# Re: [EVDL] Battery tab welder and Ebikes



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Battery tab welder and Ebikes*

I have seen other pages that used "real" capacitors (audio grade usually
have high esr and are not recommended for battery welding. You really
need inverter welder

Basically it takes a certain amount of watts to do the weld. The faster
you get it done the less heat goes deep into the cell.

While these are ok for nicad or nimh they will damage lithium-ion cells.
You need a high amp short pulse. Bill can give better specifics than me
but my research says 8-10ms. This is less than one cycle on the AC in
this country and is why even the miyachi ME-35A is not reccomended for
lithium-ion. (It uses zero crossing to detect end of pulse and you can
set in increments of zero crossing) so a minimum of about 17ms. This is
too long


The other problem is that the voltage in the pulse drops adding heat but
not to furthor welding. A lot of the CD welders advertise .1ms claiming
ms is micro second and this is comically wrong. I have heard order of
10s of milliseconds. Which is more reasonable.

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