That's a much better video than the previous one IMO. When charging LiFeP04 batteries it is important to have a good DC2DC charger that can vary its draw based on the input, such as the Victron chargers. Also, it is my understanding that our Super Duties come with "smart" alternators, which will also vary the alternators output based on input to the ECU.

 

Nothing at all against you Black Buzzard, but I am going to pick on this video and Victron a little bit.

This is either an engineered experiment designed not to explore any real scenario but to create a specific result, or just an ignorant experiment by people who don't know what they're doing.

First, some of the statements are bologna, the one that really made me laugh was "Most alternators can only deliver their rated current at high RPM speed, which works for a lead battery, but not for lithium batteries. A lithium battery will also draw a high current at low speed" Alternator speed has no bearing whatsoever on what current a battery will draw, the battery's internal resistance determines this. There is also no reason that a lithium iron phosphate battery can't be manufactured with an internal resistance that is suitable for use with an automotive alternator out of the box and in fact some are. A lead battery can also be manufactured with an internal resistance that will smoke an under-spun alternator in exactly the same way. Just for reference the typical lead acid battery has an internal resistance of about 5 milliohms, a LiFePO4 not designed for automotive use will be about 1 millohm, 1/5th the resistance so 5x the current draw. So what's the real problem here? It's that they chose the wrong battery, either on purpose or through ignorance, and headed towards failure from the battery side of the equation.

Second, their "engine + alternator" configuration is using an apparent 1:1 pulley ratio between the engine and the alternator. In the real world that ratio is typically 3:1. The RPM figures provided are coming from the motor's speed control, so when they're saying 3,000 RPM or 1,500 RPM they're giving us both motor and alternator RPM where alternator RPM is all that matters. They do correctly stress the importance of alternator RPM when talking about the alternator's fan and cooling. Then they subtly but abruptly shift the context of RPM to the hypothetical engine's RPM; talking about 1,500 RPM: "..note that this is still above the typical speed of an engine running at idle". This gives the false sense that the "low RPM" test is still actually in the alternator's favor when in fact it's exactly the opposite. The RPM of an idling engine is irrelevant, the alternator RPM is what matters and with a 3:1 ratio the alternator RPM of a typical engine running at idle is about 2,100 not 1,500, or a 40% increase from their scenario. If they were being genuine then they would have instead said something like "...note that this is well below the real world alternator speeds that you would find with an engine running at idle." So what's the problem here? They're dramatically under-spinning the alternator below real-world speeds creating a scenario that is miles off the alternator's efficiency island, headed towards failure from the alternator side of the equation.

When both of these failures are attacking from both sides they have the very predictable result of smoking the alternator. It's a good show, but it's also kind of B.S.

I don't know if it's malice or ignorance, and there's a famous saying out there not to attribute malice where ignorance is a simple explanation, so I'll give them the benefit of the doubt that this "experiment" and video was made in ignorance.

They then advertise some of their products created to solve these problems, and I'm not doubting the quality or efficacy of those products at all but I'm not at all surprised that the video is manufacturing problems in order to then push solutions. My advice is to just select a compatible battery in the first place, but if you do have the wrong battery then it looks like these guys have you covered.

 

People selling stuff always produce end of days scenarios as to why you need their products.
Lota and lots of people run DC2DC charging in their tow vehicles with zero problems. If all these alternators were being smoked, wouldn't we be reading about it on these forums?
Pure copper wire is ideal, but not necessary. These chargers are not in continuous use. Lots of people are using Chinese wire with zero problems.

I am going to wire my DC2DC charger with 1ga battery cables. One set of 30' cables will give me enough wire to go from my battery to the bumper and the bumper to the toy hauler.
Running down the road, my only power draw is the fridge. The DC charger will only draw what it needs, which is very little, especially with solar.