Making your own LFP battery

The photo shows a 12V LFP battery made of 4 cells stapped together. It is designed to serve as a backup battery for starting car in cold winter weather.

Replacing OPTIMA Yellow 65AH with 60Ah Winston LP12V60AH

The Chrysler Voyager (now Lancia Voyager) has the Optima Yellow 65AH starting battery. We have made replacement with Winston LP12V 60AH model.  The Optimal lead-acid has 28 kg. The Winston lithium battery has 12 kg. In cold weather, you can see the difference in starting the car immediatelly.

I want to replace the lead acid 12V 100Ah stating battery. Which LFP model can I use?

Answer: The performance of the LFP batteries concerning the starting current is excelling the performance of the SLA (lead-acid) batteries. Our tests and the tests of our customers show that the LP12V 40Ah battery can replace any SLA starting battery (even the 100AH, or 150 Ah models). Even big diesel machines can be started from the LFP battery at very cold weather.

For long term use and massive deployment, we suggest to make testing for each application to make sure that the replacement LFP battery will work properly for long time.

Using LiFePO4 batteries as starting batteries for the fuel cars

See the real-life demonstration of the LiFePO4 battery used for starting a car in -17 deg.C cold winter weather.

Please check more details about using LiFePO4 (LiFeYPO4) for starting your car in winter.

Lead Acid vs Lithium Iron! Guess Who Wins!

Please check the comparison datasheet with useful information on lead-acid batteries versus the LiFePO4.

Say Good-bye to the Lead-Acid Starting batteries!

Get your 12V lithium iron starting battery now. Please check our quote.

Q: How will the LiFePO4 battery be affected by the charging system of the car? 

A:  The 12V LiFePO4 battery is not affected by the charging system at all. Majority of the cars’ charging systems charge up to 14V or 14.4V.  This represents the charging level of 70% to 75% for the LFP batteries.

Q: Will the car charging system overcharge the LFP battery and shorten its life?

A: No. The overcharge for LFP battery is above 17V. There is no way to reach this voltage in the vehicle. As the LFP battery has no memory effect, it can be charged any time to any capacity. There is no shortening of the life-span when using as a starting battery.

Q: What is the starting time for the fuel engine when using 12V LiFePO4 battery?

A: The starting time for any fuel engine is given by the vehicle manufacturer. Usually it is about 5 to 10 seconds. This time is the same for LFP battery.  In any case, the fuel engine should not be started with long starting attempts. Please see the vehicle instruction for starting the engine.

Q:  What is the max current available from the 12V LFP battery?

A: The 12V LiFePO4 battery can release the energy very quickly without any limitation. The peak short connection current may reach above 1000A.  Unlike lead-acid batteries that are limited by the Peukert’s law (http://en.wikipedia.org/wiki/Peukert’s_law), the LFP batteries do not have any such limitation. However due to the high energy release, the LFP batteries should not be extremely discharged for longer than 10 seconds.

The discharge table for 12V 40Ah LP  LiFePO4 battery

20 A current   - min. 120 minute use (2 hours)
40 A current   - min. 60 minute use (1 hour)
60 A current   - min. 40 minute use

200 A - max 10 s. peaks  - approx 70 times (70*10s = 700 s. ~ 12 minutes)
400 A - max 10 s. peaks  - approx 35 times (35*10s = 350 s. ~ 6 minutes)
1000 A - max  5 s. peaks - approx 18 times (18*5s =  90 s ~ 1.5 minute)

FAQ: Using LiFePO4 batteries as starting batteries for the fuel cars

Q: Can the 12V LFP/LFYP batteries be used as starting batteries for the regular vehicles?

A:  Yes. We highly recommend using the LFP/LFYP batteries for starting vehicles. Their performance is much better than the lead-acid batteries.

Q: What are the advantages of the LFP/LFYP batteries?

A:  LiFePO4 batteries are able to provide much higher starting current than the lead-acid batteries (SLA). They work even in extreme low temperatures (bellow –35 deg. C).  They cannot “get frozen” like SLA batteries. They contain no acids and require no special care. Their life span is 10 years and more, while SLA batteries may last just 4 to 5 years.   There are no known disadvantages when using LFP/LFYP batteries.

Q: Which battery model is sufficient to start a normal gasoline car?  

A:  LP 12V 40Ah is sufficient for any range of starting batteries up to 65 Ah of the original lead acid value. For vehicles with larger battery we recommend LP12V 100Ah.  For trucks and machinery (using 24V system) we recommend 2 pcs of LP12V 100Ah connected in serial. For campers, mobile homes and other vehicles with large battery we suggest to use 12V 200Ah, by connecting two 100Ah batteries in parallel.

Q: What are the limitations when using the 12V LFP/LFYP batteries in cold winter season?

A: There are no limitations.  The 12V LiFePO4 batteries perform very well under low temperatures. We highly recommend to replace the SLA battery with LFP especially if your vehicle is parked out-side and gets very cold.  The 12V LFP/LFYP batteries are ideal for countries like Canada, Scandinavian lands, Russia – Siberia,  and other cold regions.