Battery wiring diagram for PC2100 (2008)

Hi all,
Does anyone have any good pics of the battery wiring in the 2100, or a diagram? I got 2 new batteries today and am unsure he wired them the same way they were. Also, what component in my system is the likely culprit for boiling them dry? I'd like to avoid that again.

Thanks
Gail

Hi Gail,

I will assume your 2008 2100 is unmodified, identical to our 2007 2350 when it was new with two 12V batteries.  I took pictures of mine before making any changes back in 2008.  Here they are.

It is difficult to see but there is a short 9" long red cable from + to + terminals, and a short 9" long black-taped cable from - to - terminals.  Both black cables from the motor home are connected to the rear battery - terminal.  The single red cable is connected to front battery + terminal.


In this picture, the batteries & tray are removed.  It clarifies two black cables and one red cable connecting to the motor home.

Gail

The first thing to determine is if you have 6V or 12V batteries

If you have two 6 V batteries they should be wired in series. If you have two 12 V batteries they should be wired in parallel.

Here is a link to a diagram that show 6V series and 12V parallel battery wiring:
https://sp.yimg.com/xj/th?id=OIP.Mf70114eb117fefa9a7225d71e02e030co0&pid=15.1&P=0&w=300&h=300

The easiest way to determine if your batteries are wired correctly is to measure the voltage between a negative and positive pole.  If you read 12 volts DC you are wired correct.  If you read 6V or 24V you are wired wrong.

We had a 2008 2350 and experienced a similar problem with our batteries boiling away the fluid.  I think there were two factors related to my problem.  First, the Tripp-Lite combined converter/inverter did not have the advantage of current technology (3 stage charger) and had a tendency to overcharge the batteries.  Second, as a pair of batteries age one battery will not be able to hold a charge as well as the other.  This will set up an imbalance in the electrical system that will tend to cause the converter to overcharge.  I think these factors combined to reduce the overall life of my batteries.

Barry

All good points Barry-Sue  

I most certainly favor your comment of one battery getting weaker more quickly than the other.  Then it all goes quickly down hill from there with acid boil-overs and greatly reduced battery reserve power.  That is why I switched to two 6V batteries, hoping to avoid that "imbalance" condition.  I did have to sacrifice the battery tray to get enough height clearance which makes checking water levels extremely painful.  That encouraged me to go with sealed AGM batteries.  No more fuss at all.

Ron

Thanks yes, it was 2 12v group 27 batts. Ron, my wires were the same as yours, and I thought the 2 black cables to the rig were on one terminal but the guy insisted I was wrong and put one on each batteries neg terminal. Both jumpers are on correctly after a brief but intense tussle where he tried to wire everything in series. Thank god I had the battery disconnect off. 

Glad you got it figured out without any sort of damage.

I wished the black ground cables were as flexible as the red power cable.  They are so stiff.  It was always a battle to slide the battery tray because of fighting those stiff cables.  I made the condition worse when adding the splash shield.  The negative terminals would sometimes loosen when working the tray so after closing the tray, I always crawled under the rig and reached up from below to tighten that one negative battery terminal more.  That was not fun.

It has been a joy since switching to the pair of sealed 6V AGMs without the battery tray.  No more fussing of any kind.  Because of the 6V wiring change, they also provide me with convenient front access to the thick + and - terminal posts as shown in this picture as the bright shining silver posts.  I use them all the time for fast external charging, generator supported charging during trips, and slow maintenance charging when at home.  The on board inverter/charger works well if you plug into shore power.  But we never have that privilege in the places we stay.

Thanks Ron. What are the 2 black cables for anyway? Never seen two before and it confounds everyone who works on it. :-(. My next batteries will be lithium. I'm done with the lead-acid hassle.

You ask a good question..."Why are there two ground cables?"

I wish I knew too.

Thanks Ron. What are the 2 black cables for anyway? Never seen two before and it confounds everyone who works on it. :-(. My next batteries will be lithium. I'm done with the lead-acid hassle.

One black goes to the frame ground and the other should go to the inverter negative post.

You'll need a new charger if you install lithium.  Lithium batteries take different chrrent and voltage requirements to safely charge.

All "wet" cell batteries need water now and then, the water level should be checked at least monthly and if low...you should only use distilled water to refill the cells.   If the water level in the cell gets below the top of the plates...that cell (thus battery) will quickly deteriorate.    This is especially true of batteries used in "deep cycle" operations...such as all RV coach batterirs.

Quote from: racephoto on October 21, 2015, 09:30:02 pm

Thanks Ron. What are the 2 black cables for anyway? Never seen two before and it confounds everyone who works on it. :-(. My next batteries will be lithium. I'm done with the lead-acid hassle.

One black goes to the frame ground and the other should go to the inverter negative post.

Ahh!  Makes sense.  Thank You!

One black goes to the frame ground and the other should go to the inverter negative post.

So for the electrically uninformed (me) does it matter the one black cable now goes to one negative terminal and the other goes to the other one? It will be tough to get in there to fix it and I don't want to if I I don't have to.
 
I have to say, in an otherwise stellar design, someone mst have been hungover when they came up with that battery compartment design. It's already unpleasant to work on them, and the fact that they're slathered in road grime doesn't help. I left the rig for a month plugged in and that was enough to boil the batteries so dry that they took half a gallon of distilled water. We'll, we did spill some but most of it went in the batteries.

And yep, I know I need a new charger with the lithiums....I think I already do anyway.  But the light weight and ability to use almost all the capacity of the batteries makes it a better choice.

I understand your frustration with the battery compartment.

Does your 2008-2100 have the rear tires splashing direct on the batteries like my 2007 2350 used to?  I added a splash shield between which protects them against that mess.  But because the ground cables are so stiff, I had to deal with what I mentioned up higher in this thread.

Anyhow, if interested CLICK HERE to see the pictures on how I did it.  The batteries stay so much cleaner with that shield.  They just get dusty from the wind swirling around with air bourn dust.  Today I have 6V sealed AGM batteries and no slide out tray.  No longer do I fuss with cables except when replacing the batteries which I hope will be a number of years away.

One more thing that combats wet acid batteries with terminal corrosion is doing THIS.

Thanks for the tip, that looks like a good idea. Yep, I have the exposed batteries, which after driving in wet, red mud at Hubbell Trading Post, now have about five pounds of Arizona clinging to them. Really.....who thought that was a good idea?? Thought about a double battery box but it won't fit and I couldn't lift two batteries in a box anyway. When I get the lithiums I will either move them inside, put them in a box, or get something fabricated like you did. I'm just not that handy.  I've been plagued with electrical annoyances for the past month.  Today the solar controller crapped out. It never ends......

Quote from: donc13 on October 22, 2015, 04:50:08 pm

One black goes to the frame ground and the other should go to the inverter negative post.

So for the electrically uninformed (me) does it matter the one black cable now goes to one negative terminal and the other goes to the other one? It will be tough to get in there to fix it and I don't want to if I I don't have to.
 
I have to say, in an otherwise stellar design, someone mst have been hungover when they came up with that battery compartment design. It's already unpleasant to work on them, and the fact that they're slathered in road grime doesn't help. I left the rig for a month plugged in and that was enough to boil the batteries so dry that they took half a gallon of distilled water. We'll, we did spill some but most of it went in the batteries.

And yep, I know I need a new charger with the lithiums....I think I already do anyway.  But the light weight and ability to use almost all the capacity of the batteries makes it a better choice.

No...it does not matter that one goes to one negative terminal and the other black wire to the other negative terminal.    That presumes you have 2 12v batteries in parallel.   It makrs a huge difference if yoi have two 6v batteries wired in series.