Running DC wire

[Ray D]

My hydraulic motor for the slides needs a 200 amp DC breaker, the length of the run is 10', so that means 4/0 wire.  Will the circuit operate better with a 4/0 ground wire returning to the batteries or will the bus frame be just as efficient???

Thanks,
Ray D

[HB of CJ]

Will 0000 cable be heavy enough?  Lots of times the charts will indicate a 5% voltage drop when actually the stuff will run a whole lot better with only a 1% or 2% voltage drop.  I have no idea what the voltage drop will be with 200 amps running 10 feet.

No way to make this thing work on 110 AC or even 220 AC?  Might consider relocating a dedicated BATTERY closer to the works to keep from having to run such heavy cable, then run much smaller wires just to keep it charged up?  How long will it run for?

Yep, the chassis is not a wire and should not be considered as such.  Run that return heavy DC cable or cables.  Perhaps you can gang up and run twin 0000 wire.  Crimp, don't sodder and use that heat shrink wrap stuff.  Support the cables  frequently.  HB of CJ

heavy DC cable Post

[Ray D]

I figure with 4/0 at 10 feet I will have a 3% voltage drop and the pump specs say that is acceptable.  No on the voltage, it has to be 12VDC.  I was just hoping that the frame would save some money, but it doesn't look like it.  Anyway, why isn't the frame good for this, not questioning you, just querious?

Ray D

[boogiethecat]

I'd try it using the frame and measure the motor voltage when it's running.  If the drop thru the frame is too much, it's easy enough to add a ground return wire at that time.  If the drop is acceptable, you win...

[TomC]

I believe that virtually every vehicle uses the frame for ground return to the battery with the starter.  I don't know of a higher draw device then the starter.  Since the manufacturers don't think a wire ground return is necessary for the starter, why would it be necessary for a 200 amp motor (starters are more in the 2000 amp range).  Good Luck, TomC

[Nusa]

While it's true starters are typically grounded to the engine block, the engine block itself needs to be properly grounded (can't expect motor mounts to be a reliable conductor). On some vehicles that's to the frame, on others its directly to the battery. Long ago, I actually had what appeared to be a starter failure on a 1969 Cortina because the engine ground strap had worn through.

In any case, a dedicated wire run is going to be better than a frame connection, even if a frame connection will work.

[Sean]

Maybe this is a dumb question, but wouldn't it be cheaper to put the pump next to the batteries and run extra hydraulic line, rather than four-ought cables?  I know for sure it will be easier to make the hydraulics go around corners -- the bend radius on THHN is probably close to two feet, maybe half of that on DLO.  Even welding cable in that size can't make a sharp turn, whereas you can put 90° fittings on the hydraulics.

Just a suggestion...

BTW, if 3% voltage drop is acceptable for your motor, you can get away with 00 (2.67% drop at 10')

-Sean
http://ourodyssey.blogspot.com

[Melbo]

Thank you Sean

That is what my math said

Melbo

[HighTechRedneck]

... wouldn't it be cheaper to put the pump next to the batteries and run extra hydraulic line, rather than four-ought cables? 

That is what I was thinking as I read it.  Same principle as using more air hose rather than an extension cord with a portable air cormpressor.