Small DC compressor to stay aired up?

[hcvdg]

Caveat - I have been out of bussing for a while, so this may be dumb.

How would it work out to use a small DC compressor to keep the bus aired up at all times?

I was thinking one could use a compressor (like the air suspension compressor from a Range Rover) to keep a bus aired up - and ellimate the noise of idle, or a shop side compressor prior to departing a camping location.

Is this silly, do the air systems leak too much for this?

[DoubleEagle]

No, it is not silly, many people have backup compressors, but most do it to be able to slip out of a campground spot without smoking the neighbors (too much), or to be able to listen for air leaks without the engine running. Usually these are portable AC electric compressors, not small DC compressors. There is no real need to keep the bus aired up all the time, plus if you could keep up with a small DC compressor, it would run the batteries down unless they were being charged (by an AC charger, usually). 

[hcvdg]

I was thinking if you were on shore power you would have a continuous DC source from the charger/converter (so the batteries should stay up), and if you were not on shore power there may not be anyone else to bother with the noise anyway. Some of the Aux compressors can be rather loud too (diaphragm).

I guess the question would be - what is the normal leakage rate at regulated pressure (cfm)?

[richard5933]

Our 4108a will air up in less time than it takes the engine to get wsrmed up enough to get going in the morning. Our 4106 did as well.

Would it be worth looking into the system to see if you can improve the air up time?

When parked, both buses would stay up for weeks, even if the gauge bled down. There's nothing magical about keeping the air in other than perseverance and persistence.

[jraynor]

hcvdg,

My plan is to install a small A/C compressor possibly in the front area under the driver. There is another post on this that I woke back up as well. Here is the link:

https://www.busconversionmagazine.com/forum/index.php?topic=267.msg380115#msg380115

Not sure what the space allocation is like on your bus, but mine has space. My bus used to leak down really quick. My luggage bay locks were leaking a ton. Of course this can be stopped via the valve by the driver. Since I have disconnect the bay door locks (I'm converting to electric) my bus stays aired up longer. Still leaks but not as fast. I still have a few leaks with the wipers and with some relief valves in the back. I plan to disconnect and apply some seal tape to see if I can fix those leaks. Its a game of searching for the hiss, then gaining access to it.

I believe the post I mention above mentions the best way to use the compressor to air the bus completely before even starting the bus

All in all, the time it takes your bus to air up and to lose air all depends on how many leaks there are.

I plan to tackle my other leaks then eventually get a compressor as well

Jonathan

[chessie4905]

I wonder if a small air suspension compressor like on a Range Rover would have enough capacity to do the job. They don't produce much cfm. Might be overcome by leaks. Their rated duty cycle is much shorter than you need.

[buswarrior]

Oil lubed compressor, small shop type, will give longest, satisfying, service.

I'm a fan of fooling around with free stuff on hand, but if yer going to spend money, spend a bunch once, and be done with it.

You'll burn out lesser units.

It's about CFM and duty cycle.

Happy coaching!
Buswarrior

[Geoff]

I have a small 12v refrigerator compressor that I intend to make into an air compressor.  Quiet!  Just have to find some building tips

[luvrbus]

My Humvee has a 24 v Oasis compressor it is quite and pumps a bunch of air, no telling what the military pays for one though, it looks expensive 

[hcvdg]

I found this link for modifying a DC fridge compressor. (Geoff)

Might be able to couple he compressor to a small high pressure tank to have some air on tap, as well as keeping the bus air tank topped off (quietly).

https://www.instructables.com/id/How-to-modify-a-fridge-compressor-into-a-silent-ai/

[chessie4905]

Hard to justify taking the time to build it when you can get this one this cheap. Sure, it isn't as quiet and ratings aren't fantastic, although many are happy with it. There are larger ones also. And extended warranties available.
https://www.harborfreight.com/3-gal-13-HP-100-PSI-Oilless-Hotdog-Air-Compressor-69269.html?ccdenc=eyJjb2RlIjoiNDE4NjQ2MDQiLCJza3UiOiI2OTI2OSIsImlzIjoiNDQuOTkiLCJwcm9kdWN0X2lk%0D%0AIjoiODY2NSJ9%0D%0A

[Geoff]

Thanks for the link.  I have most of the parts already.  BTW, the HF compressor would be very noisy.  Oil-less compressor motors are the loudest, I know, I have one.

[chessie4905]

Huh??? What did you say. They always seem quiet to me.☺

[jcussen]

https://express.google.com/u/0/product/8854732696752152839_3329444740726281221_1699011?utm_source=google_shopping&utm_medium=tu_cu&utm_content=eid-lsjeuxoeqt,eid-ptgtgfeotu,eid-ygcnqnyulq,4181969&gtim=COnYr9262sbX8gEQvpmu3LDylvEjGPCIzFoiA1VTRCiQmdPbBQ&utm_campaign=1699011

used this one in two coaches, quiet, draws about 20 amps when running. You will need a pressure switch.

[luvrbus]

Huh??? What did you say. They always seem quiet to me.☺

Change your hearing aid batteries