jjeff
Posts: 1487
Joined: Wed Jan 13, 2016 9:10 am
Delivery Date: 13 Jul 2014
Leaf Number: 422121
Location: MSP MN

Re: LEAF's 12V battery behaviors - and why they go bad

Fri May 05, 2017 7:16 am

GerryAZ wrote:
strowger wrote:
jjeff wrote:^^^ I think your right on what might have happened, 5ah isn't much capacity for running a large fan. As a backup should this happen when out and about, I might suggest a smallish portable 12v Li battery jumper. I always carry one in the back of my Leaf for just such occasions. It came with a 12v cigarette lighter adapter or small jumper cables, oh and it also has a 5v USB output for charging portable things that use USB.
All in all for the <$30 I paid for it on sale, I believe $39 regular price, I hope it's worth it, if I ever ran into a weak 12v battery :)
I bought mine at a big box hardware type of store(Menards) but I believe Amazon and other places sell similar models.


Be careful with assuming that those LiIon jump-start packs will jump-start a Leaf with a discharged 12V battery.

The ones I have used, will only output 12V for jump-starting for a second or two - because they are small, their cables are small, and the current required to crank an engine would set fire to them in a few seconds.

The Leaf will not charge a 12V battery which is very deeply discharged - for example, if the voltage is too low. I have seen this with mine when the 12V battery went bad and was down to <11V. The Leaf would "start" on the power button and drive, but the DC-DC converter stayed off, because the 12V battery "looked bad" to the Leaf's electronics.

This second or two of power from a LiIon jump-start pack is not long enough to both power-on the Leaf, and have the Leaf decide the 12V battery is good enough to charge & start charging.


It depends upon the quality of the Li jump starter. I have used mine to start a 4.0L inline 6-cylinder, several different V-8 engines, motorcycles, and my 2015 Leaf (completely dead battery). Both of my Leafs (2011 and 2015) started just fine and recharged their 12-volt batteries after being completely discharged.

I don't have my little jump starter in front of me now but I can say that it doesn't have small wiring, I'd say 10 gauge minimum and the Li battery itself is somewhat substantial as I recall. I've always wondered myself how well something like this would work to jumpstart a ICE vehicle(probably the main reason they are sold) but I really feel it would add just enough Oomph to a weak 12v Leaf battery to boot the computer and start the DC to DC charging. I guess I won't know for sure unless I ever need it and considering I do a weekly or biweekly charge/desulphify routine on my Leaf battery, hopefully I won't have to try it for some years to come.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
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'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
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BrockWI
Posts: 574
Joined: Fri Mar 28, 2014 6:28 am
Delivery Date: 28 Mar 2014
Leaf Number: 423875
Location: Green Bay, WI.
Contact: Website

Re: LEAF's 12V battery behaviors - and why they go bad

Fri May 05, 2017 7:20 am

I can't speak to the Li-ion packs, but I keep a 9ah sealed lead acid and unfortunately I have used it many times. I just have #14 leads (30a inline fuse) and clip it in parallel, let it sit for 30 seconds or so, then start the leaf, then disconnect the SLA battery and I am off.
3 kw solar pv - XW6048 - 8 L16's
4 ton GSHP
2003 VW TDI 170k miles - 52 mpg lifetime
evse level 2 - Clipper Creek HSC-40
2013 S model with QC package Mar of 2013

gshepherd
Forum Supporter
Posts: 174
Joined: Wed Apr 27, 2016 12:01 am
Delivery Date: 03 Jun 2016
Location: Seattle / Phoenix

Re: LEAF's 12V battery behaviors - and why they go bad

Fri May 05, 2017 10:56 pm

Thinking of picking up a lithium jump pack. Schumacher makes the SL1 which looks decent using Lithium Iron Phosphate (LiFe) cells, which are more stable and have a wider temperature range. I like that it has a voltage meter, safety cutout logic, and a 12V socket output for running something like a tire pump, or perhaps keeping a mini fridge running while the car is parked for an hour or so. Looks like it could function as a 12V UPS in that regard.

I can see these booster packs being handy to help other motorists without risking damage to the LEAF's systems.
2016 LEAF SV

greengate
Gold Member
Posts: 537
Joined: Mon Feb 04, 2013 9:31 pm
Delivery Date: 04 Feb 2013
Location: Wilmette, IL

Re: LEAF's 12V battery behaviors - and why they go bad

Wed May 10, 2017 7:00 pm

So I take my '13 SL with 22,300K miles to my dealer for a car wash. They have it sitting there for 30 minutes with the flashers on. It's getting late, so I go to reclaim the car, (which hasn't been washed yet,) and there is no light on the started button..completely dead.

They put a fast charger on the 12V for about 3 minutes and everything is good to go. I am told to drive it for about an hour and this will charge back up the 12v. I am driving home, (about 5 miles away,) and are about 1/2 way there when a huge warning comes on..Massive power failure. You have 5 seconds to pull the car to a stop and apply the parking break." Like a sudden heart attack!! I manage to do this as I am in city traffic, but with no advance warning, should I have been on an interstate..oh my God!!

I called a service who came with a portable battery, which they hooked up and left under the hood, allowing me too then drive to their garage where they replaced the OME battery with a new Interstate Megatron, (500CCA..MT51R battery,) which has a 72 month warranty. ($129.95 for the battery.)

I see this as VERY dangerous..no advance warning...I felt like I was Captain Skully and fortunately I was not at 30,000 feet or just taking off and over the river!!

Any thoughts or comments? If not, BE WARNED!!

SageBrush
Posts: 1498
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: LEAF's 12V battery behaviors - and why they go bad

Wed May 10, 2017 7:37 pm

greengate wrote:Any thoughts or comments?

A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.
So while I don't doubt your 12v was ready for replacement, I suspect that a separate problem related to 12v charging may be present. In your shoes I would buy a digital multimeter and keep a close eye on the new battery.

I suppose an alternative explanation is that the battery was so far gone that only a power charge could power up your 12v a little, while the normal functioning charger of the car could not. I don't know enough about batteries to say.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

LeftieBiker
Posts: 7402
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: LEAF's 12V battery behaviors - and why they go bad

Wed May 10, 2017 11:53 pm

A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.


A normally functioning Leaf will NOT recharge the 12 volt battery from flat to anywhere near full in one hour. Maybe in four hours, on a very good day. And given that they actually ran it flat, they also damaged it. That dealer owes you a check for the new battery. They were assuming that the Leaf has a high-amperage alternator forcing power into the battery, and they should have known that this is not how it works with an EV.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

GerryAZ
Gold Member
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Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: LEAF's 12V battery behaviors - and why they go bad

Thu May 11, 2017 3:45 am

I have had a total of 3 instances of discharged 12-volt batteries--2 with the 2011 and 1 with the 2015. In all cases, the DC-DC converter charged at a high rate (80 amperes or so into the battery), there were no ominous messages, the car performed normally, and the battery was fairly well charged by driving 30 minutes. The second case on the 2011 was when the battery was failing, but it was still able to accept some charge and the car acted normal.

In Greengate's case, the battery may have shorted or opened internally. Since the car measures charging current and voltage, the VCM may have recognized that the battery was not taking a charge and provided the ominous warning to get the car shutdown (although 5 seconds is not much time to react). I have seen cases with gas engine vehicles where the high output alternator was not able to keep the engine running after the booster battery was disconnected (depends upon failure mode of battery).
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

VitaminJ
Posts: 386
Joined: Tue Jan 03, 2017 11:46 am
Delivery Date: 07 Jan 2017
Leaf Number: 415775
Location: Morrison, CO
Contact: YouTube

Re: LEAF's 12V battery behaviors - and why they go bad

Thu May 11, 2017 9:07 am

greengate, good on you for heeding the dash warning and pulling over immediately. Any 12v battery problems should be taken very seriously as the brake booster is electrically powered and relies on the 12v to deliver initial current. There is a member on this forum who had total brake failure and rear-ended another car after having EV warning lights on the dash. In that case the dealer told him to drive away and everything would be fine, just as they told you:
viewtopic.php?f=30&t=23730&
2013 Ocean Blue SV w/ QC and LED
- +0.2 mi/kwh Aeromods
- 2lb 5Ah LiFe 12v battery

arnis
Posts: 753
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: LEAF's 12V battery behaviors - and why they go bad

Fri May 12, 2017 11:26 am

LeftieBiker wrote:
A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.


A normally functioning Leaf will NOT recharge the 12 volt battery from flat to anywhere near full in one hour. Maybe in four hours, on a very good day. And given that they actually ran it flat, they also damaged it. That dealer owes you a check for the new battery. They were assuming that the Leaf has a high-amperage alternator forcing power into the battery, and they should have known that this is not how it works with an EV.

Well, if we count 60% "not anywhere near full" then it's true. But 60% is good enough to resume half day later.
Also slow charging the vehicle will also constantly charge the 12V battery. During the night while vehicle charges.

Let's stop assuming everybody drives 2011/12 model. And if we talk about those, let's be more specific.

Running 12V battery flat doesn't damage it automatically. Keeping it that way for days does.
Deep cycling a battery doesn't damage it. It degrades. Cycle degradation. Lead Acid battery has only 100-200 cycles til 20% degradation.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

LeftieBiker
Posts: 7402
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: LEAF's 12V battery behaviors - and why they go bad

Fri May 12, 2017 11:50 am

Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

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