Signalab BMS fault...help!

[wurly]

Self inflicted fault i'm afraid.
I soldered in my spare signalab BMS to my new headway battery pack but managed to get a solder splash right across the bottom of the pcb. I removed most of it, but I should have waited until i could inspect it at work. Like a' chump' i hoped everything was ok and connected it....it wasn't. 5th cell refuses to charge....doh!

So now i have the BMS at work i have discovered one of the cell switching IC's NC800 is knackered along with a zener diode AP431. There was another problem with 4th channel but i rectified this.

So.....is there anyone here with a dead signalab BMS who would be willing to desolder a couple of componants for me...or sell one and send it to me so i can fix mine?
I will pay for postage of course.

 

[Deleted member 4366]

How many amps? How many cell volts? How many channels?

 

[wurly]

 

[wurly]

It's 12 channel Dave. Originally from a little 5Ah. I have the same BMS on 10Ah that occasionally sees 20A. It has never cut out although i was expecting it to with the headway pack. I thought i would try it first.
However, i wanted connected initially to balance the pack, but ran into the problems mentioned.
the cells werre at various voltages up to 4.1Vand down to 3.4V (floating voltage), but the problem was the 5th channel was actually reducing voltage....now i know why.
I have been monitoring the pack and loaded the high cells to bleed then down before i realised there was a problem with the BMS.

I may have the number incorrect for the diode AP431. I am looking at an earlier version circuit diagram. The number on the device is M110N and the number on the balancing IC is R2RZ.

 

[banbury frank]

Hi werly

your headway cells are LIFEPo4 they are 3.2 volts and charge at 3.6 volts You need to charge the cells one at a time till full then fit the BMS link below for UK supplier for BMS and 10 A 3.6 volt charger you MUST connect the BMS in the correct order
36V LifePO4 BMS (43.2V) 12 Cell 30A/60A


Single Cell 3.2V 10A LifePo4 Battery Charger

I did recommend in a post in the last 2 weeks that charger and he bought one if you find the member perhaps you can lone it


They also sell 36 volt 4 amp chargers


36V 4A LifePo4 Battery Charger

Hope this Helps

Frank

 

[wurly]

Hi Frank
I am now going to charge them individually with my Imax b6 charger.
Any reason why i cannot use a signalab BMS and a lifepo4 charger (as supplied by Li Ping) for a 36V lifepo4 headway pack?
(a working signalab BMS that is)

 

[Deleted member 4366]

Was that BMS a LiFePO4 one? What Frank's trying to say is that LiFePO4 is 3.65v per cell, while as LMC is 4.2v. I have a 16 channel 40 amp LiFePO4 one somewhere with a blown channel. I had a quick look for it but couldn't find it. I'll have another look tomorrow when it's lighter. It's been so dark today I could hardly see.

 

[wurly]

Yes Dave it's lifepo4.
It was a working BMS until my eagerness and bad eyesight screwed it.
If the BMS you have is a signalab? V2(i think)it will have the componants i need. No hurry btw
Thanks :0)

 

[banbury frank]

Hi werly I have built many Headway packs If they are 4.1 volts you have a problem with the BMS

also make sure you dont use bolts in the cells longer than 10 mm or you will have cells that can explode
If the bolts are to long they can stop the overcharge safety disc inside the battery from braking the disc
once the disc has broken the spot weld it is scrap this is caused by overcharging and the battery starts to GAS this distorts the disc and brakes the spot weld disconnecting the cell from the end cap permanently

Frank

 

[wurly]

Here are the cell volts as measured tonight.
bolts are not bottomed out. good info though, i can see the spot weld but i didnt know about the disc.
I have to leave it now...busy with other stuff. thanks