Toaster dump load
I got a new toaster as gift. So I kept the old one to make a dump load. It was a 750 watt toaster. So 750 watts / 120 volts = 6.25 amps. I figured my wire inside was rated to 6.25 amp without burning out. I want to keep it cool so I did not want any coil above 3 amps. I am not making toast. I carefully took it apart and ended up with three coils on fancy pieces cardboard. 2 outside coils shorter and one long inside coil.
I got a lawn mower battery, harbor freight vom, a jumper wire, battery charger and tested to see how much wire I need to make a 3 amp coil at 14.5 volts. My true charge 10 battery charger charges at 14.5 volts set on flooded battery in cold condition.
I got enough to make 4 coils from one outside coil. I took the wire wrapped it around a pencil as tight as I could and made the 4 coils. Tested each one and they all drew about 3 amps. (3 to 3.25) close enough I figured.
Then I went found a salvage fan from comp 2- 8 x 32 x 1 ½ screws and few nuts I had in my hardware junk. I put the screws tho the mounting holes put nut one them tightened them down tight to make mounting post, buss bar. Then I just use double nuts to mount coils and connect fan for power.
Now to test it. I knew it was too much for the small battery and charger I was using. So I took it to my 12 volt 400 amp hour battery bank. That I float right now on the grid with a Xantrex fleet power 10 monitored with a link 1000. I hooked it up on the output side of the shunt negative and the positive side on the bank with 14 gage alligator clip jumper wires. The fan came right on and the wires got to warm to touch but not a bit red. The link 1000 showed 15.1 amps of discharge at 13.6 volts 205.36 watts. It works I let it run for 10 min and the mounting bolts that holds the coils were warm but not hot at all. I will test this again and do a temp check on them. The fan is whatever kind of plastic they make them from showed no signs of melting. It needs to be cleaned up tested more but I have hopes to use it as stage one dump load I plan on using a gurd controllers for building a 3 stage dump load.
I could use some advice on how much to dump on each stage. I am building a 4 foot windmill from a ¾ hp ECM motor. I figure I can get another 4 coils from the other side and 8 from the center. Possible another 200 watt stage and 400 watt big dump. I can easily change the watts by adding or removing coils. I know I will have to make the big one different. I hope this small load design will take a long test. That I will do and be able to give temps of the mounting post buss bars. The only real problem I can see with this dump load could be the mounts getting hot and melting the fan and falling in on its self. If I build another one for stage two I will use longer bolts thanks a lot to Kurt from irc chat for helping me with the posting of the pictures
