Tapping 12V from the truck to charge Battle Borns

[howson]

He indicated that under no circumstances should I wire anything directly to the alternator, and only connect through the battery, otherwise the power management system is bypassed and the amperage draw could damage the alternator, especially if a short occurs. He indicated to always tie to the battery, or an up fitter switch as those are protected.

The Renogy manual states this emphatically:



The Victron wiring shown may just be a visual distraction--obviously at some point the battery is connected to the alternator (or the battery wouldn't charge).

[TucsonJim]

howson

I find it interesting in those two drawings from Victron that they identify a "Load" instead of the house or RV battery.

Secondly for those reading. You'll never go wrong with an isolated version. The primary reasoning for the fourth wire is in case there is excessive resistance on the ground path between the tow vehicle and the RV. In a motor home, there's no potential issue since the grounds are all tied to the same chassis. But in a towable product, you may find increased resistance due when you consider the connection going through the 7-Way, and to some extent the tow ball and hitch. It's just a more sure thing if you send each ground to it's respective vehicle. The down side is that more wire is required to run the second ground.

Jim

[Jpooler]

Hey howson,

I am FINALLY starting to think about adding a DC to DC charging system to my setup. (I am getting sick of arriving at boondocking locations with less than 100% charge)

I am curious after you started using your truck's alternator as the power supply to charge your coach's batteries, if you have noticed a drop in your engine's performance? Like less power uphill, or decreased MPG? I am assuming that adding another load onto your alternator would require the engine to work more. And what kind of strain is being added to the alternator? Have you needed to replace it?

[Country Campers]

Jpooler

Depending on what battery system you have in your RV and what usage you are experiencing during travel you could use a 20 amp DC-DC which your Chevy wiring circuit is already set up for and there would be no real extra draw on the alternator. I did this on my Chevy and have experienced no issues to date.

Brian

[Jpooler]

Country Campers Do you happen to have a schematic of your system? I would love to see what you did!

[ncitro]

Hey howson,

I am FINALLY starting to think about adding a DC to DC charging system to my setup. (I am getting sick of arriving at boondocking locations with less than 100% charge)

I am curious after you started using your truck's alternator as the power supply to charge your coach's batteries, if you have noticed a drop in your engine's performance? Like less power uphill, or decreased MPG? I am assuming that adding another load onto your alternator would require the engine to work more. And what kind of strain is being added to the alternator? Have you needed to replace it?

I cannot speak for Howard, but I have the same system and have not noticed any change in my truck performance. I also installed the same DC to DC on my father in laws trailer and F150 with the stock (much smaller than my F350) alternator and he has not seen a perfomance hit either.

[Country Campers]

Here is my thread DC-DC Charge install Reflection 29RS - Grand Design Owners Forums (gdrvowners.com) Plenty of others have done this as well. The hardest part is finding the correct wires from the sliver box that the 7 RV plug wire connects to the trailer wiring.

Brian

[howson]

I am curious after you started using your truck's alternator as the power supply to charge your coach's batteries, if you have noticed a drop in your engine's performance?

No impact to the truck that I'm aware of -- easily one of the best mods IMHO.

[Jpooler]

Country Campers Thank you for sending me your thread!

Thanks all for your input on your experience. I am starting to look into adding this to my setup and started to get worried about the possible impact on the truck. I just upgraded from a 1500 to a 2500 and still reeling a little from the sticker shock at the gas pump, lol. Though I definitely enjoy the 2500 more!!!

I'll keep y'all posted on what I end up doing!