Happijac new vs old?
I have electric Happijacs, possibly 4600 (numbers are illegible) that are complaining. I could: 1) remove, clean and relube 2) replace the legs with 4220 or 4820 legs 3) replace the whole set...
Forum Discussion
I believe the incompatibility has only to do with the overload protection mechanism. The old jacks have a ball clutch the slips in the event of overload. The new jacks do not. The old controller board has no overload protection beyond the fuse and depends on the ball clutch. The new controller board has current sensing overload protection, it will shut off the motor if the current indicates it is stalled.
This really only comes into play when you run the jacks fully collapsed or fully extended. You can provide your own overload protection by lifting your thumb from the button. The motors are quite audible in operation and it is very easy to hear when they begin to load up.
There are numerous vendors selling the new jack legs with the old style motors attached, HappiJac has a part number for the package, so clearly they fit. Some note that you need the new controller board but I believe that is due to the overload protection scheme. On at least some sites, the clearance required for the new motors is 8 1/2 inches above the top mounting hole. This seems accurate given the quoted dimensions of the motor.
The new controller board will also supply 25 amps (there are 25 amp fuses on each output) while mine (I checked last night) has 20 amp fuses. In addition, the new controller board specifies 8 ga wire while the old one specifies 10 ga. The 4800 jack is Acme screw while the 4600 were ball screw jacks. The ball screw requires less motor torque, at least until they get dirty. I think the increase current might be needed for a 4800 jack operated near its 2800 lbs load limit. Just swapping the board though, may not be enough, you will get significant voltage drop though 10 ga wire at 25 amps. Replacing the wiring to the controller and jacks is likely a more difficult and costly job than replacing the jacks and motors.
This really only comes into play when you run the jacks fully collapsed or fully extended. You can provide your own overload protection by lifting your thumb from the button. The motors are quite audible in operation and it is very easy to hear when they begin to load up.
There are numerous vendors selling the new jack legs with the old style motors attached, HappiJac has a part number for the package, so clearly they fit. Some note that you need the new controller board but I believe that is due to the overload protection scheme. On at least some sites, the clearance required for the new motors is 8 1/2 inches above the top mounting hole. This seems accurate given the quoted dimensions of the motor.
The new controller board will also supply 25 amps (there are 25 amp fuses on each output) while mine (I checked last night) has 20 amp fuses. In addition, the new controller board specifies 8 ga wire while the old one specifies 10 ga. The 4800 jack is Acme screw while the 4600 were ball screw jacks. The ball screw requires less motor torque, at least until they get dirty. I think the increase current might be needed for a 4800 jack operated near its 2800 lbs load limit. Just swapping the board though, may not be enough, you will get significant voltage drop though 10 ga wire at 25 amps. Replacing the wiring to the controller and jacks is likely a more difficult and costly job than replacing the jacks and motors.
