Thinking about dyno's for brushed motors

[Frankentruck]

Experimenting a bit with the gearbox I have... since I don't have a 6 gear.

[Frankentruck]

I finally came up with a sacrificial dogbone to complete my drive line assembly. I also decided to swap in a spare Traxxas ESC for the testing duties. What I found out with my initial testing is:

1. This RPM meter is are constant drain on a connected battery when not in use. It's definitely a battery killer.

2. The push button programmed ESC loses its calibration between uses. I need to switch back to an older ESC.

3. The load motor resulted in a 30,700 rpm input motor speed. With the drive line removed, the unloaded input motor still spun up to 30,700 rpm. Looks like I need to come up with a more significant load for testing.

[juicedcoupe]

2. The push button programmed ESC loses its calibration between uses. I need to switch back to an older ESC.

Just noticed this. The Traxxas esc in my Stampede does the same thing.

The older yellow version in my son's truck doesn't though.

[R6cowboy]

My brother wants a good brushed candidate for his RC10T4 he snatched up a few months back, but it came with a silver can motor and junk cheapo ESC. So I picked him up a Novak Rooster and letting him harvest a motor out of the collection. This sparked my interest to get the ball rolling again on this deal.
Soldered some connectors up last night, mounted a Speed Gems Quartz 19x2 to the motor mount and let 'er rip, up until 5.9 volts when my homemade spur mounted pinion gear started to show it's imbalance. So I ordered the largest diameter pinion I could find that was available, an Arrowmax 64P 70 tooth. The 9V battery in the tachometer was dead and I'm fresh out, so I couldn't get a rpm reading. Also ordering a clamp meter to measure the amp draw.

[Frankentruck]

Holy cow that's a big pinion gear!

These tachometers do seem to have a lot of parasitic battery draining when not in use.

[juicedcoupe]

An alternative to homemade gears.

https://dynotech-racing.com/partDetail.php?RefNum=4006

[Dadio]

Holy cow that's a big pinion gear!

These tachometers do seem to have a lot of parasitic battery draining when not in use.

I thought it was just mine that wet flat unused in the box

[R6cowboy]

Holy cow that's a big pinion gear!

These tachometers do seem to have a lot of parasitic battery draining when not in use.

I thought it was just mine that wet flat unused in the box

Well not quite, I don't leave batteries in devices that sit unused for longer periods of time (habit). So the 9V was in the carrying case, but not in the tachometer. The date on it was Dec 2017, so it's a good 14 years old. Put it to the battery tester and it barely moved the needle, less than 1/4 up the red zone.

[Frankentruck]

I'm against buying 9v batteries only for this tachometer so I made a battery adapter using the terminals from a dead 9v battery. It's more cumbersome to use with an external battery, but otherwise felt like a good compromise to avoid recurring dead battery syndrome.
.

[R6cowboy]

Just finished a complete rebuild of my brother's Rc10T4 and rebuilt a few motors to test in it. The three motors were; Speedworks Tony Neisinger signature 14x4, Trinity Speed Gems Pro Amber 17x2, and Speed Gems Topaz 11x3. I got pulled away before testing the Speed Gems Amber, but tested the other two at 7.2V the Tony Neisinger pulled 29,300 rpm and the Topaz spun 40,900 rpm. The Topaz was junk before rebuilding it and just puffed smoke when applying power to it. After a thorough cleaning, I installed a brand new Trinity Topaz 11x3 armature, bearings, springs and brushes. We were a bit surprised at it's rpm, so I hooked up my other excellent condition Topaz to compare, and it spun 40,800 rpm.

The T4 fitted with a new Hobbywing 1080 esc, 2s 5000mah Lipo and 21/87 gears, we first installed the Tony Neisinger motor and took it out for a street run. We were a bit under impressed with the accel and top end wasn't bad but seemed so-so. We then swapped to the Topaz motor and were pleasantly surprised by the accel as it seemed brutally quicker than the Tony N. and top end was nothing less than exciting. When I get the chance I'll post some pics of results, but I'd like to get a clamp meter first to get Amp readings as well.
More to come.

[juicedcoupe]

but I'd like to get a clamp meter first to get Amp readings as well.

I just added some leads with banana plugs on mine. They plug directly into my multi-meter. My Fluke is ancient but will still handle up to 10 amps.

Comparatively, my DC clamp meter is kinda slow, especially when dealing with low currents.


If you do get a clamp meter, be sure that it reads DC amperage. Most don't. Most are AC/DC voltage and AC amperage.

[R6cowboy]

I just added some leads with banana plugs on mine. They plug directly into my multi-meter. My Fluke is ancient but will still handle up to 10 amps.

My Sperry DM-4100a can read up to 10A. Getting an extra set of alligator clip leads is a much cheaper solution than buying a separate ac/dc clamp meter. Thanks for pointing out what should've been the obvious thing to do

Yeah I recently noticed clamp meters which can read DC current are much more costly than ones that only read AC current.

[Snaab9-2]

Just finished a complete rebuild of my brother's Rc10T4 and rebuilt a few motors to test in it. The three motors were; Speedworks Tony Neisinger signature 14x4, Trinity Speed Gems Pro Amber 17x2, and Speed Gems Topaz 11x3. I got pulled away before testing the Speed Gems Amber, but tested the other two at 7.2V the Tony Neisinger pulled 29,300 rpm and the Topaz spun 40,900 rpm. The Topaz was junk before rebuilding it and just puffed smoke when applying power to it. After a thorough cleaning, I installed a brand new Trinity Topaz 11x3 armature, bearings, springs and brushes. We were a bit surprised at it's rpm, so I hooked up my other excellent condition Topaz to compare, and it spun 40,800 rpm.

The T4 fitted with a new Hobbywing 1080 esc, 2s 5000mah Lipo and 21/87 gears, we first installed the Tony Neisinger motor and took it out for a street run. We were a bit under impressed with the accel and top end wasn't bad but seemed so-so. We then swapped to the Topaz motor and were pleasantly surprised by the accel as it seemed brutally quicker than the Tony N. and top end was nothing less than exciting. When I get the chance I'll post some pics of results, but I'd like to get a clamp meter first to get Amp readings as well.
More to come.

Very cool, thanks for sharing! Would love to see more runs!

[R6cowboy]

Very cool, thanks for sharing! Would love to see more runs!

I'm gonna have to make an excel spreadsheet or something to keep track, I have 70 some motors I can run. Did get around to testing the Speed Gems Amber 17x2 earlier today, not at my workbench at the moment but it did around 28,500 rpm @ 7.2V if I remember right.

[Snaab9-2]

Very cool, thanks for sharing! Would love to see more runs!

I'm gonna have to make an excel spreadsheet or something to keep track, I have 70 some motors I can run. Did get around to testing the Speed Gems Amber 17x2 earlier today, not at my workbench at the moment but it did around 28,500 rpm @ 7.2V if I remember right.

Awesome, I love to geek out on stuff like that!!! Especially on motors I have owned before. It would be great if the group could make an all inclusive spreadsheet.