Darren2018
100 W
- Joined
- Aug 18, 2018
- Messages
- 223
I just thought I would show a few quick mods I did for the Sunkko 709AD.
My goal was to increase the efficiency of this welder as I like to weld really fast and I hate waiting for things like wires, circuitry or the welding tips to cool down. I have a "boss welder" that puts out way more amps and welds copper but it just cannot keep up with high speed welding and is quite fussy which is why I use the Sunkko AC transformer welder for welding nickel (this also suffers from overheating if you go fast enough and the welding pen they supply overheats even faster). I also kept running into problems with the soldering iron when soldering really heavy AWG cables as it would cut out when its mosfet (I believe this is the reason) would over heat. The iron on this welder can get extremely hot and deal with almost anything except for things like 4AWG, soldering directly to cells or soldering 8AWG to PCB's is really easy but it cuts out after a short amount of time. I assumed this welder was supposed to be for enthusiasts or possibly light professional use but in its stock form it's not very good.
When I opened it I found a few very obvious things that were wrong. First was the mains cables were touching the transformer, these bounce all over the place when welding so I tied them up and out of the way.
The second problem was the fan, they used a 30ohm 1 watt resistor in series to the 12V 320mA fan, this gets extremely hot! The fan is switched via an IC on the board which provides 17V when the temperature of the transformer rises. I deleted the thermistor from the transformer and used a 47K resistor instead, the thermistor was around 140K at ambient (I probably didn't need the 47K resistor as shorting it might have been ok). Now the fan is on all the time and still uses the DC supply from the board, to get the desired fan speed I used a cheap buck converter which I set to around 10V. I also reinstalled the fan in the opposite direction so that I did not need to use more than the one original fan or DC power supply to be able to cool the transformer and now also the main board and the mosfets. Here is a picture of the connectors, I didn't take a picture of my board and this one only has the plug for the LEDs but I have labeled where the others will be.
The third and final problem are the cables that deliver the energy to the weld. The main tips deliver slightly more energy than the pen attachment but I prefer welding remotely so I got rid of the main welding tips and added lots of extra copper. I added some 12AWG to the stock 10AWG? wires coming out from the transformer, the stock cables were not insulated and the loose braid meant they were oxidising pretty badly. I didn't solder all the way down to the transformer so I could keep a little bit of flex but now those cables are huge and well insulated. I then added 65cm of 6AWG silicone for my main cables, this never gets hot no matter how any welds you do or however fast you go with nickel. I use 3mm diameter copper rod/nails for welding tips which I solder directly to the welding cables, these last forever and do not get more than warm with 0.15 nickel pulse settings.
When I get around to it I will be modding my "boss welder" so it can weld copper a bit more reliably (I have already been through 1 set of mosfets although to be fair it was treated quite hard). I currently use a 6Ah graphene pack but I will be paralleling another 5Ah, giving it some extra copper for the battery/source/drain, adding CPU cooler, 2AWG cables and heavy duty tips.
My goal was to increase the efficiency of this welder as I like to weld really fast and I hate waiting for things like wires, circuitry or the welding tips to cool down. I have a "boss welder" that puts out way more amps and welds copper but it just cannot keep up with high speed welding and is quite fussy which is why I use the Sunkko AC transformer welder for welding nickel (this also suffers from overheating if you go fast enough and the welding pen they supply overheats even faster). I also kept running into problems with the soldering iron when soldering really heavy AWG cables as it would cut out when its mosfet (I believe this is the reason) would over heat. The iron on this welder can get extremely hot and deal with almost anything except for things like 4AWG, soldering directly to cells or soldering 8AWG to PCB's is really easy but it cuts out after a short amount of time. I assumed this welder was supposed to be for enthusiasts or possibly light professional use but in its stock form it's not very good.
When I opened it I found a few very obvious things that were wrong. First was the mains cables were touching the transformer, these bounce all over the place when welding so I tied them up and out of the way.
The second problem was the fan, they used a 30ohm 1 watt resistor in series to the 12V 320mA fan, this gets extremely hot! The fan is switched via an IC on the board which provides 17V when the temperature of the transformer rises. I deleted the thermistor from the transformer and used a 47K resistor instead, the thermistor was around 140K at ambient (I probably didn't need the 47K resistor as shorting it might have been ok). Now the fan is on all the time and still uses the DC supply from the board, to get the desired fan speed I used a cheap buck converter which I set to around 10V. I also reinstalled the fan in the opposite direction so that I did not need to use more than the one original fan or DC power supply to be able to cool the transformer and now also the main board and the mosfets. Here is a picture of the connectors, I didn't take a picture of my board and this one only has the plug for the LEDs but I have labeled where the others will be.
The third and final problem are the cables that deliver the energy to the weld. The main tips deliver slightly more energy than the pen attachment but I prefer welding remotely so I got rid of the main welding tips and added lots of extra copper. I added some 12AWG to the stock 10AWG? wires coming out from the transformer, the stock cables were not insulated and the loose braid meant they were oxidising pretty badly. I didn't solder all the way down to the transformer so I could keep a little bit of flex but now those cables are huge and well insulated. I then added 65cm of 6AWG silicone for my main cables, this never gets hot no matter how any welds you do or however fast you go with nickel. I use 3mm diameter copper rod/nails for welding tips which I solder directly to the welding cables, these last forever and do not get more than warm with 0.15 nickel pulse settings.
When I get around to it I will be modding my "boss welder" so it can weld copper a bit more reliably (I have already been through 1 set of mosfets although to be fair it was treated quite hard). I currently use a 6Ah graphene pack but I will be paralleling another 5Ah, giving it some extra copper for the battery/source/drain, adding CPU cooler, 2AWG cables and heavy duty tips.
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