Charging Camper/Coach Battery with Running Lights Lead from Flat-4

Mark_Naturist_Camper wrote:
I am installing a brake controller on my trailer. Among other things this thing allows me to connect my camper with trailer brakes to a Flat-4 Hookup. The link is below. My question is the way the thing gets power with the flat-4 is the running lights power. If I simply Jumper the 12VDC line from the Running lights line in my 7-way (Camper) to 4-flat adapter (Car) adapter will it work Okay and also charge the coach batteries. Or will it blow up? (Melt wires/blow fuses)

I'm looking for anyone that has tried to charge coach batteries, or simply powered a refrigerator, from a flat-4 running lights lead, (running lights must be turned on).

In hindsight the flat 4 might work fine for the very intermittent power needed for this brake system. Mostly you are just running on the trailer battery.

Best to start with a mostly full charge trailer battery. Bring an extra vehicle fuse for the running lights. Although unless you create a dead short the long thin wire will mostly limit the current to a tolerable level.

If you plan to camp off-grid and expect this system to recharge your trailer battery.... it will not do well. Solar would be a good option for camping and driving in the sun.

Mark_Naturist_Camper wrote:
I am installing a brake controller on my trailer. Among other things this thing allows me to connect my camper with trailer brakes to a Flat-4 Hookup. The link is below. My question is the way the thing gets power with the flat-4 is the running lights power. If I simply Jumper the 12VDC line from the Running lights line in my 7-way (Camper) to 4-flat adapter (Car) adapter will it work Okay and also charge the coach batteries. Or will it blow up? (Melt wires/blow fuses)

I'm looking for anyone that has tried to charge coach batteries, or simply powered a refrigerator, from a flat-4 running lights lead, (running lights must be turned on).

Thank you for any help.
AUTOWBRAKE

I went to the Autowbrake website and watched the two videos and personally I would never run an autowbrake for a few reasons. But first to answer your question above.

No you should not connect the trailers 12v power to the 4 way flat. The stock 4 way wiring is not a large enough to power your trailer. The first time the battery charger comes on and tries to pull 20-40 amps through a 16 gauge wire it will blow the fuse and there goes your brakes. In fact the Autowbrake video already recommends running a separate power wire to power that unit and not rely on the vehicle running lights. Just run a fused 8 gauge wire from your tow vehicle battery to your Autowbrake using a 7 way or one of the connectors linked above and then you can also power the trailer.

As for my objections to the Autowbrake.

Their own video recommends running a separate power wire from the tow vehicle to power the unit. Now you're up to 5 wires so you might as well just put a 7 wire connector on the tow vehicle rather than run a separate plug and adapter.

If you power the unit from jumpering the 4 wire connector you have just added one more potential failure point to having trailer brakes. First failure point is possibly neglecting to plug in the trailer umbilical. Any of us who tows is at risk of this failure point. The second failure point is forgetting to turn on the tow vehicle lights. So by wiring through the 4 way you have just doubled your chances of a brake system failure.

The emergency brake application for trailer sway is on a key fob. Where will that key fob be? It must be somewhere where you can get to it extremely fast if sway occurs. Do you set it on your center console? I set my phone on my center console and it regularly slides around and sometimes falls off if I brake too hard. I definitely wouldn't want to place the fob there. Do I drop the fob into an empty cup holder to be fished out by my fingertips in an emergency? Do I clip the key fob to my regular keys as it's name implies?

Have you ever seen Top Gun, Hunt For Red October, or any other war movie where they have to flip up a red safety lever before they fire a weapon? That is exactly what you have with a key fob mounted on your key ring. The keys around the fob will act as safety lever and prevent you from applying the brakes in an emergency.

Thanks Bobbo, True on the space and I edited my post to reflect it. My original thought was the poster could use the quote button off my post to see the actual text in use. But I should know better than to leave something to chance like that.

As far as the height or width, I do it both ways, If only one number is entered, the software will automatically set the ratio for the other.

What would be really helpful is if RV.net pre-populated the height or width on the form since many people would probably leave it alone and hit the post button. Or at least change the form from "Optionally, enter a height and width for the image." to something like "Enter a height (Maximum 480) or width for the image (maximum 640)" In fact I'm going to post that suggestion over on posting support. Although I know how unlikely they are to ever make any changes.

opnspaces wrote:
@Homeskillet-Can you please resize your picture to no more than 480 high? As it is now we are forced to scroll side to side to read the posts in this thread. If you edit your post and add height=480 to the link for the picture it should resize. If you do a quote on this post you can see where I added a height = 200 on mine.
Thanks

I use width=640 on mine. (Or whatever value I am shooting for, sometimes 320.) Same result. But, you added spaces within your text "height = 200", when it must be "height=200". It is actually not the height that is causing the problem, it is the width, that is why I use the "width=???" instead.

opnspaces wrote:
You then only have to run a brake wire from your brake controller under the dash to the plug at the bumper.

I don't think there is a brake controller on the tow vehicle.
Read the autobrake link the OP provided.

The anderson connectors would work fine using #8 or better wire to keep a charge on the battery.

@Homeskillet-Can you please resize your picture to no more than 480 high? As it is now we are forced to scroll side to side to read the posts in this thread. If you edit your post and add height=480 to the link for the picture it should resize. If you do a quote on this post you can see where I added a height=200 on mine.
Thanks

I prefer to use the Hopkins (#47185) 4 way to 7 way plug. I installed one on my Suburban back in 2005 and ran it for almost 15 years. I like it because it plugs into the existing 4 way flat plug to convert the lights to a 7 way. You then only have to run a brake wire from your brake controller under the dash to the plug at the bumper. The best part of the connector is that it also retains the 4 way flat so you can tow a utility trailer without using an adapter.

Link

There's nothing that says you can't run a dedicated harness, just to charge the batteries.
Use connectors like this.

There goes bikendan again. Blunt..accurate.

Go to the web site 5 wires needed,