optima AGM deep cycle (yellow top) battery. I would have kept it for a spare if the insurance company storage yard would have let me remove it after the car was totaled. When the OEM battery in the 2015 failed, I bought another Optima. The Bosch AGM is also a good choice, although it is not classified as a deep cycle. FWIW, the Pep Boys I went to did not recommend the Bosch because their computer did not list it as fitting the 2015 LEAF. They had both the Bosch and Optima on sale so I bought the Optima from them.

Make sure that you or whoever replaces the battery charges the new one fully, before or after installation. The Leaf takes longer than an ICE to fully charge a 12 volt battery, and might not fully charge it at all, although that is mainly an issue with pre-'14 leafs.

Don't obsess about the Leaf battery... It is the same as any other car battery... I have a 2015, and the 12v battery is like new... What you should get for any car is a 12v battery charger and make sure it is charged to 100% every couple of months. If you buy a battery, get one from Costco, and be done with it... Too many nerds on the forum are talking about a lithium or agm deep cycle battery....

The leaf is just a regular car, and don't let people frighten you into buying parts that cost crazy amounts of money!!

powersurge said:

Don't obsess about the Leaf battery... It is the same as any other car battery... I have a 2015, and the 12v battery is like new... What you should get for any car is a 12v battery charger and make sure it is charged to 100% every couple of months. If you buy a battery, get one from Costco, and be done with it... Too many nerds on the forum are talking about a lithium or agm deep cycle battery....

The leaf is just a regular car, and don't let people frighten you into buying parts that cost crazy amounts of money!!

Click to expand...

I recommend AGM deep cycle for any modern "regular car" because they all drain current even while parked, which makes tolerance of deep-discharge a significant advantage which can actually be more cost-effective in the long-run than a conventional "starting battery". They also have the advantages of being maintenance-free and highly leak-resistant and will generally present a better warranty. I am definitely biased due to multiple battery horror-stories early in my driving history, which became a thing of the past with my '91 Miata's OEM AGM battery, which was a marvel.

Now some of these advantages matter more or less depending on how the car is used, and how long you plan to keep it. If price is a significant pain point then of course I'd go with one of the cheaper flooded options which can serve well as long as you keep after it in terms of maintaining the electrolyte level, checking state of charge, keeping terminals clean and avoiding situations that will deeply drain the battery (i.e., remove the battery or place on a "tender" before vacations, don't use the flashers for hours at a time, etc...).

AGM batteries are maintenance free, do not normally vent gases that cause corrosion, and typically last much longer so I will continue to recommend them. I have never connected an external charger to either of my LEAFs. The charging algorithms in both cars are (were) fine for my use patterns so the OEM batteries both lasted longer than average for new vehicles in my climate.

Like Nubo, I have a number of battery "horror stories" before AGM batteries became available and I started using them. I first started using them in motorcycles about 1984 or 1985 and the ones I used lasted 2 to 4 times the life of conventional flooded batteries with no need to add water. I started using them in cars and pickups as soon as they became readily available after having many so-called maintenance-free flooded cell batteries fail under warranty (typically 6 to 18 months in my climate) with associated inconvenience.