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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: opus on February 22, 2011, 07:25:27 AM

Title: Thinking heat
Post by: opus on February 22, 2011, 07:25:27 AM
Spent a couple nights on the road this weekend.  It was cold 10 maybe.  I dont have a heating solution yet, so I pack along a Mr Big Buddy Heater and we just close of the bunk and back lounge area.  It works fine...until you go through the curtain to the front of the bus.

2nd night I high idled the big engine and left some of the heater fans on....perfect.  I dont want to run the big engine every night though.  I wonder, if I left the Webasto running all night and the circulator pump and some fans, that should work?  I know I wouldnt do that all on the 2-8D batteries all night.  Could the Webasto handle running all night straight?

Could I: plug in to shore power and put a batter charger on them all night?  Could I run my little lawn mower engine with a 60a alternator on it all night to charge the batteries?

Not sure I know what to do, but I know what I dont want to do.  I will probably tell that when its suggested. :)

Ok, time for coffee.....
Title: Re: Thinking heat
Post by: bevans6 on February 22, 2011, 08:21:41 AM
You sound like you have some interesting options!  A Webasto, and a lawnmower engined 12 volt generator with a 60 amp car alternator!

I would say that if your webasto can produce inside heat, the way most people seem to have them arranged, then that would be my first choice.  You need to find out the power draw for it's pumps and fans, and know your battery capacity to know if it will work all night or not.  I would have running a lawnmower engine all night my personal last choice, right along side idling the big engine all night.  I think you have a 4 stroke, not a DD 2 stroke, so it can be high-idled without really hurting it.

Brian
Title: Re: Thinking heat
Post by: opus on February 22, 2011, 08:27:15 AM
Yeah, its an 8.3.  Lawnmower engine is nothing drastic but its just something else running.  I wouldnt mind it running.  We are never near people so the minimal noise wouldnt be an issue.  I would just need something to keep a charge on the batteries over night.  Those were my only 2 options that I could come up with.
Title: Re: Thinking heat
Post by: luvrbus on February 22, 2011, 08:45:41 AM
The 8.3 Cummins does not like idling any more than a DD long periods of idling was cause loss of the center section on the turbo then you have problems read you book and you can figure on around 3/4 gph usage at idle on a 8.3 and the Webasto burning 5 gals in 24 hours do the math no free lunch for heat just a lesser of 2 evils.


good luck
Title: Re: Thinking heat
Post by: buswarrior on February 22, 2011, 09:13:18 AM
Well, how-d-do! That's how my coach was equipped when I got it, and still can perform that way.

In an MC8, the Webasto makes and circulates the heat, coach HVAC blowers and temp control bypassed to run with the engine off, and a pair of big 12 volt battery chargers hooked to each battery used to make the 24 volts.

A Trace 4024 replaced the less than elegant dumb battery chargers.

As for power, the Trace meter shows 10-12 amps of 120 AC draw to keep it all running.

Yes, that big fan motor sucks power... and my Webasto is a big DBW300, but won't change much from a smaller one.

As for idling... if you're cold, run the @#$%^ engine and leave the Webasto engaged, as you've done.

We all need to reduce idling, for good maintenance, for the law, and for the air on this submarine we call Earth.

However...

Godless heathen that I am,

A busnut,
provided one is someplace that won't bother anyone,
driving before and after,
who hasn't got the conversion equipped with another form of heat yet,
isn't doing anything to that old whore of a coach,
that hasn't already been done many, many times before, and worse!

She's no virgin, no amount of ceremony will change that.

A cold weather busnut should:
Work towards minimizing idling,
and in the meantime,
stay warm with a clear conscience.

happy coaching!
buswarrior 



Title: Re: Thinking heat
Post by: opus on February 22, 2011, 09:26:49 AM
I wouldnt ever just idle and engine.  I bumped it up to 1100rpm which should be much better than 750 or whatever it is at.

Right now, for giggles, I have the Webasto running [12v] and an extra circulator pump as well as a few fans.  I have the "lawn mower engine" charger hooked up and running at about 1/2 throttle.  I'll let it run for a while and see what happens.  I would rather "test" it at home than on the road.

I have the 2-8D's  I wonder which one should have the charger on it....hmmmm.  I guess I could make it so I hook it t both batteries, eventually.
Title: Re: Thinking heat
Post by: eddiepotts on February 22, 2011, 09:52:17 AM
Just hook both batteries up with jumper cables like you would in your car and charge them both at the same time. Just disconnect the neg. to pos. cable that makes them 24v.
Title: Re: Thinking heat
Post by: opus on February 22, 2011, 10:36:06 AM
12v system.
Title: Re: Thinking heat
Post by: buswarrior on February 22, 2011, 07:18:38 PM
opus, if it's a 12 volt system, just put the "charger" connections at the same places the main cable and the main ground come off.

Put your multimeter on it, what is the voltage with the "charger" running, batteries all charged up, and no load, and then, check for after you turn it all on. You want it pretty much the same.

great belt and suspenders engineering!

happy coaching!
buswarrior
Title: Re: Thinking heat
Post by: DMoedave on February 22, 2011, 07:57:02 PM
How is the exhaust routed on your mowie engine? got any info on that set up?  stay warm, we are still using the 45,000 btu propane furnace. Its fine when parked but less than perfect rolling altho  with the engine heat its ok
Title: Re: Thinking heat
Post by: opus on February 22, 2011, 08:03:13 PM
When I am rolling you could die of heat stroke in the thing.  I think there are 3 - 80,000 btu heaters, 1-90,000 btu and a 35,000 btu heater in it.

At this time I just lay it out on the ground next to the battery bay.  I'll change that in 2 months when we are snow free.  I took the engine off a pressure washer.  It only had about 20 hrs on it.  Its stock exhaust at this time.  On the Webasto, I had a "tail pipe" made for it so it extends past the rear bumper.

I'll have to take some pix and post them.  Mind you, this is a budget operation.

If you are bored: https://picasaweb.google.com/pmilne/Bus#
Title: Re: Thinking heat
Post by: DMoedave on February 22, 2011, 08:11:11 PM
Thanks, that would be great. Nothing wrong with the low budget, i like that approach, it fosters inovations! I dont want to do a hijack but does the routing of the bus heaters fo in and out then to the next one or are there mono flo type tees and each heater feeds off the main loop? Nice work so far. thanks again, dave
Title: Re: Thinking heat
Post by: opus on February 22, 2011, 08:14:10 PM
Thanks!  They are all tied together in one big loop.  I think the coolant goes from the engine, to the front of the bus, then back through all the heaters, to the engine.  Give or take a few details.