Seneca M2 Chassis Batteries

[SloPoke]

I've searched the forum for any insight into changing/replacing the Seneca's Freightliner Chassis batteries. I have two brand new Group-31 batteries connected to the charger right now, waiting to get installed this weekend.

All that I can find in the search is that they had the Freightliner dealership do it... so I am hoping someone on JOF has already done this themselves and can provide any tips / tricks / cautions that I might be aware of before I start. The compartment is tight and cramped, that I already know from having to disconnect one of the failed chassis batteries on our last trip.

And I guarantee that the Coach batteries will be disconnected after the Shore power will be disconnected before I think of starting on the chassis batteries.

[Robbbyr]

Sorry, I can't help much. Will likely replace mine at the end of this camping season before I have a failure.

I have removed my cab steps previously to have them shot with bedliner and to improve how they were mounted because Jayco didn't do such a great job. When I had the steps off it appeared swapping the batteries would be easier than with the steps in place. On reinstalling my steps I used stainless bolts and rivnuts to make future removal easier so that is likely the way I will go.

If you have never had your steps off, it is likely to be quite a challenge and just removing the batteries while leaving the steps may be your best option. Of course that is if they indeed will come out with the steps in-place.

Will be following!

[McGintys924]

Steve,
When the breaker for the steps went out the first time, and I didn’t know how easy it was to reset, I disconnected all the batteries and stopped just short of pulling them out. One thing that I did, due to the small space, is purchased a 1/4 ratchet from Walmart (a nice little Stanley that was inexpensive) and coated the thing in electrical tape so that there was no way it could contact anything in that tiny little space. I am of no help when thinking about any influence that the lack of power could have on the computer, especially with those of us that have a transmission reprogram.
At what year interval are we thinking we need to change chassis batteries?

[SloPoke]

So… after searching the internet and JOF for tips and tricks to replace the M2 (Seneca chassis batteries) in our 2015 Seneca FK. I embarked on the journey solo with two brand new group 31 batteries that have been sitting on a float charger for the past two weeks. I have changed at least 30-40 batteries in my lifetime, but never in a dual-battery chassis of a Freightliner, Never in a Jayco and never with a limited access space as under the driver seat of a Medium duty truck.

So… did it go well? Sure it did with a lot of side work to get it done so it will last.

To start off the background… we lost one of the two chassis batteries out in the Bridger-Teton National Forest – about 15-20 miles from other humans… It had a shorted cell and we disabled the failed battery and made it back home to perform the repairs, and this was the weekend to do a project.

As I started to take the “mess of wires, hoses” apart to get to the batteries, it instantly became apparent that Jayco routed the fuel lines for the Generator over the top of the two Chassis batteries (picture below) **FIRE HAZARD ALERT** … Now remember that one of our batteries has already cooked itself to death… spewing sulfur gas and other foul gasses from the boiling electrolyte of a failing battery under charge is only a symptom of a larger hazard – we were lucky to catch it early before a fire occurred...

OK… now really thankful that we did not burn to the ground.. back to the task at hand…. Next- Shut the house power down… shut the 50A connection down.. Pull the negative on the house batteries… ALL of them. Pull the negative terminals from the chassis batteries… All loose ends are wrapped in 20kv dialectic tape and Gator Tape to protect them from any accident. Voltage check from House + to ground and chassis battery + to ground both are 0. Start to remove this mess.

The battery hold down bracket… has a rusted metal plate welded on the top of the bracket. This plate was never painted and has the three circuit breakers on the top of that (non fixed position) hardware. It is in the way and blocking access to the positive terminals, you have to remove the power cables from the circuit breakers. The two 20A breakers were rusted all over the terminals and had to be replaced as the nuts securing it was so rusted it would not break loose without destroying the circuit breaker (NAPA stocks them)

After removing the wiring mounted on top of the battery hold down bracket (instead of a location that does not flop around if you are replacing batteries) I started to access the cables from the ++ terminals of the chassis batteries, the nuts that hold down the ++ Buss Bar are blocked with cables running over the top of them, everything had to be loosened and moved around to access the battery terminals. I wrapped the loose ends in dialectic and then continue to try to access the + terminals of the batteries.
While everything was 9/16.. nothing was accessible as they layered the fusible buss over the Jayco buss, over the Freight liner buss over the battery terminals… ** TIP – wrap every wrench in tape/dialecteric insulation to prevent a catastrophic accident** it took a while to loosen everything to get the battery removed from the dual battery buss… (((I should have taken it apart and rebuilt it.. but it was covered in grease, not rusting (like the other stuff Jayco installed and looked to be Freightliner factory wiring stuff that appeared legit))) We moved on to get the batteries OUT… after the ++ terminals were unbolted from the battery buss. Once the nuts were off the batteries… and the buss was just sitting on the batteries… the left one started to be removed.
Since the handles were missing from the batteries, Tools were used to pull the batteries out… A large screwdriver to raise the battery up and vise-grips on the case to pull it out of the tray. The left must come out first, then the right one has to slide over to the left side to get it out… once they were both out, I started to inspect what the jayco team installed… and start to replace the circuit breakers. I did not have any spare fuel line, so I re-routed the generator fuel lines best I could behind the batteries, but they left no slack in the hose to do it right without requiring a splice in the hose.

Put it all back together, cover terminals in petroleum jelly to prevent corrosion and plan for a simple project where the circuit breakers will be relocated to an appropriate location.

[Robbbyr]

Thanks, will help when I do mine!

Batteries came out okay with the cab steps in place?

[Oma/opa]

Slopoke
Great write up. I was looking at mine yesterday and thought what a frigging mess created by Jayco. At my age, trying to position myself to see the terminals let alone remove the connections will be a challenge. Someone must have worked on mine before as the holddowns do not have any bolts holding them in position. I dread the day I have to replace them. Cudo's to you for doing it yourself.

[SloPoke]

Originally Posted by Robbbyr

Thanks, will help when I do mine!

Batteries came out okay with the cab steps in place?

Yes... no clearance issues on that - here is a better picture of the bottom of the battery tray and the step fairings.

[SloPoke]

Originally Posted by Oma/opa

Slopoke
Great write up. I was looking at mine yesterday and thought what a frigging mess created by Jayco. At my age, trying to position myself to see the terminals let alone remove the connections will be a challenge. Someone must have worked on mine before as the holddowns do not have any bolts holding them in position. I dread the day I have to replace them. Cudo's to you for doing it yourself.

I'm no spring chicken anymore... I spent most of the time on my knees (I put down a 2" pad of closed-cell foam for my knees.

You mention that your battery hold down bolts are gone???? That would be a "Major Concern" as the terminals on the three circuit breakers could easily short to ground just a few inches above them if you hit a big dip or something that makes your suspension bounce at the limits. The hold downs are actually L-bolts that slip into the battery tray from above. They are easy on the left battery, and a pain on the right side. (You can see the left one in the last picture I posted on post #4)

[Mark S]

Holy macheral! I think I felt better before seeing these photos. Glad it worked out. Thanks for sharing.

[SloPoke]

Originally Posted by Mark S

Holy macheral! I think I felt better before seeing these photos. Glad it worked out. Thanks for sharing.

Your sentiments pretty much sum it up...

I was faced with leaving the Seneca torn apart for a few days and fabricate a real solution to this mess... and put it back together with the breakers in the cabinet right behind the DEF tank... or get the electrical systems back together so that the fridge full of food would not spoil.

I AM going to fix this right (but not this weekend)... my engineering education along with my OCD about things being able to withstand a basic level of use demands that this gets changed. This is probably one of the reasons that Freightliner dealers hate working on Motorhomes... What should be an hour job for a service tech to swap out two chassis batteries - is complicated because the coach builder took a shortcut that did not even get painted to prevent corrosion - knowing it was sitting on top of Flooded Lead Acid Batteries.


So... now we might understand why there are so many posts on JOF about steps that wont work, breakers over the chassis battery being tripped and Hydraulic levelers that wont work right... Who would install an electrical device an inch over a set of Flooded Cell Lead Acid Batteries and expect them to survive the corrosive environment that has???? And are battery gasses considered flammable too????

[SloPoke]

Originally Posted by SloPoke

And are battery gasses considered flammable too????

oh... forgot for a minute that you and Robby R are retired Firefighting professionals...

[Crossingover]

Great instructions, thanks for sharing it with us! What brand were your old (Harris?) and new batteries?

[SloPoke]

Originally Posted by Crossingover

Great instructions, thanks for sharing it with us! What brand were your old (Harris?) and new batteries?

On the chassis... the old batteries were Alliance Truck parts. The new batteries are TRP.

On the house... the old batteries were Harris - and we put new TRP dual purpose in.

I get a screaming deal from my buddy that is a Fleet Service manager for a large construction/trucking company. $73.00 each was my cost, and that is why I had to exchange them - instead of the FL dealership who wants to sell/install their battery.

[javamon]

Thanks SloPoke for a very informative post! I remember seeing that mess when I was resetting the breaker, knowing that I will have to get in there eventually. I agree with Robbbyr about being proactive on changing out these batteries. Will probably do mine in the fall of '19. If you relocate any of that mess on top of the batteries, please let us know how it turns out.

[Oma/opa]

"You mention that your battery hold down bolts are gone???? That would be a "Major Concern" as the terminals on the three circuit breakers could easily short to ground just a few inches above them if you hit a big dip or something that makes your suspension bounce at the limits"
Thanks Slopoke for the warning. I will be installing the hold down bolts tomorrow. Not sure how I will hook the right side without removing the batteries first...Just another Seneca challenge

[SloPoke]

Originally Posted by Oma/opa

"You mention that your battery hold down bolts are gone???? That would be a "Major Concern" as the terminals on the three circuit breakers could easily short to ground just a few inches above them if you hit a big dip or something that makes your suspension bounce at the limits"
Thanks Slopoke for the warning. I will be installing the hold down bolts tomorrow. Not sure how I will hook the right side without removing the batteries first...Just another Seneca challenge

You do not have to remove the batteries... I made the mistake of putting both replacement batteries in before I moved onto the hold down bracket. It is tight, but you can feel your way to get the right bolt in - then place the hold down over that threaded end.

[javamon]

SloPoke: "The battery hold down bracket… has a rusted metal plate welded on the top of the bracket. This plate was never painted and has the three circuit breakers on the top of that (non fixed position) hardware. It is in the way and blocking access to the positive terminals, you have to remove the power cables from the circuit breakers. The two 20A breakers were rusted all over the terminals and had to be replaced as the nuts securing it was so rusted it would not break loose without destroying the circuit breaker (NAPA stocks them) "


Would you happen to have the part # for these three fuses. Would make sense to have spares on-hand. Thanks!

[SloPoke]

Originally Posted by javamon

I agree with Robbbyr about being proactive on changing out these batteries. Will probably do mine in the fall of '19. If you relocate any of that mess on top of the batteries, please let us know how it turns out.

I hoped that simply replacing the batteries would be the end of this for a few years, but finding that the design / placement of these circuit breakers and the generator fuel lines is going to cause problems in our future - they have to be fixed. I suspect that the new breakers I put in, will fail in two-three years as they are back on top of the batteries and they are not waterproof either.

I'm looking at relocating all three breakers into forward storage compartment behind the DEF tank. This will put them in a protected environment away from all the moisture, battery acid, corrosive charging gasses they are exposed to now. This will also make it 1000-times easier to access and reset the breaker that likes to trip during heavy thunderstorms.

Getting a replacement hold down bracket should be pretty easy and it wont continue to rust. I did not write down the part numbers, but the two breakers are typical BUSS style 20A and the large black one I only took a couple of pictures - here they are.

[Robbbyr]

I am so going to repeat your project when I change out my chassis batteries next Spring!

I will also "clean up" under there, and may replace any ferrous metal with stainless. I will have to come up with a place to relocate the breakers, the first compartment aft of my DEF tank is my coach batteries also open to the elements.

[javamon]

SloPoke...thanks for the photos in #18. Looks like our manual reset 100 amp breaker is an Eaton 184100F

https://www.waytekwire.com/item/4692...Surface-Mount/