Free 7 Day Trial RV GPS App RV Trip Planner Campground Reviews RV Maintenance Free 7 Day Trial ×

Thread Tools Search this Thread Display Modes
Old 02-24-2019, 08:29 AM   #1
1 Rivet Member
2021 30RB Classic
Dripping Springs , Texas
Join Date: Jun 2018
Posts: 14
Overnight Discharge in Disconnect

I have a FC 2017 which I have had only a few months. The relatively new (last October) Interstate batteries are discharging overnight when the disconnect switch is in the store position. Interstate tested the batteries and said they are OK. I measured parasitic drain with a DVM and only one lead (fat red one without the terminal clamps) showed any drain and it was only 20ma. I did not test the "charging" lead for drain.

The converter seems to be working though it did not go automatically into boost this morning even though the batteries were very low (like 1.7V). I manually put it in boost mode and that seemed to work. I am aware that the store switch needs to be in the use position for the batteries to charge.

The batteries were fully charged last night, I unplugged from shore power and set the store switch to store and had very dead batteries this morning.

Any ideas appreciated.
caseydogmusi is offline   Reply With Quote
Old 02-24-2019, 08:48 AM   #2
Vantair's Avatar
2005 25' International CCD
Westlake Village , California
Join Date: Sep 2014
Posts: 420
Images: 2
Easy Battery Check

Clearly at 1—- volt both seem shot (taken down far below 50% discharge. A lesser possibility the converter is not charging them fully.

At the battery’s terminal connections, separate them to test voltage each individually. If less than 10-11 volts in either you likely have a bad or gone dry wet cell. Replace them both matching models/production date.

If you can fit Newer AGM type, that’s a superior choice in life cycles and discharge abuse (thus 2.5 x more expensive) to flooded wet cell technology.
Vantair is offline   Reply With Quote
Old 02-24-2019, 08:55 AM   #3
Site Team
azflycaster's Avatar

2002 25' Safari
Dewey , Arizona
Join Date: Mar 2005
Posts: 14,817
Images: 62
Blog Entries: 1
I would have the batteries checked. When you said they were fully charged when you unplugged power, did you wait an hour and then check the voltage? Batteries will always look great when the converter is running.


Wally Byam Airstream Club 7513
azflycaster is offline   Reply With Quote
Old 02-24-2019, 09:05 AM   #4
1 Rivet Member
2021 30RB Classic
Dripping Springs , Texas
Join Date: Jun 2018
Posts: 14
It does seem like it might be the batteries but I took them to Interstate Friday and they charged them overnight and checked them before I picked them up. They said they looked OK and they were charged to 12.5V which I checked when I got home. I suppose they could still be bad.

Another piece of information is that the converter is currently putting 13.2V on the batteries but the boost mode is supposed to be higher. I put it in boost manually, it did not go there automatically.
caseydogmusi is offline   Reply With Quote
Old 02-24-2019, 02:15 PM   #5
1 Rivet Member
2021 30RB Classic
Dripping Springs , Texas
Join Date: Jun 2018
Posts: 14
Update on Fast Battery Discharge - New Mystery

I found that the one lead I did not previously check has a large drain on it. Its the red one that looks like a car battery connector and it provides the charging voltage when on shore power. When the shore power is connected and the batteries are connected about 1.5A is going to the batteries. However, with the disconnect switch in "Store" a large current is flowing into the unit. Everything is off inside as far as I can tell.

Bad converter? Or is there some power use I am missing?
caseydogmusi is offline   Reply With Quote
Old 02-24-2019, 02:28 PM   #6
.-. -...
Adventure.AS's Avatar
2017 25' International
Port Dover , ON Canada
Join Date: May 2016
Posts: 1,830
Do you have the inverter on? Even if you aren't running anything from the inverter plugs there is a substantial draw on the batteries.
Ray B.
Adventure.AS is offline   Reply With Quote
Old 02-24-2019, 02:54 PM   #7
1 Rivet Member
2021 30RB Classic
Dripping Springs , Texas
Join Date: Jun 2018
Posts: 14
Yes, I just checked and the inverter is off. There is a green led that come on when it is on and it is off. If I press it the green light comes on and I can hear the fan on the inverter running.
caseydogmusi is offline   Reply With Quote
Old 02-24-2019, 03:32 PM   #8
Rivet Master
Al and Missy's Avatar
2002 30' Classic S/O
Fleming Island , Florida
Join Date: Nov 2013
Posts: 4,272
Follow the red wire. If it only goes to the converter, the converter is bad. The converter should never pull current from the batteries. If it goes somewhere else, that is where your problem is. So in store mode, you had no lights or anything else using 12 volts?

“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
Al and Missy is offline   Reply With Quote
Old 02-24-2019, 04:03 PM   #9
1 Rivet Member
2021 30RB Classic
Dripping Springs , Texas
Join Date: Jun 2018
Posts: 14
Right. Nothing on that I know about. As far as the draw, it doesn't seem to matter if it's in store or use.If the converter is on the battery receives some current, about 1.5A.
caseydogmusi is offline   Reply With Quote
Old 02-24-2019, 04:20 PM   #10
Site Team
wulfraat's Avatar

2017 30' International
Broomfield , Colorado
Join Date: Apr 2009
Posts: 3,263
Images: 1
Overnight Discharge in Disconnect

In a 2017 the converter is not wired to the batteries in an isolated manner, it is wired to the pos / neg bus bars, which are removed from the circuit when the use/store relay is set to store mode.

There are a few different potential draws in the 2017 when the use/store switch is off.

1. Inverter. The switch in the wall doesn’t actually turn it off, just puts into standby mode with lower draw. Use the switch on the front of the inverter itself to actually turn off.

2. LP detector. This bypasses the battery disconnect relay and goes direct to the battery. Always on.

3. Trailer brakes. These are wired directly but will not draw unless there is a faulty trailer disconnect switch.

4. 12v lead to power jack. Likely not the issue.
wulfraat is offline   Reply With Quote

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
To disconnect or not to disconnect urnmor Towing, Tow Vehicles & Hitches 36 02-22-2017 10:24 AM
78 argosy minuet, black water discharge valve replacement argosy Chuck Waste Systems, Tanks & Totes 5 05-03-2009 04:59 PM
Random Electrical Discharge [A/S 325] Fish36991 General Motorhome Topics 27 02-11-2005 05:39 AM
battery: phantom load, or normal discharge? Chuck Batteries, Univolts, Converters & Inverters 12 08-25-2004 12:13 AM
leaky gaskets in waste discharge jaiman Leaks - Weatherstrips, Gaskets, Caulks & Sealants 1 09-01-2003 04:11 PM

Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.

All times are GMT -6. The time now is 03:28 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.