How best to make connection mosfet to fat wire ?

[Ray]

I have built a regulator to control battery charging using 4 IRF2804
mosfets, driven with a 555 timer, and it works ok, Charging is between 10
and 70 amps, depending on which generator I drive the charger with.

but trying to connect #12 wire to the small leads on the mosfets which are
mounted to a heatsink was a problem. I destroyed a couple by tearing off
the leads when trying to route the big copper wire. Also hard to solder big
wires so close together...

Thanks for any ideas

M

 

[Ray]

You need to get a piece of copper clad circuit board. Then, use a Dremel
with a fine bit or cutting wheel and remove enough copper so that you have
the two or three pads (per fet) necessary to solder your fets to, and
leave enough copper to solder heavy wires to. You could even drill holes
to route the wires through to give it additional mechanical support.

I think Radio Shack still carries this type of board. Is there a Frys near

Thanks for the answer

I had thought about something like that, but was concerned that the circuit
board thickness might not carry the current..
I guess id have to look for a fairly thick copper coating.

 

[Phil Allison]

"Ray"

I had thought about something like that, but was concerned that the
circuit board thickness might not carry the current..
I guess id have to look for a fairly thick copper coating.

** Only the source lead needs to have a large area pad - and you can make
it as big as you like as that lead is on one side.

The common drain connector is the heatsink

Running solder all over the pad and drain lead reduces resistance to a
trivial amount.


..... Phil

 

[Ray]

You need to get a piece of copper clad circuit board. Then, use a
Dremel

Instead of copper-clad circuit board, just use
perf-board. Enlarge holes as needed for the
14-gage wire, a short distance from the holes you
are using for the FET leads. Push the FET leads
and wire through the board from the top, solder on
the bottom. You may be able to bend over the FET
leads to wrap around the wire ends, or vice-versa,
or use separate hookup wire between them.

**Thanks for the idea's Guys....

Should be able to a better job on the next try

M

 

[default]

I have built a regulator to control battery charging using 4 IRF2804
mosfets, driven with a 555 timer, and it works ok, Charging is between 10
and 70 amps, depending on which generator I drive the charger with.

but trying to connect #12 wire to the small leads on the mosfets which are
mounted to a heatsink was a problem. I destroyed a couple by tearing off
the leads when trying to route the big copper wire. Also hard to solder big
wires so close together...

Thanks for any ideas

M

Many hardware store carry copper flashing, you could make heavy duty
fiberglass circuit board material.

You could bolt ordinary copper circuit board strips to aluminum
rectangular bar stock from the hardware store to beef up the current
capacity.

Just run some #8 solid wire between two insulating supports.

You can special order metal from onlinemetals.com

http://www.onlinemetals.com/merchant.cfm?id=87&step=2&top_cat=87

copper rectangular bar stock
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