Sure you can. Does your current controller have a display that tells you how many watts are being used? Without the data, you won't know how much power you added. I'd suggest a controller with a display that shows watts,
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What you're really doing is increasing current. Look at the ratio of the maximum current vetween a new controller and your present one. Your present one is probably 17-20 amps. If the new one is only 25A, that's only around a 25% difference, Hard to tell when riding, in my opinion.
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The bike will not go any faster. It will climb hills better, and carry more weight,.If the hills are too steep, you'll still melt the motor.
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