Battery on trailer

L

Larry Patrick

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C Dory Year
2008
C Dory Model
23 Venture
Hull Identification Number
CD023007A808
Vessel Name
Sea -Jo
Electric over hydraulic brakes on trailer,wondering if when you plug in and tow it does it charge battery on trailer ? Guess most remove it for winter?
 
Yes, it should be a rechargeable sealed lead-acid battery that gets charged by 12v when towing, capable of engaging the EOH brakes if the break-away pin gets pulled. You should be able to remove it and trickle charge it over the winter. Test by pulling the breakaway switch when when parked and you'll hear the brakes activate.
Consider replacing any lead-acid battery at 4 years from date of manufacture (not purchase). Expect firestorm of objections now. OK, OK I said CONSIDER it, not to always DO it!
Happy Boating!
John
 
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As you can see from the above diagram, the "hot 12 volt" will be the first one clockwise from the top. (labeled 12 volts). This will charge the trailer battery. Mine happens to have two batteries. You can check the voltage after using, as well as pulling the emergency stop.
 
If the 7 pin plug is wired properly, and the trailer wired properly also, then the break-away battery should be charging, assuming it has a charge circuit. (Most newer ones do.) Colby
 
Two Questions:

1. Would that pin also power a recharge of the boat batteries?

2. Could the power from the boat batteries be used to power the EOH brakes on the trailer?

Harvey
SleepyC :moon

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Harvey, I think that is what George does on Kerri On. Charge the boat batteries that is. #2 is possible but why? Once the boat is off the trailer, there goes your emergency braking.
 
Thanks for answers,just thought about that when connecting and hearing the noise it makes when plugging in trailer. Had totally forgot about that battery. Will be taking it out this season for winter and trickle charge it.
 
Yes, I have charged the boat battery from the truck trailer output (happened to be a 6 pin, no E/H.

I would not rely on the boat battery, for several reasons, ineluding if the boat went off the trailer in a crash, there would be no brake on the trailer. Many things --especially "Road gators" will cause damage to trailer wiring. I have had that happen twice with towed cars behind the RV. Marie ran over one in her Audi at less than 30 mph--and $8,000 worth of damage to the car. (The tire tread was flipped in front of her by a van right in front..and no way to avoid)
 
Hi Harvey, Roger is correct, Casey and I wired our boats to take the charge wire off the plug to keep the boat battery up while boaterhoming
Brent on Discovery did it also. See his album, I don't think I put mine in an album
Simple way at least on the F150 was to get a 5 pin plug to put on the truck, (it was pre wired at the factory with a 4 and a 5 pin)
Two wires go from the + and - posts as per Bob's photos
I used a simple two plug disconnect in the boat, direct to the house battery (fused). While we drive, the truck charges the house battery keeps the fridge running well
George
 
That wiring harness is designed and sized to power trailer lights, wires are too skinny to handle the amps needed to 'recharge' boat battery other than 'parasitic' losses like stereo memory...which are not really a concern on a typical Brat Road Trip.
I had a much tougher goal...to keep the 12v boat fridge running (and nothing else) while towing without totally discharging the boat batteries. Installed this TOAD-CHARGER
http://www.lslproducts.net/ToadChargePage.html
and it works great for this purpose (thanks to Bob Austin for the find). To my knowledge I'm the only Brat who's installed one on the boat. Starting out with a fully charged House battery, after 10 hours on the road it will be down 0-10% rather than 30-50% (I have a big 3.0 CF Norcold on Max Cold). TOAD CHARGER includes a Circuit breaker limited to 15 amps, VSR equivalent keeps it from discharging the truck battery when the ignition is off, and it includes multiple microprocessor-controlled fault protections, and clever polarity-preserving connectors for custom lengths. Overall cheaper and simpler than you could do on your own. Uses stranded 12g non-marine copper charging wire, but good enough for this over the road, non-marine purpose. Mine goes out from the pickup bed, velco'ed to the trailer, down the windlass hole, under the berth and hard-wired into the helm bus which includes the 12v fridge circuit and then takes advantage of the built-in huge cables going from the battery switch to the helm bus for what I would call 're-topping', not re-charging.
If I end up at a hotel etc without charging capability I turn the thermostat warmer and/or combine with the 2 105 amp-h engine batteries and it all works out.
Happy Boating!
John
 
Last winter while towing boat behind truck camper the plug in trailer cable dragged the ground. It is zip tied along 4ft tow bar,because camper extends back from bumper. When I realized what happened,I sat along road stripping wires and tapeing them back together for temporary fix,then got it fixed at Weffings. Now use heavier zip ties.Speaking of those recap alligators. One time on a bus trip ,a tractor trailer blew a tire, real loud and it hit the window like a baseball bat swung by the best hitter. Don't know how window never broke,never forgot that and thought sure wouldn't want to be on a bike next to a blowout,until you hear one or see it you don't realize the results of them. You see them all over the road,but seldom witness it. Been hearing a rear blowout on a dually can really cause thousands in damages around wheel. Change my tires every 5yrs now.
 
gulfcoast john":s7428mef said:
That wiring harness is designed and sized to power trailer lights, wires are too skinny to handle the amps needed to 'recharge' boat battery other than 'parasitic' losses like stereo memory...which are not really a concern on a typical Brat Road Trip. .....
Happy Boating!
John
Click to expand...

Yes and no. If one modifies the circuit, which I, and I suspect others have done, it can easily handle up to 10 amps or more. I found that my system was more than adequate to handle the refrigeration in the C Dory 25 over many thousands of miles trailering and boater home camping.

As mentioned. Heavier wire is used. There are various ways of limiting the current, but diodes are often effective.

The TOAD system is very effective, and what I would use if I was trailering the C Dory 22 with two compressors running as in the current rig. Still the average would not be over 10 amps...
 
I have the Ford F-150 towing package and the seven pin plug comes with a 15 amp fused power pin to feed the vehicle you are towing. I use a simple two pin quick disconnect slaved off the electric-over-hydraulic 12 volt power feed wire to run 12 volt power to the boat batteries/fridge. No problems thus far, and no fear of discharging truck battery as a Ford relay disconnects the 12 volt power trailer supply feed whenever the engine is not running.
 
The newer F150's, 2016, maybe 2015, the 12vt pin is no longer always powered. From what I've gathered, the truck has to recognize a trailer in tow, before it energizes that pin. PITA! Since I don't have the official Ford Towing Package, and I installed an aftermarket brake controller, I"ll have to run a separate wire on my own to energize that pin. Colby
 
colbysmith":21kdgp4p said:
The newer F150's, 2016, maybe 2015, the 12vt pin is no longer always powered. From what I've gathered, the truck has to recognize a trailer in tow, before it energizes that pin. PITA! Since I don't have the official Ford Towing Package, and I installed an aftermarket brake controller, I"ll have to run a separate wire on my own to energize that pin. Colby
Click to expand...

Some lessons learned with my 2011 F-150 were:
1. You can only check for 12v power pin voltage when engine is running
2. You must install the relay and fuse that is provided in the glove compartment. My F-150 has a 30 amp TT battery power relay at position 21
3, There is an electric-over-hydraulic option box in the dash screen menu I stumbled upon the other day
4. I used the Prodigy F-150 harness adapter to install my aftermarket controller.
5. Youtube has good some good video's on controller access/install
6. The 30 amp power supply has no problem keeping up with my boat refrigerator needs while supplying power to the trailer battery and EOH braking system.
 
The 2016, and I think the 2015, are entirely new animals in regards to the towing stuff. At least on my 2016, and as spoken about in the Ford F150 forums, there is no longer cb's and relays to be inserted to make that 12vt pin work. And if you add the Ford OEM brake controller later, you need to have the truck computer "flashed" to recognize and set up the towing instrumentation. Until that happens, you will not have any voltage/current at the towing harness pin. Not sure what wizzardry is used, but not sure newer is better. Colby
 
I hooked up the 12 VDC line that comes out of the trailer plug to the boat batteries. I thought that the resistance in the long wires would limit the amperage to a couple of amps. 1/2 ohm of resistance (round trip) would limit the current to 3 amps. 10 amps would be impossible.

Voltage(E)= 14-12.5=1.5 VDC This is the voltage form the alternator to the battery.
Resistance of wire (R)= .5 Ohm Resistance to the battery and return.

Current= E/R + 1.5/0.5 = 3 amps. Enough to keep the battery charged against refrig use.

Boris
 
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