An early good morning….
After removing the core twice, I made a good transformer from this one.
I really didn’t need to add those 8 windings, as I did the first time.
This one had an extra coil for 12vdc, 11 turns of 14 ga. There was also a fine gage coil, as part of the original regulator circuit.
(For this test, I must be the regulator.)
Removing the two extra coils increased efficiency & reduced heat.
Here is my test rig on the bench, with new ac cord from that new fridge I disassembled & lightly used clamps/wires from Dad’s failed charger. I used plumber’s epoxy putty for my 120v wiring. I kept all the wires as short as possible.
I did leakage checks and diode checks, then powered it up for the first time, unhooked from the batteries. Draw spiked at 6 amps then fell to 4. No-load voltage was only 36.4vdc at the clamps. ;-(
Oh no!
This is another failure… I took out 7.5 turns and now it’s too low. Not high enough to charge this nearly 39 volt pack. Curses aplenty, mates! I don’t want to strip that core again!
BUT . . . Then I hooked it up.
As the batteries charged from about 36.7v initially to 40.7 volts in under 3 minutes, I was very happy about the performance.
In that time, charging voltage topped out about 50 volts, and current draw dropped to just 2.6 amps.
Here it is in the boat, cranking out 47.48 volts into 3 rv batteries, from just 2.9 amps @ 121.2vac. They have been on about 1 minute. These batteries haven’t been charged in about 50 to 60 days.
I was very pleased!
Now I need to go fishing so I can discharge the batteries, and do a better test.