Making my Rix SA6 better

[tbone1004]

3.5hp~3000w with random efficiency losses. The general rule that I use at work for our generators is 1.5kw/hp which is basically a 2x buffer. Your 8500w generator would start it up fine. If you had a soft starter or VFD on there, then it would definitely be a nonissue.
20a outlet is ~4500w and that's a continuous rating, so it can take quite a bit more for an intermittent startup.
Now, that rule of thumb is on 3p motors which are MUCH more efficient than single phase motor. 1p is usually around 65% where 3p can be around 90% which is not insignificant when running off of a generator or running for a long time in power costs. With that efficiency loss factored in, if running 1p motors I would probably go 2kw/hp but that still gives you enough juice.
Weight and noise don't help though and can't really change that for the size of those generators.

Remember on the lead batteries that they can be charged quite quickly, and also check your generator, most of them have a 12v outlet for battery charging which will be infinitely more efficient and significantly faster than running a normal charger off of the AC side. Can see it on this one just below the AC outlets. Output is 8a so would take 24hours to fully charge a 100ah battery, but would be able to give it a big bulk charge while you're running everything else.

 

[BRT]

I only have to 1000w generator its light and fairly quiet so we can think and plot survey data and stuff like that. I fill suit gas and the booster drive gas off the compressor. And some limited amounts of OC gas for buddies.

My big 8500w generator stays at home and powers a chunk of my house in winter storms. Its too big and loud to take camping. I am not sure it would start my 3.5hp 1p motor off the 20amp 220V plug anyway? It might, never tried that. Takes me about 75mins to change the electric to gas, the mounting holes are the same and I have a dedicated belt/pully for each.

I have tried a group 24 deep cycle battery in the past, but it died recently powering my spot welder and I'm not sure I want to replace it. It would help lengthen my overnight charging times and I do have some reserve on the 1000W gen to add a 100w lead acid charger. Or run my truck and recharge with some jumpers (I have a 160amp alternator). But its one more thing (and heavy)

Your truck alternator will not put out anything like 160 amps while charging a battery unless the battery is really dead, and then only for a short time. Remember that a 200 amp/hour battery (big one) contains theoretically 2.4 hours at 1000 watts, an 83 amp load, but in reality will not hold 12 volts for long while discharging at that rate. A 100 watt charger can put out less than 8 amps.

 

[BRT]

3.5hp~3000w with random efficiency losses. The general rule that I use at work for our generators is 1.5kw/hp which is basically a 2x buffer. Your 8500w generator would start it up fine. If you had a soft starter or VFD on there, then it would definitely be a nonissue.
20a outlet is ~4500w and that's a continuous rating, so it can take quite a bit more for an intermittent startup.
Now, that rule of thumb is on 3p motors which are MUCH more efficient than single phase motor. 1p is usually around 65% where 3p can be around 90% which is not insignificant when running off of a generator or running for a long time in power costs. With that efficiency loss factored in, if running 1p motors I would probably go 2kw/hp but that still gives you enough juice.
Weight and noise don't help though and can't really change that for the size of those generators.

Remember on the lead batteries that they can be charged quite quickly, and also check your generator, most of them have a 12v outlet for battery charging which will be infinitely more efficient and significantly faster than running a normal charger off of the AC side. Can see it on this one just below the AC outlets. Output is 8a so would take 24hours to fully charge a 100ah battery, but would be able to give it a big bulk charge while you're running everything else.

View attachment 515967

Tbone, do you have any data that shows single phase motors to be less efficient in energy use than 3 phase?

 

[tbone1004]

Tbone, do you have any data that shows single phase motors to be less efficient in energy use than 3 phase?

can go check any of the manufacturers websites, but it is well documented.

This explains the why, and the specifics are going to be determined by the individual motor.
Single-Phase vs Three-Phase Power Explained | Tripp Lite Blog

 

[BRT]

can go check any of the manufacturers websites, but it is well documented.

This explains the why, and the specifics are going to be determined by the individual motor.
Single-Phase vs Three-Phase Power Explained | Tripp Lite Blog

I found Baldors website and checked two similar motors one single and one three phase. Single phase was 68% efficient at 100% load and three phase was 86% efficient at 100% load. I had always wondered about that but never tracked it down. Those efficiency ratings would mean the single phase motor would draw almost 1100 watts to produce a horsepower and the three phase motor would only draw about 870 to produce a horsepower. 26% difference. I knew I hated single phase motors.

 

[tbone1004]

I found Baldors website and checked two similar motors one single and one three phase. Single phase was 68% efficient at 100% load and three phase was 86% efficient at 100% load. I had always wondered about that but never tracked it down. Those efficiency ratings would mean the three phase motor would draw almost 1100 watts to produce a horsepower and the three phase motor would only draw about 870 to produce a horsepower. 26% difference. I knew I hated single phase motors.

ding ding. If you have something that runs near continuously, and especially if you need to put a soft starter on there, the extra money for a VFD to use a 3p motor may well pay for itself in electrical costs. Obviously single phase motors on go so large, and there is some losses associated with the VFD itself, but when you combine the efficiency bump and the other benefits of a VFD, it's definitely the "right" solution.

 

[rjack321]

Your truck alternator will not put out anything like 160 amps while charging a battery unless the battery is really dead, and then only for a short time. Remember that a 200 amp/hour battery (big one) contains theoretically 2.4 hours at 1000 watts, an 83 amp load, but in reality will not hold 12 volts for long while discharging at that rate. A 100 watt charger can put out less than 8 amps.

Yes I know, one reason why 12 gauge jumper cables aren't a crazy way to try and top up a spare battery

 

[rjack321]

Remember on the lead batteries that they can be charged quite quickly, and also check your generator, most of them have a 12v outlet for battery charging which will be infinitely more efficient and significantly faster than running a normal charger off of the AC side. Can see it on this one just below the AC outlets. Output is 8a so would take 24hours to fully charge a 100ah battery, but would be able to give it a big bulk charge while you're running everything else.

I have not used the 8A DC output as my (now dead) storage battery exceeded the specified size in the manual. I think the manual said max 40ah size. I'd rather not burn up my $700 generator over a stupid deep cycle battery. Running 24hrs continuously is definitely not gonna happen.

 

[tbone1004]

@rjack321 wasn't suggesting running the generator for 24 hours, just commenting that that is how long it would take to charge the big batteries from d-e-d dead. You can get a bunch of juice out of it and won't damage the generator though, the 40ah is just that it can't continuously maintain a battery bigger than that

 

[tbone1004]

@iain/hsm must be on holiday somewhere, so in the interest of keeping this alive and some other discussions with @rx7diver on the vintage double hose forum, I bring some other thoughts to this side of the world.

So we have the compressor stuff sorted out above. In the interest of portability, I will leave the standard coalescers on the frame and leave it as it shipped from the factory on that side of things, but instead of having a fill whip, there will be a ball valve and a QF4 body a la Bauer/fill stations. Why?
Purely portability and convenience. I have long fill whips that I use when teaching so I can fill from my car and they have QF4's on them so I can plug directly into the compressors. When travelling, I have the whips from my pelican case and don't see the need to carry more with me.
I have 3 fill ends that plug into the whips. Two of them are below, the third is a single DIN with digital pressure gauge and a check valve to use as a pressure checker. This allows me to fill 1/2/3/4 bottles simultaneously off of a single fill whip. SUPER convenient if you are filling a large quantity of bottles or if PP blending, want to make sure that you are getting identical mixes *think sidemount and bottom stage bottles*, or sidemount bottles for 2 identical dives or your buddy team. These whips also double duty as transfill whips since the check valves prevent flow out of the QF4 stems. These were not cheap to build, but if you are building a transfill whip, pressure checker, and have a fill station at home, they are nice to have. Thankfully I can get great pricing on the hoses themselves through work, but you could certainly save money by putting one of the fill ends directly onto the cross. The one annoying part is that if you are filling four tanks to different pressures, the ball valve that isolates the two means that you need to have the lower pressure bottles on the far side with the gauge if you are going to isolate, then you lose the digital gauge while filling. Most fill stations have a gauge on the whip, but if filling from the long whips it's a bit of a walk. The way we solve that is by turning the tank valves off, and if we want to check the pressure on those two bottles, we shut the ball valve, open the tank valves and read the pressure on the gauge. If they need some more juice, then we can open the valve and fill until we get to pressure then shut off again. Bit more work, but it's fine.

So, these whip ends, and the whips will be used to come out of my cascade regulator. Going into the cascade will likely be one of the 10ft whips since I have them, but depending on where the compressor is going to end up living, it may end up being a dedicated hose. If travelling, the 6ft and 10ft whips are in the booster case and can pump directly from that.