Powering an electric dive compressor

[Sawbonz]

Originally Posted by a64pilot

What would a 1 KW Life-Po bank even cost?
I hope one day for maybe a 400 AH one myself.

About $20k

[DotDun]

Originally Posted by a64pilot

Yes, 220 ones are, but there are 110 50 amp cords I believe?

Now I think about it the 50 amp ones do have dual circuit breakers.

Yes, there are 125v/50a cords. I have never seen a marina that supports it.

[Tbonem17]

https://www.youtube.com/watch?v=5bNMlG9KB5c

If you have a look at this video I think you'll get a real world view on what's possible.
This is an SV Delos video they've just posted on their scuba gear including the a/c pump they use.


Tony

[poiu]

Originally Posted by transmitterdan

You are over thinking this I believe. An 8kW generator will run a single phase 1.5HP compressor. Even if you find there are problems getting the compressor to start there are after market solutions. You can try a hard start kit for <$25. Or you can get a small single phase variable frequency drive (VFD) that can soft start the compressor. These cost about $100-$150 and are quite small. Going to 3 phase will not be efficient. I think the advice you are getting from dive shop isn't very good, I recommend visiting a different shop or looking online for a shop that has more experience with pleasure boaters. There are plenty of dive shops that cater to your specific needs.

I agree a VFD may be the best solution for the O.P. It will allow the motor to start with almost no peak amp load. A soft start unit will reduce peak loads by a third or so, so might work fine too.

Just a correction, there is no such thing as an affordable 1ph in to 1ph out VFD. You have to change the motor for a 3 ph motor and buy a standard 1ph in and 3 ph out VFD. Total cost in parts $3-500.

[softdown]

Originally Posted by a64pilot

Odd, my flexmax 80 is I think very intuitive, almost as good as Garmin stuff for being able to figure out without a manual.
Now I don't have all the bells and whistles though.

It probably is easy to use. My system came with a MATE that I seem encouraged to program over the Flexmax.

People tell me I am lucky in that "everything is prewired". Having done basic inverter/charge controller systems, I see no real advantage to the FlexPower system unless one wants to show off a whole lot of randomly dancing LED lights.

Now with two sets of 4/0 cables squeezed into the inverter, the MATE seems completely confused. While I don't feel like it fighting the solar configuration anymore. Placing the new string of 170 pound batteries in a cooler room proved to be quite a challenge. The dividing wall is a multi-layered foot thick. Running wires and cables through it was .... quite interesting.

Meanwhile both of my auxiliary 24 volt system are having their problems too. Life's challenges come in waves it seems. Never ending waves....

[nwdiver]

Your 9kw northern lights will easily operate a 3-4cfm compressor, with soft start my 5kw northern lights works as long as no other loads are on the gen set.....

[Sawbonz]

Originally Posted by poiu

I agree a VFD may be the best solution for the O.P. It will allow the motor to start with almost no peak amp load. A soft start unit will reduce peak loads by a third or so, so might work fine too.



Just a correction, there is no such thing as an affordable 1ph in to 1ph out VFD. You have to change the motor for a 3 ph motor and buy a standard 1ph in and 3 ph out VFD. Total cost in parts $3-500.

That last paragraph is great to know. I know someone who has used the same generator and I believe somehow gets 230v out of it (converted from 115v?) and converts that to 3 phase. If that's all it takes I would buy the compressor that uses 230v and 3 phase off the bat. Of course, I don't really understand all of what this means, but I'm drawing a mental picture of a situation that works that I can check out with an electrician.

As to a soft start, I'm planning to put them on the air conditioners. Are they specific to a device, or sized in some way?

[Sawbonz]

Originally Posted by Tbonem17

If you have a look at this video I think you'll get a real world view on what's possible.
This is an SV Delos video they've just posted on their scuba gear including the a/c pump they use.


Tony

Excellent find, thank you Tbonem17.

[softdown]

Can you take your generator to a store that sells the scuba tank compressor? What is on paper doesn't always match the real world. Your challenge is the compressor start up surge. If that proves excessive, seems like a soft start capacitor has been mentioned a few times.

I'm no expert on this subject, though I do have some related experience....except for the soft start capacitor subject.

[softdown]

It could also be noted that at least one scuba tank compressor manufacturer sells their gas powered model for the same amount as their electric. Memory recalls a modest engine.....4 or 5 hp.

Wish I could remember their name. Someone here reported satisfaction with their product back in ~June.

[softdown]

6hp Subaru engine: Max-Air 35 Scuba Tank Compressors

Took an hour to find that? I am slipping...

[john61ct]

Subaru makes some very high quality, long-lasting small engines. Actually made by Fuji Heavy Industries.

[wedivebc]

My buddy has a scuba compressor that runs off a hydraulic motor. I was thinking I'd install it with an electric clutch and run the compressor when motoring.

[Sawbonz]

Originally Posted by softdown

It could also be noted that at least one scuba tank compressor manufacturer sells their gas powered model for the same amount as their electric. Memory recalls a modest engine.....4 or 5 hp.

Wish I could remember their name. Someone here reported satisfaction with their product back in ~June.

Bauer does this, though it does cost about $1000 more. The problem is that when you have that engine you can't get the yacht package which also drains the compressor as you fill the tanks. There is also one more engine to maintain with its filters, oils and such.

[softdown]

Originally Posted by Sawbonz

Bauer does this, though it does cost about $1000 more. The problem is that when you have that engine you can't get the yacht package which also drains the compressor as you fill the tanks. There is also one more engine to maintain with its filters, oils and such.

One way to look at it. Another is the reduced wear and tear on the main generator. I would get the gas engine over the electric motor. I don't plan on using marina slips at all. Like staying at a hotel while backpacking. Well....maybe once every few months.