Electrical mod idea

[AllanEdie]

Hello all,

There seem to be a few knowledgeable 12v techies on here, so I would like to float an idea I have for dealing with a couple 12v issues I anticipate with our imminent 21.

Issue #1 - getting proper charge sequence to the batteries from the tug.
Issue #2 - improving the the charge regime when on shore power, as well as potential light flicker from the converter when on shore power (I know about the board replacement fix for much of this, but I don't think it would provide the control and flexibility I would prefer with regard to charge sequence for my AGMs)

I am toying with the idea of fixing both by installing a Sterling BtoB charger, improving the wire size in the tug charge circuit to drive the Sterling while mobile, and using the 12v charging output of the converter only to power the Sterling while on shore power, not to run the trailer circuits. This latter task would involve disconnecting the converter feed to the 12v fuse block, and redirecting it to the input of the Sterling. The fuse block would then be wired to the battery on the output side of the Sterling.

The Sterling will accept lower input voltage from the tug, so wire size will be easier to deal with relative to voltage drop. The Sterling will also accept whatever the converter puts out, clean it up, and output a proper charge sequence to the batteries and to the trailer circuits when on shore power.

If anyone here knows how easy it would be to redirect converter output from the fuse panel, or if I have missed anything dumb with this idea, I eagerly await feedback.

[Greg A]

I personally always like to start at the base level before doing what sounds like some expensive mods on a new trailer. Are you going FT, or is this a weekend and occasional longer trip trailer for you?
We haven’t experienced the flicker that some have talked about and doubt that’s an issue affecting a large group. Twin 6v charge fine so far on tug with no mods, at least we haven’t lacked any power to date for what we’ve needed and boondock a good bit. We don’t run fridge on 12v when traveling but use propane. I guess if we wanted to run on 12v I’d look at beefing up the tug charge capabilities.
Before we change from our current weekend usage to FT in 3 years, I’ll probably look at addressing and improving some of the power issues, but for our current usage we wouldn’t have any need to address any of the power systems.
So I guess I’m more curious as to if you are you thinking of doing these mods because of an anticipated usage/need for the trailer, or just wanting to do these mods because you just enjoy that part of the hobby?

[AllanEdie]

Perceptive response, for which thanks. For now, our plans are for trips up to a month or so, a couple times a year, full time will not happen any time soon. We typically do the trips in the off season, and will often be camped in locations where solar will not do much due to shading, so charging by the tug would be nice to have. We also, up to now, tend not to use plug ins even when in campsites, and in any case find that the power option is frequently not available as all powered sites are full. We tend not to make reservations because we like flexibility in departure and arrival timing.

All of which is to say that we may have slightly higher charging needs than typical, but as you point out, until we try the standard system, we will not know whether upgrades are necessary. In fact, I may not do the Sterling upgrade until we have some trips under our belt and see how things go.

My interest in pursuing this idea is partly from a desire for an electric system that works well from all of the three main sources, tug, solar, and plug in, and, I confess, just from my personal interest in finding solutions about this stuff. Gotta keep those grey cells busy...

Thanks for the thoughtful reply.

[Brian B-P]

Originally Posted by AllanEdie

If anyone here knows how easy it would be to redirect converter output from the fuse panel, or if I have missed anything dumb with this idea, I eagerly await feedback.

The converter sits in a compartment in the bottom of the WFCO Power Center, with just AC power in and DC power out wires. It would be very easy to disconnect the converter output from the fuse panel and connect it to the Sterling instead (with the Sterling's output replacing the converter's on same input terminal of the fuse panel).

A complication is that the "reverse polarity" fuses for the converter output are mounted on the fuse panel, not on the converter itself, so if you want those fuses between the converter and the Sterling, you would need to provide holders for them (or a single holder for a larger fuse).

[AllanEdie]

Originally Posted by Brian B-P

The converter sits in a compartment in the bottom of the WFCO Power Center, with just AC power in and DC power out wires. It would be very easy to disconnect the converter output from the fuse panel and connect it to the Sterling instead (with the Sterling's output replacing the converter's on same input terminal of the fuse panel).

A complication is that the "reverse polarity" fuses for the converter output are mounted on the fuse panel, not on the converter itself, so if you want those fuses between the converter and the Sterling, you would need to provide holders for them (or a single holder for a larger fuse).

Excellent information, exactly what I was hoping. Thanks for the alert on the fusing, I will keep that in mind if I end up doing the mod. It would be very easy to fuse the converter to Sterling connection with a large inline ATC type socket.

[rubicon327]

AllanEdie: I'm not sure of the exact electrical architecture versus what you are thinking, but nonetheless you will likely enjoy what Santiago did to his trailer. He did it primarily to utilize a 12V compressor fridge without solar (although the charger has an integrated MPPT regulator). He sold the trailer shortly thereafter, but it sounds like the system worked great. Maybe there are pieces you are interested in like optimizing charging from the tug and the DC-to-DC charger.

www.escapeforum.org/forums/f7/first-2016-classic-21ft-and-ram-1500-trip-11140-4.html#post214264

More specifics about what he used and some pictures (link to album) are in his for sale thread:
www.escapeforum.org/forums/f37/for-sale-2016-21ft-one-of-a-kind-new-condition-anaheim-ca-28-500-usd-11222.html

[AllanEdie]

Originally Posted by rubicon327

AllanEdie: I'm not sure of the exact electrical architecture versus what you are thinking, but nonetheless you will likely enjoy what Santiago did to his trailer. He did it primarily to utilize a 12V compressor fridge without solar (although the charger has an integrated MPPT regulator). He sold the trailer shortly thereafter, but it sounds like the system worked great. Maybe there are pieces you are interested in like optimizing charging from the tug and the DC-to-DC charger.

www.escapeforum.org/forums/f7/first-2016-classic-21ft-and-ram-1500-trip-11140-4.html#post214264

More specifics about what he used and some pictures (link to album) are in his for sale thread:
www.escapeforum.org/forums/f37/for-sale-2016-21ft-one-of-a-kind-new-condition-anaheim-ca-28-500-usd-11222.html

Thanks for the links, it is interesting to see (as usual) that someone else figured out the DCtoDC advantage well before I did. Santiago did more or less what I intend with regard to charging from the tug, but I will be installing solar because we want the option of longer dry camping without plugins. Thus far, we have never owned a generator, and do not want to carry one.

At this point, I may just start with the solar setup and see whether I need to enhance tug charging that much. If I find that tug charging would help, I will put in the DCtoDC system.