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Re: Replaced 12v Lead with 12v Lithium

Posted: Sat Mar 30, 2013 12:40 pm
by DaveinOlyWA
TomT wrote:Interesting since I've left mine for weeks at a time (unplugged) and never had an issue. When I had my two year battery report last month they also tested the 12 volt battery and it got the highest possible marks... Go figure.

DaveinOlyWA wrote:i found that the only real risk is if leaving the car sit for extended periods of time. cold weather aggravates any lead acid batt so outside does compound it. there was one WA guy who parked his outside for 3½ days while at the ocean and temps were a bit colder than normal with lows in upper 20's, low 30's and his battery was completely dead. I think he said he measured his at like 7 volts. he jumped it and has had no lasting issues but he puts a lot of miles on his LEAF but also takes several trips a month. he has left his car sit for similar lengths several times without issue but thinking its simply mismanagement catching up.


like any battery chemistry, lead is affected by temperatures. it has to get pretty hot to make any significant difference but on the cold end, that is very reachable by most of the country including the relatively mild weather we get in the Pac NW

Re: Replaced 12v Lead with 12v Lithium

Posted: Sat Mar 30, 2013 1:24 pm
by Stanton
KJD wrote:What is the amp hour rating of the new battery compared to the amp hour rating of the old battery ?


The Lithium battery is sized at HALF the AHr rating as the "stock" 12v battery that ships with the Leaf which puts it at around 20-22 AHrs. Remember, you really can't access anything below 50% in a lead acid, but (as we all know) you can theoretically access between 80-90% of the Lithium if necessary (protected by built-in BMS). My guess is you could run the radio (or lights, etc.) longer with this SMALLER Lithium battery than with the lead acid it replaced, but I'm not going to try it 8-)

I might take a voltage reading once-in-awhile, but I don't think I'm up for regular readings/monitoring. This battery typically sits between 12v-13v.

Re: Replaced 12v Lead with 12v Lithium

Posted: Sat Mar 30, 2013 3:17 pm
by Solangelist
Is there a built in charger in the new lithium battery pack to accept the old lead acid battery charging profile? Or did you have to modify the original lead acid charging system for the new lithium?

Re: Replaced 12v Lead with 12v Lithium

Posted: Sat Mar 30, 2013 4:02 pm
by Stanton
Solangelist wrote:Is there a built in charger in the new lithium battery pack to accept the old lead acid battery charging profile? Or did you have to modify the original lead acid charging system for the new lithium?


All of these "drop in" lead acid replacement batteries are engineered to accept the ICE charging profile, otherwise it would be too complicated for the average person to use. The difference between the good (read: expensive) and bad (read: cheap) Lithium replacements is usually built-in cell balancing and/or voltage min/max monitoring. The irony is the Leaf charging profile (very stable--and well controlled--DC charging) and maintenance "top off" checks every 5 days (with the ability to "quick charge") is ideally suited for a 12v Lithium starter battery, but they're just too expensive to put in every car.

Re: Replaced 12v Lead with 12v Lithium

Posted: Sun Mar 31, 2013 1:05 am
by TonyWilliams
For the record, the Rav4 EV Gen II has the same 12 volt issues. I've parked mine for 3 weeks, and left it on a 12 volt tender.

I also left the main traction battery unplugged as an experiment. That experiment didn't start out well when I left the daily morning heater timer on.

Fortunately, I could remotely turn it off.

Re: Replaced 12v Lead with 12v Lithium

Posted: Sun Mar 31, 2013 3:43 am
by derkraut
My 2011 Leaf has been stored in my garage, unplugged, with the main traction battery @ 3 bars, for over 30 days now. When I get home next week, I expect to be able to jump in, power up, and drive off.

This is the longest I've ever gone without driving it. So...we'll see.

Re: Replaced 12v Lead with 12v Lithium

Posted: Sat Jan 18, 2014 3:38 pm
by derkraut
Late follow up report......It powered up with no problem whatsoever.

Re: Replaced 12v Lead with 12v Lithium

Posted: Wed Jan 11, 2017 9:58 am
by Durandal
I intend on doing this when my 12v lead acid battery dies, then I'll pull the trigger on getting a Lithium 12v battery.

Re: Replaced 12v Lead with 12v Lithium

Posted: Wed Jan 11, 2017 11:24 am
by VitaminJ
Ok, so this thread is almost 4 years old. The batteries being posted about then were way too heavy and way too expensive. There is no need for a large AGM or lithium battery designed to start an ICE car.

What we need is an exceptionally lightweight battery like this motorcycle battery:
https://www.batterystuff.com/powersport ... tTechSpecs

2lbs, $145. That's more like it.

Re: Replaced 12v Lead with 12v Lithium

Posted: Wed Jan 11, 2017 11:59 am
by BillHolz
Yes, any 4 series LiFePO4 battery is likely to do the job. I would even consider an RC pack such as: https://hobbyking.com/en_us/zippy-fligh ... -pack.html which would require adapters to connect to the car top post connections. The motorcycle version is probably easier to adapt to the car.