[quote=", post:12, topic:18538"]
I am wondering where the triacs came into discussion or may be I missed something. As per OP, the BTA16 is on heatsink (presumably on the UPS kit ?)
Anyway if there is a triac somewhere in the UPS, it is for switching transformer taps and not for rectification. The UPS kit designer might have used the triac to switch the AC input to a different winding on the input side of the transformer intending to change the output voltage which will result in higher / lower charging current.
That is what I thought initially. However if you look at the first set of pics posted by Asrar, you would see (although these are in the dark in that pic) that all the triacs seem to be wired in parallal with their tabs tied to the heatsink. The heat sinks are quite obviously connected to the secondary, of which the center tap wire is clearly visible in the photograph. So I have my doubts that these are being used to control voltage on the primary side.
Many thanks for this info and the pics. I just came back from Lahore. Had I known this, I would have certainly paid Imran & Co. a visit.
While the second set of photos is excellent, my heart goes out to the first kit. The CTs and the opto-couplers and the 6-pinned white IC (probably MOC series with zero-crossing detector triac control) and a microcontroller make this kit very interesting. One can play with the firmware to improve the system without having to get into PCB designing and all that.
Regarding your battery charging, if you have a Digital VOM then don't buy a clamp meter. Instead buy a shunt. Here is a photo of it in the link given below
This will be added in-line by cutting the red wire going to the battery and inserting it there. By measuring the voltage between the two terminals you can accurately determine the current going to or coming from the battery. Should cost you around PakRs. 400/-.