Want to add batteries

[hes4all]

I have a 2006 Newmar Mountain Aire that Have 4 6 volt house batteries. I do a lot on boon dock camping and I would like to get some help if possible with the batteries. As of now, I have Interstate u2200 batteries and I am changing to AGM Lifeline batteries. The guy with Lifeline asked what I do and is said I should try to add a few batteries even with the AGM's. I can move my start batteries to make room for 2 more 6 volt. But I will I hook them up? I know it is probably really simple, but I want to get it right and hea your thoughts.

http://i190.photobucket.com/albums/z290/hes4all/batteries.jpg

 

[hes4all]

I have a 2006 Newmar Mountain Aire that Have 4 6 volt house batteries. I do a lot on boon dock camping and I would like to get some help if possible with the batteries. As of now, I have Interstate u2200 batteries and I am changing to AGM Lifeline batteries. The guy with Lifeline asked what I do and is said I should try to add a few batteries even with the AGM's. I can move my start batteries to make room for 2 more 6 volt. But I will I hook them up? I know it is probably really simple, but I want to get it right and hear your thoughts. This is alink to a picture of my batteries as of now.

http://i190.photobucket.com/albums/z290/hes4all/batteries.jpg

 

[John From Detroit]

Well, two things.. First I'm not convinced AGM's are necessarly worth the additional cost.. True, Lifeline AGM's can recharge slightly faster than flooded wet cells... But only slightly.. Absorption charge still takes hours (that's the last 10 percent more or less)

However if access for cleaning and adding DISTILLED water is an issue.. then AGM's are the best choice.

Second.  When working with six volt batteries you always do so in pairs.. Think of them something like the following ascii diagram

{Bat}{ery} 

Each half (Bat and Ery) is one six volt battery but taken together they become {Battery} which is one full 12 volt battery... If you think of them like this most all your questions shoudl answer themselves

The specific to "how do I hook them up"

You hook the two new ones in series (-SixV+===-SixV+)  like that.

Now you treat the pair as though they were a 12 volt battery and hook the positive to the positive of the other two pair (The wires that go off into the coach) and the negative to the negative of the other two pair (The wires that go off into the coach,, or to it's frame)  that simple

Your final result will be

{Bat}{ery}
{Bat}{ery}
{Bat}{ery}

With the -end of all 3 pair hooked together and the plus end of all 3 pair likewise joined together.

 

[Ned]

AGM batteries charge a lot faster than flooded cells, due to the lower internal resistance.  The final charge state is float, and can take awhile, but not usually more than an additional hour or so, but is generally not worth the extra generator run time.  When boondocking, I shut the generator off once the charger goes to float stage, and that leave the batteries at 80-90% of charge.  My AGMs get there from 50% discharge in about 2/3 the time my previous flooded cell batteries did.  But the big advantage of AGM batteries is the zero maintenance.  Also, they will take more discharge/charge cycles than flooded cell batteries offsetting some of the higher initial cost.  If you're going to be doing a lot of camping off the grid, they are definitely worth it, in my opinion.

To add the additional 2 6 volt batteries, connect them in series, and parallel the 2 with the existing 4 batteries.  Look at how the current pairs are wired and add the new pair exactly the same way.  Read this article in our library for detailed instructions on adding batteries.

 

[hes4all]

I just want to make sure of the wiring for adding the 2 batteries. If you look at my link to my batteries now where do I go from there to add the 2? I don't want to screw it up and make it 18 volts.Thank you for the help.

Picture link.
http://i190.photobucket.com/albums/z290/hes4all/batteries.jpg

 

[Just Lou]

I just want to make sure of the wiring for adding the 2 batteries. If you look at my link to my batteries now where do I go from there to add the 2? I don't want to screw it up and make it 18 volts.Thank you for the help.

Picture link.
http://i190.photobucket.com/albums/z290/hes4all/batteries.jpg

I'm not too sure your current battery bank is wired correctly.  That large red cable in the middle of the picture looks to be redundant.

Your current bank of 4-6v batteries should be wired like this http://dl.dropbox.com/u/15918372/Battery%20connect%201.jpg

They seem to be wired like this http://dl.dropbox.com/u/15918372/Battery%20connect%202.jpg
with the red wire being the dotted line on the picture.

You need to wire the 6 battery arrangement like this  http://dl.dropbox.com/u/15918372/BattereiswiredinSeriesParallel.gif

 

[Lou Schneider]

Looking at your current setup, your 6 volt batteries are connected in pairs going from left to right.  The short diagonal jumpers are the series connection that make each pair of 6 volt batteries 12 volts.  The red wire on the center terminals is unusual - maybe someone put it there in an attempt to equalize the current between all 4 batteries.  I'm also mystified by the two small wires that appear to connect to the center posts on the rear pair.

I can't read the batteries themselves, but the cables on the right with the red tape should be the (+) 12 volt connections.  The cables with the grey tape on the extreme left side of the batteries are the (-) 12 volt connections.

Are the Lifeline AGMs 6 volts or 12 volts?

 

[30yrnavy]

I agree with the above two posts. It would make it easier if you could draw a diagram showing the positive and negative terminals of the batteries and how they're connected. It would help to eliminate the guess work on those that are trying to help you.

 

[hes4all]

Looking at your current setup, your 6 volt batteries are connected in pairs going from left to right.  The short diagonal jumpers are the series connection that make each pair of 6 volt batteries 12 volts.  The red wire on the center terminals is unusual - maybe someone put it there in an attempt to equalize the current between all 4 batteries.  I'm also mystified by the two small wires that appear to connect to the center posts on the rear pair.

I can't read the batteries themselves, but the cables on the right with the red tape should be the (+) 12 volt connections.  The cables with the grey tape on the extreme left side of the batteries are the (-) 12 volt connections.

Are the Lifeline AGMs 6 volts or 12 volts?

You are correct with the wiring. The wires in the back are to a positive and a negative. And I think it has a 6 volt fuse on it. I will check tomorrow to  see. I am also going to call Newmar for a wiring schematic. I just want this to be right. This is how I got the coach for the dealer used.

 

[hes4all]

Well I just talked to Newmar and there are a few things I like about them. One, they are still in business and the customer service. This is the diagram that they sent me. My coach is a 2007, but the wiring is still the same as the diagram show. AS for the 2 wires in the back. I still don't know what they are for. Here's a link to the diagram from Newmar. And I can get the Lifeline AGM's for $230.00

http://i190.photobucket.com/albums/z290/hes4all/batterywiring2.jpg

 

[Ned]

While I don't agree with their wiring in the top left schematic, the top right one is correct for 3 sets of 6V batteries, which is what you were asking about.  I doubt you have any need for the 6V power connection.

 

[Just Lou]

While I don't agree with their wiring in the top left schematic, the top right one is correct for 3 sets of 6V batteries, which is what you were asking about.  I doubt you have any need for the 6V power connection.

Ned, can you explain what you like about the upper right diagram.  I know it will work, but i have not seen any wired with the extra intra battery connections like in my diagrams attached.

I drew those diagrams, months ago, to ask the question here on the forum, about the value of those connections, but never got around to it.

 

[Molaker]

Would maintaining the common central connection between the series battery pairs reduce the affect of a weak cell in one of the batteries?

 

[Ned]

Lou, I believe those extra jumpers are to supply the 6V connection using the 3 upper batteries in parallel to maximize the 6V capacity.  That's why I said he probably doesn't need the 6V connection and could remove those in that case.  If they were shown dotted as in the upper left diagram it would be clearer.

The upper left diagram is a better one, but the 12V house power and inverter outputs should come off the + of the bottom battery, not the top one.

 

[Gary RV_Wizard]

...but the 12V house power and inverter outputs should come off the + of the bottom battery, not the top one.

Why? I fail to see the difference. They are electrically identical as far as I can see. They are all tied together at the positive post anyway, presumable with an adequately sized wire.

 

[Ned]

There will be some voltage drop in the jumper cables and taking the + and - from opposite ends of the battery bank will tend to equalize those drops.  I just consider it a good practice.  But, yes, electrically they are the the same.

 

[Just Lou]

Okay, Ned, I was just trying to make sure that you didn't see any definitive value in those intermediate connections, other than a convenient 6v tap.

I agree with the balancing effect of at least trying to wire batteries with equal length cables.  My two sets of 6v batteries are separated by about 9'.  My I/C is approximately centered, physically, between the two banks.  I purposely made my Plus and minus cables of equal lengths, to electrically center it.  I had to use very large (6/0) cables to be able to get a common ground for my current shunt placement without a large voltage drop.  Not perfect, but I don't have a meter sensitive enough to detect any appreciable voltage drop.

 

[Ned]

Lou, I think we're on the same page.

 

[Gary RV_Wizard]

Typically those battery cables are more like 12"-16" in length, so the voltage drop or other wiring effect is negligible anyway.

 

[Just Lou]

Typically those battery cables are more like 12"-16" in length, so the voltage drop or other wiring effect is negligible anyway.

That's true, but the purpose of balancing the cable connections (and cable lengths) is to balance the current, both to and from, any given battery in the mix.  Equal charge current and equal discharge current has to account for something. 

I'm not as adamant about it as some of the fanatical battery bigots on the RV.xxx forum,  but it does have merit.