The big voltage rip off in my SUV

[NinerBikes]

Since day one, I've always had marginal charging ability from my VW Touareg to charge up the travel trailer battery on trips. Almost without fail, driving and trailering all day, the silly 1/3 or 2/3 charged wall light indicator would show 2/3 charged within minutes after stopping for a lunch break or a Wal Mart overnighter.

Yesterday, I was dinking around with the electronic control module with some Ross-Tech Volkswagen Audi Group (VAG) software, and that software allowed me to see and set all kinds of parameters. The clue to me was that even after starting up glow plugs on a cold motor, the maximum Voltage ever shown on my Scan Gauge II was 14.2V. It would drop down to 14.0 or 13.9 within minutes. And it was then, when I saw the adjustment in the Ross-Tech for voltage charging setup, that I saw that my SUV diesel is set for running a factory AGM battery... and a factory AGM battery should get, tops 14.4V, and 14.4V is not enough for my T-1275 to keep it topped off and fully charged while driving.

So forgive me for having a double facepalm moment. The point is don't mix types of batteries and expect 100% performance. Eventually, I may get an AGM battery that likes 14.4V for my travel trailer. Or just set up the solar panel quickly when I get to a campsite and hope I have a few hours of daylight left to get that last 25 or 30 AH back into the battery and topped off before night fall.

But a fussy charging 14.8 or 15.0V demanding battery on the trailer and an AGM that likes 14.2 to 14.0V from the alternator on the SUV is not the best working combo while driving down the road trying to get to my destination.

[jrnymn7]

Mex,

If you would, please elaborate on installing an "external regulator". You've mentioned it to me and a few others. And seeing as I'm looking at charging with the alternator in the future, I'd like to know what's involved, thanks!

[MEXICOWANDERER]

In this Baja California wood frame house, I am seriously considering getting a Ker-O-Sun heater and running it on ULSD ultra low sulfur diesel. It'll use a gallon per night and keep me toasty warm. The place is, ah, er, not quite airtight.

Heating Thread? Cool

[jrnymn7]

Yes, but then it may cycle on and off a lot. I'm assuming, of course, the T would only turn it on and off, not adjust its output, like the adjustment on the wave 3.

Anyhoo, perhaps the heating thread would be a more appropriate place for any further discussion. 🙂

[pianotuna]

Hi jrnymn,

You forgot the thermostat on the Platinum Cat--so if it is too warm, you can turn it down. Where I live it would not be nearly enough in mid winter.

[jrnymn7]

Yes, I'm quite familiar with the platinum cat. Nice unit. I'm concerned its 3000 btu's may be a little too much at times. The Wave 3 is 1600-3000 btu.

[pianotuna]

Hi jrnymn,

I'd encourage you to consider the platinum cat instead. Yes, it is double the price. And safer, and has a thermostat, and has a chimney.

Niner, Get an external regulator for the house bank.

X3 on the solar while driving. Heck, mine even sends some amps to the chassis.

[jrnymn7]

Niner,

Do you mean the Wave 6? If so, where did you buy it?

I'm looking at installing a Wave 3. If I do, I'll be running it off a separate 20 pounder. I carry two of them, and will not want to have to get them filled too often.

Please keep us informed as to propane consumption, if at all possible. Thanks.

[dougrainer]

If you would run a 8 gauge charge wire from your Alternator charge lug to the 7 way on your tow plug(you will have to adapt from 8 to 10 or 12 gauge at the plug to get it inside the plug. Then run a 8 gauge from your Tow trailer side to the RV battery. I will bet your charge problem will go away. Wire SIZE is critical when charging 12 volt systems. The factory tow vehicle wiring is never large enough to adequately do a good job. Also, doublecheck the ground wire also. The larger (8 gauge) ground wire is also needed. It takes BOTH large cables on a 12 volt system to flow the current needed. Hopefully you are not using the ball as the ground. Doug

14.4 is more than enough to charge your battery.

[NinerBikes]

I'm just going to go with the generator and the MegaWatt when I get there. 1 hour and 33 amps trying to go in to the 150A/H rated battery will have to be "good enough" for the first night. Then an hour again first thing in the morning.

Waiting for my solar 6 heater to arrive today, plumb it in and thinking about trying some winter style camping near Yreka on the Klamath River.

[landyacht318]

Good enough is hardly ever ideal.
Even if you were to be able to dial it upto 15v, voltage drop to the trailer would be your nemesis.

My recent roadtrip showed mine likes to sit at 14.7 even after both batteries are practically overflowing, and other times when the screwy 31 is down at 60%, it says 13.9v is just plenty even with more than enough rpm and airflow to bring battery to 14.9v, and some other times 14.9v is some magical number, but usually only after the batteries no longer need that much.

I fear for the AGM battery at long exposures to 14.9v and have removed it from the loop on longer drives.

Screwy regulators. I think they smoked too much crack and change their mind more often than a woman in a designer shoe store.

[SteveAE]

smkettner wrote:
Solar works great on the roof while driving.

X2

[time2roll]

Solar works great on the roof while driving.

[MEXICOWANDERER]

600-watt DC to DC converters are miraculous. Send 80 volts back to the trailer then tweak the second converter on the trailer to whatever you like. Wanna equalize or top charge while driving - that can be arranged...

[MrWizard]

No it's not
But you can try using an inverter in the vw tow powering a battery charger attached to the tt battery
Other members have done this
You might have a fussy battery
But unless you have strung new wire 8ga or 6ga in the tow..for the tt chg circuit
It's the small wire in the tow chg circuit that is causing a voltage drop and amps block so the tt battery is only receiving about 13v at low amps
Which is you're real problem