Basic Electrical Things

http://www.prevost-stuff.com/DSC06289.JPG

One of the things we forget about the most is the basic maintenance of the electrical system in our coaches....from the 'plug-in' all around the coach. All-electric coaches, want to have good, strong, conductive circuits. The most common problem in coaches is a loose or ineffective ground, so it seems.

The first step is to make sure that your connection is solid. Start with keeping your connections in good shape, per the picture.

Although we have 30-amp connections, an all-electric coach really wants good, solid 50-amp service. Most generators will put out about 120 Amps.

A little-known thing is that pre-1992 coaches are built without the RVIA standards and may not have a wired ground; instead, they are grounded to the chassis (in come conversions). So without a perfect connection or a straight-in plug-in, there is a chance of damage at least to the shoreline connection. (Happened to us a number of years ago). The fix on that is to hardwire a separate ground to the generator and to the main panel from the shoreline connection.

Batteries, etc., need to be maintained well and it is easy to forget about them as well, especially if the house batteries are buried somewhere in the coach.

Here's another little tip. If you have GFI circuits and plug in something, well, less than carefully, you will find that everything hooked into that circuit will be dead. Find the original place where you tripped the circuit, do a reset right there on the outlet box and you are good to go.

I am no electrician, but this is a starting point for those who are.

I love reviving old threads so here goes again.

I've been noticing our 12 volt bank of batteries discharging for no good reason so I picked up a new battery charger and set about pulling the 12 volt bank. Well one thing leads to another and I ended up pulling the 24 volt bank and the rack as well, what is left of it anyway:eek:

Another project. Debbie just loves it when I fail to finish any current project for another. Heck, it's the bus, it's all just ONE BIG PROJECT:D

So far I have found 1 bad battery in the 12 volt bank. The ONLY thing that is powered off 12 volt in the bus is lighting. I'm thinking that that bank will now be 1 battery short cause I do not want to replace all 4 right now and I don't think it is wise to put 1 new battery in with 3 old ones and they are just supplying some lights. If it is O/K to just replace 1 of 4 I will, anybody want to chime in. They are inexpensive deep-cycle wet.

The charger can desulfate so I'll also do this. It takes 24hrs to do a battery so with 8 batterys to do that will give me a week to fab up a new battery rack and get it powdercoated. I'll also add 2 cut-off switches for the house banks that were never there. This area was just another thing that was on the list:rolleyes:

Attachment 1391
The 12 volt bank rests on the top shelf and the the 4 that make 24volt go below.

Attachment 1392

Attachment 1393
I think it was by the grace of God that they didn't bust through this old plywood base.

We had some guys in a band make us an offer on the bus this weekend. I think they were just dreaming a little but when they left Deb said wouldn't that be nice, we could take the profit and get us something with more of a motorhome floorplan.:eek: All I could do is think to myself, girl you have got to be out of your mind if you think I've any desire at all to start this process all over again. Aint married life grand.

WOW, Joe, you really are into a complete overhaul of your bus, aren't you?

I am sure this job will turn out as well as your GEN Bay overhaul is.

Too bad you didn't get to POG III, and meet the Zimmerman Team? Your jobs remind me of what they did to their 99 Liberty. http://www.zimmermancoach.com/?type=webpage&id=2

Check out their website to see what they have done on their coach, to make it a "Z" Bus, much the same content as what you are doing, GREAT JOB.

Gary S

Hi Joe. I would replace all batteries. You will have less amperage w/o the 5th battery and it will put additional load on the remaining batteries. Depending on the age, they all need updating at some point anyway.

Gary I can't seem to find that bus on that sight.:mad:

In fact, I'm still waiting for them to finish their article on their gen. bay rebuild:confused:

Gary#2

I'd be taking a set of 4 down to 3 but either way your suggestion remains the same. In terms of eletronics our 86 isin't even in the same universe as yours. Those 12volt bats. power a total of 10 different lighting sources of which we do not use any more than 2 or 3 at any 1 time.

We will inevedibly keep our 2 banks of house batts. as sets of 4, although I think we could take 2 away from the 12volt and still be able to supply more than enough power for those lights. The inverter the e-spar the water pump are all 24volt.

As I go through the rest of the batteries charging and desulfating I might come across another bad one or two and I will then replace the 4 for 24 volt and have a spare or two for the originals that will work just fine for lighting on the 12volt side.

Joe,

I would be surprised if your converter installed 4 batteries just for lights.

I'm guessing you have 12 volts for the fridge control circuit (it's gas right?), maybe for inverter input, furnaces, sound system, clocks, pump, and a whole bunch of smaller items.

The inverter is used to run the TVs, make coffee, power the outlets, etc. so the batteries are an important item.

Jon The inverter is 24 volt along with the pump. We are heated with electric toe kicks and a 24 volt e-spar. The dash stereo is off of bus batteries, no clock accept for the coffee pot. The original fridge was 2-way a/c d/c but, yes, we now have a propane and it does require 12 volt for the brain board but that is a very small draw. Just lights baby.

I can't remember what the original fridge was drawing on D/C it might very well have been 12 volt and that would explaine the battery configuration.

There was some kind of a movement in the early 1990's (probably the by battery guys) to add additional batteries to coaches to supposedly increase the amount of dry camping time without running the generator. I believe it began in the Prevost Prouds and got to be quite a thing. (So much for that).

Anyway, our Angola had, when we picked it up, an extra FOUR batteries installed. One day I walked into the coach and there was this distinct acid smell going on.

So, after ripping out a plywood panel, found a bunch of the extra Super-Duper Sears batteries hooked into the 8D chassis batteries. They were corroded worse than a freighter registered in Bolivia. Yanked 'em out, disconnected all them wares (am trying to talk Southern) and the 8D's came back to life again.

All them batteries were trying to equalize and the 8D's cooked Sears Best.

Just goes to show.

Joe: You may want to check out using SS angle to fab that frame. It will last forever and may not cost much more than steel with powder coating. SS sheet instead of plywood with some of your rubber sheathing over it. Just a thought. Sorry, i'm spoiled having an industrial metal fab shop to scrounge from. Try and find some Urethane blocks to set between your motor mounts and their base.

Thank you Harry for those ideas, I'll see what I can come up with.

Joe,

Whether it is 12 V or 24 V doesn't it come from the house 12V batteries?

Usually the house 24V stuff is powered by 2 pair of 12V batteries wired on series.???

Yeeeeeeeeeeeeeeeeeees

I have 8 12 volt batterys for the house.

2 sets of 4. 1 set are paralleled for the 12volt stuff.

And the other 4 are wired as you describe, parraleled and in series for the 24volt stuff.

I must be confusing the issue because you of all people should get it:rolleyes:

Right when you think you have things pretty cleaned up this happens.

Attachment 1394

This is what I have exposed by pulling the 8 house batteries. More nastyness about the engine and starter and it looks like those last 4 batts for the bus that remain will be coming out too:eek: With all those batteries out I can get right at the powersteering pump plunger that is dripping. Powerwashing sanding and repainting are also in order. I wonder if Elgin has a part # for frame paint?

I've also decided to improve that battery tray for the house batterys by fabbing it just enough oversize to add additional inner trays that are the current dimension so that I can slide them out, top tray bottom tray.

Attachment 1395

The hoses off the OTR A/C compressor go right through that tray, you have to take the tray apart or disconnect those hoses to get it out. The hoses go under the top tray but above the bottom batteries. Currently one has a protective cover and one does not.

I don't like that at all but I gotta deal with it. I don't think they enjoy battery crud. I'll cover them better to protect them as much as I can and then just keep things clean around them.

If anyone out there knows of a way that I could convienienty isolate the 8 house batteries from eachother when not in use I would be interested in knowing.

I'm pulling this idea out of thin air Joe, but there are battery disconnects that attach to battery posts. I have seen the knife type and a type that has a wheel or knob that you turn. They are sold as a way to protect your car from theft or to turn off the battery for storage.

You would need one for each battery, but that might work.

What is missing in your pictures and I hope you have is a master battery switch and circuit breaker for each battery set located as close to the batteries as possible.

A weak link in circuit protection on all of our coaches is the cabling from the battery post to the circuit breaker or battery disconnect. That cable length needs to be as short as possible. I'll tell you why at Branson.

Joe, the marine industry has some nice battery disconnect switches available.

Joe, Don't be looking for OEM paint. Here find links to two superior products that are worthy of your time and effort.

http://www.rustbullet.com/IndTesting/Q-lab/Q-Lab.htm

http://www.por15.com/

Be sure to wear gloves as the paint will not come off your skin for weeks!!

OK heres one for all you electrical wizards.
The two diagrams below are:

FIRST-the way prevost has the 4-12 volt batterys wired for 24 volt for the bus.

SECOND-the way the converter has the 4-12 volt batteries wired for 24 volt for the house.
Attachment 1408
As you can see they aint the same, guess there is more than 1 way to achive 24 volt out of 4-12 volt batteries.

Another curious thing I've noticed. Our house voltage meters for 12volt and 24volt read 12.9 and 25.5 respectivly.

When I start the bus but before throwing the equalizer switch they go up to 13.1 and 26.9.

When the equalizer switch is turned on, with the bus running, they go up again to 13.6 and 27.1.

Why do they go up after the bus is started but before the equalizer is turned on?

The batteries look the same. Two pair of series connected batteries in parallel.

I can only speculate on the voltages. When the engine is running but not the equalizer you are charging the batteries from the bus alternator, but when you turn the equalizer on the full alternator output is entering all batteries. I assume a 12V alternator?

I'm pretty sure we have the gear driven oil cooled 450amp. 24volt monster.

Here is a pic of an old post showing it, before the leak was repaired.
Attachment 1409

Quote:

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The batteries look the same. Two pair of series connected batteries in parallel.

---

I think I'm disagreeing here. Definately both make 24 volts but in left hand side, we have 1+2 in parallel (12v), 3+4 in parallel (12v), and those two parallel circuits are in series to provide 24v

On the right hand side we have 1 and 2 in series (24v), 3 and 4 in series (24v), and the 2 24v combinations in parallel (still 24v)

So, in one case we have two pair of series connected bats in parallel (right side), and the other is two pair of parallel connected batteries in series.

Is one better than the other? Shoot, I don't have a clue. The left side for me was easier to decipher!

Ray

You say potato, I say potahto. Ray the juice coming out in the end is the same but maybe they are different.

Joe,

Are you sure about that 24 volt? Stick a meter on it somewhere. This could be something we could wager on. How about Di and I take you and Deb out to lunch or dinner in Branson if you alternator is putting out 24V?

LOL, thanks Ray. I was gonna ask Jon about his eyesight but decided it might be something I was not looking at correctly.

I'll also agree with you about the simplicity of the set for the bus and also was wondering about what set was more efficiantly wired or more powerful or if it mattered.

I was concidering changing the house set over to the same as the bus set if for no other reason than uniformity, but don't dare till I get more difinitive info.

Jon we have the same 24v generator as Joe plus a aux. 24v gen plus a 12v alt. for the house.

Good question Jon, but what makes you question this, something you see in the way things are wired up im guessin.

As for dinner, we are still waiting for the provider of the first dinner challange, the nitrogen question, sorry but we have not camped the bus since we parked it in Feb. I do still plan on doing this, so we will put that bet on hold a little longer.

Did they also make that gear driven, oil cooled alt in 12 volt? If so why in the heck didn't they put everything on the bus 12 volt?

If it is any clue, on the upper rear engine compartment wall, there is a vannar high efficiency battery equalizer and it is marked 24volt input, 12 volt output. That would tell me you would now be owing us 2 meals:eek:

Potato, potahto tomato, tomahto. Now I'm gonna have to go dig up my CDs. Sachmo and Sara Vaugn did that one the best.

It's been a long time since my engineering days, but in drawing this out as a schematic, one benefit of the left circuit become a possibility.

In the left hand side, you could actually tap off of the where where battery 2 connects to battery 3. At that point (to ground) you have 12 volts, and actually you have two batteries in parallel for extra current.

In the right hand version there is no place to do this. you could tap off a couple of places and find 12v, but it would be only a single battery worth, so the left is more valuable if you need 12v too.

My guess here is at the 24v legs, you effectively get the same thing. Maybe one version gives you a little more current, but I really don't see how that would be the case.

Ray

Thanks Ray.

We've another bank of 4 all parralell for the12 volt stuff and we also have enough other projects to worry about this. Stick a fork in it it's done.

Dig this. We picked up 8 interstate wet cell deep cycle RV/marine batteries, bran spanken new for 30 bucks a piece:p . Used our ICC# and no tax, 240 bucks total. They were factory seconds because the carry straps were missing and they were scratched. If We can get 10 bucks a piece for the old ones at this weeks local garage sale that will bring the total for all 8 to 160. Eat your hearts out:D

My 87 had the gear driven alternator. It was a 270 amp, 12V. I know the buses are 24V, but maybe the 12 on the 87 was because the DDEC was 12V. Except for the headlights all lighting on that coach was 24V.

Now the 97 has a 24V alternator. Same amperage. DDEC is still 12V, but now all lighting is 12V. Does anyone see a pattern here?

Ray, I do know Prevost does their batteries that way so they have a 12V source, such as for DDEC.

I still want to see 24V output with my own eyes.

Joe,

What's with the N bet? Refresh my memory.

I've heard that memory is the second thing to go:D

You bet me that if I put nitrogen in my tires that they would still grow when hot and deflate when cold, contrary to the sales pitch that claims they will not.

I'll stand by that. set pressures cold before you leave for Branson and at the first stop you make check the pressures.

Then go in the coach and check your wallet to make sure you have enough money to take us to lunch.

However.....I'm busy pulling up Prevost wiring diagrams and they are all calling for 24V alternators, so one day we treat and the next day you treat.

Damn.

Joe: The next hurdle to get you and Debbie to Branson should not be the polishing of your SS to look like everybody elses coach, fingerprints and all. My Royale was never polished as the others. I could read the envy in everyones eyes when they saw it at both POG Rallys. There is something to be said for nostalgia. Would you drive around in a 1932 ford three window coupe that was chromed, of course not. Bring the bus au natural but clean to Branson. You and DaleJ have become ICONS of our group with your many bus repair projects. I want a picture of both of you together with your pretty brides at your sides.

This thread originally started about doing some basic maintenance on electrical systems.

Something I have always done is to slowly go through the machine and put a healthy helping of dialectric grease in all the connections I can get to. The first one I try to get are the ones down low that are exposed to an incredible amount of heat, moisture and corrosion--the connections to the tranny are prime candidates.

Just a Saturday morning thinky.

Good morning Jimmy. 328 AM hu. That ain't even rebely yet:eek: I get up early like that cause I have to, what's your excuse, PT?

Isin't reviving these old threads fun;)

I do not know if I am satisfied with the explnation Jon gave me for why my house battery volt meters go up after the bus is started but before the equalizer switch is turned on, and then increase again when it is?

I think the house battery voltages should remain the same with the thing running or not and only increase when the equalizer switch is thrown.

Harry I think I agree with you about the stainless unfortunatly in my haste early on I began the process but not finished it. Boy am I regretting that now. Wanna help:)

Joe: Well you see you get this big end grinder and attach 3-4 buffing pads side by side on it. Get a several large sticks of roughe. Have a garden hose with a fine mist spray for temperature control. When you get it all set up you drive by Home Depot in the AM and pick up two of the strongest looking workers standing out front, take them home. After giving instructions on polishing get your lounge chair and a six pack. Before you know it the bus will be polished. This operation is best done out of site of the light green trucks with the badges on the doors. Good luck and stay out of the sun.
If the job runs into a twelve or twenty four pack, you chose the wrong crew.