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 12-31-2014, 12:20 PM   #1
4 Rivet Member
 
trekerboy's Avatar
 
1979 31' Excella 500
Charlevoix , Michigan
Join Date: Aug 2014
Posts: 350
Series Parallel Battery Wiring - Which is correct?

I've seen a couple different schematics for wiring 6v batteries in series-parallel for 12v applications (like my Airstream DC) and wondered if both were "correct" and if there was any advantage of one over the other. Thoughts?

Click image for larger version

Name:	battery series parallel.001.jpg
Views:	1725
Size:	194.9 KB
ID:	229569

I got the information from these websites:
  1. AtBatt
  2. BatteryStuff
trekerboy is offline   Reply With Quote
Old 12-31-2014, 12:33 PM   #2
Figment of My Imagination
 
Protagonist's Avatar
 
2012 Interstate Coach
From All Over , More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
Two 6v batteries need to be wired in series to produce 12 volts— negative post of first battery connects to positive post of second battery. Add voltages together, but don't add amps-hours together. Two 6v 160-amp-hour batteries in series produce 12v 160 amp-hours.

Two 12v batteries have to be wired in parallel to produce 12 volts— negative post of first battery connects to negative post of second battery. Add amp-hours together, but don't add voltages. Two 12v 80-amp-hour batteries in parallel produce 12v 160 amp-hours.

If you've got four batteries, first hook up two 6v batteries in series. Then hook up the other pair in series. That makes them the same as two 12v batteries. Then hook up the sets in parallel. Simpler to understand that way.
__________________
I thought getting old would take longer!
Protagonist is offline   Reply With Quote
Old 12-31-2014, 12:34 PM   #3
Rivet Master
 
1981 31' Excella II
New Market , Alabama
Join Date: Sep 2011
Posts: 6,145
I think what you are doing amounts to the same thing. You have to have two batteries in series to get 12V then put two of those sets in parallel to double the current. You could also hook two in parallel and then put those sets in series. So whatever works best as far as your physical layout. You want to minimize the length of the final output cables or for that matter all the cables. It does not take much length of wire to loose voltage at 6V.

I assume you are running an inverter or something that needs the extra current? You want the inverter to be really close to the batteries. A more efficient system would use 24V in which case you can run all of them in series. The higher the voltage the fewer loses you get. You can run 4 times much power through the same size wire at 24V as you can at 12 V. Power=current squared times the resistance.

Perry
perryg114 is offline   Reply With Quote
Old 12-31-2014, 02:18 PM   #4
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
What they are trying to do in the diagrams you supply is to have equal lengths of battery cables on the series and parallel portions of the 4 battery setup. Although it may seem strange and hard to believe, the very minor resistance differences of the cables and cable connections can make one set of two batteries charge and discharge more than the other if they don't have virtually identical wire connections and lengths.

I have no personal experience with this issue but have read some pretty convincing studies over the years which make a good case for hooking batteries up in ways which have identical cable runs for both sets when in a series/parallel setup.
idroba is offline   Reply With Quote
Old 12-31-2014, 02:24 PM   #5
Figment of My Imagination
 
Protagonist's Avatar
 
2012 Interstate Coach
From All Over , More Than Anywhere Else
Join Date: Dec 2011
Posts: 10,868
Quote:
Originally Posted by idroba View Post
What they are trying to do in the diagrams you supply is to have equal lengths of battery cables on the series and parallel portions of the 4 battery setup. Although it may seem strange and hard to believe, the very minor resistance differences of the cables and cable connections can make one set of two batteries charge and discharge more than the other if they don't have virtually identical wire connections and lengths.
That's actually easy enough. Find the longest cable you need to connect the batteries to each other. Then make all the cables that same length, even if they're a bit too long for the other connections.
__________________
I thought getting old would take longer!
Protagonist is offline   Reply With Quote
Old 12-31-2014, 04:03 PM   #6
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Use 4/0 class 'K' welding cable (which I use in most of my battery set-ups) and you won't have to worry about resistance.

Option 2 is a better method, but I would have the negative connection cable on the #4 battery's negative, not #1. THAT will assure even charge and discharge of the bank, which is far more important than equal connecting cable lengths.
__________________
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 12-31-2014, 04:26 PM   #7
4 Rivet Member
 
Currently Looking...
ottawa (greely) , Ontario
Join Date: Feb 2012
Posts: 390
Blog Entries: 1
First thing is get the batteries in there proper location then like others have said try to make all cables as short as possible and all aprox the same length . And make sure you use proper size cables .

Don
__________________
2012 silverado ext cab 4x4 ,5.3 L , 6 speed trans,3:42 final drive,tow package standard box 6 1/2 foot . 2014 honda forza 300 scooter, #2 2015 honda crf 250 L (Dual sport)
scamp is offline   Reply With Quote
Old 12-31-2014, 06:00 PM   #8
Rivet Master
 
tjdonahoe's Avatar
 
2013 31' Classic
billings , Montana
Join Date: Feb 2010
Posts: 3,576
Welding cable is not good for battery cables it is made for maybe 250 amps or a little more..Battery cables are able to carry 1000 amps or so when starting..I have a couple nice sets of welder cable jumper cables, took me a while to figure out they aren't t very good..Use only battery cables on batteries ask me how I know...Happy New Year and best wishes....
tjdonahoe is offline   Reply With Quote
Old 12-31-2014, 06:19 PM   #9
Rivet Master
 
1981 31' Excella II
New Market , Alabama
Join Date: Sep 2011
Posts: 6,145
Current capacity is purely a function of wire diameter. It does not matter what the wire is called. Also current capacity is somewhat subjective. The steady state current capacity is what is most important. Most battery cables are pretty crappy. Some are even copper coated steel. They are also for intermittent use. The resistance of the connections is also important. Most wire burns up because the connections are loose and the connectors get hot and fail. Equal length wires are a very good idea. Connectors that are soldered on will help a lot. Cleaning lead oxide off of battery posts is also a good idea. The oxide is an insulator. A lot of starting problems on cars are loose corroded cable clamps. There are plenty of tables on the internet that tell you what the current capacity of different size wire is. Figure out what current you really need. If you need 100 Amps occasionally don't wire for 300A. Those same cables can take 1000 A for a few seconds like for starting a car engine. Understand your application. Spec out what you are doing.

I was shocked when I learned that my 50A rated oven did not have wire over #12 inside it. The pigtail was the largest wire on the thing.

Perry
perryg114 is offline   Reply With Quote
Old 12-31-2014, 08:42 PM   #10
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Quote:
Originally Posted by tjdonahoe View Post
Welding cable is not good for battery cables it is made for maybe 250 amps or a little more..Battery cables are able to carry 1000 amps or so when starting..I have a couple nice sets of welder cable jumper cables, took me a while to figure out they aren't t very good..Use only battery cables on batteries ask me how I know...Happy New Year and best wishes....
So..........how DO you know???????

It is an interesting concept, but unfortunately could not be further from fact! Perry has pretty much hit the nail on the head.

Class 'K' welding cable simply refers to a family of wire manufactured to a specific set of standards including the use of super flexible polyurethane or EPDM insulation, along with hundreds or thousands of strands of very fine conductive copper wire, either 30 AWG or .010.

The 4/0 class 'K' cable that I use contains over 2000 strands of 30AWG conductors, is super flexible (also super expensive!) and has a listed ampacity of 400 amps at 100 feet and 600 volts continuous rating. For large (2000 watt +) inverter use, it has a practical usable length of up to 10 feet. If your cables to the batteries will be over 10 feet, then a double 4/0 cable is required to carry the current properly. All cabling should be properly matched to the load and type of use by the stated ampacity of the cables ONLY!

PS: this type of cable is also used in diesel motor homes and yachts as 'battery cable' on a regular basis, and easily handles the very large transient amperage loads that engine starting require.
__________________
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 12-31-2014, 09:27 PM   #11
Rivet Master
 
Southwestern , Ohio
Join Date: Nov 2006
Posts: 1,671
Quote:
Originally Posted by trekerboy View Post
I've seen a couple different schematics for wiring 6v batteries in series-parallel for 12v applications (like my Airstream DC) and wondered if both were "correct" and if there was any advantage of one over the other. Thoughts?

Attachment 229569

I got the information from these websites:
  1. AtBatt
  2. BatteryStuff
Looking closely at the picture, Option #2 is drawn wrong. The negative output lead is connected to the negative terminal of 6 V battery #1 and the positive output lead is connected to the positive output terminal of the same battery #1. So, as it is drawn, there will only be 6 volts across the output leads.
Nuvite-F is offline   Reply With Quote
Old 12-31-2014, 09:45 PM   #12
Senior Member
 
sheriff1's Avatar
 
2012 27' FB Eddie Bauer
Sparks , Nevada
Join Date: Mar 2014
Posts: 1,116
I think I agree, the - would need to come off of the - of battery #2?


Sent from my iPhone using Airstream Forums
sheriff1 is offline   Reply With Quote
Old 01-01-2015, 07:24 AM   #13
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Quote:
Originally Posted by lewster View Post
Use 4/0 class 'K' welding cable (which I use in most of my battery set-ups) and you won't have to worry about resistance.

Option 2 is a better method, but I would have the negative connection cable on the #4 battery's negative, not #1. THAT will assure even charge and discharge of the bank, which is far more important than equal connecting cable lengths.
As I said before, the output negative needs to be on battery #4 (it could also be on the negative of #2, but that would be counter-productive), and the positive on #1. The short cables between #1-#2 and #3-#4 are the series connections that effectively create 2 big 12VDC batteries. The long cables from + to + and - to - are the parallel connections. Positive out at #1, negative out at #4.

Another classic example of the mis-information often posted on the internet. But as we all know..........if it's on the internet........IT MUST BE TRUE!!!
__________________
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 01-01-2015, 09:24 AM   #14
4 Rivet Member
 
trekerboy's Avatar
 
1979 31' Excella 500
Charlevoix , Michigan
Join Date: Aug 2014
Posts: 350
Quote:
Originally Posted by Nuvite-F View Post
Looking closely at the picture, Option #2 is drawn wrong. The negative output lead is connected to the negative terminal of 6 V battery #1 and the positive output lead is connected to the positive output terminal of the same battery #1. So, as it is drawn, there will only be 6 volts across the output leads.
Quote:
Originally Posted by lewster View Post
Another classic example of the mis-information often posted on the internet. But as we all know..........if it's on the internet........IT MUST BE TRUE!!!
You're right! That's my mistake, I misrepresented and inaccurately recreated the diagram on AtBatt for wiring 6v Batteries in Series-Parallel!

As @Lewster said, if it's on the Internet if MUST be right! Therefore, for the poor soul who stumbles upon my original post and tries to wire their system according to it, I offer the below corrected image (which is accurate to AtBatt's diagram and should work according to @Lewster).

Click image for larger version

Name:	battery series parallel.001.jpg
Views:	403
Size:	195.6 KB
ID:	229599
trekerboy is offline   Reply With Quote
Old 01-01-2015, 10:48 AM   #15
Rivet Master
 
Jim Foster's Avatar
 
1965 17' Caravel
1983 27' Excella
Walnut Grove/Laguna Woods , California
Join Date: Jun 2004
Posts: 1,635
Send a message via Yahoo to Jim Foster
"2 is now correct. I used four six volt batteries on our 12v houseboat for 27 years. Used four Trojan 104s. Had a 1500w Readiline motor-generator to power microwave and espresso maker (not at the same time). Plenty of power for three to four days and nights.


Sent from my iPhone using Airstream Forums
__________________
Past President, El Camino Real Unit WBCCI#6620
Street Rod Builder (see avatar)
Kite flier (check out links below)
https://www.youtube.com/watch?v=Bp3nuNtlZcA&t=331s
https://www.youtube.com/my_videos?feature=mhee
Jim Foster is offline   Reply With Quote
Old 01-01-2015, 11:35 AM   #16
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Sorry guys, but you're still not there. The positive output should be at one end if the bank with the negative output at the other.

That means that the negative output should be on #4 negative, not #2.

While your latest diagram will work, the second bank is relying on the parallel connection instead of creating one big battery as stated above.

Placing the output cables at opposite ends of the battery bank assure you of even charging and even draws.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357
__________________
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 01-01-2015, 04:38 PM   #17
Rivet Master
 
SuzyHomemakr's Avatar
 
1972 29' Ambassador
Boynton Beach , Florida
Join Date: Dec 2013
Posts: 568
Quote:
Originally Posted by lewster View Post
Sorry guys, but you're still not there. The positive output should be at one end if the bank with the negative output at the other.

That means that the negative output should be on #4 negative, not #2.

While your latest diagram will work, the second bank is relying on the parallel connection instead of creating one big battery as stated above.

Placing the output cables at opposite ends of the battery bank assure you of even charging and even draws.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357
But if you create one big battery, won't it be 24V? I don't really like that drawing, so I did my own. Bear in mind that the wires that go into the junction are all the same length...

I started reading this thread, and got more and more confused!
Attached Thumbnails
Click image for larger version

Name:	BatterySeries.jpg
Views:	142
Size:	51.7 KB
ID:	229656  
SuzyHomemakr is offline   Reply With Quote
Old 01-01-2015, 05:46 PM   #18
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
Nope. 2 6VDC batteries is series (pos of #1 to neg of #2 ) create a 12VDC battery of the same amperage (2 X 300 amp/hour batteries @6VDC in series will yield a single 12VDC battery @ 300 amp/hours. Do this between batteries 1/2 and 3/4.

You then connect the positive of #4 to the positive of #2, leaving the positive of # 1 as the output or 'tap' terminal. On the negative side, you connect the negative of battery 3 with the negative of #1, leaving the negative of #4 as the 'tap' terminal. you now have a battery bank of essentially 2 very large 12VDC batteries connected in parallel.

It's the diagrams that are making it confusing! I'll see if I can find a better, easier to understand diagram and post it shortly.
__________________
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 01-01-2015, 05:55 PM   #19
Rivet Master
Commercial Member
 
Vintage Kin Owner
Naples , Florida
Join Date: Dec 2005
Posts: 7,508
I found an excellent explanation os series/parallel and combo battery connections, but could not copy and paste it here.

The link will take you to a Magnum Energy inverter/charger manual. Scroll to pages 60/61 for color drawings and complete explanations of the process and results.

http://magnumenergy.com/wp-content/u...Series_Web.pdf
__________________
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 01-01-2015, 06:02 PM   #20
4 Rivet Member
 
Currently Looking...
ottawa (greely) , Ontario
Join Date: Feb 2012
Posts: 390
Blog Entries: 1
Here you go ! This is the way it should be done remember short as possible cables and aprox same length.

Don
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	181
Size:	271.4 KB
ID:	229657  
__________________
2012 silverado ext cab 4x4 ,5.3 L , 6 speed trans,3:42 final drive,tow package standard box 6 1/2 foot . 2014 honda forza 300 scooter, #2 2015 honda crf 250 L (Dual sport)
scamp 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
Solar panels in series or parallel - but why not both? drboyd Generators & Solar Power 19 10-16-2017 08:39 PM
'93 Excella... Series or parallel? atomeve Electrical - Systems, Generators, Batteries & Solar 11 04-13-2014 07:25 AM
Battery hook up, parallel or series iamscuba2 Furnaces, Heaters, Fireplaces & Air Conditioning 4 08-15-2011 09:33 AM
Parallel not-alike honda eu series generators malimish Generators & Solar Power 26 02-04-2009 10:26 PM
Series or parallel benwd Batteries, Univolts, Converters & Inverters 52 11-03-2007 08:19 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 02:41 AM.


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