Energy Consumption & Pack size on E-Bikes

[ProDigit]

Somewhere I read, that Panasonic is the only ones who make cells of 3.6 V, and 3400mAh. Larger doesn't exist. I mean, sure, the stores rate them at 3500, and even 3700mAh, but those batteries are very short lived.
Those panasonics come in at about $20 a pair, if I'm not mistaken.
The chinese ones at half the price. But they will last half as long

[hayden55]

Originally Posted by ProDigit

Somewhere I read, that Panasonic is the only ones who make cells of 3.6 V, and 3400mAh. Larger doesn't exist. I mean, sure, the stores rate them at 3500, and even 3700mAh, but those batteries are very short lived.
Those panasonics come in at about $20 a pair, if I'm not mistaken.
The chinese ones at half the price. But they will last half as long

Nah they aren't that expensive. The high discharge ones which are like 40a/cell get to be like 10-15$.... but the average cells from lg and samsung and sony typically stay around 6 bucks or less per cell. The ones I was looking at in bulk are 3.80$/cell.

[hayden55]

Standard consesus on mid driver vs rear hub mount? Both 3000 w motors.

[ProDigit]

I've seen BMC guys installing wheel hubs on both front and rear, taking them to nearly 60mph.
A rear hub will work just fine, however a mid motor you could combine with gears.

[Stubby79]

Mid drive/gears sounds great, but that's an awful lot of power to put through a chain that's only designed to handle a few hundred watts under normal circumstances. Perhaps do research on how fast it wears out chains and cassettes first?

[ProDigit]

Bicycle chains can be replaced. Sprockets can be replaced. There are plenty of motorcycle chains, or heavy duty bicycle chains that will pull the load just fine.

If you grease them well, they will usually last well.

The force on the chain, going 30MPH isn't that much greater from 15MPH.
Once you start to get past 45MPH, wind resistance becomes an issue, and stronger chains (preferably from a 50-100cc motorcycle) are needed.

[hayden55]

I think I may have found a really good option. 3350mAh panasonic 18650s from a tesla battery pack. Nearly 0.88c each from a Tesla with 22,000 miles. That's basically brand new considering these packs can get 40,000 cycles if charged and discharged correctly.

[Hersbird]

Originally Posted by Stubby79

Mid drive/gears sounds great, but that's an awful lot of power to put through a chain that's only designed to handle a few hundred watts under normal circumstances. Perhaps do research on how fast it wears out chains and cassettes first?

KMC bike chain is supposedly able to handle it. I need to order some. I used it for my cyclone midrive running at 56 volts and 40 amps (maybe more) as the single speed chain from the motor to the pedals, but I had the stock walmart Mongoose chain to the rear wheel. I did break that chain going up a 45 degree slope in first gear with my fat butt on a fat bike and me pedaling. I was able to fix it and continue on, but it would be nice to have the better chain in the first place as it would be under $40. I need to carry more master links just in case as well.