NEED HELP FIXING MY EBIKE BATTERY (BMS)

Hello Ebikers,
I am running into some issue with my e-bike 10.4 ah - 48-volts battery (My battery pack is made of Samsung 26F). My e-bike has a sine wave dual voltage ( 36volts /48 volts) controller rated at 25 amp max discharge current. Lately, I was riding my e-bike and I notice on the display, the voltage was going up and down (48 volts, 30 volts, 20 volts). The power shut off afterward, I was not able to power my e-bike again. My cells are in a hailong case also known as Shark Case or Down Tube Case, the battery meter gage still light up. I open the battery when I arrived home and checked to see if the battery has a short circuit or a wire was cut or has melted. Everything looks good. when the charger is plug in it works fine. I concluded the issue was with the BMS. I ordered another BMS ( http://www.ebay.com/itm/35A-BMS-PCB-board-PCM-w-Balance-for-e-bike-ebicycle-48V-13S-Li-ion-Battery-Pack/172622220990?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 )
I installed the new BMS Sunday, after completion I tested the battery with e-bike and the controller power on. I then disconnected the battery and decided to add some heat shrink to the tip of the 14 wires connecting to the cells of my battery for more safety. I then tested the BMS again, the display of my ebike will light up quickly and turn off.I remioved the heat shrink and tested the battery agin, I was still having the same issue. I then used a voltemeter to test the cells of my pack the cells are ok . I measured the voltage of the cells at the pin of the 14 wire (The part that is plugged into the BMS) everything check up ok. When I charge the battery it charges ok with the new BMS, the light of the battery meter gage light up to show how much power is left in the battery. When I plug the battery into the stand on my ebike I can hear a sparkle. However, when I try to power my ebike the display will light again and turn off quickly. The battery charge OK with the new BMS (fully charged the battery is 54.6volt, when unplug for a while the battery voltage goes down to 53.8 volts due to BMS balancing the cells). I replaced the 14 small wire conecting to the BMS since the some of the wire on the old one were loose on the part where the pin that connect to the BMS is. Upon completion of the installing the new 14 wires connecting to my cells. I checked the voltage of each wires to make sure it is correctly sending the current. everything check ok.
I plug the bolck holding the wires into the BMS, then connected the battery to my ebike. I am still having the same issue. My will ebike display will power on brief (about 2 second and turn off) like it did before. The cells of my battery pack are spot wielded, I already checked the spot wield and there is no damage.
I initially thought my controller could be the issue. Therefore, I used my back up controller Sinwave dual voltage (36volts / 48 volts - 26amp max current discharge) and the stock controller (The stock controller that came with ebike is not compatible with my Sinewave controller display, it used three led light on the throttle to indicate power and the battery gave level) that came with my conversion kit (the stock controller is 48 volt controller - 26 amp max discharge current). I still have the same issue. I replaced the positive and negative wire of my pack just in case, I am still having the same issue. I have a 36 volts battery as back up and it work fine with my controllers (My 48 volts battery is my main battery pack ).
I am now thinking the new BMS might be defective or maybe I miss out on something. You suggestion are welcomed.

You need to put a voltmeter on the connection from your battery to the controller. If the voltage drops when you try to switch on the LCD, it's a problem with your battery. If it doesn't, it's a problem with the LCD.

I just tested the battery with a voltmeter on the positive and negative of the controller after installing the battery on the bike. The voltage was 50 volts then after I tried to switch the bike's display on the voltage went down from 50 volts to 9 volts and the display does not power on. The problem is now with the battery I believe the BMS, you can me correct if I am wrong. I can hear a sparkle when I connect and disconnect the battery to my e-bike. :?

I solved the problem. it turns out to be the connector on the shark also know as hailong or down tube battery case. The connectors are somehow damaged. I found out about this by replacing the positive and B- (negative of the battery connecting to the BMS and voila my e-bike power on without issue.

Supreme Kay

I too have had EXACTLY the same problem with this battery case in the last few days. Mine is a HL-2 case so a bit bigger (110mm deep to hold 65 cells 17.5Ah 48V Panasonic 18650GA 3500mah) Yours is HL-1 I believe 90mm deep

Bought from GBK, battery ran for about 150km, before I saw intermittent power failure, had to pedal home up and down some pretty big hills in full face downhill MBT helmet and full work clothes in 30c temps. for an hour on the commute home.

When I got home managed to find the problem fairly quickly, the 8 spring blades in the battery that contact the 4 ‘spades’ on the battery frame mount, (2 for 0V 2 for 48V) were spread too wide and losing contact.

So clearly over the 150km or so, the movement of the battery has put pressure on these blades, and bent them, but they have not bent back, not enough spring in the metal. I have ridden only on the smooth road, not bumpy off road.

So I think the HL2 case manufacturer has chosen or managed to obtain some bad metal that does not have enough spring in it.

Maybe this is affecting just a batch of these battery cases being shipped around the same time, like aug sep oct 2017.

I managed to get working temporarily again, by bending the blades back with a small screwdriver and by jamming some cable tie plastic in behind the blades to reduce movement. Not sure how I'm going to fix it permanently, maybe jam some rubber in there to provide the spring . This is another case of very bad materials science being applied. Rule 101, if you are going to make a spring loaded connector, use some metal that has a spring rating.