48V-20AH battery life quickly dimiished

[Derek-Makela]

I have a 1000w rear hub from Cohnis motors, with a 48V-20AH Lipo4 battery this is my second build the first one works fine. The second build in question does this...When first built, I could get about 30 km per ride without pedalling, then the distance driven on battery life decreased by about 1 km every ride, after a dozen rides I can only go about 5-6 km total. When I first built the bike and it worked fine when charging the discharged battery both LED's on the charger would be red, the first LED shortly after turns green while the second remains red while in mid-charge, towards the end of the charge while the first light is still and always green the second LED would start flashing red, and then the time between flashes would increase and eventually stay off leaving only the first green solid light indicating full charge. Now what happens is both lights are red at initial charge, the first turns green as usual, but the second red LED never goes off or even starts flashing and eventually stops like it did before. Obviously it is not getting the full charge or the second LED would eventually flash and then go out. Leaving one green solid LED. Is it possible that one of those stainless steel strips that are spot welded to all the batteries may have came loose, leaving some of the LED batteries seperated from the rest or does this sound like a problem with the BMS. I did fry the original BMS because I wired the battery polarity backwards. I ordered another BMS and the one they sent was slightly different The first one had two ports and the second only one port but with a little cutting with an exacto knife I managed to put both plugs into the wider single port on the second BMS, (see attachment) one plug has negative (-) written on it with green marker and the other green marker pluses (+). The second BMS Had a negative and positive sign written on it with black marker so I put one plug marked (-) into the left side of the port and the other on the right. I am thinking this may not be right because it seems I am slowly killing my battery every time I charge it and maybe charging some cells backwards. If this makes sense to any one look closely at the BMS it has black marker + and - signs and so do the plugs so it seems to be the best way although on the previous BMS these plugs were in two completely different places not side by side. I am thinking the sequence may be different although I am not sure. How do I know which wires from the battery are B1-B2-B3 etc. as indicated on the BMS. Any help or suggestions are greatly appreciated.

 

[dnmun]

no way to know from all this. have no idea what the commentary about the leds on the charger meant either.

do you have a voltmeter? do you have a watt meter?

can you take a picture of your battery showing the place where the sense wires come off the battery? do you have the original BMS and can you take better picture of this one and the old one?

did you build this battery from scratch yourself or did you buy it from someone else who built it from scratch or is it a manufactured battery and can you tell us who made it?

 

[e-beach]

Do you have access to the individual cells?
If so please meter them and list the voltages of each cell.

 

[Derek-Makela]

It is a manufactured Battery bought with BMS from EV battery on the conhis motors website shipped.ipped from china. I can access the cells by removing the duct tape. unfortunately I threw away the old BMS. I do have a multimeter. I will take another picture tomorrow. IF YOU GO TO conhismotors.com you can see the battery. I will take some readings. Thank you guys so much to reply. What I meant by the lights on the charger are that the red light should go off when the battery is fully charged. Now it never goes out, therefore not getting a full charge. Thank u so much . I will get back with pics. U love this forum. Take care
Is Conhis motors the same as a golden motor? The battery is a series of round blue batteries

 

[d8veh]

B0 is ground, and then B1, B2 etc are the cells, You don't need to open the cell-pack to measure the cell voltages. Put your black probe on the negative from the cell-pack, and then the red probe on each of the pins on connectors. You can get your probe into the little silver slots on the connectors. 0V is B0, 3.3v is B1, 6.6v is B2,etc.

Sometimes B0 is not on the connector, so don't worry if your first pin is 3.3v.

Post the results of the 16 pins here. You don't need to open the cell-pack to measure the cell voltages.

 

[999zip999]

I had to file down the tip of the probe to touch the silver strip on the white plug. Plus put shrink wrap on the probe just so the tip showed so as not to short and cause big problems. Voltmeters are free from harbour frieght with coupon. I just got 4 over the last two weeks ( coupons ). Free when I take the ride. And where do you live ???

 

[Derek-Makela]

Thanks. good advice. I live in Timmins, Ontario

 

[e-beach]

Thanks. good advice. I live in Timmins, Ontario

Please do this:


And also please list your battery voltages to see if your pack is out of balance.