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Author Topic: Battery charging while driving  (Read 1736 times)

69bbc

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Battery charging while driving
« on: August 31, 2016, 09:08:11 PM »
The 5th wheel is plugged into the truck which is providing power  for the brake & running lights. When driving does the rv battery receive any charging from the truck alternator. Second question, when boon-docking without shore power, can the trailer draw power from the truck batteries if we are still connected ?
Larry

2015 SABRE 321RSKS
Prince Edward County, Ontario

Rene T

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Re: Battery charging while driving
« Reply #1 on: August 31, 2016, 09:12:17 PM »
Yes, your truck will charge the batteries while traveling.
I'm told that the trailer will not draw power from the truck battery leaving you dead in the water the next morning.  Even knowing that, I still unplug my trailer so there's no chance of draining the truck battery.
Rene, Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

legrandnormand

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Re: Battery charging while driving
« Reply #2 on: August 31, 2016, 10:16:50 PM »
If your trailer battery was charged for hours by driving the truck, just unplug it while boondocking for the night; you'll be able to restart the next morning and don't forget to reconnect the trailer.  ;)
Normand
Trois-Rivieres, QC, Canada
2010 Gulfstream Independance, model 8367
2009 Smart Cabriolet

stevem

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Re: Battery charging while driving
« Reply #3 on: September 01, 2016, 05:35:19 AM »
yes and maybe yes
the tv should supply alternator output to the trailer battery.  check for this by measuring battery voltage on the trailer with the truck running and 7 pin connected.  with good wiring, you should see the same voltage at the trailer battery as the truck battery

most trailertruck combos will run the truck battery down when the truck is not running and you are using 12v stuff in the trailer.  just unplug the 7 pin to be sure
2004 Gulfstream 22ft
2008 Dodge Dakota

Gary RV_Wizard

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Re: Battery charging while driving
« Reply #4 on: September 01, 2016, 08:19:38 AM »
Quote
I'm told that the trailer will not draw power from the truck battery leaving you dead in the water the next morning.

That would depend on how the truck is wired. If the charge line is powered only when the ignition is on, that would be true. If powered via a battery connection on the truck end, it will sick it nice and dry.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Rene T

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Re: Battery charging while driving
« Reply #5 on: September 01, 2016, 08:23:34 AM »
That would depend on how the truck is wired. If the charge line is powered only when the ignition is on, that would be true. If powered via a battery connection on the truck end, it will sick it nice and dry.

That makes sense. Thanks Gary. I guess that would be easy to check by merely checking for voltage at the 7 pin receptacle with the truck key on or the truck running and then with the key off. This should only take a few seconds to check with a light or Volt Meter.
Rene, Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

lynnmor

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Re: Battery charging while driving
« Reply #6 on: September 01, 2016, 08:40:54 AM »
Unless the charge line is a very heavy gauge, the voltage drop will cause the battery charging to take a very long time.

69bbc

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Re: Battery charging while driving
« Reply #7 on: September 01, 2016, 09:16:41 AM »
thanks all for the inputs, I will put a volt meter on the trailer today . Makes sense to unplug the 7 pin for overnight stops while in transit south. Larry
Larry

2015 SABRE 321RSKS
Prince Edward County, Ontario

Aaron k

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Re: Battery charging while driving
« Reply #8 on: September 01, 2016, 05:47:56 PM »
Most trucks use "ignition on" only for the charging wire in the 7 pin connector meaning the power is cut as soon as the ignition is turned off

grashley

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Re: Battery charging while driving
« Reply #9 on: September 01, 2016, 05:57:23 PM »
All trucks are wired for this, but not all trucks have the wire connected.  Often, it is a simple matter of connecting a wire or inserting a fuse.  Check for power first!
Preacher Gordon, DW Debbie
09 Grand Junction 35 TMS  Progressive HW50C
Andersen Ultimate hitch
2013 F350 Lariat LB SRW Supercab diesel 4X4   TST TMS  Garmin 760
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It's not a dumb question if you do not know the answer.