Tip: How to Recharge the 12-volt Battery

TimLee said:

Numerous people have come back from a 10 day vacation where the EVSE was plugged up to the LEAF and found the 12V battery dead in the water.

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FWIW, I came back from a 10-day vacation to a dead 12v battery and my EVSE was not plugged into the car.

csites said:

... FWIW, I came back from a 10-day vacation to a dead 12v battery and my EVSE was not plugged into the car.

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Sorry

Has happened to a few people.

For people like yourself and BrockWI the LEAF should be left on a battery maintainer.

I have not experinced what you and BrockWI have, but a year and a half back when second 12V replacement had to be installed I started putting it on a battery maintainer every time it is parked in the garage.

Yup, my rule is 2 or more days without driving the Leaf we plug it in to the battery tender and let it do it's thing, better safe than sorry.

I do put it on the tender every Friday night and recently I picked up a watt hr meter and 2 weeks ago it took 187 Wh, charging over 12 hours at 1.25a to get back to full, last week was 122 Wh. For reference our van and wagon take about 20 Wh to top off. So either something is draining the battery or there is major deficit charging going on. And I do NOT keep the bluetooth OBD2 plugged in, which is what Nissan says the problem is.

BrockWI said:

And I do NOT keep the bluetooth OBD2 plugged in, which is what Nissan says the problem is.

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How did they know? I just bought one after 3 years of prior trouble. Can a service tech tell that I used it?

We can assume that Nissan knows about this battery problem already, and is NOT going to give a hoot about maintaining 12v batteries.... We know this due to the fact that Nissan puts a solar 12v charger on top of the SL model!!! We need to take charge of this. My suggestions, (which I also use for my lightly driven Mazda Miata..)

1) If you don't used the car daily and have the car in the garage.. get a "Battery Tender" to plug into the car to always keep the battery at 100%. The charger comes with some "quick disconnect" wires which you can attach to the battery terminals, and will make the connections to the battery almost instantly. The battery tender is computer controlled and you can leave it connected to the car permanently if needed...

2) If you do not use the car daily and park outside (gets sunlight), get a cheap $15 SOLAR battery charger from Harbor Freight and use double stick tape to mount the charger on your dashboard. You can route the wire directly to the fuse box or directly to the battery (either with included alligator clips or the "quick disconnect" harness).

3) If you use the car daily, like me, connect the battery tender to top off the 12v battery every 3-4 weeks.. Problem solved. Your battery will ALWAYS be at 100% and will last so much more... Using this method, I still have the original battery on my 2006 Ford escape with 100K miles!! and it is still strong.

csites said:

How did they know? I just bought one after 3 years of prior trouble. Can a service tech tell that I used it?

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One of the times I had the Leaf in for a software update and I mentioned the 12v battery had run dead a couple of times, he checkd it and of course said it was fine. Later I made comment about Leafspy and his eyes lit up and then he stated, well thats your problem your connecting to the OBD2 port and that will keep the car "alive" and run the battery dead. I said I knew that it does keep some things awake for a bit, but that I don't leave it connected unless I am actively using it while the car was on. He said that it didn't matter and it was becasue I had plugged something in the OBD2 port, he said he had to "reset" the car to fix it and to not use the OBD2 port again. I said ok and left. :roll:

^^^^^ That is bizarre.
I don't think the technician knows what they are talking about.

But don't understand what they "reset".

The LEAF only powers the OBDII device while the LEAF is charging, or ON, or in READY.
I don't think it pulls any power except in those states.

Now they do pull quite a bit of power, seems like some measured something like 125 mA, about five times the LEAFs normal powered OFF draw.

Nissan has decided the LEAF battery failures are normal.
They were asked about the problem at the big Phoenix town hall meeting.

They responded a few days later on MNL that LEAF battery problems were the same or less than other Nissan ICE vehicles.

Since that sorry non answer about the poor LEAF 12V charging approach, I think they have done NOTHING.

LEAF Advisory Board might have more info.
But we never hear anything from LAB anymore.
They seem to be under the cone of silence :? :roll:

TimLee said:

The LEAF only powers the OBDII device while the LEAF is charging, or ON, or in READY.
I don't think it pulls any power except in those states.
Now they do pull quite a bit of power, seems like some measured something like 125 mA, about five times the LEAFs normal powered OFF draw.

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After having 12v battery trouble every 6 months or so for 3 years, I finally bought an LELink OBDII bluetooth adapter. At minimum, there's a red LED in it that always receives power. I've left it plugged in 24x7 for a month with no trouble so far. I think I read in this forum somewhere that the bluetooth model draws an insignificant amount of power, whereas the earlier WiFi model drew more.

I believe the newer iphone compatible bluetooth dongles use "low energy" chips and should draw significantly less power than the previous bluetooth chip. In the "arduino" world it is "HM-10" (LE) rather than the "HC-05" (standard). The LE types hook up automatically - do not require the "1234" type password.

This is from a forum:
HC-05:
40mA when pairing
20mA when paired
2mA when sleeping

Also from several forums:
HM-10: ~.2 mA when paired (have not found the draw when "pairing" - assume same???)

Anyone that has updated info is appreciated as this can help explain the "bluetooth parasitic" drains. Even though 20 mA is low, the LE appears to be 100 times lower making it suitable for "button" type battery systems.

csites said:

... At minimum, there's a red LED in it that always receives power. ...

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Valid correction.
It must receive 12V power continuously.
Only CANBUS communication is off.

Android LEAF Spy Pro doesn't support the low energy bluetooth yet.
Should be added to the next version.

csites said:

When in accessory mode, you'll see around 11-12v - any less and you're having trouble. When in drive mode or when charging the drive battery, you'll see either 13v or 14v - a few minutes at 14v then drops to 13v. Ignore the red, yellow, green lights which seem to be calibrated for a gas car.

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I bought the battery monitor and have had to jump a 2011 Leaf twice in the past month even though a new battery was installed in March. I just put the car in Accessory mode and the reading was 10.10v. I am new to this world (bought used in October 2017), and am wondering how I should proceed? Do I need to replace the 12v battery? Or will it re-charge itself?

I also just learned about a Service Campaign NTB18-045 that addresses this problem that seems to occur after people upgrade their TCU to 3G (which I stupidly did as soon as I bought the car...)

Was the new battery pre-charged before installation? That can be an issue with Leafs. Generally, once you see 10 volts, the battery is damaged and should be replaced.

I would give the battery a good long charge with a good charger to rule out a bad battery. My guess is though your TCU upgrade is the issue.