Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > iRV2.com General Discussion
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 11-12-2015, 08:49 AM   #1
Junior Member
Join Date: Oct 2013
Posts: 10
voltage reading

I have new T-105, four of them, which replaced Interstate U2200. Interstates tested at 73% voltage when fully charged, so got the Trojans installed, testing at 100% after charging.

After night of dry camping, Intellitec BD1 voltmeter inside showed 12.1 volts, no better than the 6 year old Interstates were doing.

I put a voltmeter on the battery bank directly and got 12.34, a substantial difference. Is the reading directly off of the group of batteries more accurate indicator of their remaining charge? Why is the inside reading so much lower?


rrodda1 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 11-12-2015, 09:03 AM   #2
Senior Member
Skip426's Avatar

Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 11,950
Question . Were there any 12 volt loads on when your were checking voltage at the panel? Even an interior light or the fridge control board operating can lower the voltage reading at the panel.
Testing at the batteries is always the most accurate, and there is a chance of a discrepancy in the meters.

99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is offline   Reply With Quote
Old 11-12-2015, 09:27 AM   #3
Junior Member
Join Date: Oct 2013
Posts: 10
I did not put into store mode first, so there would have been 12v loads, at least the fridge.
rrodda1 is offline   Reply With Quote
Old 11-12-2015, 09:38 AM   #4
Senior Member
Join Date: May 2013
Location: North Central Vermont
Posts: 811
That is the conundrum with voltage meters. Check while charging and it shows 13.2 and up. Check while the furnace is running and it may drop below 12 volts.
2015 F350 XLT PSD CCSB SRW, Andersen Ultimate hitch
'12 Cougar High Country 299RKS, Mor/Ryde Pinbox
1/77 Armor Bn, 5th Mech, I Corps
SkiSmuggs is offline   Reply With Quote
Old 11-13-2015, 07:19 PM   #5
evesely's Avatar
Fleetwood Owners Club
Join Date: Sep 2012
Location: Duncan,SC
Posts: 99
I installed two 12v meters at the Battery location, this gives most accurate reading of voltage from the Batteries and charge amount. Any other location might give you a different reading do to bad connections and load on the wiring.
Happy Travel
evesely is offline   Reply With Quote
Old 11-14-2015, 09:10 AM   #6
Senior Member
Join Date: Feb 2010
Posts: 4,278
The accuracy of the meter and connection point both make a difference.

Good meter directly at battery best.

Many options for this.

Confirm where your meter is reading and if accurate.

We are building a panel someday to mount inside with panel meters to directly read voltages.

Meters about 2 bucks on ebay so picked up 20 of them.

The readings vary so will pick ones that are correct.

A battery charger also in works with similar meters that also show amps and these are adjustable for calibration.

You could do same or bring in fused leads as monitor points so you can measure footage from inside.
Tony & Lori
1989 Country Coach Savannah SE
TQ60 is offline   Reply With Quote
Old 11-14-2015, 05:37 PM   #7
Senior Member

Holiday Rambler Owners Club
Join Date: Aug 2015
Posts: 1,151

Companies such as Bogart Engineering sell battery monitors, should you wish to keep track of more than just voltages.

l1v3fr33ord1 is offline   Reply With Quote
Old 11-14-2015, 06:03 PM   #8
Senior Member
Join Date: Sep 2012
Posts: 4,032
FWIW - If I was seeing that much difference I would be looking for where the voltage drop comes from. It could be that the meter on the panel is tied to the 12 V line from the battery into the house after the distribution panel. If the system is operating correctly I would get nervous about more than 0.1 VDC difference. That is high but one is going through several connections by then.
nothermark is online now   Reply With Quote
Old 11-14-2015, 06:42 PM   #9
Senior Member
CJ7ole's Avatar
Winnebago Owners Club
Ford Super Duty Owner
Join Date: Mar 2009
Posts: 853
It could simply be the difference in meter accuracies.
Ole and Anne Anderson, Highland, Michigan
'02 Adventurer 32V, Ford F-53, ours since 4/08,Goodyears, Konis, SeeLevel, CHF
'84 CJ-7 , 5.3 Chevy, 3" lift, 33's, Detroit Locker, Fiberglas tub, winch, hi-lift
CJ7ole is offline   Reply With Quote
Old 11-15-2015, 06:48 AM   #10
Senior Member
Join Date: Sep 2012
Posts: 4,032
Possibly but not probably. A quarter volt drop is in the range of a dirty contact with current flowing. The easy part it that one can check at a lamp or DC socket and see what the voltage is in the house.
nothermark is online now   Reply With Quote
Old 11-15-2015, 07:20 AM   #11
Senior Member
Join Date: Feb 2010
Posts: 4,278
In a past life I was involved in switch room engineering with dc power.

Voltage drops are somewhat critical and as a result wire sizes were nuts huge.

Most automotive circuits contain smaller wire due to short runs but in a mh the wire rated for 15 amps may be a number 14 but at 12 volts dc and a reasonable run of wire it would need to be maybe a number 10 or larger yo have less than the error reported by op.

Add selenoids and connectors and it gets worse.

Measure at battery with good meter to be sure then determine reasons for other readings to confirm accuracy of that system and voltage drops.

Our target voltage drop was 0.25 volts with a 48 volt system and distribution leads to some seemingly small equipment would be number 2.

A 0.1 different reading may be gravy.

Tony & Lori
1989 Country Coach Savannah SE
TQ60 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
Odometer Reading changed Upslady Winnebago Industries Owner's Forum 6 07-24-2015 04:15 PM
Stranded in Quartzsite, depleted voltage in house batteries Dean B iRV2.com General Discussion 34 03-02-2015 09:58 AM
Voltage Reading Problem nportner RV Systems & Appliances 7 02-18-2015 06:16 PM
High battery voltage! Stan&Jacquie MH-General Discussions & Problems 26 01-23-2015 06:38 PM
Over/Under voltage concern Affinityfan RV Systems & Appliances 3 06-19-2014 06:54 PM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:58 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.