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


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-31-2015, 09:23 AM   #1
Senior Member
 
Join Date: Feb 2015
Location: Phoenix
Posts: 276
Dual battery set up problem

I have 2 Crown Marine batteries: 20 AH Rate of 75, RC minutes of 105 / 25A

They are both new and hooked up to drain equally with the negative to one and positive to other with them connected together.

Last night started with a full charge. Ran TV off 12v with 300W inverter and watched movie with surround through entertainment unit. Maybe 2 hours. No heater all night, no lights, this morning had heater for 2 hours and TV for hour. Batteries went down to empty.

This seems a bit fast. Esp for not running heater all night like I could have.

Am I wrong?
__________________
2018 Jayco 34RSBS
2015 Ram 2500 Big Horn Cummins Diesel 4x4
19xx Beautiful Wife
2 x Golden Retrievers
dangerdave is offline   Reply With Quote
Old 07-31-2015, 10:09 AM   #2
Senior Member
 
RVhiker's Avatar
 
Join Date: Dec 2010
Posts: 1,643
Are these Group 24 batteries or Group 27?

Regardless, if the two batteries were fully charged and then completely flat, I'd say that that is not what I'd expect given the energy your system used.

However. How are you determining the state of charge of the batteries? Are you using the on board led lights on the panel? If so, those led lights are not very informative. More sort of decorative. Sort of like the tank level indicators.

I use an inexpensive digital voltmeter to check my batteries; even that is not especially accurate, but much better than the led lights. The ideal is to measure the batteries when they have been allowed to "rest" for an hour or two, then check the charge with no load on the batteries.

I consider 12.7 volts charged; I discharge my batteries no lower than a reading of 12.1 volts, which is still about half charged; taking them lower can damage the batteries.

Here's a link to lots of battery information: Battery University
__________________
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.

2011 Jayco 28.5RLS; 2021 Chevy Duramax; Pullrite Superglide Hitch

RVhiker is offline   Reply With Quote
Old 07-31-2015, 10:11 AM   #3
Senior Member
 
mike837go's Avatar
 
Join Date: May 2015
Location: Campbell Hall
Posts: 2,835
The total of 3+ hours on the inverter is what ate up the bulk of your charge.


The TV and Stereo are 150+ watts 100% of the time they are running. That's about a 12A draw for 3 hours. Throw in the 7-8A draw of the heater fan....


Remember, stored electricity is not like gasoline. The top 10% of the charge is at at around 13V and then things go downhill. With liquid fuels (gasoline, Diesel, propane, etc.) every drop is the same as every other drop.


If you want to camp off the grid, either:
- Budget your battery power as the precious resource it is
OR
- Buy a generator
__________________
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck


Sitting in The Cheap Seats.
And proud of it!
mike837go is offline   Reply With Quote
Old 07-31-2015, 10:32 AM   #4
Senior Member
 
Join Date: Feb 2015
Location: Phoenix
Posts: 276
batteries

Thank you both. I have 2 Honda generators so none of this is really an emergency

I bought the inverter on the advice of someone on the board when I discovered that the TV won't run on the batteries. I can see how it would pull the batteries down.

Live and learn!
__________________
2018 Jayco 34RSBS
2015 Ram 2500 Big Horn Cummins Diesel 4x4
19xx Beautiful Wife
2 x Golden Retrievers
dangerdave is offline   Reply With Quote
Old 07-31-2015, 12:12 PM   #5
Senior Member
 
Join Date: Aug 2011
Location: Missouri City, The Republic of Texas
Posts: 5,063
are these 6V or 12V batts? The reason I ask is it sounds like you have the batteries connected in series: batt#1 + to the coach and - to + on batt2. batt2 - to coach ground.
I think that's how you'd connect a pair of 6V batts to get 12V. If you have 2 12V batts and that's how they're connected you're getting 24V.
Series vs Parallel
__________________
Cheers,
T_

2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
-SOLD- 2012 X23B
-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks
RedHorse1 is offline   Reply With Quote
Old 07-31-2015, 12:26 PM   #6
Senior Member
 
tnchuck100's Avatar
 
Join Date: Jun 2012
Location: Sparta, TN
Posts: 1,174
His description does make for wondering if he connect 2 12V batteries in series. It caught my attention too.

1. I don't think they make 6V marine batteries.
2. If he had 24V he would have blown fuses and/or damaged equipment.

Must have been in parallel.

dangerdave, check this out:12 Volt Side of Life
__________________
Chuck - Sparta, TN
2012 Jay Flight 22FB, 2 x Honda EU2000i
2013 GMC Yukon XL Denali AWD

EDUCATION is what you get when you read the fine print.....
EXPERIENCE is what you get when you don't.
tnchuck100 is offline   Reply With Quote
Old 07-31-2015, 01:06 PM   #7
Senior Member
 
Join Date: Oct 2014
Location: St. Clairsville
Posts: 225
The 6 volt batteries are typically called golf cart batteries or something similar, but are deep cycle, typically with more reserve capacity than the same footprint 12 volt batt. Another idea would be to either see if you can hack your current TV's cord to run it on 12v or buy a 12 volt TV. That would eliminate the invertor and its significant power draw. Oh, and if you hook up 24 volts to a 12 volt trailer, it blows a lot of light bulbs (oh, the things you learn)
djtho1 is offline   Reply With Quote
Old 07-31-2015, 01:48 PM   #8
Senior Member
 
Join Date: Feb 2015
Location: Phoenix
Posts: 276
batts

Hey guys,

12V batteries in parallel. with the TT connected to the neg on one battery and the pos on the other so they draw down equally.

I followed this set up on Youtube:


The only unusual thing I do is run that inverter NPower 300W Sine Wave Inverter. I run the TV and entertainment center DVD player. Probably for 3 hours. I know there's a calculation to tell me exactly what to expect but I'm not sure what it is.
__________________
2018 Jayco 34RSBS
2015 Ram 2500 Big Horn Cummins Diesel 4x4
19xx Beautiful Wife
2 x Golden Retrievers
dangerdave is offline   Reply With Quote
Old 07-31-2015, 01:56 PM   #9
Senior Member
 
Join Date: Oct 2014
Location: St. Clairsville
Posts: 225
I think that the standard A = W / V would apply. If true, then 300 watts / 12 volts equals slightly less than 30 Amps. Another site said to divide by ten, but either way by running through the invertor it's a huge power drain. 30 amps power drain for three hours equals low or dead batteries, unfortunately. At least that is my understanding and what I have experienced.
djtho1 is offline   Reply With Quote
Old 07-31-2015, 01:56 PM   #10
Senior Member
 
mike837go's Avatar
 
Join Date: May 2015
Location: Campbell Hall
Posts: 2,835
The calculations are fairly simple:


Multiply the amps drawn at 120VAC times 10. That'll be about how many amps you are drawing at 12VDC. (the actual DC amps is slightly higher because of losses from conversion). Multiply the amps at 12VDC times 3600 that product is the number of amp-hours you are using.


So 2A draw at 120VAC (24" Flat screen TV) is 20 amps from the battery. In an hour you will have drawn 72,000 amp-hours from your battery pack. Just to watch TV.


Not exactly efficient, is it?
__________________
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck


Sitting in The Cheap Seats.
And proud of it!
mike837go is offline   Reply With Quote
Old 07-31-2015, 02:14 PM   #11
Senior Member
 
Join Date: Feb 2015
Location: Phoenix
Posts: 276
bats

Interesting and thanks. So at least I understand that what's happening should be happening.
__________________
2018 Jayco 34RSBS
2015 Ram 2500 Big Horn Cummins Diesel 4x4
19xx Beautiful Wife
2 x Golden Retrievers
dangerdave is offline   Reply With Quote
Old 07-31-2015, 02:32 PM   #12
Senior Member
 
RVhiker's Avatar
 
Join Date: Dec 2010
Posts: 1,643
Here's some numbers from experience that might be of interest.

We have a 30" LCD (florescent tube lit), a DirecTV receiver, and a power inserter to power the dish. When boondocking, I power all of that from a Go Power 300 watt pure sine wave inverter. My clamp on amp meter (not a super quality one) shows about 7.8 amps when all of the TV equipment is running. Our three cheapo Walmart marine group 27 batteries allow us to watch all the TV we can stand, run the lights and equipment on the trailer including moderate use of the heater if needed.

The above use depletes the batteries to near half, and can be re-charged with our generator, usually the next evening.
__________________
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.

2011 Jayco 28.5RLS; 2021 Chevy Duramax; Pullrite Superglide Hitch

RVhiker is offline   Reply With Quote
Old 07-31-2015, 02:49 PM   #13
Senior Member
 
Join Date: Feb 2015
Location: Phoenix
Posts: 276
Yes I've read that adding batteries in parallel gives you LONGER duration of draw down but not more power per se (like series would). So if you have 3 group 27 batteries you should be really good.
__________________
2018 Jayco 34RSBS
2015 Ram 2500 Big Horn Cummins Diesel 4x4
19xx Beautiful Wife
2 x Golden Retrievers
dangerdave is offline   Reply With Quote
Old 07-31-2015, 02:50 PM   #14
Senior Member
 
tnchuck100's Avatar
 
Join Date: Jun 2012
Location: Sparta, TN
Posts: 1,174
Quote:
Originally Posted by mike837go View Post
So 2A draw at 120VAC (24" Flat screen TV) is 20 amps from the battery. In an hour you will have drawn 72,000 amp-hours from your battery pack.
20 amps for an hour is 20 amp-hours...not 72,000 amp-hours.
__________________
Chuck - Sparta, TN
2012 Jay Flight 22FB, 2 x Honda EU2000i
2013 GMC Yukon XL Denali AWD

EDUCATION is what you get when you read the fine print.....
EXPERIENCE is what you get when you don't.
tnchuck100 is offline   Reply With Quote
Old 07-31-2015, 02:54 PM   #15
Senior Member
 
tnchuck100's Avatar
 
Join Date: Jun 2012
Location: Sparta, TN
Posts: 1,174
Quote:
Originally Posted by dangerdave View Post
Yes I've read that adding batteries in parallel gives you LONGER duration of draw down but not more power per se (like series would). So if you have 3 group 27 batteries you should be really good.
Power is not dependent on series or parallel. A pair of same kind 12V batteries will provide twice as much power as one battery.

Series batteries = ADD voltage. Amp-hours remain the same.
Parallel batteries = ADD the amp-hours. Voltage remains the same.
__________________
Chuck - Sparta, TN
2012 Jay Flight 22FB, 2 x Honda EU2000i
2013 GMC Yukon XL Denali AWD

EDUCATION is what you get when you read the fine print.....
EXPERIENCE is what you get when you don't.
tnchuck100 is offline   Reply With Quote
Old 08-01-2015, 03:17 PM   #16
Senior Member
 
us71na's Avatar
 
Join Date: Jun 2013
Location: McKean, PA
Posts: 1,071
Quote:
Originally Posted by dangerdave View Post
Hey guys,

12V batteries in parallel. with the TT connected to the neg on one battery and the pos on the other so they draw down equally.
Once the batteries are connected in parallel, you can hook the trailer wires any way you want as long as the black wire goes to a positive terminal and the white wire is connected to any negative terminal. Both trailer wires could be connected to one battery and they will both still draw down together.

The crisscrossing method the guy in the video used is probably because with two batteries on the rack the trailer wires wouldn't reach the outboard terminal on the batteries to hook both tot he same battery.
__________________
2011 Skylark 21FKV
us71na is offline   Reply With Quote
Old 08-01-2015, 04:47 PM   #17
Senior Member
 
RVhiker's Avatar
 
Join Date: Dec 2010
Posts: 1,643
Quote:
Originally Posted by us71na View Post
Once the batteries are connected in parallel, you can hook the trailer wires any way you want as long as the black wire goes to a positive terminal and the white wire is connected to any negative terminal. Both trailer wires could be connected to one battery and they will both still draw down together.

The crisscrossing method the guy in the video used is probably because with two batteries on the rack the trailer wires wouldn't reach the outboard terminal on the batteries to hook both tot he same battery.
Somewhere I've read about a particular way to connect batteries in a parallel configuration that should be used to maximize battery life, similar to that mentioned by dangerdave. Does anybody know where this connection method is discussed in detail?
__________________
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.

2011 Jayco 28.5RLS; 2021 Chevy Duramax; Pullrite Superglide Hitch

RVhiker is offline   Reply With Quote
Old 08-01-2015, 04:47 PM   #18
Site Team
 
Mustang65's Avatar
 
Join Date: Nov 2012
Location: Clearwater, FL area
Posts: 5,196
Here is the most efficient method for hooking up (2) 12Volt batteries in paralllel. It produces a more even charge and discharge.

Also, go an Amazon and get an inexpensive digital voltage display that plugs into your TT's 12VDC accessory plug, so you can monitor your batterys to insure that the voltage does not drop below 12VDC. The battery monitor lights on the TT are not really worth anything.
Don
Attached Thumbnails
12Volt Batteries Parallel.jpg  
__________________
2013 Jayco Eagle 284BHS
2012 Ford F150XLT, EcoBoost w/3.73,Max Tow Pkg.
Our Solar Album https://www.jaycoowners.com/album.php?albumid=329
Mustang65 is offline   Reply With Quote
Old 08-01-2015, 04:54 PM   #19
Senior Member
 
RoyBraddy's Avatar
 
Join Date: Sep 2011
Location: King George
Posts: 2,761
My 12VDC battery bank (three each GP24 12V 85AH Interstates) connected in parallel gives me 255AH s of capacity. My parasitic drain is around 1.5 amps 24/7.

We usually start drawing around 20AMPS of DC current to run our toys and lights from 6PM to 11PM. This along with the parasitic drain drops my three batteries down to around 12.0VDC (approximately 50% charge state) by 8AM the next morning.

At 8AM each morning when allowed to run our Generator we will connect our trailer shore power cable directly to our 2KW Generator using a RV30A-15 Adapter which allows the on board PD9260C 60A Converter/Charger unit to recharge my battery bank back up to their 90% charge state in around three hours time.

Been doing this since 2009 and my GP24 12V Interstates are just now starting to fall off on performance...

If we get to the 90% charge state then we can do all this all over again the next day/night run off the batteries...

Hoping to get 2ea 12V Trojan 150AHs batteries to replace my old interstates. This will give me around 300Ahs of capacity.

I suspect in your case you did not start out with either a full charge or at least a 90% charge state. My batteries give me almost the same performce at 90% as they do at 100%. I can only only do these 50-90% charge states for 12-14 times before I have to do a full 100% charge state or risk doing internal damage to the batteries. It would take a 12 hour or so generator run time using my PD9260C 60A converter/charger to reach a full 100% charge when camping off the power grid. That is usually when we head for home

Roy Ken
__________________
Roy and Carolyn
I claim Horse Creek Country in Southern Ill - Momabear is from North Texas
We live in King George VA
RETIRED DOD DOAF DON CONTRACTOR Electronics Tech 42YRS

"We're burning daylight" - John Wayne
2008 STARCRAFT 14RT OFF-ROAD POPUP with PD9260C and three 85AH 12VDC batteries
2010 F150 FX4 5.4 GAS with 3.73 gears - Super Cab - Towing Package - 2KW Honda EU2000i Gen
K9PHT (since 1957) 146.52Mhz
"We always have a PLAN B"
RoyBraddy is offline   Reply With Quote
Old 08-01-2015, 06:10 PM   #20
Senior Member
 
Join Date: Jun 2013
Location: Camp Hill
Posts: 257
Quote:
Originally Posted by Mustang65 View Post
Here is the most efficient method for hooking up (2) 12Volt batteries in paralllel. It produces a more even charge and discharge.

Also, go an Amazon and get an inexpensive digital voltage display that plugs into your TT's 12VDC accessory plug, so you can monitor your batterys to insure that the voltage does not drop below 12VDC. The battery monitor lights on the TT are not really worth anything.
Don


I got this for display:

Amazon.com: INNOVA 3721 Battery and Charging System Monitor: Automotive
__________________
2013 Jayco X23B
Solar System: Renogy 300W/Tristar 45 PWM
DC System: Trojan T-105 225 AH/Samlex PST-600 PSW
2013 RAM 1500 V6/TF8/3.55
sebring96hbg is offline   Reply With Quote
Reply

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


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Jayco, Inc. or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 04:18 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright 2002-2016 Social Knowledge, LLC All Rights Reserved.