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


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-04-2006, 05:49 PM   #1
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
How long should a battery last?

This spring I bought a new high Amperage, deep cycle battery for my rig. I was having problems with my furnace getting into lock-out mode where I'd catch it with the fan constantly on blowing cold air.

This weekend I had the kids with me up north and it was cold every night. Battery was charged up good every evening via generator and the thermostat was set.

The first night, the furnace ran fine through the night. The second and third nights the furnace still appeared to be working fine (not in lockout) and blowing hot air but the battery had been just about toasted by 4am. What could possibly cause such a quick decrease in battery performance? This battery used to run the furnace through the night no problem.
wacnstac is offline   Reply With Quote
Old 09-04-2006, 05:55 PM   #2
Rivet Master

 
, Minnesota
Join Date: Aug 2003
Posts: 7,721
Images: 59
These are typical symptoms of a sulfated battery. Take it to the dealer and have it checked. Google "sulfated battery" for a description of causes and cures.
markdoane is offline   Reply With Quote
Old 09-04-2006, 05:57 PM   #3
Retired.
 
Currently Looking...
. , At Large
Join Date: Jun 2003
Posts: 21,276
Are you sure it was fully charged? Did you check it with a hydrometer, or just by watching the amps charged? Also, if you run the battery almost dead, it will shorten the time it will last next time, and the shorter time will be even shorter the next time you run it down, which will get easier and easier to do, the more reserve capacity you remove from the battery by draining it.
It could also be that it is getting cooler at night, and the furnace fan is running more...Sometimes the simple answers are the ones we overlook.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
overlander63 is offline   Reply With Quote
Old 09-04-2006, 07:08 PM   #4
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
I don't know what you mean by sulfated but I'll look it up. I did check the water and it was still to the top.
wacnstac is offline   Reply With Quote
Old 09-04-2006, 07:14 PM   #5
Retired.
 
Currently Looking...
. , At Large
Join Date: Jun 2003
Posts: 21,276
Quote:
Originally Posted by wacnstac
I don't know what you mean by sulfated but I'll look it up. I did check the water and it was still to the top.
It's basically the same thing I said, only "sulfated" is what it's called. When the battery gets seriously discharged, the sulphur adheres to the plates, and when it is charged back up, not all the sulphur goes back into the suspension, it stays on the plates. Kind of like the filter in your home air conditioner, when it gets full of dust, not so much air moves through it, and when the sulphur sticks to the plates, not so many electrons flow through them. It's a bad analogy, but I think you get the idea.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
overlander63 is offline   Reply With Quote
Old 09-04-2006, 07:27 PM   #6
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Go AGM

If you have to replace your battery and you regularly put it thru such deep discharge cycles, you should consider using an AGM battery instead of a liquid type.

AGM stands for 'absorbed glass mat' ad contains no free liquid, is permanently sealed, can be drawn down to 20% on ocassion and usually has a higher amp-hour capacity. These benefits don't come cheaply, but they are the best battery for RV use!
__________________
lewster
Solar Tech Energy Systems, Inc.
Victron Solar Components and Inverters, Zamp Solar Panels, LiFeBlue and Battle Born Lithium Batteries, Lifeline AGM Batteries
lewster is offline   Reply With Quote
Old 09-04-2006, 07:39 PM   #7
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
Links to AGM batteries on the web? Can they be charged with the good old Univolt?
wacnstac is offline   Reply With Quote
Old 09-04-2006, 08:21 PM   #8
Rivet Master

 
, Minnesota
Join Date: Aug 2003
Posts: 7,721
Images: 59
If you don't want to upgrade to a good three stage charger, you could skip the AGM batteries and just buy a cheap deep cycle battery at Walmart each season. It's simple and you don't need to understand any electrochemistry or keep track of voltages and charge rates.
markdoane is offline   Reply With Quote
Old 09-04-2006, 08:38 PM   #9
2 Rivet Member
 
Darrell Root's Avatar
 
2004 28' International CCD
Camarillo , California
Join Date: May 2005
Posts: 96
Link

how long will a agm battery last
Darrell Root is offline   Reply With Quote
Old 09-04-2006, 09:51 PM   #10
Rivet Master
 
2006 30' Classic
Farmington , New Mexico
Join Date: Feb 2005
Posts: 826
Images: 14
It sounds to me like it was never fully charged after each use. Pieman
Mike Lewis is offline   Reply With Quote
Old 09-04-2006, 09:58 PM   #11
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
www.lifelinebatteries.com

Depending on use, 3-5 years. Regular wet cell batteries lose 30-40% of their charge each month while disconnected due to the high internal resistance found in them. AGM's lose only 2-3% of their charge each month while disconnected. You won't have to charge them but once every 3 months (or longer).

A group-24 AGM will provide 149 minutes of discharge at 25 amps, group 27 = 186 minutes. For a twin battery set-up in parallel, double these numbers. But look at this: if you use 2-6 volt AGM golf cart batteries in series you get a whopping 492 minutes of discharge at 25 amps and as a side benefit, get many more charge/discharge cycles than with a 12V battery= longer lasting!!

If you do a lot of serious boondocking and don't want a generator to recharge the batteries, the 6V pair is the way to go!
__________________
lewster
Solar Tech Energy Systems, Inc.
Victron Solar Components and Inverters, Zamp Solar Panels, LiFeBlue and Battle Born Lithium Batteries, Lifeline AGM Batteries
lewster is offline   Reply With Quote
Old 09-04-2006, 10:06 PM   #12
2 Rivet Member
 
Darrell Root's Avatar
 
2004 28' International CCD
Camarillo , California
Join Date: May 2005
Posts: 96
link

Lewster, does the same hold true for walmart deep cycle 6 volt wired in series ,just not as lng lasting. Also Walmart deep cycles are about 1/3 the cost of glass matt makeing the cost about the same , Darrell
Darrell Root is offline   Reply With Quote
Old 09-04-2006, 10:17 PM   #13
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
here is a link to the lifeline agm batteries...

oh wait lew already supplied this info...oh well...

these are currently used by a/s IF solar equipped or 'agm' option is selected.

http://www.lifelinebatteries.com/rvcomps.php

also check out the graph and faqs and specific battery models/specs....

mine are the 100amp, model gpl 27t....65lbs each.

and shoe horned into the boxes....

supposed to be good for 1000 charges and higher charge/discharge rates and faster recharging...than gel cells.

cheers
2air'
__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman is offline   Reply With Quote
Old 09-05-2006, 07:24 AM   #14
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
1. If I hook two AGM batteries in series will they fit into the standard battery compartment.

2. Can I use the univolt with a generator to charge them (I am always permanently boondocking).

One more question, how long does it generally take a Univolt to recharge a battery after it has been drawn down to say 1/4 on the control panel?
wacnstac is offline   Reply With Quote
Old 09-05-2006, 09:48 AM   #15
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Quote:
Originally Posted by Darrell Root
Lewster, does the same hold true for walmart deep cycle 6 volt wired in series ,just not as lng lasting. Also Walmart deep cycles are about 1/3 the cost of glass matt makeing the cost about the same , Darrell
Darrell,

I'm not sure about the ratings of the WM golf cart batteries, but in general, this type of battery is made with much heavier plates that translate to higher amp/hour capacities and more charge/discharge cycles. You still have to be religious about keeping the electrolyte at the proper level.
__________________
lewster
Solar Tech Energy Systems, Inc.
Victron Solar Components and Inverters, Zamp Solar Panels, LiFeBlue and Battle Born Lithium Batteries, Lifeline AGM Batteries
lewster is offline   Reply With Quote
Old 09-05-2006, 10:07 AM   #16
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
Hmm, I'm building a generator shack. I couldn't stuff a lot, or even two of those 6 volt batteries in my trailer battery compartment, but I could stuff a lot of those batteries the shack (even 4 of them in a series/parallel combination). Then I could run some heavy gauge (3 or 6) wire from the shack buried underground to my trailer. My Honda 3000i generator is already setup to charge 12 volt batteries, which would be right next to the generator. What do you guys think?
wacnstac is offline   Reply With Quote
Old 09-05-2006, 10:13 AM   #17
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Great idea if you want to stay off-grid for a while. I have a golf cart in FL (no, I don't play golf) that the wife uses for running the dog around. It has a new set of 6 Lifelines in it ($$$$ ouch!) and it gets recharged about 1/2 the time we used to do with the older wet cells.
__________________
lewster
Solar Tech Energy Systems, Inc.
Victron Solar Components and Inverters, Zamp Solar Panels, LiFeBlue and Battle Born Lithium Batteries, Lifeline AGM Batteries
lewster is offline   Reply With Quote
Old 09-05-2006, 10:19 AM   #18
Rivet Master
 
1975 29' Ambassador
Reno , Nevada
Join Date: May 2003
Posts: 1,351
A furnace runs at about 8 amps. A typical group 27 sized battery can provide about 50 amp hours before needing recharging or 100 amp hours to totally flat. That means you can run your furnace for a total of about 6 hours before it needs a recharge or 12 hours to totally flat. A two battery system will double these times.

Whether you are running 6v series or 12v parallel won't make much difference. Going group 31 size ups the time just a tad and a group 24 is a bit more limited and AGM's will take more abuse and charge faster but won't really make much difference as far as capacity - again, these are not really at issue in the overall scheme of things.

It is not hard to get 10 hours or more on a furnace over three nights. That's only a 30% duty cycle. And that doesn't consider other pulls on the battery like water pump, lights, alarms, and other stuff.

A good rule of thumb is to get enough battery to last you 2 nights and three days for the kind of camping you do. If you do cool weather camping in a trailer, this is likely to be 2 batteries (about 200 amp hour @ 12v). For cold weather camping you often have to have more than batteries and you'll need more propane capacity, too.

And, anticipating the numbers nerds - give it a break. I am talking a practical +/- 15% or more here. When it comes to keeping warm overnight, the difference (80 AH vs 110AH) between a group 24 vs group 31 is a second order issue. This kind of difference is well within the normal variability of overnight temp and user inside thermostat preferences. Yes bigger batteries provide additional reserve. Yes more rugged batteries (e.g. AGM) will take more abuse. The parallel vs serial 'debate' is fun - But there are practical limits, cost vs benefit concerns, and other factors that tend to need first consideration.

Three nights of furnace running is going to take a lot of battery no matter what way you cut it.
bryanl is offline   Reply With Quote
Old 09-05-2006, 10:59 AM   #19
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,546
Images: 260
Quote:
Originally Posted by Leipper
...Three nights of furnace running is going to take a lot of battery no matter what way you cut it.
yep. seems to me, a catalytic heater is the way to go when boondocking. I'd only run a furnace on shore power.
__________________
Air:291
Wbcci: 3752
'73 Safari 23'
'00 Dodge Ram 1500 4x4 QC
Chuck is offline   Reply With Quote
Old 09-05-2006, 11:53 AM   #20
4 Rivet Member
 
1979 31' Excella 500
Detroit Area , Michigan
Join Date: Jul 2004
Posts: 498
Images: 43
I wasn't talking about 3 straight nights without a charge. I was charging the battery using a the univolt and a generator for plenty of hours during the day. Seems to be it should power the furnace one night after being fully charged.
wacnstac 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
battery charger ALANSD Batteries, Univolts, Converters & Inverters 8 09-16-2007 05:52 PM
Second Battery w9det 1997 - 1999 Safari 5 12-06-2002 06:42 PM
Battery lock Pahaska Our Community 8 11-23-2002 10:45 AM
Plastic battery boxes ! 77caravaner Electrical - Systems, Generators, Batteries & Solar 1 10-07-2002 12:57 PM
Battery Storage JAG Electrical - Systems, Generators, Batteries & Solar 2 07-05-2002 02:06 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

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 12:50 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.