Author Topic: Low voltage cutoff?  (Read 6306 times)

Offline tim...nz

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Low voltage cutoff?
« on: July 31, 2011, 05:22:13 AM »
Hi all, newbie here setting up a 48v 1000w MP with a 48v 10aH Ping battery.

I expect my issue is caused by the low voltage cutoff - when the charger is plugged in, the motor will run, but when the charger is off, nothing happens - no lights on the throttle or anything. Do I need to change some of the controller settings through the usb interface or should they be ok from the factory, and a low battery is causing my problem?

Last time we checked it the battery voltage was 41v, will check again later when my flatmate (guardian of the multimeter) gets home. Cheers

Offline JS

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Re: Low voltage cutoff?
« Reply #1 on: July 31, 2011, 07:06:13 AM »
When I was building my bike I tried it with different voltages. 12V did nothing, but with 24V it operated normally.

When you connect the battery, there should be a reasonably big spark, whining noise from the pie and lights on the throttle. You get none of those?

Sounds like a defective battery to me, or BMS sees a problem and cuts it off. 48V battery should be around 50-52V.

Try it without connecting any of the wires except power and throttle.

Offline GM Canada

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Re: Low voltage cutoff?
« Reply #2 on: July 31, 2011, 11:14:42 AM »
Hi all, newbie here setting up a 48v 1000w MP with a 48v 10aH Ping battery.

I expect my issue is caused by the low voltage cutoff - when the charger is plugged in, the motor will run, but when the charger is off, nothing happens - no lights on the throttle or anything. Do I need to change some of the controller settings through the usb interface or should they be ok from the factory, and a low battery is causing my problem?

Last time we checked it the battery voltage was 41v, will check again later when my flatmate (guardian of the multimeter) gets home. Cheers

41v seems low for a 48volt system. If your controller is set at 48 volts then it most likly will not run. Charge up the battery and get a meter on it to see what voltage you get.

Gary

Offline tim...nz

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Re: Low voltage cutoff?
« Reply #3 on: August 01, 2011, 09:19:43 AM »
It charged for a few hours one day and most of the next day to reach 41v. I checked the voltage of each cell and the first one shows -2.8, the rest are between 2.7 and 3.5. Could the first cell be wired it with the polarity reversed? Would this stop the current running through to the controller, explaining why the lights etc only work with the charger plugged in?

I also hooked up the USB and found that the controller was set to 24v even though I ordered a 48v kit. I set it to 36 for now, figuring it might work with the low voltage on the battery but still no lights or anything. Frustrated! Any ideas appreciated, I do have a mate assisting me who is rather more knowledgable than me on the finer points of electronics so we'll get there in the end :)

Offline Bikemad

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Re: Low voltage cutoff?
« Reply #4 on: August 01, 2011, 12:20:29 PM »

In my opinion, the title of this post says it all, the battery is not working because 41V is too low and the BMS is doing its job by activating the Low Voltage Cutoff.
Did the battery work OK at first, and then stop working after a bit of use? If so, I suspect you may have a charging fault, not a battery or BMS fault.

It's always a good idea to check the obvious first, so if the charger is not auto selecting, and has a manual selector switch for the mains voltage, make sure it is set correctly. But I think the Ping chargers are auto selecting. ;D

The charger for the Ping 48V Pack should have an output rating of 60V 2Amps.
The charger for the Ping 36V packs has an output of 45V 2.5Amps, and if your battery is new, It's possible that you may have been accidentally supplied with the 36V charger instead of the correct 48V version (60V output).


Does the charger have the output voltage marked on it, and if so what does it say?

If it is the correct charger, what is the actual voltage reaching the BMS from the charger?

Regardless of what you find, if it's a genuine Ping battery, I suggest you email Ping (pingping227@hotmail.com) and explain your problem, as he is the best guy to deal with it. ;)

Alan