FLA, small wires, Starlink, Roku, oh my!

[rpeders]

Finally experienced the limitations of media center 12v wiring in our 250RDS while boondocking in northern Canada last couple of weeks. I was really enjoying keeping my wife entertained in the evenings with new Starlink Mini+Roku setup for streaming her favorite shows in the middle of nowhere when I discovered...

We had been boondocking for 2 nights so our dual 6V FLA batteries were down a bit around 12.3v with lights on etc. We had been watching a Netflix show for a while when the video suddenly froze. After some checking and troubleshooting I come to find out that the voltage at the media center area was 12.3v with everything off but once you turn on the TV it dropped a full volt and then you add the amp and it was down to 11v which is apparently just about where the Roku, which was plugged in to the USB accessory outlet, lost its brains. Starlink was plugged into truck battery so that did fine but would have also been impacted if it had been plugged in to the trailer 12v. If we had run the generator earlier during allowed generator hours we would have been fine but of course we missed the window due to our late arrival back to camp after evening game drive on the Alaskan Highway to see Wood Bison, moose, etc.

Anyway I guess this will be a strong incentive to get more serious about throwing more $$$ into the RV money pit for a potential Lithium upgrade since their voltage doesn't sag like a FLA. If I keep FLA I may need to try to increase the wire size between fuse box and media center but not looking forward to opening up colorplast to achieve that. :( Or just make sure to schedule generator runs more frequently!

Anybody else had to consider wiring upgrade for the media center location?
Thanks....

[photopilot]

I doubt the wire size has anything to do with your problem. Your batteries are essentially dead. Open circuit voltage will be higher than when under load. Lithium might give you more capacity, depending on what you buy, and they will maintain voltage much longer. Also, how old are your FLA batteries? Running them down this far frequently will decrease their life and capacity.

Walt

[rpeders]

2 x 6V Interstate 225AH batteries are about 5 years old and generally lightly used each year. Water level always maintained with distilled water. Never heavily discharged. Currently fully charged and specific gravity reads around 1.265 consistently across all cells. Re-ran test with TV+amp+Roku and got about 0.8V drop while on. 13.1V off vs 12.3V on measured at 12V accessory outlet located at media center. Batteries getting a solar charge currently.

[Mark_K5LXP]

Wonder and guess, or measure and know. Run all your loads, measure voltage at the batteries, then at the load. You can then determine in what proportion the drop caused by the wiring and by the battery.

Mark B.
Albuquerque, NM

[Keodie]

I have had to upgrade the wires to the bedroom entertainment center. I have a dc sub panel wired directly to the batteries. After dry camping for a few days, in the fall and winter, batteries still around 60% and new, when the furnace would kick on, the sound on the bedroom tv would go out. Voltage at that location would drop more than 1 volt, down to around 11.5. Batteries were still showing 12.4.
I have definitely thought of running a dedicated 10 gauge wire to the living room entertainment center, as I did with the bedroom, just haven't gotten to it yet. This remedied the problem with the bedroom.
4 full river dc224-6 agm batteries still load test as new after almost 3 years.

[rpeders]

Thanks Keodie for sharing your similar experience! Now I don't have to wonder if I'm crazy So for the other curious armchair experts, here are my complete voltage readings:

Battery terminals, Fuse panel, Media Center 12v accessory outlet
(solar panel had just died out at dusk so starting voltage is on the high side)
12.85, 12.82, 12.77 @0.4A minimum background load (propane detector)
12.61, 12.32, 11.61 @4.1A TV+amplifier+Roku+background load

So I'm seeing a full 1 volt drop from battery terminals to media center when everything is fired up. 0.3 volt drop occurs between battery and fuse panel and 0.7 volt drop occurs between fuse panel and media center.

From those numbers and an online wiring size calculator we can make a guess at wire sizes without including any connection losses used:
~15' of 14AWG cable from battery to fuse center at 4.1A = 0.31V drop
~15' of 18AWG cable from fuse center to media center at 3.7A = 0.71V drop

Including some connector losses maybe they used 12 and 16 gauge which seems to make more sense. Haven't tried poking around to see if I can find a gauge size marking yet.

All I know is with new USB-C devices that can potentially draw quite a few amps this wiring is going to increasingly be a limiting factor. As an example, my phone can charge in 25 minutes drawing 60W or 5A at 12V. I currently use the USB-A outlets at 1 or 2A in the trailer but an upgrade would be nice...

[Keodie]

You're welcome!
12 awg wire on mine, but obviously other things connected in the factory circuit

[MKwilli]

We went from wet cell to lithium batteries, Victron controller, solar, etc. with great success.

[MrMark52]

Bottom line - more amp-hours, more time. Less amp-hours, less time.

Just like a tank of gas will only last a given number of miles, for a given load - depending on the size of the tank, you have to “fill ‘er up” or you’ll run out.