BL> You can buy switch mode regulator ICs, but you have to wind
BL> your own switching coil and stuff around with fast diodes. If
BL> you're not worried about battery life, I'd use a simple series
BL> regulator with a nice big transistor on a nice big heatsink. If
BL> you need a dropping resistor, use a 12V light bulb across the
BL> regulator.

DD> I had thought of using a "simple series regualtor" but this is
DD> intended to be used at my "country weekender" where I don't
DD> have mains. Battery life _is_ a consideration. 

 I haven't got the data sheets, but those little low-voltage IC
switch-modes struggle to get 50% efficiency, and at 50% to get 6.3 at
3A you'll put in 12.6 at 3A... so what's the difference with a series
regulator? Even if you got 70% (a miracle, IMO) you'd put in 2.2A...

 The series regulator has other advantages (besides keeping your feet
warm on a cold night). The VCR motors take a high starting current
before they get the wheels turning, and that's *just* what a
switch-mode doesn't like.

Regards,
Bob
 

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