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The 12V battery in a Cayenne is under the driver's seat, which (I would expect, anyways) would be a good spot to protect it from extreme temperatures. Not sure about either other Porsches or Teslas, but batteries like this last longer when kept cooler (and charged only when above 0C). If the Tesla battery is in the frunk or someplace that heats up lots when the sun beats on it, that's not conducive to a drop-in lithium replacement.Porsche is already offering a 12V Li-on battery option...
New Lightweight Battery Option for the Porsche 911 GT3, 911 GT3 RS and Boxster Spyder
The 12V battery in a Cayenne is under the driver's seat, which (I would expect, anyways) would be a good spot to protect it from extreme temperatures. Not sure about either other Porsches or Teslas, but batteries like this last longer when kept cooler (and charged only when above 0C). If the Tesla battery is in the frunk or someplace that heats up lots when the sun beats on it, that's not conducive to a drop-in lithium replacement.
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But I might carry a "jumper" battery just in case, so I can do my own jump start if ever needed.
I carry a jumper battery in my frunk but the problem is, there is no place I can put it in the car and gain access to it if my 12V battery goes dead. It is a stupid situation that I cannot solve. I have asked the SC and they too cannot offer up a practical solution other than to get a jump from an external source. So my only real practical reason to carry my jump battery around (along with a tire inflator) is to top up my tires in case they need air.
Hey guys, just to jump in here. I am the guy behind BattMobile Batteries.
To answer some questions/concerns;
1. The batteries do "exist" (I just added photo of an ES battery to website); I have several Engineering Samples and have installed several in test vehicles around the country. I also have a batch going through manufacturing now and will be delivering to customers with deposits in early January. I have left the eBay posting and my website posting as "deposit-only" for now in order to ensure folks don't buy them with the belief it'll be there in a few days; presently if one were to place a deposit I have a couple still available from the January batch but worst case is they would get them in March. If one were in "dire" need I would send an Engineering Sample battery to them in the mean-time (or they can just keep it since only changes will be cosmetic)
2. The price being 50% as a deposit; I get it and I agree it feels deceptive to list it that way but I didn't want to list it at full price and have folks pay me 100% up-front and then feel they were cheated b/c I don't have them ready to ship yet; similar to Tesla or other new to market products I am using the "deposit" money to help kick-start the production and get the costs to where they need to be to be viable.
3. The cells utilized inside of these batteries are Lithium Iron Phosphate prismatic cells, they have a rating of 2,000 100% DOD cycles; my data analysis of the Model S 12V battery (I have monitored my own extensively and a few others to verify) suggests that with the larger available energy of my lithium batteries the battery will never do a 100% DOD cycle, in fact it will be more like 60% with this chemistry (minimum voltage 12.8V up to maximum of 14.4V).
4. Safety/inert chemistry; Lithium Iron Phosphate is well-known as the "safe Lithium"; you can drill a hole in the side of the battery and it won't respond the way the Lithium-Cobalt/Nickel cells do (the ones used by LG that I mention in my "custom batteries" page, I use them for non-12V applications), they are more resilient to temperature extremes, etc.
As far as a "geek tear-down"; I've obviously done this myself and I am a geek and can vouch but I'm the wrong person to do that since I'm also the one selling them, haha! I have one production unit pegged for the folks at Teslarati to review and do a bit of a "tear-down" on... That will be a month or two out I'd guess at this point. And I am happy to work with any other "snarky-reviewers" who are interested as well!
Sorry, hope this post doesn't come off as an advertisement or anything like that, I just wanted to clarify to you guys since I got excited that folks are talking about my batteries!!!
I hope no one who reads that ebay ad thinks that the battery is in any way approved or sanctioned by Tesla, because obviously it is not.Available on eBay ... Tesla Model S Lithium 12V Accessory Battery | eBay
I hope no one who reads that ebay ad thinks that the battery is in any way approved or sanctioned by Tesla, because obviously it is not.
Also, it is my understanding that LiFePo batteries are not effective as temperatures approach freezing.
I hope no one who reads that ebay ad thinks that the battery is in any way approved or sanctioned by Tesla, because obviously it is not.
Also, it is my understanding that LiFePo batteries are not effective as temperatures approach freezing.
Thanks for your reply. Can you tell us more about the expected lifespan the 12V Li-fe-ph batteries?
Available on eBay ... Tesla Model S Lithium 12V Accessory Battery | eBay
The 12V battery in a Cayenne is under the driver's seat, which (I would expect, anyways) would be a good spot to protect it from extreme temperatures.
Some important facts about LiFePO4 batteries:
1) In ICE cars, which only use the battery for cranking and short term voltage stabilization, the useful element for a battery is cranking amps. Well, LiFePO4 is pretty good at this, so most batteries are rated "Ah equivalent" which is a marketing term covering up the fact that while they have the cranking amps needed, the actual energy stored is MUCH lower. It's common to see a Lithium battery saying it's the equivalent to a 50 AH car battery and it only has 12 actual AH. So you need to carefully choose.
The simple way around this? Weight. A LiFePO4 battery weighs 1LB per 90 WH. A Tesla battery is 33AH @ 12V, or 400WH. So if your battery doesn't weigh 6 LBS, it's not as big as the original 12V. And BTW, the stock battery is about 16 lbs. This battery should cost you at least $800 given current LiFePO4 prices.
2) Charge/discharge cycles in Lithium batteries are not total cycles. It's really about the total power in over the life. So you can charge 100% 1,000 times or 50% 2,000 times. But the smaller the battery, the more times you will cycle it. We know the tesla lets it discharge some and re-charge constantly as you are driving or not driving. A 30AH LiFePO4 can handle about 400KWh total energy over it's life. If you assume the vampire drain in the car all comes out of the 12V system, and vampire is 3 miles a day, that's 1 KWh a day, so a LiFePO4 might only last 400 days.
Use a smaller battery, like a $300 10AH battery? Might only last 150 days.
3) Seriously- Tesla is basically the world expert on Lithium batteries, and they used a lead acid in this application. You think you're a better engineer than they are? They could have thrown 40 18650 cells at this problem if it was that simple. There's a reason they went with a $60 Lead Acid in this application.