Chassis Batteries - to replace or not to replace?

Attachment 14020Hello All! I'm a new member here to post my first of probably many questions:) I have been following the forum for a while. I have been very impressed with the wealth of knowledge here and the willingness of the various contributors to share it. I purchased an 87 Liberty earlier this year and have been learning along the way.

I have noticed that my chassis batteries sometimes struggle to turn over the engine if it has been sitting for a while. I checked the voltage of each of the 4 batteries after letting the engine run for an hour to charge them up. With battery switch switched off, each of the batteries showed closed to 12.7 volts. When I check the next morning, 2 of the batteries are still 12.7 while the other 2 batteries are around 10.2. The 2 batteries that are doing fine seem to be much older than the two that are giving me issues.

Note: I didn't disconnect the battery cables when testing each battery. Do I need to replace the two that are losing voltage? All of them? or run a different test?

Thanks in advance for your help!

Miles

Miles,

First, welcome and congrats on your purchase.

You muse disconnect one battery terminal after the bank is charged to test the batteries. I would let the batteries rest for several hours before measuring their individual voltage.

I'm guessing one of the following, based on your readings.
-- Both of the low voltage batteries are on the 12V half of the bank and you have some 12V loads when the coach is off.
-- The equalizer is bad and it is not keeping the 12 and 24 volt half bank balanced.
-- The 2 batteries are simply bad.

How old are batteries? Some go through chassis batteries every 3 years. Personally, I wouldn't be happy if I didn't get at least 5 years out of them.

Do you have a chassis battery charger? If so, is it used and is it an intelligent charger?

Thanks for the fast reply!

I don't think this model bus came with a charger nor has one been added. The date on battery is 08 (pretty old).

Lastly, I don't think I have an equalizer. Do all 24V buses have them? If so, where would I look for it?
Thanks again for your help!

Miles,

Most buses have an equalizer. It is normally in the same compartment with the batteries. I've had three Prevosts and none came with a charger for the engine batteries. As Gil mentioned, you will need to charge the batteries, let them set for a few hours, then disconnect one lead from each battery as you check the voltage. I just installed a charger on mine a couple weeks ago .

Great catch. I didn't consider the year of your coach.

Now that I looked at the picture on a big screen, your chassis is indeed 24V.

BTW, your battery connections are not optimal. I'll draw a picture. Until then, the chassis ground is attached to the upper right battery when it should be on the left battery.

Your left side battery is not as actively participating in charge or discharge cycles. Hopefully, this drawing will show what you have and what you should have. Current takes the path of least resistance and the cables attaching the left battery present a path of more resistance. The fix is simple and it's likely the chassis ground cable will reach from the upper right battery to the left battery and was probably where I'm recommending it at some time in the past.

Attachment 14021

If there is a really bad apple in the bunch checking them imidiatly after seporating them will give indication to that bad battery.

I always do, not always but often saves time.

Thanks All! I appreciate the drawing for battery connections Gil...thanks! I just looked at an FMCA service clinic manual that came with the coach and found the same diagram. Easy fix and the cable should reach. I wouldn't have noticed otherwise... good catch.

Given the age of the batteries, I'm just going to replace them. Seems like the best deal I can find is the Alliance brand at freightliner for $114 each. They are 925cca. If anybody knows of a better option, let me know. Much ablidged!

Thought I would give an update to close out the thread. I ended up buying some reconditioned interstates in Knoxville. $53 each. This gets me 4 healthy batteries that should last a couple years. I'll have more time to shop around for new ones next time. I connected them using Gil's diagram, and they fired the old DD up with no problems. Here is the "after" pic:Attachment 14027

My 2002 H3 Featherlite batteries are totally dead and corroded, the post on 3 house batteries pushed out 4 inches. The RV service tech said he had never seen that before as the coach was parked for 2yr in the NV heat with no use. We are changing all the batteries on the Chassis and House/coach on Monday. The question is that when I was playing with the main switch panel, all the interior lights quite and the Inverters both went out. In addition the switches started to flash red and never stopped for 0.5hr or so. Is that a low voltage, short protection mode on the Trace Inverters or did we damage the inverters?

I also flipped the Emergency cut-off switches, but not totally at the same time, would that damage the equalization devices on the batteries or they were so dead it would hurt anything? Lots to learn and a new member!
There was just enough juce to run the door locks. Also were does one find the Key less entry code in the coach? Is it hidden some ware or in the books?

The Ford keyless control module should be behind the panel immediately next to the door on the right side of the step well when you enter the coach. This just below the dash. The module will have the code on it.

My 03 H-3 has a master chassis disconnect switch near the ignition key. It should be off when the coach is parked. It's also a good idea to have an intelligent charger on the chassis batteries.

You probably have eight 4D batteries over the drive axle for the house bank. If you don't try camp, you can reduce your bank size to four 4D batteries. Featherlite makes this easy as they should have each battery directly wired to buss bars. You can take two out of the 12V half bank and two out of the upper or 24V half bank.

Your flickering house panel lights when turning the DC switch off could be due to a capacitive effect in the switch controller. I wouldn't worry about that. It'seems a good idea to turn your Trace inverters off before removing the AC or DC source, but it shouldn't hurt them if you don't.

Once a battery's plates get exposed the battery can do bad things, like grow or even explode. Chassis batteries are generally maintenance-free flooded wet cells. In the heat they will still lose some electrolytes.

Thanks you!, When you say intelligent charge you mean an after market one that I put on or does the coach charge them? I am having all the batteries changed out, too late to cut back but that does make good sence if we stay in one spot.
Could one just hook the charger to the Boost point or would that not feed into the batteries?

It's always best to dedicate a charger to a particular bank. Many use Marinco's Guest marine 12/24V chargers for the chassis. The charger of choice within this product line is (CLICK HERE). There are bi-directional charging relays that could work if you have a single engine alternator. The downside of battery combiners is they would tie multiple alternators together, which I would not recommend. BTW, if you install one it would be best to plug it into an outlet that is dead when the engine is running. I say best and I haven't done so yet. Too many things on my list.