GX CS4 mod

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More To Come.

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Worked fine on my Benjamin, but the Benji needs some attention. This also assumes you have uses for the batteries to run other tools, which I do.

Yes, this time I'm trying a 24 volt to 13.8 volt DC to DC converter at 40 amp rating. Not exactly the same as GX does this in their battery powered devices, but doesn't require a rewire to get done.

No power where I need to shoot, and not going to idle my car that much while I pump. And yes I know, most of you guys get 30-40 shots per fill and think this is silly or down right stupid, I get three on my 50, and 12 on my 357.
 
Worked fine on my Benjamin, but the Benji needs some attention. This also assumes you have uses for the batteries to run other tools, which I do.

Yes, this time I'm trying a 24 volt to 13.8 volt DC to DC converter at 40 amp rating. Not exactly the same as GX does this in their battery powered devices, but doesn't require a rewire to get done.

No power where I need to shoot, and not going to idle my car that much while I pump. And yes I know, most of you guys get 30-40 shots per fill and think this is silly or down right stupid, I get three on my 50, and 12 on my 357.

If you already have the batteries on hand - go for it! I keep at least 4 Ryobi batteries on the shelf and charged at all times for my tools. Are those 900 mha batteries? In case you aren't aware of it, there are Ryobi 900 Ah clones on Amazon for $50+ each. I own several 4 Ah clones and they have been working just as well as the Ryobi branded for less than half the price. Two of them are over 2 years old and still going strong. Unlike the Ryobi branded ones, they don't slowly taper off in power when getting low which could be an issue with the compressor. They just shut off instantly when the voltage drops below the set level in the controller chip. You wouldn't want the power being shut off like that when running them as you would lose all the cooling fans.

If I didn't already have a bunch of tool batteries, I probably would be buying some just for this purpose. I would likely go with a lithium battery pack with a 12v output connector on it as long as they can provide a sustained load. This unit has alligator clamps and a 12 v power plug adapter and claims 6000 Ah for $95 with a $40 off coupon. Much easier to interface with the GX and a lot less $$ plus you can use it to start your car with a dead battery or power electronic devices. Might be worth looking into as an added power source to go along with your Ryobi battery setup, if it can run for long enough without issues.
 
Nice. The one thing I would do is get rid of those battery clamp clips and replace them with lugs like from your 12V converter. I know all these compressors come with clips but the original design intent of those clips are for jumping cars to start. Ya know, typical 5 seconds of use. They don’t pass nearly the desired amperage for longer use like on your compressor.
 
Yeah, it really came down to me already having batteries, including a pair of the 9ah which definitely run things like a string trimmer better and longer. I now have 8 of these 9ah packs and keeping an eye out for sales on the 12ah.

So far with the Benji compressor, I'd get four fills into 500cc from 2000 to 4500 psi per pair of packs. A little better than what the CS battery powered compressors are getting. So far the DC-DC converters are dealing with voltage drop, but I'm really only seeing about a volt drop during the entire process. Starts at 19 under load and ends around 18 under load. The 24 to 12 converter is rated down to 18 volts, this 13.8 converter is only rated to 19 volts, so it might be a fail. I'll have to do some testing to see before I cut the case and mount everything inside.
 
Nice. The one thing I would do is get rid of those battery clamp clips and replace them with lugs like from your 12V converter. I know all these compressors come with clips but the original design intent of those clips are for jumping cars to start. Ya know, typical 5 seconds of use. They don’t pass nearly the desired amperage for longer use like on your compressor.
Yes, those are extremely temporary. It will get wired directly to an XT60 connector to plug directly in. The clamps were just an easy way to test it. Used two pure lead cast 50 cal bullets for the terminals. I was very surprised when the compressor arrived and the clamps weren't connected through an XT60, the new internal version has the XT60 for your car powered needs.
 
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Unexpected outcome... The compressor draws more current than it rates, or the DC to DC converters do not go up to their maximums.

Compressor says 350 watts, that should be 30 amps. Both the 12 volt and 13.8 volt converters drop to extremely low voltage when I try to start the compressor. I think their rating may be wrong. The power supply is rated at 13v@50 amps. Looks like Ill need to get a more stout DC to DC converter.

I do have two 24 to 12 converters, I'll have to make up a Y cable to connect their outputs and see if 80amp max. will do the job. Then I can buy a larger capacity converter. Since I have no power where I shoot, and all but one gun requires 4500 psi, bottles are just not very useful to me. I'll need to figure this out.

I'll also need to rebuild my Benji since that one works and might be a quicker solution.
 
Unexpected outcome... The compressor draws more current than it rates, or the DC to DC converters do not go up to their maximums.

Compressor says 350 watts, that should be 30 amps. Both the 12 volt and 13.8 volt converters drop to extremely low voltage when I try to start the compressor. I think their rating may be wrong. The power supply is rated at 13v@50 amps. Looks like Ill need to get a more stout DC to DC converter.

I do have two 24 to 12 converters, I'll have to make up a Y cable to connect their outputs and see if 80amp max. will do the job. Then I can buy a larger capacity converter. Since I have no power where I shoot, and all but one gun requires 4500 psi, bottles are just not very useful to me. I'll need to figure this out.

I'll also need to rebuild my Benji since that one works and might be a quicker solution.
I’ll admit, battery technology and all isn’t my strong point, but is it possible your battery does not have the amp hour needed ?
 
Each battery will easily handle 350 watts each, your circular saw will draw that in pressure treated lumber. And I have two batteries in parallel, they should only have about a 2C draw each (18 Amps each) which is way under normal tool usage. On the battery side, the charge meter doesn't even flicker under load. My string trimmer drops the charge by 1 LED when I turn it on, so I'm way under what the trimmer is pulling per battery pack.

I think the compressor really runs at far more watts than the instruction states, but I don't have any meters that can measure that high. I should have been less trusting of the instructions and done my own testing before buying the converters. I bet this is really drawing about 500 watts (38 amps) which is a huge amount for an idling car to handle. The AC supply is rated at 650 watts.
 
No surprise here, they sort of lied about the wattage! I tracked 689 watts or 52 amps to start the compressor the first time (voltage sagged to 10.2 volts). I stopped and started several more times and did not see that kind of power draw again. And yes this was with the bleed valve open.

But I did see almost 600 watts up around the 4200 to 4500 psi area. The AC supply is rated for 650 watts. The sort of lie is that they probably averaged the draw over the entire filling cycle, and that might be 350 watts. One of those watt hours consumed divided by the time to run the test things and never looking at peak draw.

The test connections were super sketchy, so I won't show them. Maybe I'll make a video if I can clean up the connections.
 
Since I have two of the 24-12 converters, I connected both in parallel and ran another test. This time the compressor didn't take massive amps to start, but still pulled almost 50. With a quick run from 3500 to 4500 psi into a 500cc bottle, I had max of 50 amps and 600watts, minimum voltage was 11.98, max 12.21 so those converters worked pretty well.

Now the decision, do I just run both converters or do I buy a larger 80 amp to have enough overhead. Have to think about that.

That power meter that member bd2021 sent me has been very helpful. Looks like this but is a Tenergy branded version https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole
 
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