The Big 3?

Big Brother alternators go hand-in-hand with Big Brother battery chargers.

What's next?

"According to your seat weight our smart toilet paper dispenser has per-determined the exact quantity of toilet paper that is needed. This smart-system is invaluable for eliminating paper waste and is good for our planet. And the system meets California Proposition 70090546 standards. Think Brown -- err, Green"

When the vehicle voltage is uncontrollable then the DC to DC chargers can and do make more sense, but their prices are a bit on the ridiculous side.

My VR was a bipolar whack job choosing either 14.9 or 13.7 and rarely anything in between.

Now I twist a dial and choose 14.7 or 13.6v or any dang voltage I deicide will cause warm and fuzzies, and watch the Ammeter respond in kind. and it almost always reads 2/3 higher at 14.7v compared to 13.6v.

Hot Idle speed is my limiting factor, but at 1200+ rpm, I can almsot always feed my AGM battery as fast as safely possible, because I can adjust that target voltage and the alternator is capable of 120 amps when cold and spinning fast.

But before I could do so, thickening the circuit from alternatotr to battery was efffective in increasing amperage to some degree, especially when he Whackjob OEM VR was seeking 14.9v

Any alternator, no matter the control, just attempts to maintain voltage at the output. Where the power goes the alternator does not know or care. Jumper cables are fine but will be expensive and bulky if the wire is thick enough (#2)to minimize voltage drop. Although consider a 1000 watt inverter to power a 20 amp battery charger to get the right voltage right on the RV trailer battery. Low cost MSW inverter should be fine. The upgrade in the video is not going to help.

You'd be w-a-y better off making a charger genset. A Frightening Harbor 5.5 HP gas engine and a 160 amp 10-255 Motorola truck alternator. The J-180 mounting foot alternators have adjustable voltage regulators.

The new "Big Brother Is Watching You" charging systems need a hefty DC to DC boost converter. Waste of time using a remote rectifier with a Big-Brother charging system.

Thanks for the responses. My goal is to figure out a simple and easy yet cheap method for a solar equipped (no genset) trailered boondocker to daily charge up to 80-85% SOC during 3-7 days of bad wx. Simple as maybe just jumper cables from (somewhere?) in the TV (with slight enhancements) to trailer batts. I’m not worried about fuel nor engine wear.

Ok, seems the ECU is safe. What about the voltage regulator interface with the starter batt compared with the charging wire direct from the alternator + stud?. Seems there would be a slight delta unless the regulator was built into the alternator prior to the stud.

time2roll wrote:
Dang and by Big 3 I thought he was going to pull the three phase power off the stator and use a remote rectifier.

BTDT, posted here but seem its no longer on-line. I'm still chasing gremlins out of it and the mods plus hardware are expensive (nor simple).

Ya gotta remember the era in which I was working...

Dang and by Big 3 I thought he was going to pull the three phase power off the stator and use a remote rectifier.

I see no real need for this in the video unless you have some issue to resolve.
No quantified testing to determine if there was an issue or how much it helped.
Pass

Did it on my 99 Tahoe.
I added ‘05 Escalade electric fans that draw 60 amps.
So a smaller alternator pulley on an upgraded alternator (140 amp vs 105) I also upgraded the the wiring from battery to alt and battery to under hood fuse box to 2 ga.
Don’t forget to beef up the ground wire also.

RSD559 wrote:
The ECU does control the charge on newer cars, but I don't think it cares about how much resistance there is in the charging circuit.

MEXICOWANDERER wrote:
These mods have absolutely no negative or positive effect on even the newest model engine control units.
.
.
.
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.

Comw on Mexi, let's stop beating a dead horse ! You will never get a proper, full charge on a house bank by simply paralleling it with the starting battery. DC-DC battery charging !

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"