Li-ion or LiFePO4?
- Thread starter bigb
- Start date
fauconnier
Active Member
- Region
- Canada
All the Specialized models I saw on EBR reviews are lithium-ion.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
Li-Ion.
Wallykl
Member
- Region
- USA
Resurrecting this thread—I notice now that LiFePO4 has dropped some in price—and the amp-hrs would provide some incredible range. Right now I can get 70 mi on my 52V, 20 amp hour with my style of riding. It might be nice to consider a single battery that can offer 3-4x my current range and just accept the weight gain.
Has anyone switched their ride to these batteries? If so, what were the obstacles?
Has anyone switched their ride to these batteries? If so, what were the obstacles?
Chazmo
fat-tire biker
- Region
- USA
- City
- Central Massachusetts
@Wallykl Some interesting replies here:
forums.electricbikereview.com
LiFePo4 tech?
So… When I asked about solid state a while back I got crickets. I wonder if anyone will chime in here regarding LiFePo4: I’ve been reading up on lithium iron phosphate (LiFePo4). This technology seems far less prone to fire danger than current lithium ion batteries. I know a guy who built a...
forums.electricbikereview.com
gromike
Well-Known Member
- Region
- USA
- City
- City of Dreams
LFP batteries are bigger and heavier for the same power rating as LI-ion. Their power density has been going up, but so has Li-ion.
As a battery designer, one would need to balance all of the parameters.
Myself, I recently bought some 18650 battery cells and they are 3500mah, almost twice the power of previous 18650 cells. To me, that is an incredible amount of power in a small package.
As a battery designer, one would need to balance all of the parameters.
Myself, I recently bought some 18650 battery cells and they are 3500mah, almost twice the power of previous 18650 cells. To me, that is an incredible amount of power in a small package.
harryS
Well-Known Member
I think it's mainly a space/packaging problem. Existing popular battery cases can't hold enough LiFEPO4 cells of similar size to maintain the same voltage and AH.
For example, Wallyki's 52V20AH could be built with 56 21700 5Ah cells. A somewhat larger 26650 4AH LiFE cell is available and I believe 85 cells is required for 20AH. Won't fit, Reduce this to 16AH and 68 cells are needed. Won't fit. You have to go down to a 12AH battery using 51 cells,
For example, Wallyki's 52V20AH could be built with 56 21700 5Ah cells. A somewhat larger 26650 4AH LiFE cell is available and I believe 85 cells is required for 20AH. Won't fit, Reduce this to 16AH and 68 cells are needed. Won't fit. You have to go down to a 12AH battery using 51 cells,
gromike
Well-Known Member
- Region
- USA
- City
- City of Dreams
LFP cells have a lower voltage than Li-ion, so you need more in series to get your nominal voltage.
I have many surplused A123 LFP cells. 50 amp current rating per cell but only 2500mah per cell. They make great batteries, if you don't mind the size or weight.
I have many surplused A123 LFP cells. 50 amp current rating per cell but only 2500mah per cell. They make great batteries, if you don't mind the size or weight.
Wallykl
Member
- Region
- USA
Thank you for some interesting input. Definitely some issues for me to consider.
My starting premise .... let's say I want to head out for a several day trip, guaranteed a 150 mile range minimum with no charging options overnight. With my current setup, it would require me to carry at least 1- maybe 2 spare Li-ion batteries. By the time I make room for that extra space and weight (let's assume 3 batteries total on the bike), it seems that a single LFP battery might start looking attractive? Especially when faced with the task of recharging 1 vs 3 when electric available.
It would seem a problem though, to have that kind of weight, high over a rear tire on a rear rack? A person would almost need to devise a system for carrying it in a pannier rig of some type, off the front or back---and then try to counterbalance the load in the other bags?
But in the end, just carrying 2 spare Li-ion batteries, each in a pannier--ends up near the same price and less overall hassle.
Thx again for your thoughts
My starting premise .... let's say I want to head out for a several day trip, guaranteed a 150 mile range minimum with no charging options overnight. With my current setup, it would require me to carry at least 1- maybe 2 spare Li-ion batteries. By the time I make room for that extra space and weight (let's assume 3 batteries total on the bike), it seems that a single LFP battery might start looking attractive? Especially when faced with the task of recharging 1 vs 3 when electric available.
It would seem a problem though, to have that kind of weight, high over a rear tire on a rear rack? A person would almost need to devise a system for carrying it in a pannier rig of some type, off the front or back---and then try to counterbalance the load in the other bags?
But in the end, just carrying 2 spare Li-ion batteries, each in a pannier--ends up near the same price and less overall hassle.
Thx again for your thoughts
harryS
Well-Known Member
A competent hobbyist could build a 16x2 battery out of these $4 Life cells with careful soldering. That would be 51.2V fully charged and 30AH on paper. One cell is 268g, so it's about 16 pounds per side. I would consider two stand-alone 2x8 cell packs, each with its own BMS, for each side of a stout pannier bag. Run on a single battery for touring and swap over as needed.
I am more interested in lightweight ebikes with small batteries, or I would do one for the science.
I am more interested in lightweight ebikes with small batteries, or I would do one for the science.
