12 Volt Diving Compressor

[Andrew Grace]

I have been using my Bower Poseidon Dive compressor for some time now but sick of the Petrol motor.

Has anyone looked at converting their current petrol or 240 volt scuba tank compressors to work on 12 volts. ???

The below link is to a 10 hp , DC motor that should be capable of driving a compressor and can work from 6 volts to 48.

https://www.youtube.com/watch?v=hu58HYA2jRE

any feedback appreciated,

Andrew

[ErikFinn]

Bauer has 240V compressors. I can't remember specs but I reckon might be able to run from inverter.

[Andrew Grace]

Originally Posted by ErikFinn

Bauer has 240V compressors. I can't remember specs but I reckon might be able to run from inverter.

The Bauer Junior 240 v needs a minimum 7KVA Genset to get started and does not start using an inverter.

[ErikFinn]

Originally Posted by Andrew Grace

The Bauer Junior 240 v needs a minimum 7KVA Genset to get started and does not start using an inverter.

How about adding a soft starter? Could it be done then?

[Captain Bill]

A 10 hp dc motor would draw almost 600 amps. Even if it only took 30 minutes to fill a tank that's 300 amp hours per tank of air. It would require a fully charged 600 amp hour LA bank for 1 scuba tank of air or 1200ah for 2 to avoid going below 50% SOC. You better have room for lots of batteries and a very nice charging system and some very large battery cables.

[arbanais]

meaning a compressor equals petrol engine or genset?

[Brewgyver]

Yes,, same as A/C, for the same reason. Compressors are heavy loads.

[Cadence]

If you have some kind of partner, to be politically correct, get a set of bellows and put them to work. You stand a better chance than a DC compressor.

[trapoc]

Change over to propane, all will be good

[Djarraluda]

Just use Hooka

[Andrew Grace]

Originally Posted by Captain Bill

A 10 hp dc motor would draw almost 600 amps. Even if it only took 30 minutes to fill a tank that's 300 amp hours per tank of air. It would require a fully charged 600 amp hour LA bank for 1 scuba tank of air or 1200ah for 2 to avoid going below 50% SOC. You better have room for lots of batteries and a very nice charging system and some very large battery cables.

Sorry but I don't think you are quoting the correct data,

the specification sheets are showing that running at 50% (24v) its will generate 5HP of power which is plenty to drive the small bauer compressor and will draw only 100 Amps which is fine for filling a few tanks (it takes around 1/4 hour to fill one 90 cubic foot tank).

Manta II 10 HP DC Electric Motor 12 24 48 Etek Permanent Magnet with Mount BRK | eBay

[capngeo]

Forget it! You would need more solar than the ISS!

Or you could use a wind genny

[denverd0n]

Originally Posted by Andrew Grace

the specification sheets are showing that running at 50% (24v) its will generate 5HP of power which is plenty to drive the small bauer compressor and will draw only 100 Amps...

One horsepower is equal to 745.7 watts. That means that 5 hp is 3728.5 watts. At 12 volts, that is 310+ amps. This is all assuming perfect, frictionless conversion, which of course is impossible. Hence it is going to be MORE amperage than that. Captain Bill was actually a bit conservative with his numbers, and his data IS correct.

Running the motor at 24 volts doesn't really change things--it just alters the volts versus amps equation, but you still need the same number of watts coming out of your battery bank. You still need a monstrous battery bank, and something to charge it with.

By the way, if the spec sheet actually says that it can generate 5hp on 100 amps at 24 volts then it is LYING! At 24 volts, 100 amps will produce less than 3.25 hp. Simple math, and inescapable physics.

[ErikFinn]

I find it rather hilarious how folks claim it can not be done and yet here you have a guy who just does it, WITHOUT A GENERATOR:

" So now i have a 2.2kW scuba tank filling compressor running from my 3kW inverter - powered by solar (and engine alts if need be) "

https://diy-yachts.com/forum/viewtop...tart=30#p10429

[denverd0n]

Without a separate generator, yeah. Did you notice that he said that he DOES use the engine alternator, though? Yeah, I know, "if need be." I'm going to bet that it pretty much ALWAYS "need be." And, of course, I didn't see any mention of how big his battery bank is.

Of course you can power a compressor from an inverter, connected to your batteries, with your engine running to keep the batteries charged. No one said that you couldn't. What is going to be very, very difficult to do is to fill a tank on battery power alone. That will require quite a large battery bank. And if you are going to run it from an inverter, then there is no real point in getting a 12-volt system.

(Which, of course, in the link above, the guy is NOT using a 12-volt compressor. In fact, the implication is that he frequently runs it off of shore power.)