Replace car battery with LiFePO4?

[JWLV]

I've been reading about using a LiFePO4 battery in a car. Saw a few videos too. Most people say it's just fine.

Has anyone here actually done it?

What LiFePO4 battery did you use?
What model car did you put it in?
Can you take a picture of it and show us?

 

[dweick]

Sure, I did it in my Tesla Model 3, battery from Ohmmu. Take out lead acid, put in new battery no different than putting in a 12V lead acid car battery.

 

[Don B. Cilly]

You mean as a starter battery for an internal combustion engine?
The idea being, why use money when I can just throw it away?

 

[Texas-Mark]

Besides the cost, You would need a BMS capable of handling the cranking current.
Also the issue with cold weather charging.

 

[JWLV]

You mean as a starter battery for an internal combustion engine?
The idea being, why use money when I can just throw it away?

Yes, I am asking about replacing the starter battery for an internal combustion engine.

Perhaps I should have disclosed my reason for asking this question. I live in Las Vegas where the summer temperature is consistently 115+ F daily for 2 or 3 months. People in certain parts of Arizona, Texas, and New Mexico experience the same thing. This always kill SLA batteries. Whenever my car battery is nearing 2 or 3 years old, I know it will be time to replace it soon. With SLA batteries in the $125 - $150 range these days, a $400 LiFePO4 battery start to make a lot of sense. Especially knowing that you won’t have to go through the hassle of replacing the battery every 3 years or the possibility of getting stuck somewhere one night when the battery is dead.

 

[fratermus]

temperature is consistently 115+ F daily

I suspect this will clobber LiFePO4, too, only with a bigger hit to the wallet. Some LFP manufacturers specifically warn against using them for cranking.

 

[KTM-Guy]

Remember 115 degrees is the air temp. It gets a low hotter under the hood. My auto parts store says buy a cheap battery, buy the warranty, just before the warranty is up leave a dome light on till the battery is dead and bring it back for a replacement. You can get 4-6 years from the price of one battery. I’m in Phoenix.

I don’t do that. I just chalk it up to the price to pay to not shovel snow and buy a battery every few years. Actually today I am going to price batteries for one of our cars that the battery has died.

Also carry a jump pack, cheap insurance.

Todd

 

[rplarry]

Funny you should ask, I just built a starting battery for my 2020 Polaris rzr. I used 4 25ah lifepo4 cells and a 200 amp BMS, put it all into a box approximately the size of the stock battery in the rzr. Before I did the swap I checked the voltage of the system and with the lead acid battery the system voltage was 14.4 to 14.5 volts. I thought "perfect" so I installed the lifepo4 battery and it started the rzr just fine but the system voltage jumped to 14.9 to 15.0 volts which is too high. If the lifepo charges to that high a voltage the bms will shut it off so I'm not sure what to do now. Hopefully there is a simple way to drop the system voltage down to 14.2 to 14.4v.
Anyone have any ideas?
I was able to build the battery for about $150 and a good agm battery is about $225 but if I have to throw the lifepo away then not such a good investment.

 

[Bluedog225]

Been in Texas my whole life. Never noticed a problem with sealed lead acid batteries and the heat. They die every 5-7 years and get replaced. I‘ve assumed that was the normal service life.

 

[Supervstech]

Wallyworld batteries have a 3 year free replacement no questions asked warranty… and they are around $100 they have a 4 year agm line… around $200 not worth it to me…

 

[Texas-Mark]

I thought "perfect" so I installed the lifepo4 battery and it started the rzr just fine but the system voltage jumped to 14.9 to 15.0 volts which is too high. If the lifepo charges to that high a voltage the bms will shut it off....

Not sure why the system voltage would have gone so high unless the BMS cutoff had already kicked in, and there was no longer a battery load on the alternator.

 

[Hdonly]

Put a lifepo4 350cca motorcycle in my 1974 MGB. Works great. Here is a video.

 

[drwormy]

A hybrid supercapacitor / Li battery sounds perfect for your application. The supercaps do the starting. The Li battery just keeps it topped up (supercaps have a reasonable discharge rates).

A guy on YouTube has been running a supercapacitor only start 'battery'.

An off the shelf battery (not in the US though).

FPV-Power

FPV-Power

www.fpv-power.com.au

Putting the cap in the engine bay, battery outside would be a good solution.

 

[Substrate]

Many sla's in hot climes are even more prone to sulfation than normal and need additional charging believe it or not.

The is particularly seen in vehicular applications where they aren't driven regularly, or only taken for short trips of less than 10 minutes or so. By not being fully charged, the high heat advances hard sulfation.

So, if you can, consider a maintenance charger that you can open the hood and put on the battery as often or as convenient as possible.

BUT BUT - and this is big, especially in those high heat areas: The maintenance charger needs to be TEMPERATURE COMPENSATED (not just temperature protection shutdown), where the charge voltage is lowered as determined by the temp sensor.

One brand that comes with temp-sensors is Battery Minder (different than battery tender). Model 2012-agm comes to mind. No, it is not your $20 el cheapo at the parts store. But it might pay for itself if you place it on your battery as much as you can.

 

[MattiFin]

I've been reading about using a LiFePO4 battery in a car. Saw a few videos too. Most people say it's just fine.

Has anyone here actually done it?

What LiFePO4 battery did you use?
What model car did you put it in?
Can you take a picture of it and show us?

Lotus Elise toy car with exide ELTX20H motorcycle battery.
That thing is ridicuously small and lightweight(just like the car..) yet it cracks the 2.3L engine without any problem. Cold winter temps could be a problem but Lotus Elise is not really car for those days..

Easiest &cheapest 10kg weight reduction on sport/track car ever.

 

[bryn]

i Looked at changing over to a liFePo4 starter battery once my 3 year old AGM kicks the bucket

there are a few selling drop in cranking lithium battery’s here, it’s a great way to reduce weight if you need to meet GVM limits.

heat will reduce the lifespan, to what extent, is to be seen once more people use them.

I’m keen to make up a 105amp version, as I do draw 60amps out whith the DC-DC, only issue for me is that with regen braking on my camper can spike the voltage up to 15.5 volts for the stop/start battery.

cold Isn’t an issue here, that could be sorted with a heat pad , building a lithium drop in is about the same price as buying a good AGM.

The key is finding a BMS that i could program a cut off at 15.6 volts, I have no concern about cells hitting 3.9 volts for a very short period, they can handle that, but it isn’t ideal

 

[Supervstech]

i Looked at changing over to a liFePo4 starter battery once my 3 year old AGM kicks the bucket

there are a few selling drop in cranking lithium battery’s here, it’s a great way to reduce weight if you need to meet GVM limits.

heat will reduce the lifespan, to what extent, is to be seen once more people use them.

I’m keen to make up a 105amp version, as I do draw 60amps out whith the DC-DC, only issue for me is that with regen braking on my camper can spike the voltage up to 15.5 volts for the stop/start battery.

cold Isn’t an issue here, that could be sorted with a heat pad , building a lithium drop in is about the same price as buying a good AGM.

The key is finding a BMS that i could program a cut off at 15.6 volts, I have no concern about cells hitting 3.9 volts for a very short period, they can handle that, but it isn’t ideal

If your battery is in the engine compartment like many cars, the engine heat is far beyond what will kill a LFP… Mercedes uses a heat shield between the engine bay and the battery area on many of the diesels I drive. And many cars have the battery under the rear seat, or in the trunk. Those would be ideal for a drop in LFP. I use a small LFP in my 87 diesel wagon. The car has a voltage drain that KILLS FLA and AGM batteries. LFP just needs a little boost charge to bring the BMS up, and the car is good to go. So far it has not damaged the alternator I have in the car.
And I am WELL versed in replacing the alternator in that car if it does.

 

[Supervstech]

i Looked at changing over to a liFePo4 starter battery once my 3 year old AGM kicks the bucket

there are a few selling drop in cranking lithium battery’s here, it’s a great way to reduce weight if you need to meet GVM limits.

heat will reduce the lifespan, to what extent, is to be seen once more people use them.

I’m keen to make up a 105amp version, as I do draw 60amps out whith the DC-DC, only issue for me is that with regen braking on my camper can spike the voltage up to 15.5 volts for the stop/start battery.

cold Isn’t an issue here, that could be sorted with a heat pad , building a lithium drop in is about the same price as buying a good AGM.

The key is finding a BMS that i could program a cut off at 15.6 volts, I have no concern about cells hitting 3.9 volts for a very short period, they can handle that, but it isn’t ideal

I’ve never heard of regen braking on a camper…

That sounds awesome. How is it accomplished? Are there wheel motors in the trailer? What drives the regen? Tag me if you make a thread on the subject please!

Or do you mean… you tow with an ev, and regen charges the starting battery? Interesting…

 

[bryn]

If your battery is in the engine compartment like many cars, the engine heat is far beyond what will kill a LFP… Mercedes uses a heat shield between the engine bay and the battery area on many of the diesels I drive. And many cars have the battery under the rear seat, or in the trunk. Those would be ideal for a drop in LFP. I use a small LFP in my 87 diesel wagon. The car has a voltage drain that KILLS FLA and AGM batteries. LFP just needs a little boost charge to bring the BMS up, and the car is good to go. So far it has not damaged the alternator I have in the car.
And I am WELL versed in replacing the alternator in that car if it does.

My VW diesel also has the heat shield, ive noticed it does make a difference, also there is a battery company here that sells heat shield covers for batteries.

the VW T6 transporters also have a small parasitic drain, if you leave it for a few weeks, it struggles, i should point out that these are a start/stop set up, so by default the battery only charges to 80% under the car canbus system

I do have a Votronic Triple DC-DC charger that also charges the starter battery, so the solar tends to it while im not using it.

Replacing an alternator is a simple fix, not hard to do in this van

 

[bryn]

I’ve never heard of regen braking on a camper…

That sounds awesome. How is it accomplished? Are there wheel motors in the trailer? What drives the regen? Tag me if you make a thread on the subject please!

Or do you mean… you tow with an ev, and regen charges the starting battery? Interesting…

The campervan is a T6 VW, they have a stop/start system that uses regen braking to quickly charge the starter battery to reduce load on the alternator and engine, a stupid emission solution to reduce pollution, in my view the stop start is dangerous in this vehicle, but i can manually switch it off as this is an option in this van from factory.

i have nothing against reducing pollution, its just that i don't think this was the best solution

I haven't looked too much into it on the vans computer interface, but i'm sure i can do a long code to sort out the voltage issue, with the new model T6, you have to code in a new battery if you replace it.