I've been looking around the net trying to find a 72v battery charger I could afford. Well, finding one period was hard and when I did it was not one that could really do much good for me. So, I decided to take apart an old Yale 560ah 3 phase charger and get started with making it either catch fire or charge my battery bank. More than charge, I'd really like to use it to equalize my batteries. It had two transformers in it so I cut one up to see how it was wired. After counting the windings, I came to the conclusion I would be best off winding my own primary and adding wraps to the secondary. The secondary was a center tap winding so I just taped up the center tap and now use the secondary as one coil. The primary side had AWG 13 and two coils but only 97 turns per coil. I tried wiring the two coils in series but found I would have had to add around 20 more wraps of wire around the secondary to get the voltage I wanted with no room to do so. I cut the primary coils and rewound with about 142 wraps of awg 10 wire that is an insulated variety. ( I know but I was not about to pull the core apart to do a proper winding ) I added some wraps to the secondary to get the voltage I wanted out to my rectifiers. It had two in parallel 4.1mm square wires already so I added awg 2 wire in series. So, the secondary has a coil setup for filter taps so, I used them but have yet to decide on which taps to use and the right amount of capacitance. I am having a bit of trouble with the rectifiers I am using so gotta get use the them. Anyway, just having some fun cuz I was bored out of my mind. I still need to build a rectifier heat sink, install the transformer in a box and add breakers/fuses and some way to avoid connecting the batteries improperly. Yes, that black you see on the test lead and wire was a fantastic flash. ( hooked jumpers up backwards. Here is the mess and the donor. Still lots of work to do.
