Autobrake connection

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Tom in NM
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Autobrake connection

I have a new 13' with the autobrake controller. It works very well. I was having an issue and called the support line at autobrake. They are great and very responsive. In the course of troubleshooting, he was surprised that the unit is power when disconnected from the tv. Scamp apparently connected it to the battery rather than the power line from the tv. I now see in the autobrake instructions and underlined statement to not hook it up to the trailer battery. He explained that it can then draw power when the trailer is parked and if the battery charge drops a bit, the autobrake will stop working. 
 

Just a heads up. I'm going to call Scamp tomorrow but will go ahead and change the connection in the wiring box. 
 

Tom

Mr.T
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If the 12v charge wire from

If the 12v charge wire from the TV connects to the trailer battery, how could the Autobrake be wired to only the TV 12v charge wire and not the trailers battery as well? 

I'll check mine this evening when I get home.

 

Tom in NM
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Same question

I had the same question. But they are emphatic about not having it connected to the battery. My ignorance will show but is there no regulator between the TV wire and the trailer battery? The level of charge is handled by the TV entirely? I must say that other than possible drain when the trailer is sitting, I kind of like the idea that it always has power, even if the wire to the TV is somehow disconnected. 

The guy said I can just use the option of hooking it to the lighting wire. I suppose that could work for me since I always have the lights on when towing. 

Tom

Mr.T
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There's no regulator (DC to

There's no regulator (DC to DC convertor) or similiar device that I've seen.  Seems like an impossible task without it.

Mr.T
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As an aside, from memory the

As an aside, from memory the Scamp emergency brake cable operates a switch that asserts trailer battery + to the blue brake wire of the Autowbrake, all of which requires the Scamp's battery to work with a disconnected run-away trailer.

I wonder if the small current drain is the only reason they don't want full-time 12v power?

Tom in NM
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Input from autobrake later

I called the autobrake support again. They are really helpful. He's going to get with his other tech and call me back this afternoon. One of the questions he'll address is why having it hooked to the battery is an issue. I'll update when I hear from him. 
 

I also wondered about the breakaway cable system as well. Some have their own battery but I think you are correct that it uses the trailer battery. 

Mr.T
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Thanks for looking into this,

Thanks for looking into this, Tom.  Thinking the break-away through some more, the Autowbrake probably doesn't need 12+ on it's power connection to pass the 12+ on the blue brake wire.  If it did, it would not pass a TV brake signal from a TV mounted brake controller unless the Autobrake was powered up.

On another side note, I also like the way the Autowbrake does the braking.  I had a yellow light quick stop from 55 mph, no skidding and the stop seemed like there was no trailer at all.

Tom in NM
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Support input

Autobrake support did call me. They clarified about the battery hookup. If the battery voltage is low, the autobrake might not work properly. They think that was my problem and they've seen it before. They like making the connection the lights as it will always provide a solid voltage. They think the drain on the battery when sitting is very minimal. That wasn't their concern. 
 

They asked me if I'd had the trailer out to really test the system after we troubleshooted yesterday. The status lights are now all working as expected, so I think it was a low battery. I'd been plugged into shore power for a while and I supposed that brought the battery back up. Since I'm leaving on Thursday, they asked if I could test it tomorrow so they'd know it was working and if there are any remaining issues that we can get it working correctly. They are going to call me tomorrow afternoon to make sure all is working. Wow. I'm impressed by these guys. 
Tom

Mr.T
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When you observed the problem

When you observed the problem, did you happen to start the engine and see if the voltage came up enough for the status lights?  Do you know the voltage at the trailer at the time, or perhaps how bright the indoor lights were?  Any chance you turned the battery disconnect to OFF with the TV connected to see if the status light problem went away?

Most 12V automotive devices work down to around 10 volts (or even less), but factors like wire size to the 7-pin connector and whether the engine was running could make a big difference in the time to build decent voltage at a dead trailer battery.  You might want to check the relevant fuse in the TV.

On the flip side to the trailer battery dead issue, a TV charge line fuse blown or similar failure mode would let a charged trailer battery actually run the brakes for quite a while instead of loosing the brakes immediately without a trailer battery connected -- Which is essentially the same as turning the battery disconnect switch to OFF. 

Been looking at DC to DC convertors for a while and your post revived my interest.  The Redarc BCDC1212T is what I'm considering. (https://www.etrailer.com/Battery-Charger/Redarc/RED96FR.html#exp-product...)

 

ac0gv
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My first thought

  on a DC to DC convertor is that I would like to mount it under the hood in the 12 volt line of the 7 pin.

 

Tom in NM
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Autobrake in the trailer

The autobrake controller is mounted in the trailer. The 12v line from the 7-pin is the power line is where it is connected now. 

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