Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-15-2013, 08:11 PM   #1
4 Rivet Member
 
Silver Hawk's Avatar
 
1975 31' Sovereign
Palomar Mountain , California
Join Date: Feb 2013
Posts: 353
Amps from/to TV?

Could use a little insight from those more experienced. Hooked up my TV today prior to a trip - it wasn't what I expected. Using my Trimetric monitoring system this is what I get:
1. -.06 amps draw when everything is unplugged and turned off.
2. -1.6 amps draw when I plug into my TV - engine not running.
3. +2.4 amps charge when I turn on the engine - same at 800 rpm idle or 2000 rpm - normal travel rpm.
Questions:
1. -.06 isn't much, but what do others get? is it normal?
2. what's the -1.6 draw from the TV? Is this normal - what can it be from? do others experience this draw.
3. +2.4 charge - (seems it would be 4.0 charge if you add the -1.6 draw and the 2.4 charge) - is this the normal amount of charge on can expect from a TV? I expected more.
Would appreciate replies as to what is normal and what others experience to see if I have a problem or can improve my situation.
Thanks for amy reply as this is my first time with a TT and don't know what to expect.
__________________

__________________
Silver Hawk is offline   Reply With Quote
Old 06-15-2013, 08:48 PM   #2
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
The -0.06 draw is 60 mA and the tri metic itself may be taking that amount. Other parasitic losses such as radios which are always "hot" to keep stations on, Television anetnna amps etc could cause this.

The -1.6 when you plug into your TV simply means that for a while the batteries in the AS are at a higher charge state than your TV battery. They will equalize with a bit of time. I see this on my sensetive metering system too. After siting plugged together the current will drop to near zero.

The + 2.4 amp charge you are seeing when you start the TV simply says that some current is flowing from the TV to the AS. If the battery(s) in the AS are pretty much charged, fully, there is no real need or possibility for the TV to push more. A battery only takes as much charge as it needs, and if full, not much will go into it.

Now, you probably will never see much more than about +10 amps from the TV to the AS due to the wiring resistance and distances involved. TV charging is fairly minimal in most situations due to those issues.

All said, your numbers don't concern me at all. They are not far from what I see on my own rigs.
__________________

__________________
idroba is offline   Reply With Quote
Old 06-15-2013, 10:21 PM   #3
Rivet Master
 
Tom Nugler's Avatar

 
1972 25' Tradewind
Currently Looking...
McHenry County , Illinois
Join Date: Jul 2003
Posts: 1,129
Images: 5
I agree that a slight parasitic draw can be expected under most circumstances and the readings would appear to be within reason.
Quick Question.
Is that –1.6 amp draw on the coach batteries with the ignition on or off?
Ignition on would make sense if the trailer batteries had been recently charged by the converter and feeding the TV battery.
Most of the factory tow packages would have an isolation relay to separate the truck’s B+ circuit from the trailer charge circuit when the ignition is off. The idea is to prevent accidental discharge of the trucks staring battery if the umbilical is connected, and, there’s a excessive draw or fault in the trailer.
That 1.6 +/- draw seems too high even considering the coil current limiting diodes and capacitors found in automotive relays.

Just wondering,
Tom
__________________
AirForums # 2806
WBCCI / VAC # 6411
TAC IL-11

Not All Who Wander Are Lost.

Avid supporter of trailing edge technology.
Tom Nugler is offline   Reply With Quote
Old 06-15-2013, 10:23 PM   #4
4 Rivet Member
 
Silver Hawk's Avatar
 
1975 31' Sovereign
Palomar Mountain , California
Join Date: Feb 2013
Posts: 353
Thank You IDROBA!
Very clear -
My batteries were fully charged - what your saying, it's really a balance between the two sets of batteries.
Thanks
__________________
Silver Hawk is offline   Reply With Quote
Old 06-15-2013, 10:33 PM   #5
4 Rivet Member
 
Silver Hawk's Avatar
 
1975 31' Sovereign
Palomar Mountain , California
Join Date: Feb 2013
Posts: 353
The 1.6 draw was with the key off. I didn't try it with the key on, but without the engine started. What your saying is I seem to be missing a " isolation relay" on my truck. It was a factory insulation - Dodge RAM. To get around this I would have to unplug it whenever I stop - pain.
__________________
Silver Hawk is offline   Reply With Quote
Old 06-16-2013, 07:43 AM   #6
Wise Elder
 
Jammer's Avatar
 
2010 30' Classic
Vintage Kin Owner
South of the river , Minnesota
Join Date: Dec 2009
Posts: 4,119
Quote:
Originally Posted by Silver Hawk View Post
The 1.6 draw was with the key off. I didn't try it with the key on, but without the engine started. What your saying is I seem to be missing a " isolation relay" on my truck. It was a factory insulation - Dodge RAM. To get around this I would have to unplug it whenever I stop - pain.
Not unusual, not a cause for concern, and no need to unplug when stopped. The cause varies widely. Having an interior light on in the truck would be enough to create a little more draw. Or as suggested it may be the batteries equalizing.

The only reason you would want to unplug would be if you are spending a night or more without shore power and are concerned that the power draw from the trailer may deplete the truck battery to the point where it won't start.
__________________
To learn to see below the surface, you must adjust your altitude
Jammer is offline   Reply With Quote
Old 06-16-2013, 10:03 AM   #7
Rivet Master
 
RickDavis's Avatar

 
1961 24' Tradewind
1969 29' Ambassador
1970 21' Globetrotter
Jamestown , Tennessee
Join Date: Jul 2008
Posts: 1,781
.06 amps (100 amp shunt) is what I see on mine also and I assume that is what the trimetric itself draws.
Everything else sounds normal. Don't expect much charge from your tow vehicle as others have said.. Probably 2 to 5 amps would be normal .
I think Ford has an isolation relay but I know my 99 dodge did not. I wouldn't worry about unplugging unless you are parked for days.
Actually I did put an isolation switch in my Dodge, but only because I was delivering trailers and the new trailers usually didn't have a battery and all the lights would be on inside and want to run off my truck. Since I have solar I rarely turn the charge line on.
I guess this is pretty much what everyone else has said.
Just as an aside if I disconnect the cord or put the jack down while stopped somewhere with out unhooking I will wrap the seat belt around the steering wheel as a reminder I need to do something.
__________________
Rick Davis 1602 K8DOC
61 tradewind, plus a few others
13 Ram 2500 TD
99 Dodge TD 577K miles

RickDavis is offline   Reply With Quote
Old 06-16-2013, 03:21 PM   #8
Rivet Master
 
Tom Nugler's Avatar

 
1972 25' Tradewind
Currently Looking...
McHenry County , Illinois
Join Date: Jul 2003
Posts: 1,129
Images: 5
Got your TV info from your profile. Pulled up the wiring diagrams from Alldata.
I don't see any indication of an isolation relay. Lots of relays with fuses in the Power Module for running lights and turn signals though.
If your concerned it would be fairly easy to install a relay in the charge line.

Tom.
__________________
AirForums # 2806
WBCCI / VAC # 6411
TAC IL-11

Not All Who Wander Are Lost.

Avid supporter of trailing edge technology.
Tom Nugler is offline   Reply With Quote
Old 06-17-2013, 07:25 PM   #9
4 Rivet Member
 
Silver Hawk's Avatar
 
1975 31' Sovereign
Palomar Mountain , California
Join Date: Feb 2013
Posts: 353
Sounds like it's a issue (or non-issue) of the two battery systems trying to equalize. The TT was fully charged and the TV wasn't. Normally the TV will be charge up and the TT will be low on the road. When parked I just have to unplug the cable. I'm going to look in to having a relay in line since it's a pain to remember to unplug every time I stop.
Thanks for all the help; once again Air Forms comes through! Started knowing nothing - with your help - ended understanding. RobertC
__________________

__________________
Silver Hawk 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



Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:35 AM.


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.