The Big 3?

These mods have absolutely no negative or positive effect on even the newest model engine control units. The ECU will not throw a code if the wiring is connected correctly.

• Motorhomes are seldom wired correctly to provide as little voltage drop between the alternator output stud and battery positive as compared to a sedan or pickup truck
• So, the modification makes sense on an RV, it makes zero sense on a sedan with a standard alternator
• The operator of this video suggests 2/0 cable is an option - and that is ridiculous. A waste of time and money
• Even a "hot" performance alternator of 140 amps would satisfy an automobile charging circuit using 6AWG wire
• Let's take a class C with factory 240 ampere alternator -- the chassis battery does fine with the original wire gauge. If the house batteries are another 20' distant AND are big enough to accept a 180 amp charge rate then 4 gauge cable would be appropriate. FOR A 180 AMP Charging Rate.

Then there is the "issue" of the battery to chassis negative (ground) cable. The cable is plenty large enough to take care of a starter motor 130 amp draw.

With an RV the chassis negative cable is definitely important. The battery to chassis wire is OK but various chassis to house load negatives are highly suspect. A good way to minimize problems is to use power buss bars both polarities.

I have used more than a half-mile of six gauge cable improving motorhome alternator to house battery voltage drop problems. With newer 150+ amp alternator vehicles and large battery banks four gauge would be in the forecast.

For crying out loud, discharge the batteries, the use a digital volt meter to check voltage at the alternator output stud as compared to house battery voltage. "It eliminates the BS factor"