Questions on Signalab BMS

[DavCbr]

I just bought a Signalab BMS. It looks exactly like this:

I bought this on EBay [ http://www.ebay.com/itm/BMS-for-38-..._DefaultDomain_0&hash=item2591f13666#shpCntId ] after I decided that the BMS that came with my Headway 36v 12-cell battery was not functioning properly. I finished wiring it and plugged in the charger. When the charger cycled off, I noticed immediately that the LEDs were not lighting up. At this point, I started measuring voltages, and could see that there were no static voltages. So, I decided to wait and see. No cell went above 3.92 volts, and after a couple of days attached to the charger, all cells were at 3.66volts, +/- 5mv - except for one, which read 3.91v. [ btw, what might this one cell indicate?]

So, the board appears to be able to balance the cells, and no really dangerous voltages are being used. However, it would be nice if the LEDs worked. I have not seen any one of them light up during this process. Back to the other hand, it appears that this board is doing what I need.

My question is, would any of you go thru the paypal hassle to try to get a replacement that may actually have a different problem?
Also, I have very little experience in electronics. Might there be a reason the LEDs are not working that I have missed? I followed the wiring diagram in the illustration I included. Or, I think I have included. Here is the page link I got my image from:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=53155#p790889

One other thing - I cannot find any references to what appears to be a thermal cut-off that does not show on the attached photo, but is at the end of the two large white wires at the top left that lead off the photo. Where should this be placed?

Any opinions would be appreciated.
Thanx
dc

 

[Nobuo]

When You say that the leds are off, are you referring to Charger leds?
Have you tested to charge the battery directly without bms?

 

[amberwolf]

http://www.endless-sphere.com/forums/search.php?keywords=Signalab&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search

 

[DavCbr]

Nobuo: The LEDs I'm talking about are on the BMS. As I wrote, the battery is charging and balancing OK

Amberwolf: I did all kinds of searches on and off this site for info on Signalab BMS's and nowhere have I found answers to the two questions I posed. That's why I posted questions here. I don't appreciate being treated like an idiot.

 

[Ypedal]

If all the cells reach 3.6v your cells are all fully charged, the led's not comming on is ok... they only come on if the cells reach over-charge condition and this is not desireable.

The thermal thing should be taped to the surface of a cell, or in the case of headway, in the crevice between them should be fine... but stick it in place so it don't bounce around otherwise it will eventually break off at the solder joints.

 

[DavCbr]

Thank you. I had assumed that the lighting of the LEDs was result of current flowing from a cell that merely had a higher voltage than another; so, from what you say, the lighting of the LEDs would actually be a cause of some concern.

Again, thanx
dc

 

[amberwolf]

Amberwolf: I did all kinds of searches on and off this site for info on Signalab BMS's and nowhere have I found answers to the two questions I posed. That's why I posted questions here. I don't appreciate being treated like an idiot.

i wasn't, i just pasted the search in because most people don't even think about looking at prior threads or don't think of possible search terms, etc., and you'd said "Any opinions would be appreciated."

apparently that was a iie.

sorry i couldn't help you, i'll leave you alone now.

 

[dnmun]

so the intent of your thread is for us to explain to you what argument you can make to demand that the seller replace your BMS with another one?

what was wrong with the one you decided was broken? did you test it in any way such as checking to see if the shunt transistors worked and if the balancing current was as expected?

i see no evidence you know anything about how the BMS functions so i wonder how you determined that this one and the other one are defective.

why don't you manually drain the high cell down and force the pack into balance?

 

[999zip999]

Tuff crowd. The signalab bms light when a cell is somewhere about 3.65v mainly higher. Then stay on on the high cell (s) till bleed down and turn off after bleeding down the high cell (s). Exact led turn on voltage can change, bms from bms. The led light (s) should light if charger is adjusted right. Charger voltage ?

 

[riba2233]

Are you even sure that your bms have led's installed? Better check that, I saw them without led's.