Lifepo4 48v bms

[Azzkhan]

Hi guys!
I'm new to this forum and am looking for some help. Basically i built a custom bike with a rear wheel 48v 1000w wheel powered by a lifepo4 48v 30ah battery. Things were good for about a year but then one day it stopped working. So not knowing about ebikes i irdered a new controller. Once i connected the controller it still didn't work and after some investigation i found that the bms had gone! I found this out by opening the bms case and the board was giving a funny smell and some of the diodes/chips had blown, visibly i could see scorch marks on the board. So i ordered a new bms and once arrived i connected the bms up and it still didn't work. I then ordered a new wheel kit consisting of new controller, new wheel and new throttle and brakes. I have now connected this up to the bms ready to take power but nothing! This is really doing my head in. I'm based in birmingham west midlands and would appreciate it if someone could tell me how to fix it. Or if local i could drop it off or get someone to come round and check it. I really don't wanna throw it all away as i have spent in excess of £1500 on the bike so far and it would be a shame just to bin it. Please help i am contactable on azzkhan (at) yahoo (dot) co (dot) uk. Hope to hear from some one soon.

Regards
Azz!

 

[dnmun]

do you know if you wired up the BMS correctly? put the charger on the pack and measure the voltage on each cell while charging.

post up the measurements here, from #1 at the bottom to #16.

 

[999zip999]

Azzkhan Welcome You will find help here. Birminham west midlands and I would know where that's at if I was from the USA ? Ya Ya U.K. yes ? Check Battery voltage and charger output. Plus follow what Dnmun says. Please write it down on a peice of paper in front of you. And check back and let us know your progess good or bad. You will get the ABC's here. It will be easier if you post the cell voltage per cell like #1 - 3.2v
#2 - 3.4v or what they are. pack voltage and charger voltage.

 

[dogman dan]

Yeah what they said. On the many wires to the bms, find the voltage of one cell by measuring two wires with a voltmeter. Methodiclally moving both probes down the row will give us the voltage of each cell of the pack.

One dead cell, say 1v or less, turns off a bms. So that's one possibility for your problem.

If the main pack wires have the right voltage, then you have the bms hooked up right. 48v is just about discharged, and the bms would turn off if below 44v or thereabouts. Fully charged should be about 56v, but might be less on an older battery. Mine for example, shows only 53v these days, but still briefly shows the full 60v when just fresh off the charger. Your charger should be putting out at least 58v.

 

[Azzkhan]

Hi guys many thanks for all your replies. I realised i had not charged the battery for at least 8 months so i tried charging the battery through the new replaced bms and once i connected the charger, it blew up. So i have today received my new charger (48v 5amp). It has now been plugged in for over 6 hours and on the charger both green and red lights are on. Even when i unplug the charger from the bms the charger still has green and red lights on. So hopefully will check in the morning to see if it has charged or if charger lights have changed after 12 hours. Just in case it doesn't do u think its advisable to plug the charger directly onto the battery bypassing the bms? Will keep u updated!

 

[dnmun]

you need to explain why you replaced the first BMS, what kind it was, a ping or another type, what is the new BMS, with a picture of the wiring, and you need to explain what the red and green lights are and what kinda charger, pictures help. you will need to verify the pack is taking charge and then measure the voltages on each cell to see if one is shutting off the charging.

on the charger that blew up, do you know if something inside the charger blew up or did the fuse blow up? if it is not the fuse you can open up the broken charger and take some pictures of what you find inside.

 

[999zip999]

Go back and follow the instrutions on post 2-4 and report back. First thing first. And post. These steps are to find the state of the battery as in state of charge.