Viewing post history: Re: low cost DIY battery spot welder

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This page shows all versions of the post, starting with the most current version.

Current post: Re: low cost DIY battery spot welder

Postby tatus1969 » Fri Jul 07, 2017 9:01 am

fechter wrote:Really nice looking board. About the only thing I would worry about is the board foil carrying all the current the short distance from the FETs to the bus bars. Some Riba welders managed to blow the foil off. If the copper is heavy enough, no problem. Alternative is to add copper where needed.

Thanks :D I am also afraid of that. But the board is double sided, and if it is not strong enough, then I can double the copper thickness. The cross section is approx 2.3 mm^2 for the top layer, and the length is 0.5mm. This makes a resistance of 3.7 micro ohms, and at 3kA the power dissipation would be 33W. That should hopefully work out even without bottom layer. And I have deliberately made the bus bars thick for good heat transfer, otherwise they are overdone even for these currents.
Edited by tatus1969 on Fri Jul 07, 2017 9:02 am.
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Original post: Re: low cost DIY battery spot welder

Postby tatus1969 » Fri Jul 07, 2017 9:01 am

fechter wrote:Really nice looking board. About the only thing I would worry about is the board foil carrying all the current the short distance from the FETs to the bus bars. Some Riba welders managed to blow the foil off. If the copper is heavy enough, no problem. Alternative is to add copper where needed.

Thanks :D I am also afraid of that. But the board is double sided, and if it is not strong enough, then I can double the copper thickness. The cross section is approx 2.3 mm^2 for the top layer, and the length is 0.5mm. This makes a resistance of 3.7 micro ohms, and at 3kA the power dissipation would be 33W. That should hopefully work out even without bottom layer.
Resistance is futile - We Are The Watt.
User avatar
tatus1969
10 W
10 W
 
Posts: 98
Joined: Fri Mar 17, 2017 7:36 am
Location: Germany

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