I purchased a commercial diversion controller for $129. I must have had to much current on the diversion load and the controller stopped working. I soaked the box in petrol to disolve the tar and this is what I found. . 1 bosch 50 amp relay $4.75. 1 zenner diode 25 cents. 1 reed relay $3.80. 2 x 220 uf capacitors 25 v $0.25 each. 1 printed circuit board wouldn't cost more then 2 dollars to make. 1 plastic container 1 dollar or less a bit of tar also cheap. The whole unit wouldn't cost more the $15 dollars to make and the Zenner diode can be sellected to suit the type of batteries you are charging. see up loaded photo for simple circuit diagram. Not sure if copy right but I drew the circuit based on the hardware I had in front of me. This controller can be used to drive a high amp relay so that the 50 amp relay doesn't get burnt out as happened in my case.
129 for 15 dollars of parts seems a bit rich.
Duplicate, please discuss in the other copy [with the circuit diagram in it] [CLOSED]