|
06-08-2021, 02:44 PM
|
#1
|
2 Rivet Member
2019 23' Flying Cloud
2018 22' Sport
LittleCity
, Colorado
Join Date: Jul 2019
Posts: 22
|
Batteries only charge to 12.9 volts
Hi, I'm wondering if I've damaged my batteries ... when hooked up to shore power (at my house, prior to going camping) my batteries seem to top out at 12.9 volts ... thus, based on my understanding with 13v being 'full' or '100%' I'm never able to get a 'full' charge ...
Should I replace my batteries or is the normal?
Thank you!
|
|
|
06-08-2021, 04:17 PM
|
#2
|
Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,740
|
Hi
What sort of batteries do you have? If they are flooded cells, first thing to do is to check the fluid levels. If they are AGM's, there is no way to do that.
How long have you let things run? It will take *hours* for the batteries to go from empty to full. A 24 hour charge is a good idea at the start of the season.
How are you checking the voltage? The stock voltmeters *do* go nutty. Best to check at the battery terminals with a multimeter. If you don't have one yet, head over and spend $30 on one. ( Yes, you can spend more and get better versions, a $30 meter will do just fine in this case).
What happens if you disconnect one battery? What happens if you disconnect the other? ( assuming you have two ). If the voltage pops up when you disconnect one ... yup... that's a battery problem.
If you still are wondering, pull the batteries and take them over to get tested. This could easily be a blown converter / charger ....
If you do replace the batteries ( .... if you have two ...), you should replace both of them at the same time.
Lots of twists and turns ... sorry about that !!
Bob
|
|
|
06-08-2021, 06:47 PM
|
#3
|
3 Rivet Member
2017 25' Flying Cloud
Raleigh
, NC
Join Date: Jul 2017
Posts: 170
|
You did not mention what type of batteries you have. Assuming your camper is plugged in, and you unplug it and then immediately read that you are at 12.9 v, you are reading your batteries with a draw on them that drops the voltage (all the background stuff such as refrigerator, propane detector, etc.).
I have AGMs and at 100% charge, they will read 12.9 volts when I disconnect.
To get an accurate fully charged voltage, you would pretty much have to disconnect the batteries and then take a voltage reading to see an accurate charge state based on volts.
|
|
|
06-08-2021, 08:10 PM
|
#4
|
Site Team
2017 30' International
Broomfield
, Colorado
Join Date: Apr 2009
Posts: 3,555
|
12.8-12.9v is a very good thing for lead acid batteries. Technically 12.6v at rest with no loads is "full" for most brands.
|
|
|
06-08-2021, 08:32 PM
|
#5
|
Moderator
2004 30' Classic Slideout
Fenton
, Missouri
Join Date: Mar 2002
Posts: 10,408
|
I've got 2 new Interstate flooded batteries. I know that once they come off the charger and sit for a bit they settle down to 12.9 volts.
Jack
__________________
Jack Canavera
STL Mo.
AIR #56 S/OS#15
'04 Classic 30' S.O.,'03 GMC Savana 2500
|
|
|
06-09-2021, 07:40 AM
|
#6
|
2 Rivet Member
2019 23' Flying Cloud
2018 22' Sport
LittleCity
, Colorado
Join Date: Jul 2019
Posts: 22
|
Quote:
Originally Posted by uncle_bob
Hi
What sort of batteries do you have? If they are flooded cells, first thing to do is to check the fluid levels. If they are AGM's, there is no way to do that.
How long have you let things run? It will take *hours* for the batteries to go from empty to full. A 24 hour charge is a good idea at the start of the season.
How are you checking the voltage? The stock voltmeters *do* go nutty. Best to check at the battery terminals with a multimeter. If you don't have one yet, head over and spend $30 on one. ( Yes, you can spend more and get better versions, a $30 meter will do just fine in this case).
What happens if you disconnect one battery? What happens if you disconnect the other? ( assuming you have two ). If the voltage pops up when you disconnect one ... yup... that's a battery problem.
If you still are wondering, pull the batteries and take them over to get tested. This could easily be a blown converter / charger ....
If you do replace the batteries ( .... if you have two ...), you should replace both of them at the same time.
Lots of twists and turns ... sorry about that !!
Bob
|
Hi, Yes, I have two AGM Group 24 12v batteries in parallel. This morning I disconnected the shore power, turned off the battery usage switch (located in my trailer) and then used a multi-meter to check voltage. I get 13.06 on one battery and .. 13.1 on the other ... which is super cool (I suppose!) as this must mean my batteries are 'ok'.
Now however, the 'battery level' check in the trailer (when pressed) reads 12.6 (this with everything turned off and no shore power connected).
Why would by SeeLevel display not know the correct voltage on my batteries?
|
|
|
06-09-2021, 07:50 AM
|
#7
|
diesel maniac
Airstream - Other
Tucson
, AZ
Join Date: May 2017
Posts: 2,548
|
Quote:
Originally Posted by El Juncal
Hi, Yes, I have two AGM Group 24 12v batteries in parallel. This morning I disconnected the shore power, turned off the battery usage switch (located in my trailer) and then used a multi-meter to check voltage. I get 13.06 on one battery and .. 13.1 on the other ... which is super cool (I suppose!) as this must mean my batteries are 'ok'.
Now however, the 'battery level' check in the trailer (when pressed) reads 12.6 (this with everything turned off and no shore power connected).
Why would by SeeLevel display not know the correct voltage on my batteries?
|
Once the batteries are fully charged and disconnected from everything you need to let them rest an hour or more for an accurate un-loaded reading. They are probably not over 13 volts but 12.6-12.9 as mentioned which is right where they should be. The See Level device puts a load on the batteries as well as the battery switch being on can allow for other loads to be present. Also the See Level battery monitor is not the greatest and will be affected by loads, a true shunted battery monitor is best if you want to know exactly where you are at.
__________________
Brian
|
|
|
06-09-2021, 07:55 AM
|
#8
|
Rivet Master
Currently Looking...
Evergreen
, Colorado
Join Date: Aug 2020
Posts: 2,592
|
As mentioned above, I think your batteries are fine. My AGMs tend to show 13.6V when connected to shore power, but after I disconnect and they settle down, they show 12.9V.
__________________
Dennis
Past:
Airstream International Serenity 23FB
Newmar Ventana 3715
|
|
|
06-09-2021, 11:51 AM
|
#9
|
2 Rivet Member
2015 27' Flying Cloud
Olympia
, Washington
Join Date: Aug 2011
Posts: 31
|
My fairly new flooded lead acid top out at about 12.7 after relaxing from a full charge. I’d say 12.9 is unusual unless you just shut off charging.
|
|
|
06-09-2021, 02:10 PM
|
#10
|
Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,740
|
Quote:
Originally Posted by El Juncal
Hi, Yes, I have two AGM Group 24 12v batteries in parallel. This morning I disconnected the shore power, turned off the battery usage switch (located in my trailer) and then used a multi-meter to check voltage. I get 13.06 on one battery and .. 13.1 on the other ... which is super cool (I suppose!) as this must mean my batteries are 'ok'.
Now however, the 'battery level' check in the trailer (when pressed) reads 12.6 (this with everything turned off and no shore power connected).
Why would by SeeLevel display not know the correct voltage on my batteries?
|
Hi
The SeeLevel stuff can be wrong for a variety of reasons. The simplest one is that they do break ....Being off by 0.2V in either direction is not that unusual.
Bob
|
|
|
06-09-2021, 02:55 PM
|
#11
|
Rivet Master
2007 30' Classic
Oswego
, Illinois
Join Date: Jul 2010
Posts: 13,669
|
Quote:
Originally Posted by El Juncal
Hi, Yes, I have two AGM Group 24 12v batteries in parallel. This morning I disconnected the shore power, turned off the battery usage switch (located in my trailer) and then used a multi-meter to check voltage. I get 13.06 on one battery and .. 13.1 on the other ... which is super cool (I suppose!) as this must mean my batteries are 'ok'.
Now however, the 'battery level' check in the trailer (when pressed) reads 12.6 (this with everything turned off and no shore power connected).
Why would by SeeLevel display not know the correct voltage on my batteries?
|
There are a variety of reasons. The long run, from the batteries to the wall location offers resistance. Each connection in that run offers more resistance. The circuit to the SeeLevel (in my unit) runs from the battery, through a breaker to the positive buss bar, to distribution panel then out on a non-dedicated circuit....some 24 feet or so to the rear of the SeeLevel. All of that creates a voltage drop, due to resistance.
All that said, mine only shows a 0.1V drop when compared to my Victron and Tri-Metric readings.
My anal retentive nature would make me hunt for the cause of your difference.
__________________
-Rich-
"If the women don't find you handsome, they should at least find you handy." - Red Green
|
|
|
06-09-2021, 03:08 PM
|
#12
|
diesel maniac
Airstream - Other
Tucson
, AZ
Join Date: May 2017
Posts: 2,548
|
Quote:
Originally Posted by Dennis C
As mentioned above, I think your batteries are fine. My AGMs tend to show 13.6V when connected to shore power, but after I disconnect and they settle down, they show 12.9V.
|
If you are using the See Level or similar device, or a multimeter, you are seeing the charging voltage, not the actual battery voltage.
__________________
Brian
|
|
|
06-09-2021, 03:23 PM
|
#13
|
Silver Star
1970 23' Safari
Victoria
, British Columbia
Join Date: Apr 2014
Posts: 352
|
Quote:
Originally Posted by wulfraat
12.8-12.9v is a very good thing for lead acid batteries. Technically 12.6v at rest with no loads is "full" for most brands.
|
I would agree ....on my sea level I get up around 13.6 while charging and around 12.6-12.7 at rest after a charge.
|
|
|
06-10-2021, 06:20 AM
|
#14
|
3 Rivet Member
2017 25' Flying Cloud
Raleigh
, NC
Join Date: Jul 2017
Posts: 170
|
Even with your switch in the store position, your propane detector stays on, potentially other draws, which means you are not getting a true "at rest" reading like you did when you disconnected the batteries.
I have a Merlin Smartgauge with dedicated cables to the battery terminals, and it always gives me a higher voltage reading than the Airstreams built in voltage gauge...I suspect for the reason others have said, length of run, resistance in connections etc.
|
|
|
06-10-2021, 06:24 AM
|
#15
|
Rivet Master
Currently Looking...
Evergreen
, Colorado
Join Date: Aug 2020
Posts: 2,592
|
Quote:
Originally Posted by ITSNO60
If you are using the See Level or similar device, or a multimeter, you are seeing the charging voltage, not the actual battery voltage.
|
I’m not. I’m using a Zamp charge controller that shows battery state of charge.
__________________
Dennis
Past:
Airstream International Serenity 23FB
Newmar Ventana 3715
|
|
|
06-13-2021, 09:11 AM
|
#16
|
4 Rivet Member
2018 30' Classic
Lake Charles
, SW Louisiana
Join Date: Oct 2019
Posts: 279
|
If not mistaken, When connected to shore power, the battery charge rating your seeing is being controlled by your inverter/charger.
__________________
"Finding the Roads that Await Us!"
Rick & Lydia Williams
|
|
|
06-13-2021, 09:50 AM
|
#17
|
1 Rivet Member
Chesterville
, Ohio
Join Date: Sep 2013
Posts: 8
|
Using voltage alone to determine state of charge is flawed unless you allow the batteries to rest, not charging or discharging, for several hours. A shunt is a much better tool to monitor batteries so you can see amp hrs in and out.
|
|
|
06-13-2021, 12:04 PM
|
#18
|
2 Rivet Member
1975 25' Tradewind
Woodland
, California
Join Date: Aug 2010
Posts: 21
|
Depends on the battery, how it's connected, how you measure, and the charger. I have found most chargers will not charge a deep cycle battery beyond 12.9 volts. The same chargers will charge a good automotive battery to between 13.1 and 13.7 volts
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|