Hi,
Ok, so If you do not own a LIPO RC charger the solution to buy Lipos without BMS is not for you unless you buy a RC charger with at least 2 outputs:
http://www.banggood.com/Ultra-Power-UP100AC-DUO-100W-LiPoLiFeNiMH-Battery-Balance-Charger-Discharger-p-1042945.html?p=A720061271257201502N
And this is a cheap one with integrated Power switch unit. Yes, LIPOS are cheap but chargers aren’t. With a good separate power unit and 4 outputs it’s more than double the price.
+
LIPOS: 2x5s, you can build a 8Ah pack or a 16Ah pack with these batteries:
https://hobbyking.com/fr_fr/zippy-flightmax-8000mah-5s1p-30c.html
And off you go because normally your controller has a current limit so it won’t blow up.
With this solution you will have good torque and the speed will be the stock one maybe a bit more.
OR
You can go Li-ion but do not buy a cheap chinese Ebike pack like I did, it works but it has so much voltage sag that you don’t get much range and it hasn’t got a BMS.
Or you could buy a 48V one but your controller may detect overvoltage and then you will have to modify the relay inside (not too complicated).
If you can source good 18650 cells (not my case) you can build a 36V or 48V Pack yourself if you are patient. If you don’t own a spot welder (like most people
) you will have to buy cheap Battery holders like these ones (do not solder directly on the battery pads with a classic solder iron):
http://www.banggood.com/10Pcs-DIY-4-Slot-Parallel-18650-Battery-Holder-With-2-Leads-p-964983.html?p=A720061271257201502N
To this you add a BMS and buy a Liion Charger
http://www.banggood.com/36V-37V-42V-45V-5A-Battery-Charger-For-10s-10x-3_6V3_7V-Lithium-Li-ion-Battery-p-1115729.html?p=A720061271257201502N
If you can’t or don’t want to make your own pack (like me) you can buy a good liion pack with integrated BMS already built but the cost is high.
https://lunacycle.com/batteries/packs/36v/36v-panasonic-ncrb-13-5ah-bottle-ebike-battery/
But before going further my question would be: Is stock speed enough for you? For me it is ok as long as I have torque and range (don’t wanna charge each and every day for my small trips)
If you want more speed >> More Volts >> may need to change the controller >>> May need to change motor