Need regulated 12v output to handle 70A

[perts]

I need a circuit that will take in 14 v and put out a regulated 12v with a max load of 70A for 4 minutes. Any ideas of what circuit I can make?

 

[ScottyUK]

A voltage regulator? There are many designs for low drop-out regulators out there. Which ones have you tried? 70A is a fair bit of current but not ridiculously high. Given the option a switch-mode type would have the lowest losses but dropping a couple of volts is certainly possible using a linear type if you don't mind a big heatsink and a fan (or a really big heatsink and no fan).


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If we learn from our mistakes I'm getting a great education!

 

[iop95]

Difference between input and output is prety small, only 2V and have to supose that input voltage drop at full load will be very small.
Depending what mean "regulated" 12V - what % is allowed for application, one simple way and cheap is to put 2 or 3 series power diodes to obtain 11.9 - 12.4V output voltage. Large heatsink may be needed. If is not acceptable you'll need a converter, maybe with transformer 1:1 or even slightly higer to overcame this small input-output voltage difference and by PWM control to obtain a very stable 12V output.

 

[MikeHalloran]

I wondering why/if you actually need a regulated 12V.

Most of the current consumers I can conjecture that have a nominal voltage of 12, are actually intended for use in automobiles, where the system voltage at which devices are expected to operate ranges between 8-ish and 14.5-ish volts.



Mike Halloran
Pembroke Pines, FL, USA

 

[MiketheEngineer]

Dumb structural here - but wouldn't a big car battery work?? Or maybe a couple in parallel??

 

[waross]

Car battery voltage may be over 14 Volts at no load, and below 12 volts when partially discharged and under heavy load. 13>8 Volts has been a widely used full charge voltage for automotive batteries and I have seen higher settings.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zzzjim]

At 70A , make sure wiring losses don't spoil your 2V !

 

[IRstuff]

With total load of 171 m[Ω], you don't have much margin for parasitic losses

TTFN

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[VEBill]

Many power supplies of this sort of current class would provide 'remote sensing' terminals to accommodate voltage drop in the cabling to the load.

What's the application?