I have a front wheel road runner motor on a MTB. I use a 48V 10ah LiFePo4 with a BMS. The system has been working well these past few years. Just yesterday I rode to work in the morning, and it worked great. But after work on the ride home, the ebike was not functioning properly. When I apply the thumb throttle, the motor lunges slightly for a split second, then cuts out - repeatedly. Basically it clicks repeatedly, as if there is a loose connection somewhere. I have gone over the whole electrical system and I don't see any loose connections.
Do you have any idea what might be going on?
There are several possibilities, but can you give some detail about your bike? eg if it's a brushless motor look at the three phase wire connections. Also did you disconnect the connectors for your check or just look at them? Just looking can miss many things like loose or broken joints, and corrosion of the connectors.
It's a LiFePo4 48V 10ah. I bought it off ebay (Not Ping) and started using it in late 2008. It's possible that it is the battery, I suppose. Can I check the battery with a voltmeter?
praskal, Please update your profile and add a location so we know where you live. It helps us with recommendations for local help and sometimes parts and sales. At least let us know what country you are from.
I would start by unplugging, examining and then replugging all your connectors together to see if something changes.
Then, using your DMM, test the voltages of each individual cell in your battery pack to see if one or more is low enough to cause a lvc cutout. Maybe the pack is out of balance. 2008 was a while ago and your battery has given you a long life service. The pack could be dead, but to know for sure cell voltages are critical to know. After metering your cells, charge the battery and check the cell voltages again to see if they are all taking a full charge.
Darn it. I am leaving early tomorrow morning for a week out of state. So I am going to have to get back to this upon my return, when I have some time to spend on it. I appreciate all the excellent help though...
Something has gone wrong with the pulse timing on your phase wires:
Faulty connection
Blown FET in the controller
Blown hall sensor
Order one of these now to save a lot of messing about later:
http://www.ebay.co.uk/itm/1PC-24V-36V-48V-60V-Car-Scooter-Brushless-Electro-E-bike-Motor-Controller-Tester-/181246430524?pt=UK_Motorcycle_Parts&hash=item2a33210d3c
You can also get them from Em3ev.com and other places
I actually think it's the batt pack. Ok. Initially the battery read 53.8v at full charge.
I then applied throttle and the motor jerked. And the volts read 44.4.
It's a 48v 10ah I bought off a Chinese guy (not Ping) in 2008. I've been using it pretty steady since 2009. Is this about the right life for a lifepo4 pack?
Some guys around here only get 3 years out of their LiFePO packs....but that doesn't mean your pack is dead. I could be a bad cell or 2 or it could be something else.
If you want to figure it out start with the steps I outlined previously. Check your connections and meter you cells and post the results.
The reason the voltage went down was because with a missing phase on the motor, you're putting a massive load on the battery. You will draw the same current as a stalled motor. You should have tried an ammeter rather than a voltmeter.
