Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 

Go Back   Keystone RV Forums > Keystone Tech Forums > Repairs & Maintenance
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 03-07-2018, 11:26 PM   #1
WanderOne
Member
 
Join Date: Feb 2018
Location: TEMECULA
Posts: 34
Battery Meter - How to Calculate

Hi,

I have a new Cougar 25RES 5w and wanted to ask the seasoned pros her about how to know the % left in my battery.

There are the 4 idiot lights on the control panel, but I don't believe them.

I am looking to know when I am at 50% levels of my battery, for good maintenance.

Is there a calculation by looking at the voltage with multi-meter? Or do I just need to get a better digital gauge?
WanderOne is offline   Reply With Quote
Old 03-08-2018, 02:18 AM   #2
chuckster57
Site Team
 
chuckster57's Avatar
 
Join Date: Jul 2014
Location: Modesto
Posts: 20,237
Here is a chart:
https://www.energymatters.com.au/com...age-discharge/
__________________

2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.

Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.
chuckster57 is offline   Reply With Quote
Old 03-08-2018, 06:43 AM   #3
drdarrin
Junior Member
 
Join Date: Jun 2016
Location: Sacramento
Posts: 24
The idiot lights are aptly named. You can measure the voltage at the batteries when they are not under any load or use a hygrometer to measure specific gravity.

Or, if you really want an accurate measure, get and install a TM-2030.


Sent from my iPhone using Tapatalk
drdarrin is offline   Reply With Quote
Old 03-08-2018, 06:46 AM   #4
JRTJH
Site Team
 
JRTJH's Avatar
 
Join Date: Mar 2011
Location: Gaylord
Posts: 26,846
The "four idiot lights" for the battery condition is probably the most accurate measurement on that panel. That said, what does 2 lights really mean??? Hard to tell objectively, so I installed a voltmeter panel above the stereo in our Cougar so I can get an accurate voltage reading by turning on a switch. The switch is just to the right of the panel and when turned on, powers all three devices. There is a "cigarette lighter socket", a USB plug and the volt meter. The switch must be turned on to power any of the devices and during use, I can monitor the battery voltage. For my purposes, this allows us to power the TV (with a plug in inverter) and monitor how much battery power is remaining during the entire time we're watching TV. Same with recharging devices using the USB connections. The switch also gives us the ability to remove the volt meter drain (even though it is a very small drain smaller than the propane monitor, stereo backlight, etc).

If I were you, rather than dig out a multimeter, walk out to the tongue (or battery box) to measure remaining voltage, I'd suggest considering installation of a device similar to this.
Attached Thumbnails
Click image for larger version

Name:	DSCF3161.jpg
Views:	193
Size:	178.9 KB
ID:	15572   Click image for larger version

Name:	DSCF3158.jpg
Views:	209
Size:	242.3 KB
ID:	15573  
__________________
John



2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
JRTJH is offline   Reply With Quote
Old 03-08-2018, 07:52 AM   #5
Hodgy
Senior Member
 
Hodgy's Avatar
 
Join Date: Nov 2017
Location: Bragg Creek
Posts: 636
I like that install John.
__________________
2016 Bullet 1800RB, UVW 3260, led by a 2005 Chev Silverado Z-71 1500, Crew Cab, 5.3L, 4WD, Tow & Off Road Package with 4.10 Rear Axle, GVR 7000 lbs, Front GWAR 3925 lbs & Rear GWAR 4000 lbs., Payload 1600 lbs., Hellwig 6012 Air Bags. 97' Honda Goldwing GL1500.
Home Base is the Alberta Foothills at 4300 ' ASL.
Hodgy is offline   Reply With Quote
Old 03-08-2018, 09:06 AM   #6
WanderOne
Member
 
Join Date: Feb 2018
Location: TEMECULA
Posts: 34
Quote:
Originally Posted by JRTJH View Post
The "four idiot lights" for the battery condition is probably the most accurate measurement on that panel. That said, what does 2 lights really mean??? Hard to tell objectively, so I installed a voltmeter panel above the stereo in our Cougar so I can get an accurate voltage reading by turning on a switch. The switch is just to the right of the panel and when turned on, powers all three devices. There is a "cigarette lighter socket", a USB plug and the volt meter. The switch must be turned on to power any of the devices and during use, I can monitor the battery voltage. For my purposes, this allows us to power the TV (with a plug in inverter) and monitor how much battery power is remaining during the entire time we're watching TV. Same with recharging devices using the USB connections. The switch also gives us the ability to remove the volt meter drain (even though it is a very small drain smaller than the propane monitor, stereo backlight, etc).

If I were you, rather than dig out a multimeter, walk out to the tongue (or battery box) to measure remaining voltage, I'd suggest considering installation of a device similar to this.
I really like this too. Simple install gives you the same control over the main worries.

Simple and smart.
WanderOne is offline   Reply With Quote
Old 03-08-2018, 01:42 PM   #7
dcg9381
Senior Member
 
Join Date: Jul 2015
Location: Texarkana, TX
Posts: 1,052
Voltage is OK. There are "more advanced" power control systems (hundreds of dollars) that actually monitor the charge/discharge of the battery in terms of amp hours and you setup specifically for your battery type.... If you want a true %, you have to do it this way.

John's way is next best and WAAAY cheaper. Not to mention much easier to install.
dcg9381 is offline   Reply With Quote
Old 03-08-2018, 03:28 PM   #8
fourfourto
Senior Member
 
fourfourto's Avatar
 
Join Date: Apr 2016
Location: Bainbridge NY
Posts: 214
I bought 2 of these use 1 in truck and 1 in camper ,mounted it over inverter,
pics of inverter before I put in meter

cheap buy 2 easy install
https://www.ebay.com/itm/12V-Digital...UAAOSwEFNZnPe9

added small rocker switch from radio shack a buck or two
Attached Thumbnails
Click image for larger version

Name:	014.jpg
Views:	206
Size:	259.5 KB
ID:	15577  
__________________

2017 Keystone 1750rd
2006 Hummer H3
1968 Oldsmobile 442
1983 Honda CX650C
fourfourto is offline   Reply With Quote
Old 03-08-2018, 03:42 PM   #9
Steveo57
Senior Member
 
Join Date: Dec 2017
Location: Lisbon
Posts: 551
Quote:
Originally Posted by fourfourto View Post
I bought 2 of these use 1 in truck and 1 in camper ,mounted it over inverter,
pics of inverter before I put in meter

cheap buy 2 easy install
https://www.ebay.com/itm/12V-Digital...UAAOSwEFNZnPe9

added small rocker switch from radio shack a buck or two
I installed one of those little meters on my control panel. Going to add an inverter similar to what you did by the power panel. Easy access to the battery supply there to hook up the inverter.Click image for larger version

Name:	IMG_20180306_133454.jpg
Views:	155
Size:	93.8 KB
ID:	15578

Sent from my Nexus 7 using Tapatalk
__________________
2018 Keystone Cougar 22RBS
2020 Ford F-350 XLT SC SRW 6.7l Powerstroke.
Steveo57 is offline   Reply With Quote
Old 03-08-2018, 03:59 PM   #10
fourfourto
Senior Member
 
fourfourto's Avatar
 
Join Date: Apr 2016
Location: Bainbridge NY
Posts: 214
nice set up mines just a 300 watt portable one I installed, good enough for 19 inch tv and dvd.
I use a flat plugged 3 foot extension cord with a 3 plug end to reach up where outlet is .

I don't dry camp much , usually for overnight at casino or rest area
__________________

2017 Keystone 1750rd
2006 Hummer H3
1968 Oldsmobile 442
1983 Honda CX650C
fourfourto is offline   Reply With Quote
Old 03-08-2018, 06:19 PM   #11
JRTJH
Site Team
 
JRTJH's Avatar
 
Join Date: Mar 2011
Location: Gaylord
Posts: 26,846
If you're looking for something that's about as easy to use as it could possibly get, you can always just get one of these, plug it into the 12 volt socket on your TV antenna booster. I used one similar to this in my boat before I bought a GPS/sonar system with a "real" voltmeter built in. It's somewhere in the bottom of a tackle box, I think....

https://www.amazon.com/Zeltauto-Ciga...cket+voltmeter
Attached Thumbnails
Click image for larger version

Name:	LIGHTER VOLTMETER.jpg
Views:	191
Size:	20.4 KB
ID:	15583  
__________________
John



2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
JRTJH is offline   Reply With Quote
Old 03-09-2018, 05:51 AM   #12
flybouy
Site Team
 
Join Date: Oct 2011
Location: Joppa, MD
Posts: 11,714
I used this voltmeter https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Click image for larger version

Name:	guage.jpg
Views:	142
Size:	74.0 KB
ID:	15584
It's waterproof so I installed it into the front of the battery box, and a battery disconnect on the lid. When I go to hitch up in storage the battery state is easily seen and when setting up I can see when the ems kicks in and the converter is charging.
__________________
Marshall
2012 Laredo 303 TG
2010 F250 LT Super Cab, long bed, 4X4, 6.4 Turbo Diesel
flybouy is offline   Reply With Quote
Old 03-10-2018, 06:51 AM   #13
BrentB
Member
 
Join Date: Oct 2016
Location: Central
Posts: 63
Or install one of these and it will do the calculations for you, and function as a true "fuel gauge" for your battery:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
BrentB is offline   Reply With Quote
Reply

Tags
battery

Thread Tools
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
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RV® is a registered trademark of the Keystone RV Company.


All times are GMT -8. The time now is 08:34 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.