12v Battery Recommendations

[GerryAZ]

I have no idea how a "middle-of-the-pack quality" standard battery would perform in Walmart testing because I don't know their test sequence and I have been using high-quality AGM batteries for many years to minimize the inconvenience of frequent replacement (and dealing with prorated warranties). I could have received free replacements from Nissan for the original batteries in the 2011 and 2015, but chose to replace them with deep cycle AGM batteries to minimize the risk of corrosion under the hood and avoid the inconvenience of premature failure.

Edited to add:
You can get an inexpensive battery tester from an auto parts store or Harbor Freight that will put a load on the battery and give a good test. Here is a photo of the Harbor Freight tester I purchased a while back on sale. It is a voltmeter with a resistor load that can be momentarily connected (don't exceed 15 seconds to avoid overheating the resistor). It put a load of about 80 amperes on my battery and the voltage under load stayed above 10 so my 15-month old OEM battery is in better condition than I expected.

 

[SageBrush]

Fair enough.

What AGM deep cycle do you buy ? My searches keep finding marine batteries with different posts. I was beginning to wonder if it is reasonable to buy a marine battery along with SAE adapters.

 

[GerryAZ]

Take a look at my previous post. I added a photo of a battery tester I recently purchased--I just tried it on the Leaf battery. I used Optima Yellow Top deep cycle AGM batteries in the previous LEAFs (size 51R) and plan to get one for the 2019 as soon as I notice weakness in the OEM battery. I use Optima Red Top starting batteries in ICE vehicles if they match OEM size. I use Odyssey batteries in power sports vehicles and also in my SUV that uses a Group 65 (which is larger than available Optima Red Tops).

I would not recommend marine batteries because of the extra terminal space/height.

 

[lorenfb]

I assume that they use a device called a "Battery (capacity) Tester." I didn't know it took an hour, and I suspect it's more like half that. I'm going to use one on our sump pump backup battery.

Does the routine include a discharge test ?

I think it's more what Gerry mentions below: the device places a brief high current load on the battery and looks at the voltage drop.

This basically does what most automotive service department's battery tester does;

https://www.amazon.com/gp/product/B01ANF1BRW/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

[LeftieBiker]

Thanks for that link. Many auto parts store will also "loan" tools like this. The way it usually works is that you buy the tool, and they will accept it back after use for a refund, no questions asked. I assume they rely on many people keeping the tool, whether from a desire to have it, or from absentmindedness...

 

[Gigawatt]

So in debugging my battery issue I learn't or relearn't some battery theory. Obviously my 10.5 volts was a symptom of a dead cell - 12.6 - 2.1 and I did indeed find the dead cell by the use of a battery hydrometer $6 tool and also by removing the tops off the battery and voltage testing each cell - something I forgot one could do - simply dip your multimeter probes down in the battery acid and touch the battery plates ( clean your tips afterwards or they get all corroded like mine are now)

Sure enough the last cell read 0.3v and the specific gravity according to my hydrometer was very low. Now bear in mind I took this same battery to my local parts store and it load tested fine. My dead cell batter charged up fine and read 12.6v but after a hour or so it drifted back to 10.5v. My replacement battery was free from Costco even though it was installed in 11/19 so not charge for me.

So I learnt a ton but of course I now can start from scratch with my original issue, perhaps the draw is not as bad ie the poor car computer gets all crazy around 10.5v. but at 12.6v it's better? Look back at this now I did have a similar issue with the Toyota hybrid, battery going flat all the time and I recall a load test showing it was fine but I also replace it - used an identical battery 51R and the problem disappear.

 

[LeftieBiker]

Great detective work. It's also news to me about testing cell voltage at the plates. As for the load test: I suspect that 5 new cells, plus one bad cell, equal just enough capacity to fall into the "Good" range on the tester.

 

[Gigawatt]

Yes, I have a friend who is a bit of a know it all! I was bragging to him how I figured out the cell was bad with the hydrometer and he piped up and that he worked in a Sears years ago with batteries as a young lad and just pop on the multimeter probes to check it as well!