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Electric Motorcycle Conversion / Re: Special bike (old trial) converted but weak
« Last post by Bikemad on October 28, 2024, 01:09:05 AM »I'll try to disable the boost function and raise the maximum current... but do you think the controller is the "weak link" or the battery comes first?
How big of a battery would it need to work properly?
If the controller was cutting the power it should also be emitting one or more error codes (a series of audible beeps & LED flashes) but as you have not mentioned any sign of an error code I'm assuming that it's the battery/BMS that's the "weak link", not the controller.
It is not down to the size of the battery, it's your battery's inability to deliver the required power that is most likely causing the problem.
To produce the maximum power from your motor/controller setup you would need a battery and BMS that can ideally deliver 110 Amps continuously and 180 Amps peak.
Unfortunately, the limited space on your bike means that you will probably need a custom made battery using high current cells that would fit into the existing battery space.
I think it should be possible to have a 48V 35Ah battery built that could supply up to 200 Amps of power from 140 x 30A 18650 3500mAh cells in a 14S10P configuration along with a 200 Amp BMS in a battery size of around 200mm x 150mm x 140mm (8" x 6" x 5.5") but 30 Amp 18650 cells are not cheap!

One question: this bike is set so there's a small 12v battery to activate lights and the "starting relay"... but I've never seen another converted vehicle wired like this.
Would it be easy to remove the relay and the battery? 'Cause if it's down, the controller won't work.
If it's a high current relay (contactor) that is physically switching a main battery power lead you would need to replace it with a heavy duty (high current) battery isolator switch, but if the relay is only switching the e-lock wires on the controller, it can be replaced with a simple On/Off or key switch.
Alan