I have an electrical question related to a 12 volt powered truck winch application. 

I was planning to use the truck winch with an A-frame built out of 2x6 to lift my exterior walls into the vertical position. Upon opening the new winch today I see that 1.) there are two sets of power wires, one set goes to the battery, the other set goes to the "car", and 2.) the instructions state that pulling a 500 pound load, the motor will draw 32 amps at 12 volts DC. 

I had originally planned to use my 12 volt battery charger power supply to run this thing, but it's max output is only 6 amps; so I'm a lot of amps short.  So, what I'm now considering is to hook up a car battery in the circuit (ie emulate it being hooked up to a running engine) so that under load it will draw power both from the battery and the charger. 

Here's my reasoning (and that reasoning could be faulty); which I'm depending on all of you to point out.  When the engine is running the alternator charges the battery, but I'm thinking it doesn't put out 6 amps of charge; I'm thinking it puts out substantially less than 6 amps.  So, if I charge the battery at 6 amps while the winch motor is running, this all should provide me enough power to lift a wall up to 500 pounds in weight (I'm expecting the wall to weigh less than 400 pounds, AND I don't have to LIFT all that weight clear of the ground).  So, maybe the "effective" weight I'm lifting is maybe 200 pounds.

Second point.  The winch says it will pull a 500 pound load at 9.5 feet per minute (while it is drawing 32 amps).  So, I'm thinking it is gonna take a minute (two minutes max) to pull each wall to the vertical.  So, even if the battery charger isn't keeping up (completely) with the amp load, the duration of lift won't drain the battery enough to hurt it.

Comments/suggestions...thanks 

Your car altinator will put out way more than 6 amps probley around 30-50+ amps depending on the type. It is hard on a charger to run a winch due to the load. For as fast as you can build a wall I would just use the cars battry and charging system to run the winch with. Let the car idle once in a while between lifts if needed. You altinator should keep up with the winch/battry with that small a draw while it is running. Just the 2 head lights draw around 8 amps when there on. Mark

n74tg not exactly sure what type of winch you have but I would check if it is rated for Horzontal or verticle pulls.  A Horizontal pull winch will not pull verticle.  No I am not kidding.  I tried to pull 5 gal of concrete up to the top of the flue with mine.  The guides were made for Horzontal and it ended up wrapping around the shaft.  Took a long time to get it straightened out.  A solution is to use a pulley system and cable to change the angle of the pull.

I would much rather you plan to use a simple long wire rope or fabric rope (with hooks) ... and just pull up the walls with your vehicle ... used as a "vehicle".  An a-frame "ginny" (spelling?) pole would allow you to get vertical lift while your vehicle moves horizontally.

Of course, allways assume the thing will FALL!  It will!

Short lengths of chain make good tie down hinges for such as wall bottoms.  Wrapped.  Several loose loops.  Secured as though your life depends on it ... it may!

Redover is right. There's nothing worse than a birdsnest on the winch spool. Use snatch blocks to direct the pull where you want.

The winch idea is good. I do it fairly often. Use a deep cycle battery and you will get a good number of lifts without a charger.

If your attaching to the top of a wall and just lifting the same as you would if you had several people walking it up, the pull weight will be less due to the leverage and lessen as the wall comes up.

The best way to do this is attach a solid crossbrace on the A frame and mount the winch pointing up to a snatch block on the top. Make sure the A frame is anchored well and yank that wall up.

JRR is also correct that a gin pole is very useful....I;d rather use the A frame than the gin pole for what your doing because it's more stable.

If you can't anchor the A frame, use it like a gin pole and dig two shallow holes for the legs and attach the winch to the top of the A and a short leash from the top to the wall while the A is leaning. Winch the whole mess up.

Tony
Are you planning on someway to stop it from going over such as a couple of strongback's nailed to the band joist with a leg from the top to the ground?

Mike

MVK:
Someone else here on the forum used a method I like to prevent the wall "going over the top".  He used the 3-4-5 triangle idea to measure a correct length line which he attached to wall top and the appropriate distance back from the wall.  When the wall was upright, the line will be fully extended and prevent over-rotation.

Yes, there will be rigid bracing too, to prevent it from going back the other way.

Good idea, never thought of that.

Mike

This is the way I stood my 85 foot wind generator tower- I used a come-along. - OMMV

Interesting drawing Glenn.  I think I may have confused a few people in the way I described use of the truck winch.  First off, I do not have room on either side of the house to use the truck in any manner.  I have only 8' to the property line on two sides , a tall fence on one side and another house on the other side.  So, the lifting mechanism will have to be located on the subfloor itself. 

Second, the winch was bought specifically for this purpose.  It has never been installed on my truck (and never will be).

Still, an interesting drawing though...thanks

Yeah - mostly informational.