12V battery replacement

[Maxx]

$160 for a 12v 50ah LFP battery (will it fit?), been using one in my work van to run a compressor, 4 of them power my riding lawnmower that were switched from AGM. Brought the machine to life compared but that's another story. Then I have a boat load more I run my house with when needed, that's a 51.2v system. All LFP batteries have an internal BMS.

Also have a Li battery in my motorcycle since 2012 and still cranks the bike like new. If I can make it fit, I'm pretty sure it will, I'm replacing with the 50ah and never worry about it again, they carry a 10 year warranty.

If you do use it and nothing blows up, let us know what exactly you used.

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[RLXXI]

If you do use it and nothing blows up, let us know what exactly you used.

Not worried one bit, they don't explode like traditional li batteries can and have in the past. I keep 43kWh worth in my attached garage I power my home with when needed. Here's the current battery I will use when the time comes, and it will, unless they come out with something even better. I know batteries all too well. Nothing special about Absorbed Glass Mat batteries, it's still a lead acid battery with those mats between the plates, that's it.

The LFP batteries don't care if you run them flat and you can't over charge them due to the built in BMS. My only concern is space, I haven't poked around in the battery cavity to see if it will or not. There are other brand LFP batteries made likely using the same exact brand of cell and in different size configurations.

 

[Maxx]

Not worried one bit, they don't explode like traditional li batteries can and have in the past. I keep 43kWh worth in my attached garage I power my home with when needed. Here's the current battery I will use when the time comes, and it will, unless they come out with something even better. I know batteries all too well. Nothing special about Absorbed Glass Mat batteries, it's still a lead acid battery with those mats between the plates, that's it.

The LFP batteries don't care if you run them flat and you can't over charge them due to the built in BMS. My only concern is space, I haven't poked around in the battery cavity to see if it will or not. There are other brand LFP batteries made likely using the same exact brand of cell and in different size configurations.

I didn't mean the battery physically blowing up. I meant Lightning BMS getting confused about when to charge the battery, how often and at what voltage.

Frankly I am surprised Ford didn't at least have the option for Li-Ion since they built the Lightning after Tesla had already switched to Li-Ion 12V. 98 KWh of of Li-Ion in it's belly and cheeping out on a small important one up front makes no sense.

Thanks for sharing the details. Let us know if you find out anything new about how Lightning talks to this battery vs the old one.

 

[El Duderino]

Some context might help provide color to this conversation.

Looking at individual cells nominal and 12v cells in series voltages can help explain how different or similar a lead acid, lithium iron phosphate, and lithium ion batteries are.

Nominal cell voltages:

Lead acid = 2.1 v
Lfp = 3.2 v
Lithium ion = 3.6 v

Nominal voltages of cells in series to fit a 12 volt battery application:

Lead acid (6) cells = 12.6 v
Lfp (4) cells = 12.8 v
Li (4) cells = 14.4 v

So lithium ion is quite a bit different than lead acid. But Lfp is pretty close to lead acid when comparing the whole battery voltage in series.

Without getting into the specifics of Ford's lead acid charging algorithm, you can at least see how a 12v Lfp battery charged with a 12v Lead acid charging setup would be close enough to not necessitate changes to charging voltages.

This post isn't the whole enchilada per se, but I am trying to illustrate that lithium iron phosphate 12v batteries aren't radically different than your standard lead acid 12v battery we have all known forever. The guts are different, cell balancing is more important in Lfp, but 12.6v vs 12.8v nominal is only 1.6% difference in amount...

 

[Maquis]

Interesting. I haven’t seen a cutaway. Thanks.
I think then I’ll stick to replacing my AGMs every few years.

Basically run of the mill cells and a circuit board held in place with spray foam.

 

[Robert1380]

Basically run of the mill cells and a circuit board held in place with spray foam.

So those Ohhmu batteries aren’t any good?

 

[SpaceEVDriver]

Basically run of the mill cells and a circuit board held in place with spray foam.

No hard mount on that circuit board!? It would jar loose in the first week of owning it with my road and the use I put my truck through. Nothing to stop the circuit board from contacting the terminals.

You couldn’t pay me to put that in my truck.

 

[RLXXI]

Basically run of the mill cells and a circuit board held in place with spray foam.

Damn that's some shoddy construction right there.

 

[johnnyonetime]

No hard mount on that circuit board!? It would jar loose in the first week of owning it with my road and the use I put my truck through. Nothing to stop the circuit board from contacting the terminals.

You couldn’t pay me to put that in my truck.

Not worried at all, 50k miles and 2 years later it still works every time I push the button!

 

[SpaceEVDriver]

Not worried at all, 50k miles and 2 years later it still works every time I push the button!

I am truly happy for you that it hasn't caused any problems for you.

I'll still keep using the AGM until there's a better solution that I trust.

 

[Maxx]

Some context might help provide color to this conversation.

Looking at individual cells nominal and 12v cells in series voltages can help explain how different or similar a lead acid, lithium iron phosphate, and lithium ion batteries are.

Nominal cell voltages:

Lead acid = 2.1 v
Lfp = 3.2 v
Lithium ion = 3.6 v

Nominal voltages of cells in series to fit a 12 volt battery application:

Lead acid (6) cells = 12.6 v
Lfp (4) cells = 12.8 v
Li (4) cells = 14.4 v

So lithium ion is quite a bit different than lead acid. But Lfp is pretty close to lead acid when comparing the whole battery voltage in series.

Without getting into the specifics of Ford's lead acid charging algorithm, you can at least see how a 12v Lfp battery charged with a 12v Lead acid charging setup would be close enough to not necessitate changes to charging voltages.

This post isn't the whole enchilada per se, but I am trying to illustrate that lithium iron phosphate 12v batteries aren't radically different than your standard lead acid 12v battery we have all known forever. The guts are different, cell balancing is more important in Lfp, but 12.6v vs 12.8v nominal is only 1.6% difference in amount...

‘Thanks for a very informative post. It would be nice if @johnnyonetime could measure the voltage at battery terminal with negative before and after BMS. When the truck has been off for a while and when it is on and share the results so we can compare with our original batteries connected.

No hard mount on that circuit board!?

In the company video, internals don’t look that bad. The board seems to be screwed in. Not sure if this is a newer version or a different model. With all the Chinese (I assume) written on the cover, it may even get more expensive than $500. Their Sodium batteries are $100 less expensive.

Min: 6:58

 

[SpaceEVDriver]

Hmmm. Maybe they’ve improved over the past few years. Dunno.

I do know that I wouldn’t do a direct replacement of an AGM with a Lithium battery without some kind of system in between to convince the Ford BMS that it’s got the right battery. The charge curves are so different and with the very flat charge curve of the lithium battery, the voltage level of the lithium will make it appear that it’s almost full when it’s almost empty. Maybe the Ford BMS is smart enough to only care about counting coulombs and doesn’t ever lose track or need to measure voltage, but I’m doubtful. I’d be happy to be wrong.

(Yes, the y-axis is scaled to 58 volts—that’s irrelevant for the shape of the curve. Each cell has the same shape).

 

[Lytning]

I bought and installed in my Lightning an Ohmmu Li-H3-BH (LFP) 12 Volt Battery two weeks ago, based upon positive user comments on this forum. I just returned from a 25 mile errand trip. Ohmmu 12 volt SOC, easily accessible in the Ohmmu app, is at 100%.

Among several reasons for rewarding Ohmmu with my purchase, them delivering an easily accessible 12 volt battery SOC was near the top of my list ... something that @Ford Motor Company would not do in over 3 years.

Now, if Ohmmu sold BlueCruise 1.4 ...

 

[chl]

All LFP batteries have an internal BMS.

Since they are being used to swap with conventional or AGM lead acid batteries it makes sense they would include the BMS as a component, for safety and longevity, by balancing the cells.

They'd still need to be designed to match the charge curve of the thing they are put in or used with to, have optimum performance and longevity I'd think.

Years ago when my battery powered lawn mower's batteries died for the second time (24V lead acid pair in a Ryobi 48V mower RY14110) I bought a pair of 22V LiPo batteries (Turnigy 5000mAh 6S 40C Lipo) and a pair of chargers (SKYRC IMAX B6AC V2 Professional Balance Charger/Discharger).

Balance charging before mowing (about 45 min) and balance discharging after for storage until next mowing, is time consuming and the LiPo batteries have to be charged/dicharged and stored in fire-proof-ish containers, just in case.

Unlike a vehicle, the mower itself doesn't have a charger built in, but the SKYRC's will work with Lithium Iron Phosphate batteries and several other types.

The problem is 24V LFP batteries are larger and more expensive than the LiPo I have, and I'd need two x 24V or four x 12V LFPs, which would cost more than a new inexpensive mower (SunJoe for example) which is all I need.

I have been slowly eliminating the monoculture lawn for low maintenance ground cover anyway.

If it comes to fruition, I imagine the CATL sodium ion battery could make other Li batteries obsolete, and be a big boon for solar as well as EVs and general battery use.

Hopefully tariffs on China will be gone by then.

 

[chl]

Some context might help provide color to this conversation.

Looking at individual cells nominal and 12v cells in series voltages can help explain how different or similar a lead acid, lithium iron phosphate, and lithium ion batteries are.

Nominal cell voltages:

Lead acid = 2.1 v
Lfp = 3.2 v
Lithium ion = 3.6 v

Nominal voltages of cells in series to fit a 12 volt battery application:

Lead acid (6) cells = 12.6 v
Lfp (4) cells = 12.8 v
Li (4) cells = 14.4 v

So lithium ion is quite a bit different than lead acid. But Lfp is pretty close to lead acid when comparing the whole battery voltage in series.

Without getting into the specifics of Ford's lead acid charging algorithm, you can at least see how a 12v Lfp battery charged with a 12v Lead acid charging setup would be close enough to not necessitate changes to charging voltages.

This post isn't the whole enchilada per se, but I am trying to illustrate that lithium iron phosphate 12v batteries aren't radically different than your standard lead acid 12v battery we have all known forever. The guts are different, cell balancing is more important in Lfp, but 12.6v vs 12.8v nominal is only 1.6% difference in amount...

The Ford AGM battery may have a different terminal voltage than the 12.6V though.

And the critical factor is really the charging current/voltage curve difference, which is why the BMS is so important for the LFP.

An AGM-compatible battery charger sends more amps into a lead-acid battery while keeping the voltage less than 14-15 volts. AGM chargers go through the three charging phases (bulk, absorption and float) just like a regular charger. However, a regular charger could exceed 17 volts when charging a battery.

Which is why you need a charger compatible with an AGM battery - most newer ones seem to be.

If kept on an AGM battery maintainer, the Ford AGM should last longer than a normal lead acid battery, the problem has been the Lightning didn't keep the AGM fully charged and would let it fall below 50% which is a no-no for AGMs.

In case anyone wants to do that with their Lightning, hook the maintainer up to the jump terminals under the top panel on the passenger side of the Frunk, or to the proper terminals inside the battery compartment (the blue circles not the red X's):

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