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12 Volt Lithium battery
- Thread starter dfdtruckie
- Start date
Ostrichsak
Well-Known Member
I wouldn't do it. Lithium batteries are more sensitive to operating temperatures than lead acid. This is why the Li-Ion HV pack has a state-of-the-art thermal control system in place. The 12v has nothing to regulate it's temperature. It's exposed to whatever ambient temperature exists on that day/night. Being as your location is listed as "Denver" I would guess that this could be especially troublesome in the winter time. This is why I just run a lead acid 12v and call it a day. Especially since all it does is power your 12v accessories so it's night like you need cold cranking amps to turn over a 6.0L high-compression gasser engine in the dead of winter in negative temps or anything like that.
Same thoughts here. I really thought about it(12v Li-Ion). I drive up and around Lake Superior to visit friends in the winter.
More reading it turned out unless it has some type of temp control it could not behave when you want in extreme cold as mentioned above. Weight savings might mean having to plug in a battery blanket for your LI-ion 12V.
That is one of the issues I am having moving to LI-Ion on my trailer. Different application I know. Must have a conditioned battery for longevity and accepting safe charge. Warming blankets etc...
I just did a proactive replacement of my 12v in December for my S. Was coming in on 100k and it had been fine. Didn't feel like finding out it didn't work without warning. Some don't get the warning. Most do.
Ostrichsak
Well-Known Member
Agreed up to the point where you proactively replaced your 12v battery. With the warning system on these Teslas you likely will start getting a warning that it's failing months in advance giving you plenty of time before a full failure. In fact, that's one of my big complaints is it's almost too sensitive to voltage drops but I prefer this over traditional cars that tell you by not starting in the dead of winter often times as their first symptom. So I see no real reason to replace a perfectly good 12v battery.
Fair enough. My time stranded is never worth a dead battery. Did mine prior to a 7k road trip in middle of winter. Didn't want to hear Tesla Roadside blame a bad 12v.
There have been posts that where the 12v went without warning. For me that could be in Radisson, Quebec. Spare tires and Tesla 12v batteries are hard to find. Could cost me a day. Could cost me a week and a grand for tire or part.
Have done that every 3 years on every car. Nominal when you think of cost. They don't throw away the battery. So do I pay a bit more? I guess, but the battery was replaced what 6 months prior to it dying? So over my car driving lifetime I bought 4 extra 12 v batteries. I never have to think about those cold cranking amps.
More or less if you take giant road trips. Those lights that go off change the mood. For minimal dollars in advance I can keep that mood.
BluestarE3
Active Member
Ah, battery blankets... brings back memories of living in Alaska. That and in-line block heaters. I guess I can claim I had a plug-in car of sorts way back in the '70s. 
Dukeybootie
Member
I have had my Ohmmu lithium 12V for about 8000 miles now. It has been working great so far.
I did proactive OEM 12V replacement at 4 years/95000 miles so I'm of the same mindset as @outdoors when it comes to preventive maintenance. A local installer did it for me -- it took about an hour and required a fair amount of work. About $430 for the battery and $100 for the labor. I plan on keeping the car at least another 4 years, so hoping not to need another 12V in that time.
Having said all that, I live in CA without exposure to freezing temps. I would not go lithium 12V if I were in Colorado.
I did proactive OEM 12V replacement at 4 years/95000 miles so I'm of the same mindset as @outdoors when it comes to preventive maintenance. A local installer did it for me -- it took about an hour and required a fair amount of work. About $430 for the battery and $100 for the labor. I plan on keeping the car at least another 4 years, so hoping not to need another 12V in that time.
Having said all that, I live in CA without exposure to freezing temps. I would not go lithium 12V if I were in Colorado.
The one I was considering has a BMS built in. There is a definite cost difference.
Ostrichsak
Well-Known Member
It also adds one more point of failure to what would otherwise be a simple solution.
Ostrichsak
Well-Known Member
As far as Teslas having a 12 volt battery fail without warning, I've got to working theory on that based on personal experience...
I had an issue with a high volt battery pack that left me stranded on the side of the road 7 and 1/2 miles from the next supercharger with 13 miles of range displaying on the readout. When Tesla techs tried to remotely connect there was a whole list of issues but they blamed it on a 12 volt battery. I got flatbed toad to the next supercharger where I sat plugged in for about five minutes before it resumed charging as normal. being as we were in the middle of a lengthy road trip and basically in the middle of nowhere I had little choice but to continue the trip while proceeding with caution. Other than a random issue a couple of days later on the return trip where it displayed Jack mode at 80 miles per hour nothing else indicated any issues at all.
I went on to drive the car for months afterwards without a single hiccup and the only thing I changed was I didn't ever let the range get lower than 20 or 30 miles at any point.
I think that one of the error codes that gets thrown when you have a high volt pack issue is 12 volt battery failure and I think text are all too quick to grab that as the culprit since it's a relatively easy and inexpensive fix compared to what is probably the real issue.
LTO chemistry solves the temperature issues down to neg 30 degrees Celsius for charge/drain at massive C rates. Also these cells last 'forever'. Five 2.3v cells in series makes up a lead-acid replacement pack since the nominal voltage is lower with LTO.
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Lasttoy
Active Member
I tried to buy a 12v battery at my SC. Sorry, none for months, China not shipping now. Stop by next month.
Lasttoy
Active Member
The engineers that designed a system with this weird battery should be tarred, feathered and drug in th sand. If u have not looked for or at your battery. You will be shocked. The Gen 1 cars have the battery hidden under cabin filter. The poles are offset, with the breaker board mounted on top of the battery. It is the Ruth Goldberg of battery designed. Just insane. Yes it cost $150, u can only buy at Tesla. Gen 2 has battery out front on the cross bar. But still have to buy from Tesla.
Good luck if u need one.
Good luck if u need one.
How do they make and sell any new cars if this is the case? Maybe they are just prioritizing what they do have for new cars?
The problem is not in finding an electrically equivalent battery (UB12350 deep-cycle 35amp SLA is readily available) but that the posts are reversed in the tesla-spec and also it uses weird posts. Extension cables to an easy-access frunk location could get the car going asap.
Any Li-Ion solution is impossible now since the high voltage spikes that Tesla superimposes on the DC-DC output will over time destroy any chemistry lithium battery, sad to say.
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Any Li-Ion solution is impossible now since the high voltage spikes that Tesla superimposes on the DC-DC output will over time destroy any chemistry lithium battery, sad to say.
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More questions.
What is an LTO battery? And is one available for a Tesla?
What are these voltage spikes that Wycolo posted about?
Would a LiFePO4 battery be better than a Li polymer battery for this application?
What is available that fits and has the needed terminal orientation?
Early 2016 S 90D
What is an LTO battery? And is one available for a Tesla?
What are these voltage spikes that Wycolo posted about?
Would a LiFePO4 battery be better than a Li polymer battery for this application?
What is available that fits and has the needed terminal orientation?
Early 2016 S 90D
I've misplaced that article re voltage spikes. Awaiting delivery of new oscilloscope to run a check on ModelS dc-dc output waveforms. Until then no one should connect any assembled Li-ion 12 volt battery without verifying that max charging voltage is 14.7 vdc preferably by using a 'scope. Anything above that, including spikes, will damage *any* chemistry Li-Ion cells by creating dendrites which penetrate the cell layers eventually shorting it out. Find the per-cell max v for whatever chemistry cells you are entertaining and be sure not to ever reach that voltage. For example LTO chem cells (2.3v nominal, 2.7v max - an odd cell for sure!) do not subject to more than 2.6v on a continuous basis. So 2.6 x 6 = 15.6v which should be plenty of headroom in a normal vehicle charging system. But how many different dc-dc units have appeared in Tesla's to date? And why do they create spikes in the first place??
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