Whats the ulitmate Lithiom iron battery to run a 200w brushless motor on an electric bicycle.?

Question

What size battery can i go to without wrecking the motor Bike currently has 36v 10ahm lithiom iron battery

Answer 1

Mate, your going to have to check the motors specifications. They will state the voltage that the insulation can withstand. There should also be a temperature rating.

The motors ability to get rid of heat, ultimately determines how much power can be drawn out of it. If your motor doesn't get a good flow of air, it can burn out well below 200 watts.

Assuming that your motor is rated to around 36 volts and you can keep it cool enough to get 220 watts out of it.  The most current draw needed to supply this would be about 6.1 Amps (220/36)(power =voltage x current)

lithium ion batteries suffer less from what is called peukert effect than most batteries. (the ability to maintain voltage at high current draws.) So it is possible that a 36volt 1 amp hour battery could supply the maximum current draw that you need. It will be light and give great performance. Hassle is that it won't last very long. (less than ten minutes to dead flat)

Lithium irons are usually  36 v nominally. This means their average usable discharge voltage is 36 volts. It could charge as high as 42 volts.

Tickling up the voltage does mean a little less heat is produced at a set power. Higher voltage also places more stress on the insulation. The higher the voltage the quicker the insulation will break down.

My tip is to match the nominal battery voltage with the rated voltage of the motor. Select your battery amp/hour rating based on how long you want the  motor to run for between charges. (guide 36 v 10 a/h should last about 1.44 hours at 200 wattts) (36 v x10a/h /200watts x 80% depth of discharge)

Another thought if you are healthy. Try training. Most people can manage more than 200 watts for many hours at a time with a bit of training.

Answer 2

ion!