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I am trying to build my own e-moped for university in Hawaii and I am in need of some advise for the right pack. I currently have two orders awaiting payment on alibaba. They are both 48v 50ah and I have requested that each battery can safely pull 70A.

What the suppliers are claiming: Both suppliers claim that my custom battery pack will have a 70A BMS and will safely discharge 70A without damaging the pack. I'm unsure about this claim because that is a lot of power for 48v lithium and LiFePO4 batteries!

Size of each pack (50ah): Lithium: 370x136x170mm Lifepo4: 380×170×105mm

Price (🇨🇦): Lithium: $1150 Lifepo4: $909

What do you guys think I should choose? My bike will bull about 65A constant at max speed.

TIA for helping me out, I greatly appreciate it and whatever decision I make I will be sure to update you guys on how good Alibaba battery packs are :)

Cheers!

EDIT

**I went for a lifepo4 battery. I confirmed all the information above with more suppliers and it seems as though they can produce the battery to spec.

Why did I choose a lifepo4 battery? Well, I went for lifespan (very long compared to 'average' lithium) and the fact that the VOLTAGE SOMEWHAT REMAINS THE SAME for MOST of the discharge cycle. However, the voltage does decrease rather quickly when it does reach a certain point. So, That means great performance for the whole ride with the cost of an inaccurate battery capacity monitor!**

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  • \$\begingroup\$ The average drone and aero modeller will be pulling 70+A from their battery packs. \$\endgroup\$
    – Kartman
    May 14 '21 at 10:29
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I would have also opted for LiFePO4 rechargeable batteries. Long life, intrinsic safety during storage even fully charged. I am curious about further info.

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  • \$\begingroup\$ 70 A from 50 Ah = 1.4C = a very modest drain for almost any lathe Li chemistry cells of any sort. | LiFePO4 are generally the better choice but usually are somewhat more costly all else being equal. However there are so many makers and sellers that there is no certainty on price. Note that some sellers have sold used cells as new. Check for signs of use, impedance, matching terminal voltages (less certain), ... . Test capacity early on at specified discharge rates. Not fully charging or discharging adds to lifetime. More important with LiIon. \$\endgroup\$
    – Russell McMahon
    May 17 '21 at 11:01

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