lorenfb
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Mon May 16, 2016 10:37 pm

erichz wrote: Preferably one that doesn't involve hooking up to a battery tender every week or so?


That's not necessary if the electrical system is functioning properly, e.g. no controller failing to enter its
"sleep mode" (low current draw) or something causing a current drain greater than 50 - 80 milli-amps.
There's been speculations of an inadequately designed Leaf 12V battery charging system, but data to
fully corroborate that have only been anecdotal.

LeftieBiker
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Mon May 16, 2016 11:44 pm

There's been speculations of an inadequately designed Leaf 12V battery charging system, but data to fully corroborate that have only been anecdotal


You mean as opposed to signed confessions by Nissan engineers? There is plenty of data to support the "bad algorithm" theory. The only real uncertainties are the exact driving patterns that make the issue worse, or minimize problems, and whether using a larger SLA battery solves the problem or just helps in some situations. The evidence seems to suggest that lots of short trips, especially with heavy 12 volt accessory use, drive the battery's SOC down, while longer trips with light to moderate accessory use tend to keep it at least 75% charged. This likely being the case, then using a higher capacity deep cycle SLA battery should alleviate the problem, except in cases where there is a phantom drain in the system. Even then I'd want to charge that battery externally at least once a month.
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.

lorenfb
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Tue May 17, 2016 8:38 am

LeftieBiker wrote:
There's been speculations of an inadequately designed Leaf 12V battery charging system, but data to fully corroborate that have only been anecdotal


There is plenty of data to support the "bad algorithm" theory..


Really? I've yet to see any exhaustive study to corroborate that. Generally, we find posts that intimidate
new Leaf drivers to a potential unfounded Leaf problem before any analysis is done on the vehicle with
12V battery problems, e.g. determining the sleep current draw, making sure no courtesy lights remain
"on", or that no OBDII plug-in devices remain "on".

Again, anecdotal data doesn't qualify!

erichz
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Tue May 17, 2016 10:31 am

Isn't most automotive reliability data anecdotal in nature? I feel like once you've heard enough reports of a problem, you can start to believe it's a defect. From what I've seen, we can safely assume 12V battery longevity is an issue on the Leaf compared to ICE vehicles.

Anyway, I'm going to monitor my current battery. If it dies again or looks like it isn't being charged properly, I'll replace it, perhaps with an AGM, or perhaps just the cheapest thing I can find. In the meantime I'm investing in a jump box. I don't think Lithium 12V replacement is the answer in my climate.

Reddy
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Tue May 17, 2016 10:50 am

erichz wrote:My 12V battery up and died on me yesterday. .......Snip..... but do we have a long-term solution? Preferably one that doesn't involve hooking up to a battery tender every week or so?
That's my long-term solution (I'll reach 5 yr this August, hopefully on the original 12V battery). I put it on a tender once or twice a week, sometimes more, but I'm not super worried about it. Most times it takes 4+ hr to reach full. My driving is basically all in-town, 35 mph and less than 5 mi one-way. Interestingly, I put the charger on my 1990's ICE battery which I hadn't driven in a few months, and it was FINE, filling in less than 15 min. So definitely, the older cars with fewer (almost no) electronics don't drain down the 12V battery like the newer cars.
Reddy
2011 SL; 9 bar, 46.44 AHr; 40,067 mi; rcv'd Aug 18, 2011
Long: http://www.mynissanleaf.com/viewtopic.p ... al#p226115"
Cold: http://www.mynissanleaf.com/viewtopic.p ... 60#p243033"

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Marktm
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Tue May 17, 2016 12:32 pm

The thorough data taken by "69800" that started this thread shows that (his) Leaf's charging profile is VERY inadequate for proper charging of any lead-acid technology battery. The most robust deep cycle off-grid (solar application) batteries would likely fail quickly with this charging profile (maybe less than a year of daily cycling) - well maybe not fork lift batteries :lol:

IMHO - the extremely light duty that the Leaf's battery is exposed to, combined with just barely keeping the charge voltage (there is no staged charging profile really) above sulfation level (70% SOC), combined with trying to minimize all continuous energy draws - maybe the Nissan Engineers felt their design is a good compromise? Also, It seems the OEM battery is a very high quality "CCA" type battery of which they certainly are familiar!

However, to design in a failure mode that is just a matter of time - and is often unannounced - is very problematic.
2012 Leaf SL; 36,000 miles. Battery replaced November 1st, 2016.
Rural cabin with 6750 watts Grid tied PV. Off-grid solar Leaf charging capable (level II).

lorenfb
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Tue May 17, 2016 9:23 pm

Marktm wrote:The thorough data taken by "69800" that started this thread shows that (his) Leaf's charging profile is VERY inadequate for proper charging of any lead-acid technology battery.

However, to design in a failure mode that is just a matter of time - and is often unannounced - is very problematic.


A sampling data on one vehicle in a population, hardly justifies an extrapolation to the whole population
and a robust conclusion!

Bob
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Wed May 18, 2016 7:35 am

About this argument on whether the Leaf is bad to 12V batteries - It's all relative.

There is certainty that the Leaf charges the 12V battery.
There is certainty that the Leaf does not charge the 12V battery for optimum battery life, far from it. This is easy to determine by parking the Leaf and measuring battery voltage over time. You'll see it drop into the range where 12V batteries are known to start seriously sulfating.

There is also lots of anecdotal evidence about people who have had Leaf 12V batteries fail in <3 years.
There is also lots of anecdotal evidence that a bad Leaf 12V battery will lead to problems.

To all Leaf owners, my personal advice is either:
1) replace the 12V battery every 3 years, or
2) use an external battery charger like the Battery Tender Plus.

Your mileage may vary.

Bob

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Marktm
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Wed May 18, 2016 2:50 pm

lorenfb wrote:A sampling data on one vehicle in a population, hardly justifies an extrapolation to the whole population
and a robust conclusion!


All the similar data that I've taken with my Leaf confirms the extensive data from 69800 - never seen voltages on my battery that is appropriate for proper charging and most often well below voltages that prevent sulfation, except for a very brief instant. I agree that a Leaf dying and leaving someone stranded in traffic is anecdotal to the charging profile, but why take that chance?
2012 Leaf SL; 36,000 miles. Battery replaced November 1st, 2016.
Rural cabin with 6750 watts Grid tied PV. Off-grid solar Leaf charging capable (level II).

LeftieBiker
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Re: Solutions to 12 Volt Batteries and Chargers Posted Here

Wed May 18, 2016 5:46 pm

Loren doesn't seem to understand that virtually everyone who uses a battery maintainer gets to see, via the LED indicator on the unit, whether the car's accessory battery is full (almost never!) near full (rarely) or requires significant charging (usually) when it gets connected. We can also, if we check back regularly, see how long it takes to top off the battery. Knowing the output of the maintainer gives us, more or less, how many AHs had to be added to the battery. That is how I know that short trips with heavy accessory use drain the 12 volt battery much more than long trips with light accessory use. These observations have also been confirmed by others. The idea that all this is based on the behavior of one Leaf is very mistaken.
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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