Vatanen

I like the idea of geared rig very much, and i hope you can make such system and hopefully share how to make one. But my question was about minimum voltage that the md2 can handle. That one guy (Troy Carter) was able to get some results with 1s, but motor was cogging. So did he use one or two 1s lipos? or why is the motor cogging. i think he was also using external power source and to me its wery weird that motor is cogging.
Imo if you balance charge to 4volts its as consistent as any other volt.

howardcano

iTrader: (37)

That will require a flywheel with twice the moment of inertia. But since you are a talented guy, I'm sure it won't be a problem!

I would welcome your input over here:
http://www.rctech.net/forum/radio-el...no-thread.html

Troy Carter

iTrader: (22)

I ran two 1s packs, both charged to 4.20 volts and used the external power supply for the dyno which is required because 4.2v is not enough to run the dyno electronics.

The motor cogged with an LRP SXX that I've been using when running 2s packs which ruins the dyno data because the RPM's jump around too much. I did also try a HW v3.1 1s esc with the built in booster and the data looked much better but not as consistent at when using 2s packs. I'm not sure if it's an ESC issue or an available power issue. Looking at the data it the initial hit drops the voltage to 3.0-3.3v when using good 1s packs which which can't be good for consistent dyno runs.

Because 1s packs were inconsistent I have not been able to compare to see if changes made to a motor effect the 1s dyno results the same as 2s results.

Vatanen

Ok, maybe 5,2v could work as it seems that drop is about 1v.... I have another idea to trick the system, can anybody imagine what would happend if half of the flywheels holes were covered?

Left Front Tire

iTrader: (37)

I'd like to power my dyno as well as my motor analyzer with something other than a 2s lipo just so I can have a consistent power source for comparative testing. Is there any reason I would not be able to use my power supply for such a purpose?

robk

iTrader: (22)

You need a power supply that is close to 8v. There are 7.5v supplies out there.

nexxus

iTrader: (315)

On a Dyno run you can get an initial current draw of over 30-40 Amps (and thats only on a 21.5 from my testing), so your power supply would need to be capable of delivering 2s voltage at 30-40 amps (higher amperage capability needed for lower turn motors, I'd allow for at least 60A). Which is why batteries are favoured for Dyno runs.

howardcano

iTrader: (37)

Stall current for a 17.5 at 8.4V is about 200 amperes. Yes, it's only momentary, but make sure your power supply will handle it.

dave-man

iTrader: (21)

Here is what I use - http://www.nextwarehouse.com/item/?1716642

It's adjustable from 6.8v to 9v. 600w. 0-80 Amps.

YoDog

iTrader: (28)

Oh yeah, the flywheel definitely will be bigger. I purchased a steel timing belt pulley that I will turn to the appropriate diameter and fine tune the overall mass to meet the max allowable by the Dyno.

YoDog

iTrader: (28)

I'm curious as to why some folks are hell bent to use a power supply for dyno testing when we all use LiPo batteries for racing anyways and these batteries are portable, powerful and reliable. They provide the exact power source for which we are testing motors for in the first place. They are capable of delivering hundreds of amps and absorb fluctuating voltage transients. So why seek an alternate source that may or may not be representative of actual usage in the field?

Just sayin...

nexxus

iTrader: (315)

..if this were facebook I'd hit like on this post!

howardcano

iTrader: (37)

It might be because these folks are curious about the behavior of just the motor, and wish to separate it from as many other effects as possible to get a better understanding of what's going on. Also, comparing results with a power supply to results with a battery will show just how much loss of performance is caused by the battery.

Troy Carter

iTrader: (22)

Agreed. In my case I have not worried about it too much.

However, every time that I dyno a new motor I first re-dyno a known motor as a baseline to compare against. I also compare the new baseline of the known motor to the previous runs on that motor. This is all in an effort to minimize variances that can occur from anywhere, including the lipo's. So, if I were to run this off a consistent power supply this extra step may not be required.

matt prigmore

Hi,

What software file are you guys using from the eagle racing webpage.

There's 3 to choose from.

USB_cdc_device_driver.zip
Eagle_md2.zip
Eagle_md2_v1.1.zip

Regards

Matt