On Sat, 13 Apr 2013 23:03:57 -0500, Ignoramus17560 wrote:

I need to install a 12v winch and a battery next to it, on a trailer.
This winch may need a huge amount of current.

I hope that this auxiliary battery will provide the power needed to run
the winch, however, I want it to be charged from the vehicle's auxiliary
12v supply.

What concerns me is that when the winch is working, the battery may
demand a lot of current from the vehicle, and blow a fuse. At the same
time, after use, it may also require a lot of current with the same
result.

Ideally, I would like a current limiting device, of some kind, between
the vehicle and the wnich battery, that would limit current to some low
value, like 15 amps, happily supplying any amps under 15, but
automatically limiting the current to 15 amps only.

Is there anything of the sort, that I can purchase off-the-shelf?

I do realize that I can just wire a resistor in series, and I do have a
1.4 ohm, 290 watt resistor and some others, but I was hoping for
something more elegant.

I'd go to an RV store, off-road equipment supplier, or a truck mechanic,
explain your needs, and see if they have a suggestion.

This could all be done fairly easily with one magic electronic gizmo, and
maybe it has -- if it has, one of those above three should have what you
need.

If not, the light bulb idea sounds like a good one.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com