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General Category => Magic Pie & Smart Pie Discussions => Topic started by: Thuktun on April 26, 2018, 05:27:32 PM

Title: My new diy battery works but doesn't, any suggestions?
Post by: Thuktun on April 26, 2018, 05:27:32 PM

I'm stumped. Made a new diy battery. It works, when on a multimeter shows the correct voltage at the outlet. Plug in the bike, nothing. Plug in an old battery, powers up fine. Polarity is correct and it's using the same outlet plug my last diy battery used with the same plug on the motor cord so it isn't a poor connection there. I have no idea what the problem is. Any suggestions?

Anyone know how much current is drawn when you switch on? I can't see it being enough to cause the BMS to cut out, especially since I'm using a precharge resistor.

Motor is a Magic Pie Edge 26", battery is 14s7p with BMS.

Title: Re: My new diy battery works but doesn't, any suggestions?
Post by: Thuktun on April 26, 2018, 06:00:23 PM

It has to be a bad connection somewhere, it just turned on. Weird because I could turn it on, read a voltage, plug in the motor and get nothing then unplug it and still read a voltage. Unless the bad connection is on the socket...

Title: Re: My new diy battery works but doesn't, any suggestions?
Post by: Thuktun on April 27, 2018, 10:38:02 AM

One of the balance lead wires was loose. The BMS would read a voltage but it was actually 1 cell too low and it wouldn't put out any power. Seems fine now.

Title: Re: My new diy battery works but doesn't, any suggestions?
Post by: Bikemad on April 27, 2018, 10:43:54 AM

Good to hear that you've sorted the problem.

Alan