Sourcing LiFePO4 pack

James28

Finding my (electric) wheels
Feb 2, 2022
24
12
Hi i'm new here and have been wanting to build an ebike for a long time. I found a wheelset with a bafang 250w motor for a bargin price but i'm struggling to find a battery.

I understand the weight penalty of LiFePO4 over Li-ion and i'm willing to accept the for the longer pack life and saftey. Plus I only need a 36v 10ah pack as my commute relativley flat and only 8 miles per day.

So far I have these options.

I can buy this and build a case for it.


Build these into a 12s2p pack.


Or build these into a 12s1p


I'm an engineer and feel more than competent enough to build a pack but would rather avoid it due to extra expense with tooling and materials.

After weeks of searching I cant find any other options than what i have now. I"m quite happy to pay for quality but i cant seem to find anything reputble so would apprieciate anythng you guys can suggest. Thanks
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,855
1,342
Hi i'm new here and have been wanting to build an ebike for a long time. I found a wheelset with a bafang 250w motor for a bargin price but i'm struggling to find a battery.

I understand the weight penalty of LiFePO4 over Li-ion and i'm willing to accept the for the longer pack life and saftey. Plus I only need a 36v 10ah pack as my commute relativley flat and only 8 miles per day.

So far I have these options.

I can buy this and build a case for it.


Build these into a 12s2p pack.


Or build these into a 12s1p


I'm an engineer and feel more than competent enough to build a pack but would rather avoid it due to extra expense with tooling and materials.

After weeks of searching I cant find any other options than what i have now. I"m quite happy to pay for quality but i cant seem to find anything reputble so would apprieciate anythng you guys can suggest. Thanks
From the first metre of riding my ebike I realised I was onto something, and immediately possibilities sprang to mind that I would never have thought possible before.

Key to getting the most out of it are minimum weight and maximum range.

So I would treat the difficulty of finding what you would prefer as a signal that there is not a sufficiently strong market perception of the need to provide it, and take advantage of the lighter weight or greater capacity for same weight of lithium ion, and address safety by choosing a quality product from a reputable source, and looking after it well.
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
2,047
757
61
Devon
I think you will struggle to find a ready built pack of known brand cells due to the fact that LiFePO4 cells are considered rather old tech in the ebike world. Headway was a brand back in the day, which had screw terminals, so self build was an easy option, still available from BMS batteries, but may have been on the shelf a few years. As another option, It might be worth speaking to Jimmy at ebikebatteries. He has 12Ah Li-NMC pouch cells, which have a 2000 charge cycle life. He should be able to assemble these into a pack for you.
You could of course go with the flow and buy a decent, high capacity Li-ion pack which with your short commute would prob. only need charging once a week and therefore extending it's life span.
 
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James28

Finding my (electric) wheels
Feb 2, 2022
24
12
Thank you for the response, as far as using the bike for anything apart from my commute is unlikely, i live in a rural area and everywhere else i go is a 30min drive on a roads.

Im quite happy with old tech, it worked then and from what i've seen is still working today for people.

The saftey aspect is my biggiset priority. I ive in a top floor flat and have no garage or out house to store a battery and i've seen enough about lithium fires. I apprieciate its a low risk and can be minimized further but if they do fail its catastrophic.

I think i will go down the diy route with some LiFePO4 cells, I will order what i need plus a few extras and test each cell properly before i assemble them.

thank you
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,855
1,342
Thank you for the response, as far as using the bike for anything apart from my commute is unlikely, i live in a rural area and everywhere else i go is a 30min drive on a roads.

Im quite happy with old tech, it worked then and from what i've seen is still working today for people.

The saftey aspect is my biggiset priority. I ive in a top floor flat and have no garage or out house to store a battery and i've seen enough about lithium fires. I apprieciate its a low risk and can be minimized further but if they do fail its catastrophic.

I think i will go down the diy route with some LiFePO4 cells, I will order what i need plus a few extras and test each cell properly before i assemble them.

thank you
Your experience will be useful to others, let us know how you get on.