Rogue MegaWatt 30Amp bulk charger.
Been using my Megawatt 30 amp PSU now for over a year with the fine adjust pot, when mxwanderer suggested a 500 ohm 2 watt 10 screw potientiometer to replace the rather touchy one screw micro pot. ...
Forum Discussion
Here I though I was done with this topic.
The worst case scenario for any PS is turning it into an oscillator. I'm not saying that's the case there, but after the mod, the PS should be tested for oscillator tendencies. After all, the cable is connected to the most sensitive area within the PS.
You can minimize noise injection by limiting the cable length to <1.5" and using a bracket to mount the pot. Now there's no human body contact with the cable.
If there is oscillation, it's most likely not going to affect the battery as it is a huge capacitor. Perhaps you now have a "pulse charger". The oscillations may however exceed the limits of some of the components within the PS. That would be the primary concern.
Before doing anything further, I would test the output (unloaded) with a scope (ac setting, 200 mV/div). If the trace is flat, even when grabbing the cable or pot, then no further work in required.
Another potential problem is if one of the pot cables breaks off. What happens to the output voltage? Does it go to zero volts or does it go sky high? Or is it limited to a safe value? If it goes high you'll hear the output caps go pop. The PS reliability definitely decreased with the added pot. Mounting the pot to a bracket will help a lot.
The worst case scenario for any PS is turning it into an oscillator. I'm not saying that's the case there, but after the mod, the PS should be tested for oscillator tendencies. After all, the cable is connected to the most sensitive area within the PS.
You can minimize noise injection by limiting the cable length to <1.5" and using a bracket to mount the pot. Now there's no human body contact with the cable.
If there is oscillation, it's most likely not going to affect the battery as it is a huge capacitor. Perhaps you now have a "pulse charger". The oscillations may however exceed the limits of some of the components within the PS. That would be the primary concern.
Before doing anything further, I would test the output (unloaded) with a scope (ac setting, 200 mV/div). If the trace is flat, even when grabbing the cable or pot, then no further work in required.
Another potential problem is if one of the pot cables breaks off. What happens to the output voltage? Does it go to zero volts or does it go sky high? Or is it limited to a safe value? If it goes high you'll hear the output caps go pop. The PS reliability definitely decreased with the added pot. Mounting the pot to a bracket will help a lot.
