My 30ah Ping battery shuts down at 16ah

[jtmjtm2001]

I have a Ping 30ah battery I bought last winter of 2008 and it seems to cut out at 16 ah on the Cycle Analyst. Do I need to calibrate the Cycle Analyst some how. There a lot of options in the advance options I don't understand except throttle v, poles and wheel diameter. Is it the bms set the shut off at 16ah? The battery seems have good output and the lowest voltage with load was I think while 46 or 47 volt with no load of 51.5 volt I think. Can the bms be easily hacked to add more distance? I only ran it down to 16ah 3 times (last spring and 2 in summer) since I had the pack for about a year and most of the time I only run it down to 7-9ah daily. Thank you. John Morris

 

[dogman dan]

Holy smokes that's horrible. Run it down again and check each cell with a voltmeter. The bad cells will show then. You must have some bad cells in there. Better find em before they take the others that are paralelled with them down too. That kind of use really shouldn't have killed cells , I wonder if you have some bms wires disconected, or something wrong with the bms lvc. Could your cycleanaylyst lvc be shutting it down early?

 

[Russell]

This is possibly proof you CAN have too much battery. If you never run a big battery pack to near its rated capacity you might never be aware it has a problem :|

-R

 

[dogman dan]

Very true. I do a range test every 3 months or so, but maybe I should do it more often. Anybody know what pings bms is supposed to cut off at?

 

[jtmjtm2001]

That sounds scary. I'll get it out soon and check the wiring and by a new volt meter. If things go well I hope to get the results in a few day to a week. John Morris

 

[jtmjtm2001]

I forgot to say the battery is 48 volt and fully charged it reads 60.somthing volts. The Cycle Analyst goes black when it cuts out and the voltage cut off is set to 42 volt. John Morris

 

[mud2005]

ping makes 48V 30AH packs?

 

[dogman dan]

Probobally does for a custom order. It does sound like a jimmywu, east, mp3hk, deal though doesn't it. If the bms wire on one cell is disconnected, it could cause the problem he describes. What exactly are you running on this battery? Even a 5300 clyte should be under 1c average discharge rate, making cell death unlikely. Is this on a 5000 watt scooter or something? Even though it's a year old now, do talk to Ping about it. Maybe you just need a new bms. You will know a lot more about what is going on when you check the voltage of each cell group. Sometimes a weak cell can be brought back by charging each cell individually, but it will be a PITA.

 

[JinbaIttai]

ping makes 48V 30AH packs?

+1

How did the OP buy the pack? Last time I checked, 20ah is the biggest you can buy from ping.

Either way, it does sound like a bad cell(s).

 

[jtmjtm2001]

I have a 30a limit and run it at an average 600 to 1000. I have a 5304 26" and my round trip to work is 11 miles.

 

[dogman dan]

Well if you are averaging 30 amps or less, that is 1c so it shouldn't be too much motor. I was starting to wonder if you had a dirt bike or something. I've been pulling 1 c out of my ping for 2000 miles with no detectable loss of range. But like with the round cell packs, if one cell died, it could pull down the others in the parallel string with it. So you may have some dead cells now. There is a guy selling some cells in the for sale section now if you want to try to fix it. We need a lithium pack doctor on this continent. But most likely we'll just have a bunch of sharks who want to help you dispose of dead packs to scavenge cells.

 

[jtmjtm2001]

I'll look in to those cells on ES forum if I do have some dead "poptarts". I would hate to pony up a ton of $$$ for a new battery though those Thunder Sky 20 ah 12v on Elite Power Solutions are tempting though.

 

[JinbaIttai]

It wouldn't cost anything to do a test with and without the cycle analyst. You'd have to figure out a route that takes you beyond 16ah and repeat it, preferably with the wife waiting by the phone to pick you up in the car...

 

[jtmjtm2001]

It wouldn't cost anything to do a test with and without the cycle analyst. You'd have to figure out a route that takes you beyond 16ah and repeat it, preferably with the wife waiting by the phone to pick you up in the car...

I have no wife and still looking. I'm planning to go on a long trip on my next day off to run the battery down and when it hit around 13 ah start heading home and if it dies I can pedal it though it's not fun.

 

[jsmay311]

I have a Ping 30ah battery I bought last winter of 2008 and it seems to cut out at 16 ah on the Cycle Analyst. Do I need to calibrate the Cycle Analyst some how. There a lot of options in the advance options I don't understand except throttle v, poles and wheel diameter.

It's been quite awhile since the original post, so hopefully you've got this figured out by now. If not, here's my guess.

To answer your question on calibration... yes, you do need to calibrate the CA. Specifically in your case, it sounds like the R_shunt value might be off. When I first installed my CA, I was shocked by the awful efficiencies that it was telling me I was getting. It turned out that the R_shunt value in the CA was too low by about a factor of 2, which made my current draw (amps) appear too high by a factor of 2.

To calibrate it correctly, I had to get a clamp-on amp-meter and add some extra wiring in between my controller and battery pack so that I could get the clamp around only one of the wires. Then I did some test runs and modified the R_Shunt value until the amps displayed by the CA matched the amp-meter.

Another option is, if you know the current limit of your controller, just modify the R_shunt value until the maximum current displayed by the CA when you're at full throttle matches the current limit of the controller. A third option would be to crack open your controller and directly measure the shunt resistance.

To modify R_shunt value, you hold down the button on the side of the CA when you turn on your battery pack. This will send it into setup mode. The instructions are here: http://www.ebikes.ca/drainbrain/Cycle_Analyst_Manual.pdf

Hope this helps.