Is 7 pin trailer connector enough to charge house battery?

Anything electric, AC or DC

Is 7 pin trailer connector enough to charge house battery?

Postby facethewolf » Fri Dec 30, 2016 8:56 am

I have read in other threads that you need a thicker gauge cable connecting the starter battery to the house battery, preferably with an ACR in the middle. I think this means you can't use the +12V pin in a 7-pin connector. Is there a standardized (large 2 prong?) plug that sits next to the 7 - pin connector on the TV? May I see pictures of what this looks like?
Thank you for your help.
Sean
User avatar
facethewolf
Teardrop Inspector
 
Posts: 24
Joined: Mon Dec 05, 2016 5:53 pm

Re: Is 7 pin trailer connector enough to charge house batter

Postby daveesl77 » Fri Dec 30, 2016 9:11 am

My F150 was factory wired to the 7 pin, using a 10 ga power wire and controlled by a digital relay. I used it with my 25' coachmen TT. With my van, I shifted from flat4 to 7pin and I essentially ran the same thing to charge Conch Fritter's battery, with the relay shutting down the connection when the switch is off. Being able to send 5-10 amp to the trailer battery is more than enough in most situations. I run a 3.3 cu ft dorm fridge, running off of an inverter as we travel and never had a problem. Total length, which is what matters on a DC circuit, a 10 ga wire at 25' has essentially no voltage drop. Oh, and i have a diode/regulator circuit to protect the car system.

dave
*******
Dave and Regina - Enjoying old age, a LOT!

Build Journal - http://www.tnttt.com/viewtopic.php?f=50&t=62386
User avatar
daveesl77
Donating Member
 
Posts: 783
Images: 271
Joined: Tue Jan 27, 2015 4:33 pm
Location: Central Florida

Re: Is 7 pin trailer connector enough to charge house batter

Postby Socal Tom » Fri Dec 30, 2016 9:11 am

You can use the 7 pin to charge the house battery, but recognise it will be a slow charge, probably in the 10 amp range. Also, it should be disconnected when not driving, to protect the starter batt.
Tom

Sent from my Lenovo A7600-F using Tapatalk
Socal Tom
Donating Member
 
Posts: 935
Images: 9
Joined: Sun Jun 29, 2008 9:21 am
Location: San Diego Ca
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby facethewolf » Fri Dec 30, 2016 9:57 am

Thank you very much

Sent from my SM-T230NU using Tapatalk
User avatar
facethewolf
Teardrop Inspector
 
Posts: 24
Joined: Mon Dec 05, 2016 5:53 pm
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Dale M. » Fri Dec 30, 2016 10:06 am

Socal Tom wrote:You can use the 7 pin to charge the house battery, but recognise it will be a slow charge, probably in the 10 amp range. Also, it should be disconnected when not driving, to protect the starter batt.
Tom

Sent from my Lenovo A7600-F using Tapatalk


Charge rate will be what ever "house battery" requires to equalize its self with starter battery.... Current inrush may be as high as 40-50 amps initially and reduce its self to mere trickle as batteries equalize, and depends on how much "house battery" is discharged.... MY Chevy PU has 10 gauge wire from fuse block and 40 amp fuse in line to 7 pin connector... Only negative to Chevys concept to put 12 volt power to 7 pin connector is there is no relay in circuit to protect start battery from draining along with "house battery"....

Dale
Lives his life vicariously through his own self.

Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.

Image
User avatar
Dale M.
2000 Club
2000 Club
 
Posts: 2647
Images: 18
Joined: Thu Jun 09, 2005 8:50 pm
Location: Just a tiny bit west of Yosemite National Park
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Socal Tom » Fri Dec 30, 2016 10:18 am

Dale M. wrote:
Socal Tom wrote:You can use the 7 pin to charge the house battery, but recognise it will be a slow charge, probably in the 10 amp range. Also, it should be disconnected when not driving, to protect the starter batt.
Tom

Sent from my Lenovo A7600-F using Tapatalk


Charge rate will be what ever "house battery" requires to equalize its self with starter battery.... Current inrush may be as high as 40-50 amps initially and reduce its self to mere trickle as batteries equalize, and depends on how much "house battery" is discharged.... MY Chevy PU has 10 gauge wire from fuse block and 40 amp fuse in line to 7 pin connector... Only negative to Chevys concept to put 12 volt power to 7 pin connector is there is no relay in circuit to protect start battery from draining along with "house battery"....

Dale

Well, at some point the wire gauge limits the current that can be carried between the two batteries. I put a 50 amp circuit breaker on my wire.
Tom

Sent from my Lenovo A7600-F using Tapatalk
Socal Tom
Donating Member
 
Posts: 935
Images: 9
Joined: Sun Jun 29, 2008 9:21 am
Location: San Diego Ca
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Dale M. » Fri Dec 30, 2016 10:23 am

Only problem with that theory is conductor will try to carry as much current as "load requires" until conductor over heats and melts through or fuse blows which ever happens first...

Dale
Lives his life vicariously through his own self.

Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.

Image
User avatar
Dale M.
2000 Club
2000 Club
 
Posts: 2647
Images: 18
Joined: Thu Jun 09, 2005 8:50 pm
Location: Just a tiny bit west of Yosemite National Park
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby facethewolf » Fri Dec 30, 2016 8:30 pm

So if understand this correctly, Bottom line is that if I run a thick gauge to the 12V pin on the 7pin, and put an appropriate sized circuit breaker on the line, then the 7pin connector will be able to handle it.

Sent from my SM-T230NU using Tapatalk
User avatar
facethewolf
Teardrop Inspector
 
Posts: 24
Joined: Mon Dec 05, 2016 5:53 pm
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Socal Tom » Fri Dec 30, 2016 9:01 pm

Dale M. wrote:Only problem with that theory is conductor will try to carry as much current as "load requires" until conductor over heats and melts through or fuse blows which ever happens first...

Dale

I have a waeco 12v fridge, the compressor won't start if it senses low voltage. With the battery fully charged, it wouldn't start with 12g wire because the voltage dropped . with 10g it works fine. Charging the battery works the same way, the charge line has to carry the amperage at a voltage above the TD battery, or charging won't happen.
Tom

Sent from my Lenovo A7600-F using Tapatalk
Socal Tom
Donating Member
 
Posts: 935
Images: 9
Joined: Sun Jun 29, 2008 9:21 am
Location: San Diego Ca
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby swoody126 » Fri Dec 30, 2016 9:35 pm

Ford factory towing pkg shuts the 12v feed off when the engine is turned off and i would suspect most factory towing pkgs are set up in a similar manner

if you are still un-easy about the draw on the TV then you can use a 2 wire connector like the ones used by 4x4/winch wiring systems like these

http://www.tractorsupply.com/tsc/produc ... _vc=IOPDP1

GOOD LUCK W/ YOUR PROJECT

sw
"we are the people our parents warned us about" jb
swoody126
Teardrop Master
 
Posts: 208
Joined: Mon Feb 22, 2016 6:11 pm
Location: north of Ft Worth
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby H.A. » Fri Dec 30, 2016 10:45 pm

[quo
Last edited by H.A. on Thu Jul 06, 2017 4:25 am, edited 1 time in total.
H.A.
The 300 Club
 
Posts: 428
Images: 0
Joined: Tue Nov 15, 2011 8:16 pm
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Dale M. » Sat Dec 31, 2016 9:52 am

Socal Tom wrote:
Dale M. wrote:Only problem with that theory is conductor will try to carry as much current as "load requires" until conductor over heats and melts through or fuse blows which ever happens first...

Dale

I have a waeco 12v fridge, the compressor won't start if it senses low voltage. With the battery fully charged, it wouldn't start with 12g wire because the voltage dropped . with 10g it works fine. Charging the battery works the same way, the charge line has to carry the amperage at a voltage above the TD battery, or charging won't happen.
Tom

Sent from my Lenovo A7600-F using Tapatalk


But you are talking appliance and discussion was about current transfer (flow) from start battery to "house" battery.... Which generally has no "control" other the safety item as fuse or circuit breaker and may or may not have connect/disconnect relay... You are taking about apples, we were discussing coconuts... My experience and knowledge come from working for 38 years in telecommunications and working with slightly higher voltage (52 Volts DC) and higher amperage DC power systems and its possible to transfer several thousand amps instantly through a conductor that is to small (gauge) and instantly turn conductor into a fuse and burn completely open...

Your theory and application is OK for your situation, but does not always apply to DC power in general...

Dale
Lives his life vicariously through his own self.

Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.

Image
User avatar
Dale M.
2000 Club
2000 Club
 
Posts: 2647
Images: 18
Joined: Thu Jun 09, 2005 8:50 pm
Location: Just a tiny bit west of Yosemite National Park
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby facethewolf » Fri Jan 13, 2017 3:23 am

I just found the answer to my own question about mounting a dedicated high-current plug next to the 7-pin connector on the tow vehicle. It's an Anderson plug, and Kickass makes a version specifically for the back of the TV.
[youtube]https://www.youtube.com/watch?v=iJIOHyy-xdY[/youtube]
User avatar
facethewolf
Teardrop Inspector
 
Posts: 24
Joined: Mon Dec 05, 2016 5:53 pm
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby Dale M. » Fri Jan 13, 2017 10:28 am

facethewolf wrote:I just found the answer to my own question about mounting a dedicated high-current plug next to the 7-pin connector on the tow vehicle. It's an Anderson plug, and Kickass makes a version specifically for the back of the TV.
[youtube]https://www.youtube.com/watch?v=iJIOHyy-xdY[/youtube]


Link works without the {youtube} code...

https://www.youtube.com/watch?v=iJIOHyy-xdY

To make link work with youtube code it needs to be configured as below ....

Code: Select all
[youtube]iJIOHyy-xdY[/youtube]


Example...


Dale
Lives his life vicariously through his own self.

Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.

Image
User avatar
Dale M.
2000 Club
2000 Club
 
Posts: 2647
Images: 18
Joined: Thu Jun 09, 2005 8:50 pm
Location: Just a tiny bit west of Yosemite National Park
Top

Re: Is 7 pin trailer connector enough to charge house batter

Postby dancam » Fri Jan 13, 2017 11:13 am

I spent many hours looking into this. A battery will not draw a lot of current to charge, i believe 10-15amps. As long as your feed wire from the starting battery to trailer battery is ALWAYS off when your drawing load off the trailer battery 10awg is fine. However if you draw off the trailer battery while its connected to the starting battery you will likely melt the 7 plug connecter or the wire itself. 12vdc has huge line losses over that distance. Go to an online voltage drop calculator and youll see. I want to be able to draw off the starting battery from the trailer so i ran a seperate 6 round plug and run 12awg wires from it.
Make sure you fuse every wire you run at the battery. You can get larger connectors in the 12-10awg range. I found it cheaper/easier to run just a round 6 plug connector full of power wires in addition to the power wire in my 7 round.
Make sure that for whatever power wires you run you have a ground that can handle the load as well.

Sent from my SM-G920W8 using Tapatalk
dancam
The 300 Club
 
Posts: 436
Joined: Wed Jun 01, 2016 3:27 am
Location: Edmonton Alberta Canada
Top

Next

Return to Electrical Secrets

Who is online

Users browsing this forum: No registered users and 2 guests