Reply
 
Thread Tools Search this Thread Display Modes
 
Old 11-13-2009, 10:13 AM   #15
Rivet Master<br><img src="/ugala/forums/images/5rivet.gif">
 
CanoeStream's Avatar

 
2006 25' Safari FB SE
St. Cloud , Minnesota
Join Date: Aug 2003
Posts: 13,279
Images: 19
Blog Entries: 3
Quote:
Originally Posted by reddogfox View Post
At first I did not add a fuse because I feared running down the truck battery if I forgot to unplug when parked.
Some time ago Foiled Again woke up one morning to a dead truck. I seem to recall reading that more recent tow vehicles have a diode installed to prevent current flowing from the trailer into the truck. Somebody more knowledgeable would have to verify this. I probably won't get out of the habit of unplugging the umbilical when I park for a quick getaway and don't unhitch at night.

If you have a Prodigy brake controller, be sure not to fiddle with the umbilical while the TV ignition is on -- the Prodigy will fry. I've also blown a fuse in my previous TV when changing marker light bulbs with the ignition running. Back to the thread already in progress ...
__________________

__________________
Bob

5 meter Langford Nahanni

CanoeStream is offline   Reply With Quote
Old 11-13-2009, 10:42 AM   #16
Rivet Master
Commercial Member
 
rluhr's Avatar
 
1968 17' Caravel
2005 30' Safari
Somewhere , roaming America
Join Date: Apr 2003
Posts: 1,093
Images: 39
Quote:
Originally Posted by Rawn77 View Post
I have a somewhat different experience than those of the other posts. ...I would then drive the next day for about 6 hours. At the end of each day of driving my batteries were always fully charged.
No, they really weren't fully charged. The voltage was back up to a level that the battery monitor interpreted as "full charge," but the batteries were well below their full amp capacity.

The standard battery monitors put into most travel trailers are incredibly inaccurate. They guess the state of charge based on voltage, which is kind of like guessing how full your truck's fuel tank is by sniffing the fumes. Did you notice that the battery monitor rather quickly dropped to the "yellow" status after a short period of power use?

As 2air points out, you can read more about this in other threads. The only truly accurate battery monitor I've ever seen is the type that measures the amps going in and out of the battery using a shunt. We use a Tri-Metric 2020 for example, and there are many other brands as well.

Quote:
Originally Posted by Rawn77 View Post
Maybe it was my TV (Mercedes ML320 BlueTec), but I can't imagine it charges any differently than other TV's.
You're right, it doesn't, except that the Mercedes has some extra-fancy computer controls to manage signals to the 7-way plug. The "charge line" from a tow vehicle isn't designed to really do much charging. The wire is too thin, the amps are too few.

Quote:
Originally Posted by Rawn77 View Post
I've never done any tests to determine the exact amount of amps and volts going through the umbilical cord; just my experience at the end of each day seeing that my batteries once again were at full charge.
That's why you've been misled. Voltage-based battery monitors lie. I wish RV manufacturers would stop using them. They're worthless.

The only way you're going to get an accurate reading from one of them (if you can even call RED-YELLOW-GREEN "accurate" under any circumstances) is if the batteries have been at rest for at least an hour. No charging, no discharging, and no load when you check their status. Then and only then is a voltage-based reading close to an accurate estimate of amps remaining.

So, to the original poster: There may be nothing wrong with your tow vehicle. Before you start diagnosing a problem that may not exist, consider that 2air got it right.

Repeat after me, all together now ...

Quote:
Originally Posted by 2airishuman
it's a rookie urban online gypsy myth

that the tv does MUCH to juice 'em.
If you want your batteries to charge while you're towing, get a solar panel. That solution really works!
__________________

__________________
Former full-timer | AIRSTREAM LIFE magazine | Tour of America (old blog) | Man In The Maze (current blog)

rluhr is offline   Reply With Quote
Old 11-13-2009, 01:07 PM   #17
4 Rivet Member
 
Currently Looking...
holland , Michigan
Join Date: Oct 2007
Posts: 436
Images: 1
Quote:
Originally Posted by CanoeStream View Post
Some time ago Foiled Again woke up one morning to a dead truck. I seem to recall reading that more recent tow vehicles have a diode installed to prevent current flowing from the trailer into the truck. Somebody more knowledgeable would have to verify this. I probably won't get out of the habit of unplugging the umbilical when I park for a quick getaway and don't unhitch at night.

If you have a Prodigy brake controller, be sure not to fiddle with the umbilical while the TV ignition is on -- the Prodigy will fry. I've also blown a fuse in my previous TV when changing marker light bulbs with the ignition running. Back to the thread already in progress ...
Can the prodigy be damaged and still activate the brakes?, I have had to wiggle the umbilical to get the c reading back on some occasions. All done with engine running etc. I remember my wife saying she smelled something burning. I now use a asparagus rubber band to hold it in. Brakes work great. This is why I wonder if the 7 pin is rusty or dirty.
__________________
safari 28 is offline   Reply With Quote
Old 11-13-2009, 03:17 PM   #18
4 Rivet Member
 
Currently Looking...
holland , Michigan
Join Date: Oct 2007
Posts: 436
Images: 1
Quote:
Originally Posted by rluhr View Post
No, they really weren't fully charged. The voltage was back up to a level that the battery monitor interpreted as "full charge," but the batteries were well below their full amp capacity.

The standard battery monitors put into most travel trailers are incredibly inaccurate. They guess the state of charge based on voltage, which is kind of like guessing how full your truck's fuel tank is by sniffing the fumes. Did you notice that the battery monitor rather quickly dropped to the "yellow" status after a short period of power use?

As 2air points out, you can read more about this in other threads. The only truly accurate battery monitor I've ever seen is the type that measures the amps going in and out of the battery using a shunt. We use a Tri-Metric 2020 for example, and there are many other brands as well.



You're right, it doesn't, except that the Mercedes has some extra-fancy computer controls to manage signals to the 7-way plug. The "charge line" from a tow vehicle isn't designed to really do much charging. The wire is too thin, the amps are too few.



That's why you've been misled. Voltage-based battery monitors lie. I wish RV manufacturers would stop using them. They're worthless.

The only way you're going to get an accurate reading from one of them (if you can even call RED-YELLOW-GREEN "accurate" under any circumstances) is if the batteries have been at rest for at least an hour. No charging, no discharging, and no load when you check their status. Then and only then is a voltage-based reading close to an accurate estimate of amps remaining.

So, to the original poster: There may be nothing wrong with your tow vehicle. Before you start diagnosing a problem that may not exist, consider that 2air got it right.

Repeat after me, all together now ...



If you want your batteries to charge while you're towing, get a solar panel. That solution really works!


You know, life is a humbling stage of events. I have over 210 nights in her, and tugged her over 26k miles nationwide in just over 2 years, and still a Rookie. This forum is indeed a good for check on your ego.
__________________
safari 28 is offline   Reply With Quote
Old 11-13-2009, 04:05 PM   #19
Rivet Master
 
SilverRanger's Avatar
 
2005 19' Safari
1968 24' Tradewind
Rural , Delaware
Join Date: Jun 2005
Posts: 1,475
Thumbs up

"I have had to wiggle the umbilical to get the c reading back on some occasions. All done with engine running etc. ... I now use a asparagus rubber band to hold it in."

Wow! On my 1997 Chevy TV, I used one of my kid's hair tie/ pony tail holder things (kind of like a mini bungee cord with a fluorescent colored plastic ball on each end) for the same purpose, with no damage to the Prodigy.

Necessity is the mother of invention.
__________________
2005 Bambi
1968 Trade Wind
2007 Ford F250 4x4 Crew
WDCU
SilverRanger is offline   Reply With Quote
Old 11-14-2009, 06:14 PM   #20
More than one rivet loose
 
thecatsandi's Avatar

 
Currently Looking...
Keymar , Maryland
Join Date: Feb 2006
Posts: 3,754
Quote:
Originally Posted by CanoeStream View Post
Some time ago Foiled Again woke up one morning to a dead truck. I seem to recall reading that more recent tow vehicles have a diode installed to prevent current flowing from the trailer into the truck. Somebody more knowledgeable would have to verify this. I probably won't get out of the habit of unplugging the umbilical when I park for a quick getaway and don't unhitch at night.

If you have a Prodigy brake controller, be sure not to fiddle with the umbilical while the TV ignition is on -- the Prodigy will fry. I've also blown a fuse in my previous TV when changing marker light bulbs with the ignition running. Back to the thread already in progress ...
Ford disconnects the charge line when you turn off the ignition. GM and Dodge did not last time I checked. I am glad I have a Ford!
__________________
Michelle TAC MT-0
Sarah, Snowball

Looking for a 1962 Flying Cloud

thecatsandi is offline   Reply With Quote
Old 11-14-2009, 07:02 PM   #21
4 Rivet Member
 
Currently Looking...
San Diego , California
Join Date: May 2008
Posts: 331
Images: 6
Did you ever install the relay in the fuse box under the hood when you got the truck? They (Ford) puts the relay, a 4 pin adapter (for U-haul trailers) and instuctions in a plastic bag in the glove box or under the seat or somewhere when you get. It won't charge without that.

I met Dan Neil, the auto writer for the Los Angeles Times in Yosemite in July of 2008. He had a new Expedition and a new Airstream (to test and write about). When he got there the batteries were on their last leg. Somebody forgot to install the relay. Sounds just like your problem.

Randy Bowman
__________________
OB Bambi is offline   Reply With Quote
Old 11-14-2009, 09:16 PM   #22
Rivet Master
 
Mexray's Avatar
 
1978 28' Ambassador
Morada , California
Join Date: Jan 2006
Posts: 1,583
It's time to get out your cheapo digital meter (VOM), your 7-way plug wiring diagram and check the proper pin/terminal for POS 12 VOLTS - with the TV's engine running (alternator operating).

If you don't have 12 volts on the 'charging' pin at the 7-way plug - then check the fuses of your tow harness wiring, under the TV's hood - check your owners manual to find the proper fuses, etc...

If the fuses are OK, you then have to find the relay that powers the towing POS circuit when the ignition is ON - test the relay for proper operation...perhaps the relay has given up the ghost from age, etc...

Our Ford was equipped with the tow harness option when built - the relay was in place, but there were no fuses installed for the charging, brake, tail and stop light circuits...a quick check of the manual showed the proper amp rating and location of the required fuses...
__________________
Ray & Pat; Morada, CA
Mexray is offline   Reply With Quote
Old 11-14-2009, 10:33 PM   #23
4 Rivet Member
 
Currently Looking...
holland , Michigan
Join Date: Oct 2007
Posts: 436
Images: 1
Quote:
Originally Posted by OB Bambi View Post
Did you ever install the relay in the fuse box under the hood when you got the truck? They (Ford) puts the relay, a 4 pin adapter (for U-haul trailers) and instructions in a plastic bag in the glove box or under the seat or somewhere when you get. It won't charge without that.

I met Dan Neil, the auto writer for the Los Angeles Times in Yosemite in July of 2008. He had a new Expedition and a new Airstream (to test and write about). When he got there the batteries were on their last leg. Somebody forgot to install the relay. Sounds just like your problem.

Randy Bowman
Thank you, not sure if this was done but i remember the plastic bag. I bet this is the culprit. Anyway, today running from Sacramento and now in the koa in acton and this place is a trip. I-5 is the worst road in the country, and the grapevine has degraded into a 3 rd world rated road. I am always impressed the old streamer takes the pounding and everything works. She really is a durable beast...
__________________
safari 28 is offline   Reply With Quote
Old 11-14-2009, 10:55 PM   #24
3 Rivet Member
 
2009 25' SS International
Pasadena , California
Join Date: Jul 2009
Posts: 147
Quote:
Originally Posted by safari 28 View Post
.... I-5 is the worst road in the country, and the grapevine has degraded into a 3 rd world rated road....
amen... your tax dollars (not) at work...

unfortunatly most of my trips start with that POS I-5
__________________
flmgrip is offline   Reply With Quote
Old 11-15-2009, 07:06 AM   #25
4 Rivet Member
 
Currently Looking...
holland , Michigan
Join Date: Oct 2007
Posts: 436
Images: 1
Any good parks close to the pasadena convention center? Big show for my industry wednesday. thanks!!
__________________
safari 28 is offline   Reply With Quote
Old 11-15-2009, 11:28 PM   #26
3 Rivet Member
 
2009 25' SS International
Pasadena , California
Join Date: Jul 2009
Posts: 147
Quote:
Originally Posted by safari 28 View Post
Any good parks close to the pasadena convention center? Big show for my industry wednesday. thanks!!
none that i know off... at least for camping or parking an AS... sorry
__________________

__________________
flmgrip is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
batteries not charging jasper2222 Batteries, Univolts, Converters & Inverters 6 10-25-2009 08:15 PM
Battery charging from tow vehicle ? rwnash Batteries, Univolts, Converters & Inverters 3 07-29-2008 09:17 AM
Charging the batteries using tow vehicle bci 2006 - 2010 Classic (all lengths) 22 06-09-2008 10:57 PM
Charging AGM trailer batteries from vehicle mswartz Batteries, Univolts, Converters & Inverters 5 05-15-2004 03:34 PM
tow vehicle isolated from A/S batteries?? BOBHASTINGS Electrical - Systems, Generators, Batteries & Solar 13 02-05-2004 01:50 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:19 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.