why does my ebike die so quickly
Posted by Putrid-Lifeguard-307@reddit | ebikes | View on Reddit | 21 comments
i have a 48V 1500W conversion kit(not sure about ah) and it seems to lose battery in seconds when i full throttle for at least a minute. Is it supposed to drain that quick when im full throttling? also i cant seem to charge it past 3 bars on the sw900 screen.
goingneon@reddit
I experienced something similar on my 1500w 16ah bike. i think its the battery at fault. i admittedly use a cheapo unit and it does not like sending 30 amps all the time. you cant really "motorcycle" these kind of bikes it seems.
SnowDrifter_@reddit
What do you mean lose battery in seconds?
What voltage is your battery? Charger? What does a multi meter say the full charge voltage is? What voltage is your display set to?
Connections good, wire rated for that much power? Any ghetto crimps or jank connections along the way?
And how do you not know how many amp hours your battery is? This is a need to know. You can't just suck 30-40 amps out of a random battery dude come on. This is safety related
Putrid-Lifeguard-307@reddit (OP)
i’m gonna check all of this now. in my defense i bought this ebike for £500 expecting a proper working ebike. Voltage is 48V the charge has like 3 pins display is set to 48
Relative-Display-676@reddit
high chance they sold it cause it had electrical problems and new battery is probably $300. but it sounds like your battery is toast.
SnowDrifter_@reddit
If the software config is set properly, then you'll need to get checking stuff and pull some hard numbers before we can go any further.
Putrid-Lifeguard-307@reddit (OP)
i’ll get a chance to check everything properly tomorrow
MaxTrixLe@reddit
Voltage sag because of a cheap battery possibly? Does the battery % go back up when you stop using tje motor?
Putrid-Lifeguard-307@reddit (OP)
yes but not by very much, the battery bar flashes
MaxTrixLe@reddit
Hmm did you set the correct voltage on the display?
Putrid-Lifeguard-307@reddit (OP)
i can’t send a picture right now but i did set the voltage to 48
MaxTrixLe@reddit
Is the battery 48V? Also you might need to configure: magnet count on motor, low voltage cutoff. When you give it full throttle what power does the display read? Can you make it show live power draw like amps or volts or wattage
Putrid-Lifeguard-307@reddit (OP)
when i bought this bike on marketplace it was shown as 48V 1500W however i haven’t opened the battery case and inspected the battery properly so im just going off the sellers word
MaxTrixLe@reddit
If you’ve got a multimeter you can test the battery voltage once it’s fully charged , that’l give you an idea
chuckwolf@reddit
i'm beginning to think his battery isn't fully charging also,
MaxTrixLe@reddit
The charger will have a voltage cutoff , you can use a 48V charger on a 72V battery but it will stop at 54.6V which is 48V cutoff, that might be what is happening as well
chuckwolf@reddit
actually a 48 volt charger should have a 54.6 volt cutoff, my 60 volt charger cuts off at 67 volts, a proper charger charges until the battery voltage matches the output of the charger
SnowDrifter_@reddit
If your 72v battery is ever at 54.6v you've already goofed
And please don't ever connect a 48v charger to a 72v battery. Unless you're willing to bet a house fire and your bike that one or both sides have diode protection in place.
MaxTrixLe@reddit
Some cheap batteries have really suspicious voltage cutoff, esp no name batteries with poop BMS . I fully agree though never use the wrong charger
chuckwolf@reddit
what you're experiencing is Voltage Sag, it's temporary and normal... it only happens when the controller is asked to send high amperage and voltage to the motor.
it's simply reflecting how many volts you're using combined with the amps of the controller to make the 3000 watts the motor wants, once you stop using the throttle voltage should turn back to normal.
Putrid-Lifeguard-307@reddit (OP)
so are you saying that this is temporary meaning the more i use the bike the less ill experience voltage sag
chuckwolf@reddit
no meaning it only does it while you're actively using full throttle, if you pedal or only use part throttle voltage goes back to normal.
btw don't rely on the bars for voltage info, go by the actual voltage readout on your display