48V 10AH LITHIUM BATTERY FOR SMALL OFF ROAD BIKE

[Jimmy1234567]

I am building a small off road electric bike for my young son and want to power it with a 48v 800w brushless hub motor. I am planning on using a 48v 10ah lithium battery (similar to photo) but can anyone tell me roughly how long this would run the bike for. Altogether with everything attached and with my boy on it it would weigh about 70 kg and would not be used for long distance runs, although maybe sometimes, but mainly for going around a paddock. I have been looking at various lithium batteries and obviously the more ah they are the more expensive. If I can get away with a 10ah that would be great. I don't expect very accurate answers but some idea would be great as I would have no clue myself .
Thanks

 

[Nealh]

The battery is 480 wh , a reasonable rider can use about 10-20wh per mile depending on terrain at an average of about 15mph.
A lot will hinge on the controller amp rating used and the cells used inside as well as the power control used, 2 hrs run time may be possible. Too many variables to be more definite.

 

[Jimmy1234567]

The battery is 480 wh , a reasonable rider can use about 10-20wh per mile depending on terrain at an average of about 15mph.
A lot will hinge on the controller amp rating used and the cells used inside as well as the power control used, 2 hrs run time may be possible. Too many variables to be more definite.

Thanks for your reply and advice. J

 

[Woosh]

in general, you need to make sure that the battery can provide more than enough current to the controller, the reason being the battery's internal resistance rises quickly with the amperage and that generates a lot of heat, killing the cells.
The choice of motor is thus important. For an off-road bike, speed is low priority, torque is high priority. You will want a motor that remains as efficient as possible in the low revs. This is usually large geared hub or a crank drive like the Bafang BBS02. High torque motors demand high current, typically 20A and over. The rule of thumb here is don't draw more than 1.5C on Chinese cells, 2C on Samsung 29E cells and Panasonic F,B.
You need to tell us which motor you want to buy before we can tell you if your battery is well matched to it.

 

[Deleted member 4366]

The battery power needs to match the controller's power, not the motor. As a general rule you should aim for a battery that can provide the controller's maximum current continuously, so if you use a 20A (max) controller, you need a battery that can supply 20A continuous.

The picture of that battery is meaningless. You need to post the specification.