Sunday, 1 January 2012

Low part-count charger (Part2)

Because we are using a wall-wart (the origional supply for this charger) 100uF input filtering is more than ample. Hence in the pre-boxing picture from the last post, it's a bit hard to see where things are. In the background is the breadboard ith some of the parts still left behind. As is usual for me I order duplicate parts, sometimes in case I blow things up. The other case for spare parts is when you actually want to have a prototype that works, and a finished article at the same time for debugging.
Part 2 adds a 'full' indicator, at the moment the indicator is not bistable, and it does not switch off the charger. Ideally we actually want the trickle-charge step to trip in and out, a little hysteresis should do the trick. Here is the final diagram. (right-click and view image separately to zoom in)

Since I have not got the enclosure I ordered, (which will go under this bit) that's another reason this project is not yet closed off.

You should just be able to see the battery pack connections on the pack (top of shot) and base, I have re-built the connections with some small pieces of un-etched PCB.

1 comment:

  1. Due to a blogger error, I cannot post the circuit diagram, appologies. I will keep on trying.