Phil's Manifesto on Wire Size vs Amps

[Phil314]

Warn sells 24' of 2AWG because winching is intermittent duty and they know the voltage sag mostly costs you line speed, not function. Quick math: 2AWG is 0.1563 ohms per 1000 ft. A 24' extension is a 48 ft round trip (power + ground), so about 7.5 milliohms. A 12k winch near rated pull draws 430-460A. At 450A that's 3.4V dropped in the extension alone - before the cradle leads, the quick-connect pairs (figure another 0.3-0.5 mohm each), and the winch's own pigtails. You can easily be down near 9V at the motor terminals on a hard pull. A series-wound DC motor shrugs that off - it just slows down and the pull takes longer. For the average customer doing occasional partial-load recoveries, it works, it's flexible, and it ships cheap. It's a duty-cycle compromise, not good engineering for sustained max pulls.

Lots of good info here. And ran across this today also. Specs for the Badlands winch. Look at the 5% duty cycle.
That's 45 seconds of winching and then 14 minutes and 15 sec of cool down.
This is also why they can get away with selling 2 awg winch cable.

If your controller and number of batteries in series can support, at the exact same power draw and wire gauge, a 48v system experiences 1/16th the percentage of voltage drop compared to a 12v system. Just something to consider! (I'm sure it was discussed in your previous thread)

This is gold. Long runs of wire in 12 volt systems are a nightmare for voltage drop (like a winch at the back of a super duty). You often have to go up 2-4 wire sizes to try and get close to a 3% drop. That just isn't worth the price in a lot of case. Not to mention physically running and bend large cables is not easy.
Going to 48v makes a huge improvement in longer runs. That's why it's become popular in off-grid cabins/house and such. It just hasn't been popular with the RV market. But that is changing. 48v batteries are a lot more readily available now as are some other components. Which brings me to the Bluetti RV5 system. If you're building an RV solar/battery system, it's should be a strong consideration. In concept it's a huge step forward. Its an all in 1 48volt system (solar, inverter, dc-dc). Makes for a super simple install. I strongly looked at it, but it had a few things I didn't like (for my situation).
1. The system is well price, but the batteries are ridiculously expensive. Unfortunately they are somewhat proprietary so you have to use theirs.
2. The solar input is limited to 50v to meet some RV safety standard. So with larger solar arrays, you'll be pushing a lot of amps (larger wires).
3. It has a 5000watt inverter built in. That is massive overkill for RV. 3000watt would have been better. Smaller footprint and cost.
If they fixed these issues, the RV5 would be a game changer for rvs.

 

[MVI]

I'll see myself out now

 

[The Evil Twin]

When are we gonna get crazy and talk about paralleling conductors?
You can use 2 smaller hot wires instead of a larger single conductor. Makes long runs and tight bends easier to manage Sometimes less expensive even though it’s twice the lineal feet.

 

[Apples]

When are we gonna get crazy and talk about paralleling conductors?

BBR, Post #19 in this thread. To be fair, it was buried in the middle of a bountiful post!

Your 2/0 plan is the right call, and I wouldn't lose sleep over not running 4/0. Assume ~20 ft to the rear bumper with a dedicated ground run (double coverage of bolting a ground to the frame in tandem is what I prefer), so a 40 ft loop:

2/0 = 3.12 mohm, 1.40V drop at 450A
4/0 = 1.96 mohm, 0.88V drop at 450A

Going from the 2AWG extension to 2/0 recovers about 2 volts. Going 2/0 to 4/0 buys you half a volt for triple the routing misery. If you ever want more, two parallel 2/0 runs (~1.56 mohm) beat a single 4/0 anyway.