Community Forums

USMCRET · 05-07-2012, 08:29 AM

I'm putting my noobishness on full display here.

I'm going to be replacing the four house batteries in my coach. I keep it plugged in to shore power. Do I simply toggle the battery disconnect and change them out, or is there more involved?

dwkerch · 05-07-2012, 08:49 AM

It's that simple!

Barbaraok · 05-07-2012, 08:59 AM

First, get a picture of the current battery set up and all of the cables. I know you think you will remember what goes to what, but trust me, take the picture so you are sure when you finish that everything is connected the way it was before.

Then, we take the inverter off of charge setting - not sure if you have a converter or inverter/charger, throw the disconnect switch and start working. This is also the time to really clean out the tray, so have water, baking soda, gloves, wire brush to clean the cable ends, etc., and wear old clothes.

Make sure everything is tight when you reconnect. Look at the picture you took before and manual retrace each cable to make sure it is connected right, throw the switch back, set the inverter to charge and your good to go.

Barb

Dave78Chief · 05-07-2012, 09:06 AM

I believe on Newmar coaches, if you have a large inverter/charger (which I suspect your 39ft rig has) the inverter is connected directly to the coach battery via something like a 300 amp fuse (not isolated by the battery disconnect switch). This means the inverter/charger would be attempting to charge the battery or maintain float voltage. I think you would be best to disconnect from shore power while replacing the batteries otherwise you will have inverter/chahrging voltage present on a positive battery cable. I would not run generator during this evolution either as they typically have a DC charging circuit output also.

Dave

stuhly · 05-07-2012, 09:20 AM

And when you think you have all the wires hooked backup, look one more time. Some of the smaller wires have a way of sneaking off when you are not looking.

paz · 05-07-2012, 01:47 PM

I also recommend turning off the fridge using the power switch on the fridge itself, especially if you have a Norcold. I replaced our house batteries last year and only turned off the 12V disconnect switch. Somehow, it accidentally got turned back on, and when I connected up the batteries, the voltage surge caused the Norcold recall box to trip. Norcold replaced the switch at no cost, but I had to pay for the mobile service call myself ($75).

bronk · 05-07-2012, 02:14 PM

I second the recommendations to take a photo and to disconnect shore power and turn off fridge, etc. It is a pretty straight forward operation with the biggest hassle (at least for me) is getting the batteries out of their holder/s and out from behind the steps. Oh for a slideout tray!!

Semper Fi ! Bronk

Mr_D · 05-07-2012, 06:26 PM

Take a photo, I did and was glad. I unplugged from the shore power and disconnecte the positive terminals, then the negative. Replaced them and reconnected in opposite order (negative then positive). Working fine.

alfalfa · 05-07-2012, 07:39 PM

When I removed my three 8D batteries, I used my lable maker to identify all the Pos. & Neg. cables. Makes hooking back up easy. I didn't need a photo because all Pos, & Neg cables go to their respevtive posts on my unit.

Muddypaws · 05-07-2012, 10:15 PM

Turn everything off. Label every wire. Take pictures. Draw pictures. Test the voltage before you turn anything back on.

Oh, and get help. Those things are freakin' heavy.

I learned these things the hard way.

Mr_D · 05-07-2012, 10:36 PM

All mine were color coded too so that along with the pictures helped, even so I missed a charge line from the alternator. It fell back behind the tray, didn't take long to figure out it was missing and to find it.

sgtjoe · 05-07-2012, 10:47 PM

Like all have said, cut shore power, hit the battery disconnect switch, take a picture and tag each wire. I also draw a picture showing where the pos & neg posts are on my 4 batteries and which wires go to them ie; pos post marked #1 on paper and a tag is placed on the wire or wires marked as #1. To make sure I don't forget a wire, if there are two or more wires connected to a post I use a plastic wire tie to keep them together. I prefer to disconnect negatives first and when reinstalling negatives last. Just my thing.

BTW, I also installed the pro fill battery system, a lot easier to maintain the batteries. And since using it I have not had a problem with battery corrosion.

okmunky · 05-07-2012, 10:55 PM

I was told to disconnect neg first, then pos. Also, to disconnect the neg on the chassis battery as there can be power coming from there as well.

Remember to lift with your legs, NOT your back.

Dwillie · 05-07-2012, 11:45 PM

Before installing the new batteries, as stated earlier clean the area good, so it is free of any battery acid. Let dry completely and coat the entire area with the black "under coating" you can get this from Wal Mart or the auto parts house. This will help protect the metal from further rust.