Battery Charger build

A while ago I had acquired an old 8 amp selenium rectifier car battery charger.

I took the parts from that and built a new one.

 

But I needed a case. I had discarded the old one.

Recently I found this Brumberger film carrier:

 

 I drew up plans in autocad for the front and back:

 

I laid them out on the front and cut the holes out.

The timer I got is a Haydon Model ADI 1A001C D130302.

The actual timer on the back is a General Time E15450 A2631A1 timer.

The cover plate (which is a sticker) says OFF, EQUALIZE, and NORMAL CHARGE. It appears the only source for these is here: http://www.electronicsurplus.com/haydon-1a001c-d130302-0-16-hours-adj-timer-120v-spst-28a

The unit has 2 black wires for 120vac 60hz and 2 spade connectors for the switch. The switch can handle 250vac 28 amps. The shaft is a standard D type.

I will use a 25 watt 10 ohm POT's so I can vary the input voltage to the transformer. This charger originally had selenium rectifiers so the output voltage is about .5 volts too high. I need to reduce that and do not have any diodes that can handle the 14 amps that this charger can put out before the self resetting circuit breaker kicks in. I want to vary the input voltage anyways to experiment with some of the charging methods I have been reading about. I only need to adjust between 1 and 8 ohms to reduce the input voltage from 125 vac to 115vac if needed. My wall voltage can get rather high sometimes. I do not want to use a variac. I also do not want to over complicate the charger with a DC voltage regulator.

The finished unit:

I used a 50 amp quick disconnect so I can connect the charger to standard clamps and to other types of connections.

There is only one fan on the back, the bottom is just a vent hole.

The timer is set by moving it clockwise or counter clockwise to either "normal charge" or "Equalize". The timer moves clockwise and opens the charging circuit when it hits off. The separate power switch means that the fan will continue to cool the unit once charging has completed.