Lifepo4 battery 12v replacement?

  • Thread starter Thread starter BriKo
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BriKo said:
Found this battery that seems like a deal.
https://www.renogy.com/lithium-iron-phosphate-battery-12-volt-50-ah/
If this can still start the car at 0 degrees farenheit I'd get it.
Has anyone sucessfully used a Lifepo4 battery or lithium such as this?
https://antigravitybatteries.com/products/starter-batteries/automotive/rs-30/

My battery is looking like it's not going to last the year. it's 3.5 years old now.
Click to expand...
The charging parameters don't match the Kona EV charging system. ~13.5V (YMMV) run mode, and as high as 14.8 V utility mode- above the charge cut off voltage.
I will add this post referring to a similar Life-po4 type change.
Temperature parameters look pretty restricted as well.
I would read thru the posts I referred to in your first post (repair issues and fixes).
 
Last edited:
BriKo said:
Found this battery that seems like a deal.
https://www.renogy.com/lithium-iron-phosphate-battery-12-volt-50-ah/
If this can still start the car at 0 degrees farenheit I'd get it.
Has anyone sucessfully used a Lifepo4 battery or lithium such as this?
https://antigravitybatteries.com/products/starter-batteries/automotive/rs-30/

My battery is looking like it's not going to last the year. it's 3.5 years old now.
Click to expand...

Check this one out
https://dakotalithium.com/product/d...r-starter-deep-cycle-lifepo4-battery-1000cca/
 
I was planning to replace mine with lifepo4 but the old battery beat me to it. It failed at 39500kms and 22 months, just inside the warranty (according to the dealer) of 40K and 2 years, so it was replaced (with lead-acid) at no cost to me. The old one luckily had failed at home, and a quick boost got the car going.
It happened a couple more times, but forewarned is forearmed and I had my trusty booster on board, so it was not a problem.
At home, I turned on the parking lights and it only lasted 10mins before going completely flat. The dealer confirmed the failure with his fancy equipment, but it seems in the process he damaged my BM2 monitor, which I had left connected (mistake!) However, I'm not complaining about a new 12v battery.
The new battery came from Austria!!?? Don't they make batteries in Nth America!?
If this had not happened, I would have changed to lifepo4, which would probably outlast the car, but it is a more expensive option. I'm fairly sure I've seen them with a BMS bypass switch, so if the bms stops the battery discharging, it only takes a button-push to get emergency power.
 
My replacement 12v battery is a part# 5140RMF 445CCA 76RC made by East Penn Manufacturing, PA, but built in Austria. They also applied the VCULDC control logic improvement, which seems to have a more aggressive charging profile, still maxing out at 14.7v. Subject to the inherent limitations of a lead-acid battery, I'm very happy with the warranty fix. Time will tell.
LiFePO4 is clearly a superior technology, but is also subject to a few serious limitations that are still being worked out in the marketplace. About double the cost, dependent on electronic control, chopped output at low voltage. I have a fair amount of experience with Li batteries: 2 electric cars, 4 electric bikes, electric outboard, 2 motorcycles with Li batteries, and a workbench littered with associated bits and pieces. I have had the dubious pleasure of falling out of a canoe into salt water, and destroying my $500 battery. If it was lead-acid, it would have been fine, but the salt water on the Li bms destroyed it.:-(
Something I learned today: "Reserve Capacity" unit is minutes, not AH.
 
I thought LiFePO4 battery chemistry doesn't permit charging below freezing, so for this to operate normally in a car, you'd need to get a heated battery. (In addition to the problem of the cars charge controller not having the correct charge parameters for a LiFePO4 battery)
 
What about this battery? They make batteries to fit the Kona and many other cars.
The site looks a little hokey, but if they honor their warranty it's not a terrible price.
I'd think you could have a temperature and voltage activated heater pad.
I'll ask lithium moto how they charge at low temps.
https://www.lithiummoto.com/tesla-12v-battery
 
"Hokey" is right, lol! I wish they were a bit more clever about understanding that "lithium" is not lithium-ion. It normally means lithium-metal which is a "primary" cell, meaning not rechargeable. Those are the ones that can bring down freight aircraft when they fail and are normally considered dangerous goods.

A few years back I worked in a team designing animal tracking collars for researchers. We used mainly lithium-metal cells because they have the highest energy density and work over a wide range of temperatures. Lithium-ion on the other hand starts to lose performance over 0°C downwards to -30. What helped us is that many animals hate being cold and keep their collar warm under their neck.
 
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