GIANT Roam XR E bike problem

[dde17]

Hi , Recently purchased second hand Giant Roam XR Electric bike with rear hub Hybrid drive motor, 36V battery. Bike had only done no more than couple hundred miles and that was confirmed by local Giant dealer where the bike originally had been purchased. However after using it happily for a week or so I have an issue -
when bike is indoors, where it is normally kept it powers on as it should , when I take it for a ride it works fine for 10-15 mins or so and then dies. After brought back indoors it sort of warms up and seems to be fine.
Checked all the connections and cant see any obvious problem, any ideas of what could be the possible issue?
Thanks

 

[Nealh]

More then likely a battery issue could be out of balance/ a couple of very low cells. Check the docking unit could be a bad connection/hook up.
How old is the battery ?
Also charge it up and tell us the output voltage.

When indoors all will feel fine because there is no load for the battery to fail, but once out and riding you are asking for a load to be applied so at some stage it can't cope with the demand. Under what circumstances is the battery failing.

 

[dde17]

I will buy multi meter tomorrow and check the voltage, the battery is 3 years old but only has had 15ish charges, I am also thinking that it is the connection at the dock or a cold solder joint. where is the actual control unit, is it the small bit in the dock where the battery connects or is it inside the battery?

 

[dde17]

also , the user manual is pretty bleak, by a chance has anyone got more extended instruction manual and/or possibly wiring diagrams of the bike mentioned ?