Battery click sound, now showing far too low of voltage.

[fechter]

Very strange.

The meter won't give proper readings while the BMS is attached to the pack. If those readings are true, then it would appear the discharge FETs are all open, which is a very unusual failure. The top FET in the picutre is the charge FET, which looks to have a normal reading. They should all look like that one.

 

[ihategeeks]

From Ping

The discharge circuit on the BMS has been shorted.

He has agreed to replace the BMS for the cost of shipping, and the cost of shipping back the bad one.

A+ + , would do business with again.

 

[fechter]

Ping has always stood behind his stuff. Good deal there.

Troubleshooting remotely through the forum is difficult. Moot point if you get a free replacement, but understanding how those things work and how to fix them is a challenge.

If you did actually touch your voltmeter probes together to short the output, there should be a couple of little burn marks or craters where they touched. The BMS has 'short circuit protection' but I've never trusted that feature to work on any of them. A fuse or circuit breaker is always a good idea.

 

[edventure]

Ping has always stood behind his stuff. Good deal there.

Troubleshooting remotely through the forum is difficult. Moot point if you get a free replacement, but understanding how those things work and how to fix them is a challenge.

If you did actually touch your voltmeter probes together to short the output, there should be a couple of little burn marks or craters where they touched. The BMS has 'short circuit protection' but I've never trusted that feature to work on any of them. A fuse or circuit breaker is always a good idea.

I think fixing them would be a relatively easy task if a schematic was available. I have been repairing electronics for years but the difference between having a schematic and not is like night and day. Even without having seen one of these boards or having worked on one I could easily troubleshoot it with the correct schematic. I checked and someone had created a schematic for one of the older Signalabs BMS, but I did not see one for this 2.5 version. If anyone wants to donate a burnt or broken board I would be willing to spend time creating a schematic for it. It is time consuming, but can be done and useful when trying to troubleshot one in the future.

 

[dnmun]

unfortunately, i have tested the short circuit shut off on the ping signalabs and it does work. the spot where the leads of the battery shorted on the output showed a burn but not much metal blown out. it shut off relatively fast imo.

the v2.5 signalb board is relatively simple. the opto transistor on the outer row are for the HVC and they connect to the gate of the charging mosfet and ground so when the opto turns on it grounds the gate of the charging mosfet.

the opto chain on the inside row is for the LVC and it goes to that comparator/gate driver for the output mosfets.

the circuit current comes off the top of the 4th cell. you can see the little 1kR resistor that the current passes through if you look at the traces on the underside for channel #5 and the power comes of the ground side of #5 or the top of #4.

there is spot in the corner where there are two little holes with a white square. that is where the thermal breaker plugs in normally. on the back side the vias are connected by a trace from side to side which you can cut and insiert a DIP switch in the circuit current path there so you can turn off the battery.