Really Matt - 120F?
You know I think torque limiting should be electrical (and can be with sensors) to save weight and Q factor but if you telling me that your motor (3220 4T I presume) maxxed out at 120F (you did wait 25/50 seconds before taking can reading right) then Delrin becomes a viable sensor ring material which would work wonderfully and could reduce production costs of Hall Timing Systems for Astro and other Inrunners as needed down into the sub 5.00 (minus labor) point - According to the manufacturer rep, delrin will support 160F and I can do just as I do now and embed for an addtional 2.00 cost, the NTC heat sensor calibrated to trigger an isolated interrupt if the temp exceeds a preset value (resistor sets the value).
What is your current gearing on this DaVinci drive, I know your looking at 4:1 stage #1 (currently) and I presume 100t 5mm is within the realm of possible for some of your builds, with the new belt tensioning system - you could perhaps even reduce the primary drive sprocket from 20T down to 17t or even smaller due to additional belt wrap and proper tension. That could in theory put you at 5:1 or even as high as 5.8824:1 for your first stage.
I know you gear out for 40ish mph most of the time (especially on the 3220s) so I would assume the 12S gearing is likely about (presuming 26" rear wheel) 13.5 or 14:1... assuming the highest stage #1 reduction is 4:1 that would mean a final drive ratio of 3.5 : 1.
If you were to jump up to 16S and sensors (done properly) - the temp should stay lower (by producing more torque sooner and for a longer pull to provide faster time to efficient zone, also by running in the optimal power / efficiency range of the motor) so the new reduction you would want (presuming you had 14:1 before for 40mph) 19.3545 : 1 total which means without changing the pulleys you would need to acheive 4.8386 : 1 in stage #2 - could use #25 chain to do this, 80t rear sprocket with 18t drive #25 sprocket - or you could have a custom rear 130mm BCD chainring made, using 13t odessy freewheels you would need a 63t rear chainring to get close but wouldn't that put you into a much more powerful and efficient motor speed?
Sorry to go OT - had some successful results with the aluminum sensor rings lately and considering producing them on a more mass scale - don't worry Matt a free 9FET infineon controller modded for 60v nominal operation to be run with 16S packs (it will work from 12S to 20S) at 100A or 6KW continuous, phase current is set to 2x or 200A but reducing this if there is belt slippage will reduce startup torque - block time would be one other item to play with - we can discuss this at more length once you receive your rings and your controller... I will include two wired and ready to go rings in aluminum and 1/2" thick, you already know where they go and between the hint you mentioned Bob gave you about a year ago with regards to ABC locations, it seems wiring them 90% of the time will be step by step easy (call it 10 minutes + perhaps drying time, depending on how you mount).... I will add two small dimple screws (pointed set screws) you can use to gently lock the timing rings in place - normal 5 conductor wire can be used as extension if needed but I will also include 2 10cm 5S JST-HXT Male/Female Extension Cables so you can wire up plug and play.... Even if one of your motors turns out to be difficult to calibrate, it's about 15 minutes total with the watt meter in place and the bike suspended or rear/drive tire lifted to get lowest no load currents.
Back OT: Three Questions:
1.) So when are you going to be ready to ship these / my NuVinci drive??
2.) When do you expect to be able to offer 1 - 1.5" mounts again??
3.) How many AH/WH did you pull durring your testing, what are your stats (what happened to the days we posted our Eagle Tree or HV ICE logs?)
Matt - PM or call me about the drive pulleys we spoke of, there may be an issue (or may not be) depends how fast you need em?
I know to many 585 or more is alot for a "drive mount" as they see it, but let me aliken it to my Generator (somthing I just discovered in the Hurricane recently past) - the unit is 199.99 new (great deal right), for 1000w (really 800w constant, just enough for the fridge) and I only paid 50.00 for it but the freaking 2 stroke **(yep I made a foobar and bought 2 stroke gene, it's going don't worry) is rated as 2HP... so it take 2HP of ICE (internal combustion engine) to provide just a touch above 1HP of continuous power, 1.25 hp max for a few seconds? Thats worse than 50% efficiency.
Add to that a full Astro 3215 or 20 will set you back 560.00 or 695.00 and even if you add hall sensors plus the few additional bits of chain and sprocket (sans power / battery) your looking at worst about 1500.00 with an HV160 setup about 1800.00 still without power so is it for everyone, no... but run properly it's 90-93% efficient. A good 3KW gas generator is about 85% efficient, a decent hub motor (run at the proper design voltage / current for the wind and copper weight) is at best 80%... in price comparison, a good 3kw generator will run you several thousand dollars (1-3K) and a hub motor kit of a higher end (figure capable of 3KW) would run you in the neighborhood of 450.00 without power for a 26" rear but you would also need to fully rewire the system, replace the controller with a 200-250.00 aftermarket setup, shorten the leads, replace the phase and power wires and that all adds up to about 800 - 1000.00 if done right, including the torque plates you would have made to street that power without breaking your frame - oh yea, at an additional weight offset of approx 16 lbs, again without power.
Now does the 1500-1800 for the mechanicals seem so expensive now? Not really, especially if it's setup properly - done right the Astro Solution (even a lowly 428.00 3210) will provide a more efficient, more able ride with ample power in reserves and the ability to climb hills like a billy goat (if geared low enough or shiftable)?
IMHO (as Matt can tell you) for the time he puts into it, the wonderful machine work and polished or annodized finish, the constant re-evaluation of the status quoue to improve it either in thermal, power output, ergonomics, strength, or any other enhancements... That's why I ordered one and once the 1.5" mounts are available again (because they are cleaner than anything I could make for tube mounts) I will be ordering at least 2-3 more for customer builds
Oh yea - for the record, though I speak with Matt often... I don't work with him, for him, receive a discount for anthing I say or don't say - heck I have to pay for my review units with him (limited production runs, it's fully understandable) and not at dealer cost but at retail... so there is no incentive but love (in that respect the man kinda way) for my words.