Had some codes that implied my battery was going...

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Klausstein

Active member
Joined
May 17, 2024
Messages
33
Location
Portland OR
I checked codes on my 2013 Leaf S with 89000 miles. Since it is new to me I plugged in an OBD2 and used LeafSpy Pro. Some of the codes that cam up were showing low voltage, after doing some digging it looked like it may be time for a new battery. When I pulled the battery out it was dated 11/19 so it was pushing the 3 year warranty. It was a lead based battery. When I took it in to the battery place the scan showed it was good, but only at %50 charge. I decided to buy an AGM battery since they seem to be better for the leaf. After clearing all codes and driving around for a bit none of the codes came back. My question is....Should I be concerned that the old battery was only at %50 charge? I worry that something could be wrong with the charging system. I haven't noticed any problems with the car, but the auto parts guy got me thinking that maybe something isn't right. Then again...what does he know. :) Sorry I don't have the codes. I'm new to Leafspy, and totally forgot to screenshot them to share.
 
For Lead acid battery: If you unplug the connector for the current sensor on the battery, then it will be kept charged better (higher voltage for longer time).

Another trick is to run the rear window wiper, for some reason the DCDC voltage is kept higher when the wiper is On.

The charge voltage goes up to 14.4 after starting to READY mode, but it drops down to about 13.1 in a short time. So it's mostly trickle charging and not held high long enough to desulfate the plates.
 
For Lead acid battery: If you unplug the connector for the current sensor on the battery, then it will be kept charged better (higher voltage for longer time).

Another trick is to run the rear window wiper, for some reason the DCDC voltage is kept higher when the wiper is On.

The charge voltage goes up to 14.4 after starting to READY mode, but it drops down to about 13.1 in a short time. So it's mostly trickle charging and not held high long enough to desulfate the plates.
Thanks. So for an AGM battery I don't have to worry about this as much? The codes haven't returned so it must have been the battery.
 
Thanks. So for an AGM battery I don't have to worry about this as much? The codes haven't returned so it must have been the battery.
That's not the point: any (low) 12v battery can be the source of incorrect/unreliable codes in a Leaf. There are plenty of threads on 12v battery options for the Leaf; the closest thing you can come to "don't have to worry" is a Lithium-based 12v...but that's a whole other discussion.
 
IMO an easy solution is get a decent trickle charger. The 12v charging algorithm on the early Leafs were not so good. Combine that with a relatively small battery exposed to constant drain and it's a recipe for pulling the voltage down chronically, which stresses the battery, and shortening the life.
I have a 14 and top off the battery at least monthly.
FWIW I kept both my Leaf and Prius going for over 2 years beyond when the battery would usually be replaced.
 
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Another trick is to run the rear window wiper, for some reason the DCDC voltage is kept higher when the wiper is On.
My guess, and it is only a guess, is to provide an "equalization charge" every so often. Unless you live in a desert, sooner or later you are going to run your wipers for a trip, and when do, keeping the charge voltage high enough to balance the cells.
The other way would be to have active BCM for the 12 volt also
 
i used a voltmeter that plugged into the cigarette lighter socket to measure the 12V battery charging voltage. Give it a try with the rear defrost that's a good idea.
 
I wonder if using rear window defrost would do the same thing and have no visible sign. Running wipers dry isn't the best for them. With dirt on the window also isn't good for the glass either.
Plus it can streak things And actually create visibility problems. Hit your window cleaner then wiper the water off. Even in Minnesota they don’t put alcohol in the water unless it’s winter and then barely any. “Washer fluid” is basically just water with blue dye in it. Toss a shot glass of isopropyl in a gallon of water and you’ll have multiple times what they put in the blue garbage. Enough to actually not freeze on a really cold day. To me light blue slush just says “we cheated you”
 
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Thanks for all the replies. Being new to the leaf world, this has been super helpful. What I'm seeing is that the the low battery thing is an issue. How often should I be checking the 12V battery voltage, and running rear window defrost? I only drive the car a few miles a day.
 
You shouldn't need to run the wiper dry, you don't need a equalization charge every time you use the vehicle, once a month is the normal period recommended, and that is for deep cycle packs that are used hard.
As I have posted in other threads, I have three gp 51R's in vehicles and IIRC my oldest is going strong at 6-7 years, and it starts a diesel and only has a 20 amp charging alternator.
 
Thanks for all the replies. Being new to the leaf world, this has been super helpful. What I'm seeing is that the the low battery thing is an issue. How often should I be checking the 12V battery voltage, and running rear window defrost? I only drive the car a few miles a day.
Driving any vehicle on a few miles a day may require charging, it isn't if it is charged by an alternator or a DC to DC charge board, it is that that the charge time is too short.
On another forum, a guy was chasing his tail trying to sort out a charging problem on his grandma's car only to find most of the use was her driving down to her mail box and back! He put two alternators from different makers on, and several batteries, trying to sort out the problem, but there was nothing wrong other than not enough time.
Unlike the above example, the Leaf will not suffer damage for short trips, the 12 volt may need to be charged, however.
 
Great
Driving any vehicle on a few miles a day may require charging, it isn't if it is charged by an alternator or a DC to DC charge board, it is that that the charge time is too short.
On another forum, a guy was chasing his tail trying to sort out a charging problem on his grandma's car only to find most of the use was her driving down to her mail box and back! He put two alternators from different makers on, and several batteries, trying to sort out the problem, but there was nothing wrong other than not enough time.
Unlike the above example, the Leaf will not suffer damage for short trips, the 12 volt may need to be charged, however.
Great. Thanks.
 
After my 2 year old 12v died (shorted cell), and replacing it, I added a very reasonably priced BM-2 battery monitor. Has an App and uses Bluetooth, so you don't have to be in the car to read it. Also will graph both daily and 7 day voltage levels.
 
A battery monitor is not a bad idea. I put a simple tiny voltage meter hard wired into the system (very minimal drain). I do have to open the hood and look, and it's only slightly less trouble than getting the voltage meter off a near by shelf.
But, if the battery is low you still should do something about it.....like charge it. ;)
So....if you are going to spend $30 to DO something, I still recommend a trickle charger:
 
Thanks for all the input everyone. I already have a trickle charger sitting around in the garage. I bought a cigarette lighter plug that reads volts. If they start getting low I’ll stick it on the trickle charger when I am charging the big battery. I assume that’s okay to do both at the same time.
 
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