Correct Process For Battery Replacement

[DKO]

I purchased our coach well used nearly 4 years ago and I was warned that the chassis batteries would need to be replaced soon. They have lasted well beyond what I had been told to expect but the day to replace is near. They will not hold enough charge to start after a week even will both voltage switches (12v & 24v) off.

I currently have 4 Interstate Workaholic 31 MHD batteries. I have located replacements and will remove the old and install the new next month if all goes well.

Is there anything I need to know about the process of replacing these batteries. I won't be able to remove and replace one at a time because of all the wiring and the position of the batteries. Are there any special precautions I should take?

I plan to take pictures and then draw a diagram, number each post on the batteries and label each wire with corresponding numbers. Any better way to keep things straight?

How should I remove the wires? Should I remove all negatives first, or all positives or one battery at a time or does it matter?

Anything else I should disconnect?

Any particular order for re-installing the wires?

Will I need to to wrap or tape each lead as I take it off to prevent sparks?

I certainly do not want to burn a computer or even blow any fuses. Any direction at all is much appreciated. I have be reading and learning here for a very long time but I joined today to prepare for the battery replacement.

Thanks for all your help in the past. I have learned quite a bit from reading your responses to the questions that others post.

Thank you and God bless,

DKO

[beaverfever]

great idea taking pictures and drawing's. just remove negative first and replace it last.
its a good time to clean and paint battery box.

[DKO]

Thank you.

Should I remove every negative first or the negative on one battery then the positive on that battery and then move on to the next?

Davy

[wa8yxm]

BEFORE YOU START:

Get two cans of spray paint, Testor's (Model paint) is a good choice, Nail polish also works. One Red, One black.

On the battery one post is marked either POS and/or +, Spray all wires hooked to this post RED.

The other post is NEG and/or - That gets the BLACK.

Then, once it's dry remove and replace and do not be asking as so many have before you "Where does this wire go? Because you will KNOW the ones with RED are Positive and the ones with BLACK, go to the other post!

[Davdeb1]

A good idea would be to use the battery disconnect switch before you replace batteries.
Just my .02

[Ed-Sommers]

Disconnect the Negative wires from the post that goes to the power distribution, or inverter, Ect first, and connect it last.

By disconnecting the wires on that one main negative post you disable the entire array.

Ed

[DKO]

Davdeb1, Yes, I should have said in the original post that I will be turning off the disconnect switches.

wa8yxm, The paint is a good idea. But I have 8 posts and some of them have 4-6 wires so I think I will number every wire as well.

Originally Posted by Ed-Sommers

Disconnect the Negative wires from the post that goes to the power distribution, or inverter, Ect first, and connect it last.

By disconnecting the wires on that one main negative post you disable the entire array.

That makes sense. I think it all feeds to an equalizer that distributes 24v and 12v as needed. I do see a big ground going from one battery to the frame and the battery in the back looks like it feeds the equalizer.

Thanks much,

DKO
Mile Markers-Boggs Blogs

[Ramblin]

Originally Posted by wa8yxm

BEFORE YOU START:

Get two cans of spray paint, Testor's (Model paint) is a good choice, Nail polish also works. One Red, One black.

On the battery one post is marked either POS and/or +, Spray all wires hooked to this post RED.

The other post is NEG and/or - That gets the BLACK.

Then, once it's dry remove and replace and do not be asking as so many have before you "Where does this wire go? Because you will KNOW the ones with RED are Positive and the ones with BLACK, go to the other post!

Or save a buck and eliminate the black paint. Use the process of elimination instead!

[mhs4771]

Ensure shore power is disconnected or the breaker to the inverter/charger is off. If this isn't done and the positive lead comes in contact with any frame metal you have sparks flying (voltage coming from the inverter/charger, not from the batteries)

[TQ60]

Remove ALL grounds

Then confirm with a meter from positive post to ground no volts, could be other batteries.

Also have shore power unplugged.

Then remove all positive from one battery and change it connection everything positive as you go.

Make sure all us off and connect ground

Some light sparking if normal as chapter charge or a light may be on

[DKO]

Thanks for the advice.

My inverters do not charge the chassis batteries but you still recommend that I turn the inverters completely off? That is easily done but I hope I can get a warm afternoon next month to change these things. That way the coach will not get too cold. Of course no sense working in the cold if you don't have to...

Thanks again. Anything else?

DKO

[paz]

Originally Posted by DKO

Thanks again. Anything else?

DKO

It is also be a good idea to turn off the fridge using the button on the fridge control panel before you begin starting to replace the batteries, especially if you have a Norcold 12XX that has the recall box installed. Reconnecting the batteries can cause a voltage surge that may trip the recall box and cause it to shut down the fridge even though there is no overheating problem. You will then have to call someone to replace the recall box, which will have to be special-ordered from Norcold. Don't ask how I know this.

[CLIFFTALL]

Originally Posted by paz

It is also be a good idea to turn off the fridge using the button on the fridge control panel before you begin starting to replace the batteries, especially if you have a Norcold 12XX that has the recall box installed. Reconnecting the batteries can cause a voltage surge that may trip the recall box and cause it to shut down the fridge even though there is no overheating problem. You will then have to call someone to replace the recall box, which will have to be special-ordered from Norcold. Don't ask how I know this.

Good advice.

[Dave78Chief]

DKO,
With you having a Prevost bus conversion, the vast majority will not have a clue as to how your system is hooked up (including me). As such, comments like isolate the inverter/charger come from the experience they have had with their type of rigs. Even so, the important points are:

Mark/Lable/Photograph the existing wires so that you know where they connect back to. If possible, even if you do have a wiring diagram, I would even go as far as determining which wire/cable feeds what. Having that information for future reference could turn out to be invaluable.

Start out by disconnecting the ground leads. You want to isolate the batteries from the rest of the coach. Removal - Negative then positive. Install - Positive then negative.

Caution - Remove the battery cross-connect leads last and connect them first. You do not want to inadvertantly touch a ground lead to the bus frame when a positive distribution lead (say to disconnect relay) is already connected. That could create a unexpected current draw. Also connect both ends of all positive cross connect cables then go back and connect the negative leads (build battery bank before connecting battery bank to rig). This way you reduce the risk of a positive and negative lead shorting together. If these leads accidently get touched to gether, the current will be high enough to weld them together. Just work slow with caution.

If you have something like a BIRD controller that controls an isolation relay (chassis/coach battery system cross connect) then the inverter comment is valid. Again, many have no clue what features are built into a Prevost bus conversion.

Having 12/24 Volt systems means the Group 31 batteries are connected together in a series/parrallel configuration like 4 6 volt batteries for a typical coach system. Difference is that you use both 12 and 24 where a coach only would use the final 12VDC circuit. WHen you mark your wires, also indicate on the lable if it is a 12VDC circuit or a 24VDC circuit. Will aid (keep head straight) in putting things back together.

Dave