Need Help Choosing the right lifepo4 battery for ebike

[Supreme Kay]

I own a mountain bike with front and rear suspension that I converted to an ebike, the controller of my ebike is rated at 36 volt with a 22 amp controller. I currently own a lifepo4 battery pack 36volts with 10ah that I am going to return to the seller because I am not getting the desired range out it which is a minimum of 40 miles with a speed of 15 mph with pedal assist. I don't use throttle with my ebike while riding. I get around 30 miles with pedal assist going at about 12 mph with my current lifepo4 36 volt 10 ah battery. My ebike max speed is 20 mph with only throttle used at it max. I weigh about 140 lbs live and I live in Tallahassee, Florida there are few hills here. I am looking to upgrade my battery, I am willing to spend up to $380. I will be using my bicycle to go around town looking for a second job, I am mostly going to ride over 40 miles. I came across four batteries set on eBay , I need advice to choose the right one . I would appreciate any input to help choose the right battery, one that performed better over a long period of time and last long:

Here is what I came across of onEbay

1- 15AH 36V LiFePO4 12S Battery 3A Charger BMS Rechargeable Power 500W Ebike By UPS

http://www.ebay.com/itm/15AH-36V-LiFePO4-12S-Battery-3A-Charger-BMS-Rechargeable-Power-500W-Ebike-By-UPS-/232065811576?hash=item3608334478:g:RrwAAOSwxg5Xw7ce#rpdCntId


2- Lifepo4 Lithium 36v15ah Portable Battery E-Bike Scooter Built-in BMS +Charger

http://www.ebay.com/itm/Lifepo4-Lithium-36v15ah-Portable-Battery-E-Bike-Scooter-Built-in-BMS-Charger-/281710110554?hash=item41973b275a:g:VUMAAOxyx0JTggIs


3- Lifepo4 Lithium 36v20ah Portable Battery E-Bike Scooter Built-in BMS +Charger

http://www.ebay.com/itm/Lifepo4-Lithium-36v20ah-Portable-Battery-E-Bike-Scooter-Built-in-BMS-Charger-/281683342055?hash=item4195a2b2e7:g:BAMAAOSwPhdVQE~5


4- Lifepo4 Lithium 36v20ah Portable Battery E-Bike Scooter Built-in BMS +Charger

http://www.ebay.com/itm/Lifepo4-Lithium-36v20ah-Portable-Battery-E-Bike-Scooter-Built-in-BMS-Charger-/191733123974?hash=item2ca42f4b86:g:9FQAAOSwYHxWH-Dd


Are batteries from sun-ebike.com reliable?

 

[amberwolf]

 

[dogman dan]

Who the hell told you 40 miles from 36v 10 ah was normal? More like 20, and then only if you pedal pretty hard. 30 possible for some folks, but more typical is about 2 miles per ah of 36v at that speed. At 20-25 mph, 1 ah per mile.

Oh sure,,, somebody has done 40 miles on that size battery, but who cares how far you can pedal not really using the motor?

Your current battery is fine,, but you need at least 20-30 ah for the trip distance you want. So don't go whine to the battery seller if you are getting 30 miles now. Just get a second battery. It's not the first battery sellers fault.