Mr.Dangerous

Hey, I have built an ebike with a 60v compatible controller and a 60v compatible twist throttle which displays accurate live voltage. The battery is a 60v 20ah battery.

When fully charged the throttle displays 67 volts and It of course decreases as I keep going. I ride the bike for around 24 miles and then the display eventually goes down to exactly 50 volts and then in goes to a 49/48 shortly after and the motor shuts off and the voltages drop to 0 and the bike automatically shuts down. Is that normal? Is it supposed to die at 49 volts and require a recharge again? its been happening every time.

I am not sure if im getting the full experience im supposed to get with a 60v 20ah battery. Thanks for looking into this!

xroadcharlie

I get about 72 miles based on 1200w (60V x 20A) /200w motor load for 6 hours @ 12 mph.

Most standard E bikes w/500w battery are said to go about 40 - 50 miles. They are likely much more efficient.

Perhaps your controller is not optimized for that set up. And yes, At a predetermined voltage the motor should shut down to protect it from burning out.

gregf83 

Depends entirely on how fast you're riding those 24 miles. Once the battery voltage gets close to 3V/cell the internal resistance goes up and the voltage will drop quickly if you continue to draw the same power. Voltage under load is not a very good indicator of the remaining capacity in the battery. If that's all you've got you'll need to experiment a little to determine when to slow down or recharge.

2old

What is the number of cells in series for the battery? If it's Li ion (except LiFeSO4, AIR), 14s is 58.8V (4.2 X 14). The LVC (low voltage cut-off) possibly shut the battery down in order to protect it. Beware, running a battery too close to "exhausted" isn't good for the battery and could be dangerous. At 18 or so mph (no wind, flat terrain, normal load, throttle only), you should get 40 - 45 miles. Any deviation in either direction (hill, decrease; pedal, increase) will influence this number. JMO!

Doc_Wui

If this is a 16S battery using 3.7V cells, it will be 67.2V at fill charge, 59.2V when half charged, and a 60V controller will shut it down around 48V, which is 3V/cell.

You're only getting 24 miles? That's a 1200WH pack, and running it down to 3V/cell leaves you with about 20% left. SO you burned about 1000WH, which is 40WH/mile. That's high. Are you going about 30 mph? Range depends on average speed.

My little cruiser bike just went 10 miles at 15 mph, and I used about 12 WH/mile. If I had 1000WH, I could go 75 miles, but it would take me 5 hours.

Mr.Dangerous

Thanks everybody! I pieced it all together from all of your replies. My battery is after all an adequate battery.