I selected the LC-110 (from AOA) for 115V, lighter weight and lower cost in a well supported "real scuba type" compressor that is easy to work on and has good availability of parts and service in the US. I decided to replace the genuine Coltri filter tower that Daystate left out and add a PMV to maintain dry air in the output, rather than using a third party filter housing. I also added an hour meter, so I'm creeping back toward the T2 feature set. But I don't want the weight and 220V requirements, so a T2 was not the solution for me. The T2 has the filter tower and the hour meter, but the rest of the improvements I did are not on the T2 as it comes.
I want to stress that there's nothing wrong with a third party filter solution, I just decided to make it close to stock which has some minor advantages. The Coltri filter tower drops right into the existing mounting ring and bolts to the existing slot in the base plate and has its own matching bleed valve just like the existing separator. The formed metal tube in between is factory Coltri and fits perfectly. The air exits the tower on the side without interfering with the removable top that allows access to the filter cartridge, and there's a spring that pushes the cartridge up and out of the tower for easy access. I use the 13x molecular sieve cartridge for drying the air, they have twice the moisture capacity of the scuba type cartridges. The Coltri tower parts, bleed valve, adapters and tubing were about $250 and the cartridges are about $30. I'm working on an easy way to repack the filter cartridges which is about seven times cheaper with sieve material purchased by the pound.
The PMV is the common 211 model at the tower outlet. This feeds the existing fill whip. With the necessary adapters it was about $100. The pressure maintaining valve makes the moisture separator much more effective and extends the life of the filter considerably whenever filling from below 2000 psi.
The hour meter I started with is an internal battery self contained vibration sensing unit from Amazon, under $20. I also have an AC powered unit which requires a housing, so I 3D printed a housing but I have not installed that one yet. I may change to it because it can be read even if the compressor is off, but it does require wiring into the motor power. The vibration sensing type requires pushing a button to read if the compressor is not running.
I also changed from the DIN300 at the end of the whip to a Foster female and added a bleed valve. This is useful for filling small tanks and airguns as well as my SCBA tank. The bleed valve is required because the PMV blocks the standard bleed valves from draining the whip, and the small tanks and airguns don't have a bleed on them. This upgrade was about $75.
I designed and 3d printed a wrench for the filter tower which makes checking the filter indicator and replacing the filter cartridge quick and easy.
I did my first tank topoff yesterday with filtered dry air and it worked well. Now I'm ready to start looking for a big bore.
A big thanks to Coltri dealer Ray Contreras for helping with the details and from whom I purchased most of the parts for this project.