LiFePO4 vs. NMC Chemistry

[Ronno6]

Bigbattery.com has this setup: 48V BDGR KIT GEN-2 - NMC - 86Ah - 4.2kWh
For a fair bit less than their 48v HSKY, which in LiFePO4 and 105ah.

What are the pros/cons of NMC vs. LiFePO4 ?

The HSKY would be tricky to fit in my 98 DS, but the 2 batt setup would be much simpler.

[Pat911]

I’m generalising here…..

LiFePO4 has a higher cycle life compared to NMC
LiFePO4 is safer than NMC when abused
LiFePO4 can handle accidental over voltage better (not recommended though)
LiFePO4 has better thermal stability
NMC has higher discharge currents
NMC has a higher energy density (lighter for comparable Ah rating)

LiFePO4 is more expensive for a reason
Having said that, I’m using NMC in both my carts.

Cheers
Pat.

[WC53]

They are both topping out at 130a continuous if that works for your application. There is some discussion of Big Battery over at diysolar

[Ronno6]

Originally Posted by WC53

They are both topping out at 130a continuous if that works for your application. There is some discussion of Big Battery over at diysolar

My cart is a stock 1998 club car DS.
I have no idea what max amp draw would be.
How many amps will my Duracel 8v 165ah FLA batteries flow??

[Volt_Ampere]

I have two carts running NMC (Leaf modules). I prefer this chemistry for my use - your results may vary. Another "feature" of NMC is that you can pretty accurately predict SOC from the terminal voltage. My cart has a SOC readout that is probably good to 5%. I used the published discharge curve for my cells to program a table lookup SOC that I use to determine when to charge. I also have an odometer on my cart and I know from experience that I can play three rounds of golf including driving to and from the course and still have 25% SOC.
I have used LiFeP04 cells in other applications and it is near impossible to measure SOC based on cell voltage. To measure SOC with these cells, you need to use a much more complex method like "coulomb counting". Doing the accurately in a golf cart with the pulsed current loads requires tricky circuit design.

[Volt_Ampere]

130Amp continuous is probably ok if your cart isn't lifted with large tires. My cart cruises at 20mph pulling about 70 amps. My peak current is set to limit at 300 amps by my Alltrax controller. I have never measured my run current climbing any significant hills - we don't really do that here.

[Tom47]

Originally Posted by Ronno6

Bigbattery.com has this setup: 48V BDGR KIT GEN-2 - NMC - 86Ah - 4.2kWh
For a fair bit less than their 48v HSKY, which in LiFePO4 and 105ah.

What are the pros/cons of NMC vs. LiFePO4 ?

The HSKY would be tricky to fit in my 98 DS, but the 2 batt setup would be much simpler.

Ronno, I commented in an earlier thread that the 48V BDGR KIT GEN-2 would not fit in our DS carts. I'm not sure but I believe this mounting sketch that I drew would work. The individual packs would mount with the voltage readouts facing each other.

Unless the angle towards the front of the cart is raised 2", the packs would sit at a 12 degree angle. I'm not sure if that is okay or not. This would leave a lot of room for relocating the controller and solenoid, voltage reducer, fuse blocks, etc.

[Ronno6]

Originally Posted by Tom47

Ronno, I commented in an earlier thread that the 48V BDGR KIT GEN-2 would not fit in our DS carts. I'm not sure but I believe this mounting sketch that I drew would work. The individual packs would mount with the voltage readouts facing each other.

Unless the angle towards the front of the cart is raised 2", the packs would sit at a 12 degree angle. I'm not sure if that is okay or not. This would leave a lot of room for relocating the controller and solenoid, voltage reducer, fuse blocks, etc.

Thanks, Mr. Tom. Big Battey told me that the batteries can be mounted in any position other than standing on their heads.......
That being said, laying on their sides and at the angle of the frame rails would be fine; or I think your mounting frame would do the trick. I will have to check, but I believe there is more than adequate room beneath the seat to level the batteries to the highest point of contact with the frame.

What batteries are you running?

According to BB.com the LiFePO4 battery should last 2x as long as the NMC.... that could be a game changer...

[Tom47]

Originally Posted by Ronno6

Thanks, Mr. Tom. Big Battey told me that the batteries can be mounted in any position other than standing on their heads.......
That being said, laying on their sides and at the angle of the frame rails would be fine; or I think your mounting frame would do the trick. I will have to check, but I believe there is more than adequate room beneath the seat to level the batteries to the highest point of contact with the frame.

What batteries are you running?

According to BB.com the LiFePO4 battery should last 2x as long as the NMC.... that could be a game changer...

Well....right now I'm running some very strong, will not die, 8-1/2 year old Crown Cr-165's.

I've been waiting three years for them to go. During the wait I have learned a lot and watched the lithium progress.

I'm still leaning toward the ECO Battery for easy cart fitment and single battery, single BMS which many say is the best way to go. Whether that is ECO or some other compact one, I'm not sure.

Again, I can get Trojan T875's for $892 out the door, 20 miles away, in stock every day. So I'm still on the fence.

Good luck with your choice and setup!

[Ronno6]

ECO 48V batteries are sold out....72ah and 105ah.....