Charging the batteries using tow vehicle

[bci]

Hi:

My 2007 30'SO is wired _not_ to charge the batteries from the tow vehicle. The power goes only to the hydraulic disk brakes.

In the drawings, it show a dotted line where the charge line from the 7-pin connector would have gone, if not diverted to the brakes.

I would like to change the batteries while I am moving the trailer. When traveling cross country, we drive, then sleep at a truck stop, then repeat until we are at our destination. I _really_ do not want to have the generator running in the back of the truck, plugged into the aux generator port I had installed on the trailer, while driving down the highway.

Any ideas?

Kent Behrends

[overlander63]

You should be able to charge the battery from the tow vehicle, there should be one pin of the 7 that is exclusively for this. The brake line should be separate from the charge line.
IIRC, the charge line is either the very top pin, or the one right next to it, in the plug.

[azflycaster]

It sounds like the charge line is used to power the hydraulic pump for the break system and does not connect to the trailer battery. If you tied the battery and the pump together it would charge the battery, but run the pump all the time (even when disconnected) as well. Since you have only 7 pins to work with you could eliminate one and run a separate charge line. The backup lights (center pin) would be my logical choice if I was doing this. You would have to rewire the truck as well as the trailer and document everything for future reference. The other possibility would be to run a separate wire fro your truck to the trailer. This would be much simpler, but not as clean of an install.

[thecatsandi]

Originally Posted by kent@bci.com

Hi:

My 2007 30'SO is wired _not_ to charge the batteries from the tow vehicle. The power goes only to the hydraulic disk brakes.

In the drawings, it show a dotted line where the charge line from the 7-pin connector would have gone, if not diverted to the brakes.

I would like to change the batteries while I am moving the trailer.

Any ideas?

Kent Behrends

Changing the batteries while moving that would be a feat! Charging the batteries should be accomplished using the batt line on the 7 pin connector. The actibrake uses this for power. If it can't use the TV it uses the trailer batteries. Check the fuse for the charging line. It is probably not there or blown.

If you have a Dodge or GM. Disconnect at night. A Ford will disconnect this line when you turn off the ignition. the others do not.

[overlander63]

Michelle, if the charge line does not go direct to the Actibrake, it will use the trailer battery? Why not install a slightly heavier charge line, and let the Actibrake draw power from the battery.
Also, if his batteries are mounted up front, he could do an "Indiana Jones" battery swap while his co-pilot drives...

[DPeakMD]

Kent-

You've got an interesting point. I won't pretend to know how your trailer's actually wired. But, I think you're finding out something, at least in the printed material, that jives with what I found in my instructions from Actibrake.

I called Actibrake and spoke with them about this when I did my installation. If you read their instructions carefully, they want you connect the 'charge' line to the umbilical as you've described. The battery would be accessed only in the event of a breakaway. And the trailer battery would not be charged. (I confirmed that with them).

They told me they did it that way for the reason that most non-RV setups use a small battery only for break-away purposes. It had to do with low voltage on those batteries because they sit around uncharged often times. He told me it was OK to hook up the power to a shared common point between the lead coming from the tow vehicle and the positive lead to the battery. He said to cap the other lead and not use it. (The one that would otherwise go to the trailer battery).

So, back to your situation. I'd see how your trailer is actually wired. Call Airstream or Actibrake for confirmation, but there is definitely no reason that I'm aware you couldn't charge your trailer battery from the TV.

Now whether the battery charges very much, that's subject to a lot of other factors!

Good luck!

[Lumatic]

I would check the wiring from your TV matches up with the wiring in the umbilical. I had to switch my wiring around to get my 99 Ford to match up with my 71 AS.

[thecatsandi]

Originally Posted by overlander63

Michelle, if the charge line does not go direct to the Actibrake, it will use the trailer battery? Why not install a slightly heavier charge line, and let the Actibrake draw power from the battery.
Also, if his batteries are mounted up front, he could do an "Indiana Jones" battery swap while his co-pilot drives...

The charge line does not go directly to the actibrake. It only uses the brake line for signal. Not power to the unit.

[JPAIRSTREAM]

On the new Actuator you will not see 12 volts by testing at the seven way on the trailer. The actuator is controlling the charge to the batteries thru its board. Allowing the power to go into the system but not back out to the 7-way.This has not always been the case. On the original old style the vehicle charge was still ran direct. Then the newer style had a control built into it to monitor and control it.

[HowieE]

Can you post a picture of the diagram you referred to? I would like to see this dotted line. Who wired your trailer with respect to the hyd. brakes, factory or dealer.

[azflycaster]

This is from the install manual on line. It does look like the charge line has been moved to the brake system. It does have a connection from the trailer battery to the system, but it is for the break away function to work.

[bci]

Originally Posted by HowieE

Can you post a picture of the diagram you referred to?

The "dotted" line was at the Airstream dealer (I was working with the service technician), when I brought it back because the batteries were not charging while connected to the F-350.

I have the Airstream electrical diagram here and the wiring diagram from ActiveTechnology owners manual here.

Please notice in the ActiveTechnology diagram, the lower image shows a "retrofit" where they left the charging line goto both the brake and the trailer trailer 12vdc system. My configuration is the upper image.

The ActiBrake is not an option on the 2007 30'SO, the Airstream owner's manual electrical diagram shows the charging line is to be used in the trailer. From the factory, this line is missing.

So with the 12vdc charging line diverted from the trailer to only the braking system, when the tailer batteries are dead, just by connecting the truck, I am not be able to power the trailer.

I was able to power my Safari using the 12vdc system in the truck (2 large 12v batteries + diesel charging system), but not my new classic. When the break-away switch failed (while in storage), I came back to hook up and found both batteries dead and the fuse for the brake system blown. After connecting the 7-pin to the trailer, not even the radio would come on... I was required to get my generator to power the trailer and charge the batteries.

This year at Quartzite, AZ, I needed to dig out the generator and charge the batteries using the converter (the solar panels - 2x85w - were not enough to charge up the batteries by the time I wanted to leave) to bring in the slide and bring up the stabilization jacks. This is a pain.

[HowieE]

Originally Posted by azflycaster

This is from the install manual on line. It does look like the charge line has been moved to the brake system. It does have a connection from the trailer battery to the system, but it is for the break away function to work.

Without seeing what the wiring diagram inside the ActiBrake looks like this does not tell us much.

If I had to guess #5 and #2a will be tied together in the ActiBrake and thus the battery would charge while towing.

The way to test this is with the TV off read the battery voltage on the trailer battery. Now put the TV headlights on for 5 mins. and then start the TV and take another reading. If the voltage has gone up it is wired as I suspect. The reason for the head lights is to force the voltage regulator to call for a heavier charge just after starting. That will make any voltage increase at the trailer battery easier to see depending on your voltmeter


I posted the above before seeing your post.

That is one messed up diagram from Airstream. I can only assume the 4 breakers above the battery have a common Bus. If so the charge line from the TV should charge the batteries.

Again you would have to test the battery voltage as noted above to see if a connection to charge the batteries is present through the ActiBrake.

If there is not a connection within that system I would call them and ask why not.

[overlander63]

Something I would be concerned about is the Actibrake always being energized if you follow our suggestions. The way Actibrake and Airstream have it set up, when the tow vehicle isn't plugged in, the Actibrake isn't getting power.

[Over59]

Run a separate #4 line from a connection block with a connector for the trailer. From there to the house circuit. That line in the 7 way isn't going to do much charging, too small.

[Fyrzowt]

IMO, the easiest solution is do do what Terry and Over59 suggested and install a dedicated, seperate charge line. Use a bullet connector or similar that can be simply disconnected at the same time as your 7-pin.
Dave

[bci]

I just took a look at the current version 2 manual on the Active Technology web site. in particular, the new wiring diagram does have the battery in parallel with the brake controller. I wonder if I take this version 2 manual to my Airstream dealer if they will re-wire it to the current spec. The trailer is still under warranty. And it would bring it into compliance with the airstream users manual for use of the charge line.

[bci]

Originally Posted by Over59

Run a separate #4 line from a connection block with a connector for the trailer. From there to the house circuit. That line in the 7 way isn't going to do much charging, too small.

Yes, I've also been thinking along this line - A power cable like the big rigs have, a coiled 12vdc to some sort of connector. Anyone know the connector type?

But I am thinking about running it via a battery box, with say, 4 more gel batteries in it to give me more amp hours running dry (solar).

-- 12vdc truck --> battery box --> trailer

The battery box can live in the truck bed being charged by the truck or the trailer's solar unit until I locate a camping spot, then placed by the front end of the trailer for the stay. This would give me more stored power and a separate charging line from the truck to the trailer.

[Tom Nugler]

Originally Posted by bci

Yes, I've also been thinking along this line - A power cable like the big rigs have, a coiled 12vdc to some sort of connector. Anyone know the connector type?
The battery box can live in the truck bed being charged by the truck..........

Just put a new battery in the GT and was looking at these trolling motor connectors. Boater Sports Trolling Motor Connectors - iboats.com
Water proof and heavy gauge. Unfortunatly they didn't have a full set in the store. I went back to the stock configuration.
It's been reported that the charge lines from the TV don't do a very good job of recharging. The wire gauge is typically too small and the voltage drop too great.
A seperate charge line to the bed makes sense.

Tom.

[lewster]

Originally Posted by bci

Yes, I've also been thinking along this line - A power cable like the big rigs have, a coiled 12vdc to some sort of connector. Anyone know the connector type?

But I am thinking about running it via a battery box, with say, 4 more gel batteries in it to give me more amp hours running dry (solar).

-- 12vdc truck --> battery box --> trailer

The battery box can live in the truck bed being charged by the truck or the trailer's solar unit until I locate a camping spot, then placed by the front end of the trailer for the stay. This would give me more stored power and a separate charging line from the truck to the trailer.

Kent,

Be very careful if you are intending to go solar. There are a lot of systems out there that promise you the world and simply can't deliver the amperage to properly charge your batteries.

Further, if you are intending to run a charge line from your solar charge controller to a separate battery bank in your TV, you had better plan on using the exact size and type of batteries with the possibility of replacing the existing ones so all of the batteries match. You'll have charging problems otherwise. Plus, don't expect your TV to adequately charge a remote battery bank unless you have a very large alternator and a properly integrated battery isolator or separator.

Also, given the distance from your trailer to your TV, anything less than 4/0 cable will present an unacceptable voltage drop to the remote battery bank. This stuff is about an inch in diameter and very expensive!

Your idea is workable, but complex and needs to be properly planned with the right equipment and will require a significant investment ( I sell and install solar charging systems, and just installed a 200 watt 2-panel system with 4 new Lifeline batteries and a 2000 watt sine wave inverter for $5K in equipment).

You might just buy a Honda or Yamaha generator if your only desire is to keep your batteries charged while boondocking, like lots of folks here on the forums.