Robaroni
New member
- Joined
- Jun 22, 2018
- Messages
- 17
Hello builders,
I'm new here but this seems to be the place to be for building powerwalls. I'm starting mine and before I study what the builders here have posted I thought I'd show the tab welder I just designed.
I started from scratch and after a lot of research and failures of my own I have a developed a very good welder. Let me give you a little background.
First I thought I would use supercaps. While I think it can be done I feel it's a poor choice for several reasons.
1. SCs require special chargingalgorithms.
2. they require a supply that current limits, not for the caps especially but to keep the power supply manageable.
3. they are not immediatelyconsistent from weld to weld because the time it takes to recharge the cap to its original point is slow.
4. they have a relatively short life. Maxwell and Eaton run 3 or 4 years if kept fully charged according to their data sheets.
Secondly I tested transformers.
1. It's hard for others to duplicate designs because transformers, while they can be rewound require cores that not everyone can easily acquire.
2. they draw a lot of power to make satisfactory welds.
Finally I chose batteries. Not just any batteries but batteries that are sealed (AGM) and are used for engine starting. The batteries have high CCA (cold cranking amps). They are also the cheapest solution but you have to know how to employ them in the design.
The batteries worked extremely well and I built a trickle charger into the designto keep the batteries charged while the welder is idle. These batteries, in this application, should last several years.
The cost should be well under $100 dollars if you build it yourself.
The function is very simple even though it uses a uC (microcontroller). The display shows mS (milliseconds) from 1 to 99. Once you get the right welding level pushing the knob in saves the value in non volatile memory. The uC prevents accidentally double hitting the foot switch after the weld process has started. It did take some experimenting to get the welds to be good welds at both electrode points but I did figure the best way to do it which I'm happy to share. It's a little technical but not bad for most of you to understand.
I've posted some pics of the finished boards andthe welder. The case, complete with boards and batteries is about 6x6x9 inches. Smaller than most batteries alone in some of the other projects I've seen.
I do have boards and programmed chips. I'm not going to sell them for a lot, just to recover my costs if anyone is interested but you will have to know how to solder SMD chips. There are plenty of YTs for those who want to learn. The design is specifically biased to builders and DIYers although it is sophisticated and functions better than most designs I've seen.
And please understand, I'm trying my hardest to be retired so please keep that in mind. I'm not going into business selling battery welders but I do value the DIY community and the ingenuity it constantly displays so I'm sharing this design with you.
I'm new here but this seems to be the place to be for building powerwalls. I'm starting mine and before I study what the builders here have posted I thought I'd show the tab welder I just designed.
I started from scratch and after a lot of research and failures of my own I have a developed a very good welder. Let me give you a little background.
First I thought I would use supercaps. While I think it can be done I feel it's a poor choice for several reasons.
1. SCs require special chargingalgorithms.
2. they require a supply that current limits, not for the caps especially but to keep the power supply manageable.
3. they are not immediatelyconsistent from weld to weld because the time it takes to recharge the cap to its original point is slow.
4. they have a relatively short life. Maxwell and Eaton run 3 or 4 years if kept fully charged according to their data sheets.
Secondly I tested transformers.
1. It's hard for others to duplicate designs because transformers, while they can be rewound require cores that not everyone can easily acquire.
2. they draw a lot of power to make satisfactory welds.
Finally I chose batteries. Not just any batteries but batteries that are sealed (AGM) and are used for engine starting. The batteries have high CCA (cold cranking amps). They are also the cheapest solution but you have to know how to employ them in the design.
The batteries worked extremely well and I built a trickle charger into the designto keep the batteries charged while the welder is idle. These batteries, in this application, should last several years.
The cost should be well under $100 dollars if you build it yourself.
The function is very simple even though it uses a uC (microcontroller). The display shows mS (milliseconds) from 1 to 99. Once you get the right welding level pushing the knob in saves the value in non volatile memory. The uC prevents accidentally double hitting the foot switch after the weld process has started. It did take some experimenting to get the welds to be good welds at both electrode points but I did figure the best way to do it which I'm happy to share. It's a little technical but not bad for most of you to understand.
I've posted some pics of the finished boards andthe welder. The case, complete with boards and batteries is about 6x6x9 inches. Smaller than most batteries alone in some of the other projects I've seen.
I do have boards and programmed chips. I'm not going to sell them for a lot, just to recover my costs if anyone is interested but you will have to know how to solder SMD chips. There are plenty of YTs for those who want to learn. The design is specifically biased to builders and DIYers although it is sophisticated and functions better than most designs I've seen.
And please understand, I'm trying my hardest to be retired so please keep that in mind. I'm not going into business selling battery welders but I do value the DIY community and the ingenuity it constantly displays so I'm sharing this design with you.
