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

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > RV Systems & Appliances
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  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 09-27-2022, 04:28 PM   #1
Member
 
Join Date: Mar 2001
Posts: 64
Do I need to replace these batteries?

My coach batteries are 2 Trojan GC2 T-105 6V FLA. They are 5 years old and generally stay hooked to shore power in the garage, but are sometimes unplugged. Over the years they have had a couple of episodes of low water where you could see some part of the plates was dry. I always used distilled water.

I am going to describe their behavior today involving a newly installed Dometic 12V DMC4101 refrigerator. Please let me know if any of this indicates they may be on the way out. The 12V fridge places a greater load and greater importance on having good batteries. I do not have any interest in boondocking but there are brief times during a trip where the batteries alone must power the fridge. When traveling my chassis generator and sometimes my coach generator charge the batteries.

All readings are at the fridge terminals (approx. 20-25' 10 gauge, wired by Tiffin). Converter had charged batteries for at least 24hrs.


13.5V - Fridge off, Shore power
13.1V - Fridge on, Shore power
12.6V - Fridge off, Batteries only
12.1V - Fridge on, Batteries only
Fridge runs for 5 minutes
11.5V - Fridge on, Batteries only
Turn fridge off
12.4V - Fridge off, Batteries only

thanks very much,
Fred
__________________
2007 Tiffin Allegro 28DA
2001 Jeep Wrangler Sahara
fred42 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 09-27-2022, 05:56 PM   #2
Senior Member
 
traveldawg's Avatar




 
Ford Super Duty Owner
Grand Design Owners Club
Join Date: Feb 2000
Location: Titusville, FL
Posts: 1,014
I'd say the batteries are old and need replacement.

The only sure way to know is to the batteries and have them load tested. What you're doing isn't exactly a good test. You need a heavy load on the batteries to test them.

if only one is bad, replace both at the same time.
__________________
2018 F350 CC, SB
2019 Grand Design Solitude 310GKR
traveldawg is offline   Reply With Quote
Old 09-27-2022, 06:14 PM   #3
Senior Member
 
Join Date: Jul 2014
Posts: 31,765
The stock wiring for your fridge was installed to power the controls, not a compressor type fridge.

Your batteries may be failing but that doesn't account for the voltage drop in the wire run.

1/2 a volt drop don't seem like alot but it can effect the fridges operation.

What does the install manual say about wiring it.
twinboat is online now   Reply With Quote
Old 09-27-2022, 06:37 PM   #4
Member
 
Join Date: Aug 2022
Posts: 76
Age wise, you are right at the point where I would no longer trust my battery's.
And I would be careful to keep the water level up. When you can see the plates there is room in the battery to build up gas. with two plates exposed there is the possibility of arcing if the electric system draws full power.[ usually a direct short]. This can cause an explosion. We don't hear about this as much now with newer battery's, but is still possible. A couple things that cause the water to boil off is heavy usage and a charger that is adjusted to high.

The fact that your batterys went 5 years tells me you are not abusing them, just be careful to check the water more often. Good Luck DR
DR60 is offline   Reply With Quote
Old 09-27-2022, 07:04 PM   #5
Senior Member
 
Ray,IN's Avatar
 
Join Date: Aug 2001
Location: North America somewhere
Posts: 27,313
The best at-home test is by using a hydrometer the test the liquid in each cell;https://deepcyclebatterystore.com/us...ry-hydrometer/
__________________
2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy
Ray,IN is offline   Reply With Quote
Old 09-28-2022, 08:17 AM   #6
Senior Member
 
Join Date: Nov 2018
Location: Beaver Dam, Wisconsin
Posts: 3,776
2 Trojan GC2 T-105 6V FLA. (225 AH) They are 5 years old and generally stay hooked to shore power in the garage, but are sometimes unplugged. Over the years they have had a couple of episodes of low water where you could see some part of the plates was dry. I always used distilled water.

Dometic 12V DMC4101 refrigerator. (15 A w/variable speed compressor)

I do not have any interest in boondocking but there are brief times during a trip where the batteries alone must power the fridge. When traveling my chassis generator and sometimes my coach generator charge the batteries.

All readings are at the fridge terminals (approx. 20-25' 10 gauge, wired by Tiffin). Converter had charged batteries for at least 24hrs. (10 gauge wire at 25 feet is good.)


13.5V - Fridge off, Shore power (Normal, are any other 12 volt devices "on"?)
13.1V - Fridge on, Shore power (Normal, indicates high load on converter)
12.6V - Fridge off, Batteries only (Fast loss of surface charge. Other 12 volt devices may be drawing power. Maybe an inverter is working.)
12.1V - Fridge on, Batteries only (Heavy load on batteries)
Fridge runs for 5 minutes
11.5V - Fridge on, Batteries only (Very heavy load on batteries)
Turn fridge off
12.4V - Fridge off, Batteries only (Still heavy load on batteries, but less.)

Battery voltage dives fast even when on shore power. Please post make and model of converter/charger, or inverter/charger. The RV may be drawing 12 volt power for other things. You may need a bigger battery bank to support that load.

Batteries reaching the end of life have less capacity. Voltage drops fast. Replacing the batteries may allow longer running on batteries. 5 minutes is very short.

It is hard to know without measuring current in and out of the battery bank. Refer draws 15 amps at full load. It draws less when low load. It probably draws a lot less with no load. There may be other 12 volt appliances drawing power which also pulls battery voltage down.

The 15 amps needed for the refer theoretically lasts 15 hours. Battery terminal voltage drops under heavy load, then recovers when load is removed. Static voltage can be used to estimate battery capacity. See attached document for how to interpret battery terminal voltage.

Load testing at an automotive store may indicate time to replace. If they don't pass the automotive test, they need replacing. However, automotive testers are sometimes not the best way to analyze deep draw batteries.

You need to be able to measure both voltage and current at the battery terminals for a while to know for sure. Good batteries supplying low voltage means you need a bigger battery bank. Defective batteries will also supply low voltage under load.
Attached Files
File Type: pdf Charging Lead Acid Bat.pdf (131.4 KB, 6 views)
__________________
Paul Bristol
Kodiak Cub 176RD
Nissan Pathfinder 2015
Persistent is offline   Reply With Quote
Old 09-28-2022, 08:25 AM   #7
Senior Member
 
Winnebago Owners Club
Workhorse Chassis Owner
Join Date: Nov 2018
Posts: 1,837
Adding to Persistent's post, you're mostly guessing here because you don't know what the current draw is during your load testing, and you don't specify where the voltage measurement was taken. Capacity cannot be determined by applying arbitrary loads for varying times and watching battery voltage. A transient (starting battery) load test will not adequately test storage batteries. A means of monitoring current, a voltmeter at the battery and a means to load the battery to the 20 hour rate (11A for T105's) will reveal the actual capacity of the batteries. From there a conclusive decision can be made to keep or replace.

Mark B.
Albuquerque, NM
Mark_K5LXP is offline   Reply With Quote
Old 09-28-2022, 01:52 PM   #8
Member
 
Join Date: Mar 2001
Posts: 64
Thanks everyone for the advice.

There were no other loads other than the usual propane detector type loads and one overhead led. The talk here of my situation imitating heavy loads makes me think the batteries are not well.

All measurements were at the terminals on the rear of the fridge.

No inverter, converter is an IOTA DLS-55 with charge wizard permanently unplugged. When the charge wizard would do its 14.4 thing while driving with the house generator on, it presented the alternator with a higher battery voltage than the alternator output and caused a flickering battery light. Alternator manufacturer said that is harmful to the alternator. IOTA said on this model I still get anti-boil low charge behavior without the wizard plugged in.

Tiffin included 10 gauge stock wiring in case someone ordered the Norcold 3-way. They fused it with a 30amp auto-reset breaker.

As for taking the batteries for a test, that is not going to happen. I have a bad back and a hernia and will only be removing them once to trade them in. At the moment, I am leaning towards replacement.
__________________
2007 Tiffin Allegro 28DA
2001 Jeep Wrangler Sahara
fred42 is offline   Reply With Quote
Old 09-28-2022, 02:06 PM   #9
Senior Member
 
Arch Hoagland's Avatar
 
Monaco Owners Club
Workhorse Chassis Owner
Join Date: Aug 2002
Location: Clovis, CA, USA
Posts: 12,041
I recently replaced my two batteries with AGM batteries from Sam's Club. $179 each.

No more adding water!!!
__________________
2004 Monaco La Palma 36DBD, W22, 8.1, 7.1 MPG
2000 LEXUS RX300 FWD 22MPG 4020 LBS
Living is hazardous to your health.
Arch Hoagland is offline   Reply With Quote
Old 09-29-2022, 08:31 AM   #10
Senior Member
 
Join Date: Nov 2018
Location: Beaver Dam, Wisconsin
Posts: 3,776
IOTA DLS-55 has excellent voltage regulation. Dropping voltage due to high draw should not happen until the capacity (possibly 55 amps) has been exceeded.

15 A plus a little should not cause quick deep voltage drop unless batteries are defective.

You do not need to remove the batteries to test them. Just drive to automotive store and ask to have them tested. They will probably be delighted to change them for you if they fail the test.
__________________
Paul Bristol
Kodiak Cub 176RD
Nissan Pathfinder 2015
Persistent is offline   Reply With Quote
Old 09-29-2022, 08:41 AM   #11
Senior Member
 
Winnebago Owners Club
Workhorse Chassis Owner
Join Date: Nov 2018
Posts: 1,837
A capacity test can be done as well with the batteries in place, in your own driveway if you like. All you need is an ammeter, a voltmeter (harbor freight grade OK), loads inside your RV that equal the C/20 rate (11A) and a clock. If you have a battery monitor all you would need is the clock. In under a day you'll know the exact capacity of your batteries.

Mark B.
Albuquerque, NM
Mark_K5LXP is offline   Reply With Quote
Reply

Tags
ace, batteries, replace



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
Need to replace both 12v chassis batteries - what size are these? Doug427 Class A Motorhome Discussions 6 01-18-2022 04:27 PM
Portable Black Tank - People have these - What is the typical application of these swduns Gear and Product Discussions 30 11-30-2021 09:06 AM
Replace these tow dolly wheel lug bolts? atikovi Toads and Motorhome Related Towing 4 04-19-2021 01:33 PM
Replace my 2 group 27 house batteries with group 31 batteries? SuperDad iRV2.com General Discussion 10 03-05-2021 06:46 PM
Replace these tires? Bowtie Jim Travel Trailer Discussion 26 09-29-2020 06:10 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 11:52 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.