2S, 3S, and NiMH…. Oh My!

Whatcha’ Doin’?

I have the eBay truck and I really want to know if I can get the brushed motor to hit almost 40mph. So, I desired to figure out a cheap way to get some GPS data and also to do something totally wicked! Okay, so I cannot bend cars or life cars up one handed, but if I could…. well, I would be a super hero. That is a very long and winding way to say that I wanted to get some baseline speeds on these trucks as I do some experimenting.

My motivation for this is a dad telling his kids that the hobby looks fun, but it is crazy expensive. I want to see how expensive and how fast. Please keep in mind that I live by the motto penny wise and pound foolish! I will spend 3 dollars to save a penny. I am not saying this is wise, but it is the consequence of being raised as a cheap skate.

Why Ya Doing this?

I mentioned in my previous post about how a dad claimed that RC cars are so expensive.   My goal is to see how close I can get to 40MPH without breaking the bank.  I have tried the 3S and the 2S LiPO batteries.  I personally think that my new, to me, red FURY has been burned up....I mean the speed contol smells like electrical fire so it does not surprise that the motor is probably cooked.

I am going to run it till it will not run anymore and that might be a fun video in itself.  However, when electric motors quit they most just skip a bit, and then stop moving.  It is not that dramatic to be honest.  It is not completely gone, but we might have to just keep running it and see if we can get it to smoke.  This is only done for the sake of science and not because I am a little child. 

How did you do it?

So, back on point. I wanted to get some consistent speed ratings. My son designed a GoPro mount that would fit on the back bumper of the trucks. This is why I could use the same camera in the same location in each truck. If aerodynamics are impacted, then it would be consistent for each truck.

I did not use the 360 Max, but plan to use it once I get a protective case for the camera. We used a Hero 7 that has been turned into GoPro through their exchange program.

I made an adapter that would connect an IE5 connector to a Deans or T Plug. I don’t think I lost enough power to really knock the results. This allowed me to use the same battery and to see how the trucks perform with the battery. I also did the test two different times and switched up 2S batteries in the trucks. The results were the same.

I took the trucks to a parking lot and I set up cones. I ran the trucks to where they topped out and did a few laps. In the video, I said that I would do 3 laps, but in reality, I did 6 laps for each truck.  I pulled the videos off the camera and used GoPro’s online service to put the speedo sticker on the video. It works pretty slick, but I have also been playing with Race Render app, which has been pretty slick. It feels a bit 80s to 90s, but once you get the customization figured out, you can add some pretty cool gauges.

The GoPro software if only available when you subscribe to their online service. If you want the gauge on the video, then you select the speedo. You can only add the stickers to the corners. Each time you touch the sticker results in the sticker moving to the next corner. So, first touch is the left corner, second touch moves that gauge to the right corner, and then bottom right…. etc. When you tap it more than four times then you clear the gauge off the screen. It works slick, and I am not sure that I would recommend the GoPro’s online service at this moment, but that could change. I think that review is for a later day.

This was nice because I could do the butt dyno and guess how the cars performed, and there was no way for me to see the results until I pulled the video. Once I pulled the video, I selected the fastest 4 laps and overlaid them in the video.

The gallery below shows what we did to capture the video. We are working on setting up a place to download STL files to offset the blog cost.

What are the Results?

The goal of this test is to set the baseline. I wanted to know how fast these trucks are right out of the box. My predictions are below:

• NiMH 18 MPH

• 2S LiPO 25MPH

• 3S LiPO 30MPH

The way that I got the results is I used a GoPro camera and attached it to the truck.  I know that this will cause the truck to lose a little speed, but the video looks SOOOOOooo cool.  I then took the video.... call me a hypocrite.... I used the GoPro sticker option.  I would save the video.  I ran about 4-6 laps each time.  I wanted to make sure I got the high speed runs.  I took the fastest time and put it in the video below.  You can watch the G meter and see that the top speeds are at different times, but the speeds are pretty consistent each time.  I did this once on a nice, clear day with no wind, and I did it again on a cloudy day.  The results were dead on the same.  

Here are the results:

This is the bone stock truck right as you would open the box. I did take some time to break in the motor with some revving up, then running at slower throttle, and then revving it again. I am not sure if that makes a difference, but this truck is quicker than I thought.

This is the 2S LiPO. I was surprised that the results were pretty much the same. The only thing that I would say is improved is the run time. Other than that the speed was dead on the same.

This was very disappointing. I am thinking that the motor is shot. It is possible that the Deans or the T Connector might not be as good as the Spectrum connector.

This was the most disappointing. I really thought we could get closer to 30mph or at least over 25mph with the 3S LiPO. There is something going on with the motor and I might want to check the card programming. I did check the throttle trim on my controller, and it was all set to 100%. I am still suspicious of the motor.

Conclusion

NiMH is nothing to scoff at.  I never took those batteries too seriously because as the battery drains, the car slows down. LiPO only added about a MPH or 2 at most.  It barely made a difference.  The big advantage is that the LiPO is pretty consistent right up until the ESC cut-off point.

When you put the GoPro on the back of it.... well, the rear gets heavy, and man does it understeer.  That was something I did not expect.  I think I might have to suck it up and buy a GPS module. I am curious to see how much the GoPro on the back impacted the top speed. I would also like to know how accurate the GPS is in the GoPro.

I had a lot of fun performing this informal test. These trucks melt the stress away. I just love hearing the tire noises, and I cannot wait to see what a new motor will do to the red truck. The problem is that I am falling out of the bargain class, but this is all for the sake of science, right?

I am going to say again... if you want a truck that is fun to bash or to race, then get one of these Furys or is it Furies…. not sure with the way that the kids spell these days.  The way that they corner and lift a wheel is just awesome to watch.  It is totally hilarious.  When you corner hard and then hit the brakes, you hear the tires squeal. I did not add the tire noise in the video. That sound is 100% from the truck. The last time I checked, A Main Hobbies had some great deals on the Fury! I get no clams for that link so that is just my kindness.

Thank you again for reading. Until we meet again, may the Lord’s blessing and peace be upon you.