A nICE Bus - Blue Bird CS RE 3904 - Full-Time Home

Your drawing validates my concern.
 
Last edited:
This looks like a really cool project, one that requires alot of think-through....

so basically you simply cutting out two sides/areas of the floor which will then expose the underbelly storage compartment. this was some really creative dreaming, I mean that in a good way...

I share Nikitis concern about the structural integrity/strength of the underbelly itself. most time they are simply tacked in and not built for passengers walking on them.

I'm not a fan of giving up the that wonderful underbelly space but...in your case (since it's not MY bus) go for it!

I came up with a thought I want to share on your build..

Have you considered building a sub-cage, on that would drop into the void your making.

I feel this might have some useful advantages. By dropping in a cage:
1) you would not have to touch, cut or modify the existing exterior sidewalls or underbelly floor.
2) you could secure/hang this "cage" to the existing floor with angle brackets.
3) you could provide "beefier" sidewall protection against a side hit on the bus.
4) depending on how you build it, you could leave just enough space to be able to store your dump/water hoses and misc tools.

I was thinking this "direction" would make the build a tad bit easier and provide more protections if your were walking on it while driving. it would also cut down on any road noise since you could insulate or sound proof now between the exterior walls and the floor cage walls.

Any how, i'll be watching as this project is a "cool' one!


Edit: I'm terrible at drawing but I tried.
 

Attachments

  • drop down floor.jpg
    drop down floor.jpg
    14.6 KB · Views: 15
Last edited:
Might be good to add a little extra reinforcement though from the C-Channel island down to the below floor frame so it won't feel as flimsy.
I share Nikitis concern about the structural integrity/strength of the underbelly
Have you considered building a sub-cage

Cheers and thank you for the well wishes 🍻

I actually have! I envisioned a drop in cage or two which could then simply be hung by the body & frame on either side of the frame rail space to avoid depending on the storage assembly at all...looked pretty much as you drew which, is more than sufficient illustration for this application LOL

I'm hoping to harness both the existing body and storage frame to make one holistically stronger structure. If you cut the bus in half through its mid-section, the living compartment would basically look like a donut where the hole is the frame rails.
_
I have actually been wondering what might be too much added reinforcement.

I can put as many uprights as I want against the walls, clad everything in 12ga sheet, run several supports through the island to the ceiling, and make it the bomb shelter of the bus if I want...but at a certain point it would create problems. Tension issues at the margin of the existing body and the new frame as they flex differently. Also just, weight.

So I need to find the line between safe and unsafe, then take a few paces onto the safe side without going overboard. 🧠😬🧑‍🏭


I'm not a fan of giving up the that wonderful underbelly space

I know. It's ironic to be going this direction after specifically hunting down a bus w/storage, but tbh I have been looking for this kind of unique take on the Skoolie. I have a certain contrarian in me that wants to do something new and different. It will a fun challenge both physically and creatively.

I also just really respect the project that a roof raise would be on this bus and I would like to keep the scope within my own ability to complete within a reasonable timeframe. That said, we do have a bit more time than anticipated, so I can afford to dip into something more intense without needing to chuck bags in the underbelly and slip town.

I can compensate by adding external storage to the roof as we work out our solar setup and other roof-relevant assemblies. The dropped area will end up having some sort of storage function while not in use, so I'm telling myself we can be smart about what we put in there and make it work. Easier than hanging storage under a bus that doesn't have it. Downside is COG when we try to load heavy **** up there. 🤷‍♂️
 
4) depending on how you build it, you could leave just enough space to be able to store your dump/water hoses and misc tools.

You're touching on a very important aspect of how I'm going to put this together. More and more I have been leaning towards dropping the entire length between the axles on both sides of the bus as much as feasible. The generator is mounted so nicely already that I'll probably work around it for now, but there is a lot more space to be reclaimed for insulated & conditioned envelope.

My current concepts leave the generator and plumbing systems out in the cold, as well as any storage I might retain. If I can work around the bones and organs of the bus well enough, it would be better to bring those systems into a crawlspace or chase inside the insulation layer. There is only airspace between the fresh water and larger storage compartments, so they could be merged easily.

Outdoor storage unit < Indoor air-conditioned unit.
 
Sounds good. I look forward to detailed pictures so us and future us's can review or copy.
 
Looks like my bus as of last week. Just cleaned it all up with my daughter, and looking good now. Words of encouragement.
 
Battery Box

Pulled the battery compartment apart today to clean everything and throw some paint around. There was some mild corrosion on the contacts and everything was just grimy. I'm a prima donna I can't do proper maintenance in these conditions.

Used some old black polyurethane 250 that's been neglected on a shelf for a couple years. Mix it until it's mixed, then mix it some more. Per the product specs, you're supposed to clean down to bare metal, but I don't need maximum performance from this overkill coating. I just gave it a solid wire-wheeling, rusty primer and sent it. Left the bottom of the tray in primer so it'll slide on the rails a little better.

Yes I painted around the wires. No I'm not going to finish the rest. You'll never see it once the tray is installed and a coat of primer will more than suffice. Based on the minimal rust, the tray catches almost all of the water anyways.

Bad Battery?

It seems even with the battery bank disconnected, it still kills itself overnight (down to around 10V). While I had them separated today, I charged each one until the charger switched to maintenance mode. One of them is losing voltage fairly rapidly. The other two seem fine, but in parallel one bad battery spoils the bunch. I think... that's only based on a common-sense understanding and I'm sure I need to read up on it more.

I put them back in parallel and put it on the charger. We'll see how things look in the morning. Not too concerned for now; it's restarted during daytrips with no issue.

1000008789.jpg


1000008796.jpg


1000008797.jpg


1000008803.jpg


1000008794.jpg


1000008800.jpg


1000008798.jpg
 
Bad Battery?

It seems even with the battery bank disconnected, it still kills itself overnight (down to around 10V). While I had them separated today, I charged each one until the charger switched to maintenance mode. One of them is losing voltage fairly rapidly. The other two seem fine, but in parallel one bad battery spoils the bunch. I think... that's only based on a common-sense understanding and I'm sure I need to read up on it more.

I put them back in parallel and put it on the charger. We'll see how things look in the morning. Not too concerned for now; it's restarted during daytrips with no issue.
Good attention to detail. I only dusted out my battery tray, I plan to do all of this when I paint the bus. I did rewire it completely because I did not like the way it was wired up. Now it's far cleaner wiring and the tray.

It could be your 3rd battery being worse off and the issue, but what it likely is, is the ECU and/or a 3rd party aftermarket device wired to the battery, the bad one likely pulled from it first more and killed it cause it's closer to the devices. A battery disconnect will solve this problem, and you're batteries will last for 2 years without a crank if you do so.

Every bus has drain from the ECU/ECM. This is why we tell people to add a battery disconnect on the ground.

I only have 2 batteries in mine. You really don't need a 3rd. Majority of buses only use 2 so if one is dying or causing problems, just remove it for now.

I attached 2 pics of before and after on my bus. I left nothing out, just rearranged it. The second battery is turned 180 degrees from the other so the cabling will be the right distances. There should be a chassis ground cable that's simply screwed to the chassis. Take that cable and mount it to the battery disconnect like I have on the after picture.

Also take the battery ground cable and mount it to one point on the disconnect, and then combine the main ground cable going to starter and the ground cable going to the chassis to the other point together. Then poke a hole in the side of the battery box and stick the disconnect through it and screw on the handle from the outside. Anytime you get out of the bus and are done for the day, walk around and turn that switch to disconnect it. Nothing will drain your batteries any longer.

I prefer ground line disconnect because there's only ground plane between your batteries and chassis of the bus, and if there was a jolt ever from the disconnect, it won't blow up any of your devices. If there was a surge on the positive side with a disconnect, there's a small chance it could blow up sensitive devices.
 

Attachments

  • battery_before.jpg
    battery_before.jpg
    175.6 KB · Views: 5
  • battery_after.jpg
    battery_after.jpg
    154 KB · Views: 7
Reassembled the battery box and took her for a run this morning. Beautiful day for a drive here in MD.

It does have a shutoff switch that appears to be a ground disconnect as suggested by @nikitis. Despite disconnecting this switch, I still get significant discharge overnight.

1748965239815.png 1748965345033.png
1748965481063.png 1748965702588.png
__________

I need to convert one of the 50A three-prong shop outlets to receive my four-prong shore power plug. Then I'll be able to keep the bettery tender onboard and connected while it sits, eliminating the obnoxiously long extension cord. Seems like this can be done with a simple male/female adapter, but I want to be absolutely sure I'm not going to burn the shop or my bus down... 📚📖
 
Last edited:
I've highlighted your likely culprit for the drain. This device is bypassing your disconnect, and is likely your cause for draining. You'll need to tie that wire to the other end of the disconnect. Being connected to the battery in that way is bypassing any disconnect. Extend that small wire and tie it onto the output of the disconnect.
battery_drain_ground.png
 
Additionally the way you have all of the other accessories tied to a single battery on the right is also likely why one battery is in worse shape than the others. You want to spread any load across all 3 evenly,

The best way to do this is to have all positive wires end up leaving from one battery on the left. (This is done already for your batteries main line), but your accessories are connected to the positive terminal on the middle and right terminals (This is causing excess drain from your middle and right battery more than your left battery) Those accessories should be on the left positive terminal, and the ground line should leave your bank on the back right terminal which should go to your battery disconnect input. Then on the battery disconnect output, you should have that accessory ground wire hooked to that, as well as any ground and starter ground wires all to the same ground output on the disconnect..

It's okay to have multiple accessory wires on the one positive terminal of the battery bank, but for the ground, you don't want ANY accessory ground wires connected to the battery at all, only the output of the disconnect so you can control device drain.

So all positives should leave from the front left battery terminal, and all ground should leave the battery system from the back right terminal.

Back right terminal to disconnect, and then disconnect out to chassis and starter, and that accessory. In this way your batteries in the future should discharge evenly. (It'll also look way cleaner as well and make more sense if someone else had to look at it someday.) This is an example of a mechanic error I'm pointing out because someone wired it this way with no thought about tying to the disconnect properly, or uneven battery drain. A mechanic who knows his craft should understand this but apparently they were either too lazy or didn't understand electricity flow properly.

So it should have all the positive connections on that one terminal the picture is pointing to. Remember batteries are a circuit too inside of them,

battery_positive_hookup.png
 
Last edited:
Additionally the way you have all of the other accessories tied to a single battery on the right is also likely why one battery is in worse shape than the others.

But if the three batteries are wired in parallel, wouldn't that make them behave like one larger battery? Shouldn't the drain be even across the entire bank, not just the one? Also, the one that's discharging was doing so while completely disconnected, isolated and out of the bus. Other two stayed at a stable voltage overnight while isolated.
 
Additionally the way you have all of the other accessories tied to a single battery on the right is also likely why one battery is in worse shape than the others.
I doubt that. The only way that would matter is if that HUGE red cable isn't connecting to the other batteries....so it's possible....
 
It's about distance. Even short distances such as that parallel cable, it's gonna pull juice as first come first serve. By forcing output to specific terminals it does help with spreading the load.

If the circuit can only be drained out the back right terminal you force the flow more through the batteries than you would if you didn't. It's not perfect, but it's better to do.
 
It's about distance. Even short distances such as that parallel cable, it's gonna pull juice as first come first serve. By forcing output to specific terminals it does help with spreading the load.

If the circuit can only be drained out the back right terminal you force the flow more through the batteries than you would if you didn't. It's not perfect, but it's better to do.
Wrong. Distance does not matter, it's resistance. Can you see how small the load wire is compared to the HUGE battery cables connecting the batteries together?

If a battery runs down quickly when it's not connected to a load, it's a bad battery. Batteries can sit on a shelf for months and be nice and charged.
 
battery_drain_explained.png

This is the better way. It is about resistances, path of least resistance gets used more.

The above setup forces the resistance evenly across the batteries because flow has to go through the ground as well to complete the circuit.

Currently Busjamin is doing it the bottom image way.

But out side of that point, Busjamin is still draining the battery because his ground for his accessory is bypassing his disconnect. I'll produce a diagram for him on my next post for that to better illustrate.
 
View attachment 1316820
This is the better way. It is about resistances, path of least resistance gets used more.

The above setup forces the resistance evenly across the batteries because flow has to go through the ground as well to complete the circuit.

Currently Busjamin is doing it the bottom image way.

But out side of that point, Busjamin is still draining the battery because his ground for his accessory is bypassing his disconnect. I'll produce a diagram for him on my next post for that to better illustrate.
NO. NO. NO. :frusty:

If your cables are so bad (have such high resistance) that you need to add more cable to make the circuit like that top pic, just spend the money on better cables instead.
 
@Busjamin Just do your wiring like this and it will work and your batteries will drain evenly. Will also fix your disconnect switch being bypassed and draining the battery.

Proper_batterysetup.png
 
Last edited:
This way is far cleaner wiring, makes it easy to troubleshoot as well. It's also about electron flow through the batteries themselves too, not just wiring.
 

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top