12V battery diagnosis and replacement: My experience FWIW

[latebrent]

Leaf spy was occasionally showing sub 12 voltages, so I suspected my 5 year old battery was nearing end of life.

After driving, I left the car off for 5 hours with a Digital volt meter hooked to the battery. Starting at 12.2, every hour the battery voltage dropped about another .1 volts ending up at 11.8.

I took it for a drive to go buy a battery and the leaf charger quickly takes it up to 14V (leafspy reporting). Weather was bad so could not replace the battery immediatley.
However, to quickly mimic the 4 hour "off" wait, I pressed the ON button twice without pressing the brake, the car comes in an an accessory mode. Reading the battery voltage after a few seconds, and the battery was at 11.8V and falling rapidly, turning on more accessories made it drop faster (internal resistance of the battery is getting high!)

This morning after being off for several hour, I simply replaced the battery.

Leaf powered up fine, but threw a few TCU errors (leafspy DTC read) which I cleared in leafspy. Done and Done. Nothing horrible.. just did it. By the way purchased a 51R, bolted right in...
The only wierdness is that the battery clamp was loose prior to replacing the battery.

 

[nlspace]

Great report, thanks for sharing.

 

[khbkhb]

Handy to have a load tester, like this one from amazon. Obviously, we don’t need a lot of cranking ;>, but testing under a resistive load is the best inexpensive way to judge the health of a lead acid battery.

If replacing the battery oneself, it can also be handy to keep the car under power. A bit pricey, but pretty idiot proof. Otherwise, various state/history can be lost. It isn’t the end of the world if you lose it, so this is a bit of gilding the lily, as it were.

 

[JJoynt]

Leaf spy was occasionally showing sub 12 voltages, so I suspected my 5 year old battery was nearing end of life.

After driving, I left the car off for 5 hours with a Digital volt meter hooked to the battery. Starting at 12.2, every hour the battery voltage dropped about another .1 volts ending up at 11.8.

I took it for a drive to go buy a battery and the leaf charger quickly takes it up to 14V (leafspy reporting). Weather was bad so could not replace the battery immediatley.
However, to quickly mimic the 4 hour "off" wait, I pressed the ON button twice without pressing the brake, the car comes in an an accessory mode. Reading the battery voltage after a few seconds, and the battery was at 11.8V and falling rapidly, turning on more accessories made it drop faster (internal resistance of the battery is getting high!)

This morning after being off for several hour, I simply replaced the battery.

Leaf powered up fine, but threw a few TCU errors (leafspy DTC read) which I cleared in leafspy. Done and Done. Nothing horrible.. just did it. By the way purchased a 51R, bolted right in...
The only wierdness is that the battery clamp was loose prior to replacing the battery.

My leaf is 9 years old. I am on my third 12 VDC battery. The first one was OEM Nissan lasted 2 years, second one was Autozone lasted two years. The present one is a bright yellow OPTIMA it has lasted 5 years.

 

[Bombastinator2]

Reading the forum, I see people having good results with LiFepo4 batteries. They’re 12.8 rather than 12 nominal (batteries are a bit like balloons) and leafs don’t seem to like it if their voltage is even a little bit below 12, so it seems like the way out. The problem is I don’t know what battery to buy.