Is your xaiomi battery like these?
If so, it's only meant for maybe 15-20A at most (probably only for short bursts), some say only about 250W (which would only be about 7A). Above that the BMS is likely to shut the output off to protect itself, which it might indicate by a flashing light.
What does the controller label say on it for current limit, or a number with A on it, like 30A, etc. ? If you're not sure, post a picture of the controller label and we might be able to tell. Or if the vehicle itself came prebuilt, a link to the seller or manufacturer page for it, or at least a complete name and model number for it might let us look it up.
You shouldn't change the fuse to a different rating. It's there to protect things and is rated what it is for a reason.
The amps on the fuse doesn't have anything to do with the volts of the battery, if that is what you are asking.
BTW, if the original lead acid in there was only 24v, but you replace with a higher voltage battery, it may be harder on the controller (many can handle that voltage, but some might not) and may overheat the motor with the higher power level that can give if it's under high load a long time.