Is 12vdc compressor from solar possible

[iain/hsm]

Just a couple of points really to register my interest in small scuba compressors and this very interesting great topic.
But first for fun. Sitting on my office desk is a very small oil free and oil less High Pressure 4500 psi bottle filling air compressors (That are capable of compressing from ambient air) and are available in both 12 and 24 and 28 volt DC Just no one has thought yet that the yacht market would be a suitable application.

The “bottle” you lot call “tanks” is the little round silver thing on the end of my finger and its purpose is, once filled to 4500 psi to be attached to a device that really does kill tanks.
I will hook it up filling a standard 80 and find out tomorrow how long it takes but I expect most of the working day.
I dare say I have a better cheaper solution we are working out for a client with a catamaran mounting the scuba compressor upside down hanging it from the ceiling in the engine compartment and has a similar requirement but not as interesting. But for now just to show there are small HP 24 volt compressors around.

The air intake filter is the small 28mm polyester white disc on the middle right side
The power socket is the small Anphenol socket lower left and the long silver and black
"coffee" flask under my hand is the HP zeolite filter assembly.
Weight is under that of a small dog 11 kilos (24 lbs)
Power wise using a 19 to 32VDC range and 28VDC nominal
Draw is 6 amps worse case (at 269 bar) and 10 amp for one (1) second on start
(Peak current on start up is 25 amps for 15 seconds when the gas heater is operative)
Current between 15 seconds and 2 minutes is 10 Amps Maximum
Current over 2 minutes and 39 minutes is 9 Amps maximum
Current after 39 minutes running drops to 6 Amps worse case
The gas heater current is 3 Amps at 28 VDC
Operational range sea level to 10,000 ft
Excursions to 20,000 ft
Survival Sea level to 60,000 ft (18288m)
(all in height altitude in case anyone is foolish enough to ask verification.
Attitude: Roll Pitch 30 degrees
Design philosophy is the same 3 stage swash plate principle as the more commercial SA-6 160 LPM 6 SCFM design just smaller.

[/URL]

[/URL]

 

[NotWavingDrowning]

Thanks all

Cunning plan as of today ...............

3hp 12Vdc electric motor, probably from a 4x4 or quad bike electric winch.
Wired directly from the 12Vdc battery bank < 1m of 2/0 wiring
Maybe use a cheap/disposable air gun compressor - such as Yung Heng - I would like some advice on this due to concerns about air contamination
40cf tanks to 3000psi
Can fit up to 1.8kW of solar, will probably fit 1.2kW
500Ah of battery available

I expect a typical tank top up to take 20min < 1kWh allowing for efficiencies

I have been advised to rethink my air filtration, I was going to make my own but now would prefer a certified system. Any recommendations

 

[NotWavingDrowning]

Hahahahahaha just read an old thread on the cheap compressors.

Disregard that

 

[Wookie]

Just a couple of points really to register my interest in small scuba compressors and this very interesting great topic.
But first for fun. Sitting on my office desk is a very small oil free and oil less High Pressure 4500 psi bottle filling air compressors (That are capable of compressing from ambient air) and are available in both 12 and 24 and 28 volt DC Just no one has thought yet that the yacht market would be a suitable application.

The “bottle” you lot call “tanks” is the little round silver thing on the end of my finger and its purpose is, once filled to 4500 psi to be attached to a device that really does kill tanks.
I will hook it up filling a standard 80 and find out tomorrow how long it takes but I expect most of the working day.
I dare say I have a better cheaper solution we are working out for a client with a catamaran mounting the scuba compressor upside down hanging it from the ceiling in the engine compartment and has a similar requirement but not as interesting. But for now just to show there are small HP 24 volt compressors around.

The air intake filter is the small 28mm polyester white disc on the middle right side
The power socket is the small Anphenol socket lower left and the long silver and black
"coffee" flask under my hand is the HP zeolite filter assembly.
Weight is under that of a small dog 11 kilos (24 lbs)
Power wise using a 19 to 32VDC range and 28VDC nominal
Draw is 6 amps worse case (at 269 bar) and 10 amp for one (1) second on start
(Peak current on start up is 25 amps for 15 seconds when the gas heater is operative)
Current between 15 seconds and 2 minutes is 10 Amps Maximum
Current over 2 minutes and 39 minutes is 9 Amps maximum
Current after 39 minutes running drops to 6 Amps worse case
The gas heater current is 3 Amps at 28 VDC
Operational range sea level to 10,000 ft
Excursions to 20,000 ft
Survival Sea level to 60,000 ft (18288m)
(all in height altitude in case anyone is foolish enough to ask verification.
Attitude: Roll Pitch 30 degrees
Design philosophy is the same 3 stage swash plate principle as the more commercial SA-6 160 LPM 6 SCFM design just smaller.

View attachment 507377[/URL]

View attachment 507378[/URL]

That’s very cool

 

[2airishuman]

Just a couple of points really to register my interest in small scuba compressors and this very interesting great topic.
But first for fun. Sitting on my office desk is a very small oil free and oil less High Pressure 4500 psi bottle filling air compressors ]

Nice, Ian. I think you should productize it. What is the output volume per minute? Is it loud?

Thanks all

Cunning plan as of today ...............

3hp 12Vdc electric motor, probably from a 4x4 or quad bike electric winch.
Wired directly from the 12Vdc battery bank < 1m of 2/0 wiring

They aren't continuous duty and will melt if you run them under load for 20 minutes.

I have been advised to rethink my air filtration, I was going to make my own but now would prefer a certified system. Any recommendations

You really have to buy one. They have to withstand your output pressure (3000 or 3500 PSI or whatever) and they are big enough that there won't be anything left of you or your yacht if they explode. People used to use hydraulic accumulators but that's widely regarded as a bad idea now, because some of them exploded.

You also want to be sure that all the gas goes through the filter, and you need a coalescer, which is hard to make. Something like this:

August Industries - P0 or P21 Triplex Filtration System

You can use any old pump but you've got to get the filtration right or you'll end up with contaminated air that can injure or kill whoever breathes it.[/quote]

 

[iain/hsm]

Nice, Ian. I think you should productize it. What is the output volume per minute? Is it loud?

Not sure I can be that specific on an open forum but volume wise it is so small its measured in grams per second G/s or lbs per hour lb/hr hoverver noise is negligible. Filling a scuba cylinder 11L water capacity standard 80 size to 207 bar 3000 psig (from empty) your talking all day to fill.
And to be fair it was for illustration example purpose only and never intended for scuba applications just one specific application that we need not get into.

The intriguing question to me at least is if we can match a suitable scuba compressor to this solar powered application and for that we need to choose a block that we can reduce the motor size the current draw together with the RPM
And this is where you leave recreational scuba blocks such as the Bauer far behind and use compressor blocks that can be reduced both in motor size and RPM without damaging the running gear due to oil starvation

Going from 1500 RPM and running down to say 500 to 900 RPM for say a 3600 psi filling pressure to cover most applications

1.0 scfm flow with a 1.0 BHP draws 9.1 amps at 115/1/60 (115 volt 1 single phase and 60 Hz)
1.6 scfm flow with a 1.5 BHP draws 13.5 amps at 115/1/60 (115 volt 1 single phase and 60 Hz)
Also
1.6 scfm flow with a 1.5 BHP draws 6.8 amps at 230/1/60 (230 volt 1 single phase and 60 Hz)

2.5 scfm flow with a 2.0 BHP draws 18.1 amps at 115/1/60 (115 volt 1 single phase and 60 Hz)
2.5 scfm flow with a 2.0 BHP draws 9.0 amps at 230/1/60
And for us Eurosceptics
2.5 scfm flow with a 2.0 BHP draws 7.5 amps at 230/1/50

3.5 scfm flow with a 3.0 BHP draws 13.5 amps at 230/1/60
3.5 scfm flow with a 3.0 BHP draws 9.6 and 8.6 amps at 208/230/3/60
3.5 scfm flow with a 3.0 BHP draws 9.6 and 4.8 amps at 230/460/3/60

For the larger Yacht typically using a marine generator maximum flow would be around 6.5 SCFM
at say 4500 psi to enable bank charging/filling

6.5 scfm flow with a 5.0 BHP draws 14.4 and 13.0 amps on a 208/230/3/60 supply
6.5 scfm flow with a 5.0 BHP draws 11.3 and 13.0 amps on a 200/208/3/60 supply
6.5 scfm flow with a 5.0 BHP draws 22.5 amps on a 230/1/60 supply

Finally again for the Brits in Europe
6.5 scfm flow with a 5.0 BHP draws 19.0 amps on a 380/3/50 supply

 

[iain/hsm]

@2airishuman splash lube compressors can typically go down to about 2/3's of nameplate RPM before it's an issue. The Junior is spec'd to run between 1500 and 2300rpm depending on power availability. 1500 for 2hp 110v motor, 2100 for 3hp 220v motors, and 2300 for the 6hp gas motor.

And by contrast the Rix SA-6 oil free spec to run 1450 RPM and deliver 160 LPM (than the Bauer Junior II 100 LPM)
you can run to below 500 RPM if you like with zero damage or consideration just reduced flow balanced to any motor size and output

 

[iain/hsm]

I should clarify that we have a Bauer Junior II compressor, have had it for 17+ years and done over 4,500 fills.

Again by consideration this equates to less than 1500 hours total running over 17+ years. Last even longer if you use the thing even less I guess but my point is that it's not much of a claim or consideration when you consider that the average dive shop would run 1500 hours in less than 3. And that 1500 hours is not a great deal of use however long.

By contrast I have customers that have run SA-6 compressors every day for 8600 hours in less than six.

 

[clownfishsydney]

Again by consideration this equates to less than 1500 hours total running over 17+ years. Last even longer if you use the thing even less I guess but my point is that it's not much of a claim or consideration when you consider that the average dive shop would run 1500 hours in less than 3. And that 1500 hours is not a great deal of use however long.

By contrast I have customers that have run SA-6 compressors every day for 8600 hours in less than six.

You realise that this is a compressor used by two people only? That is a very large number for a Junior II used by two people. It shows that they are very reliable and that perhaps I know a bit about small compressors and for using them on yachts etc.

 

[iain/hsm]

You realise that this is a compressor used by two people only? That is a very large number for a Junior II used by two people. It shows that they are very reliable and that perhaps I know a bit about small compressors and for using them on yachts etc.

Yes I figured that out, your running two fills a day over 17 years hence my comment that it has only run less than 1500 hours. All of which is very light duty cycle and use. Further at that you only managed to achieve this in some 17 plus years.

No it does not, and no way near imply reliability, it implies long life (the 17 years) and only then if used very light duty and cafefully treated but in reality its what.......... two fills a day?

As for reliability in general it shows nothing of the sort any more than making claim one fill a day you will last 30 years.
This is not how you measure a claim of reliability, its a misleading statement that unsuspecting buyers people fall for this type of sales hype. Hence my point.

Any more than finding someone running a 50 year old compressor at one fill a week is more reliable because in your book that makes it more reliable? Iain