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Jshwaa
2015.03.09, 02:33 PM
I wanted to make my own chassis which can be configurable for 4-cell, 6-cell, or li-po, and hopefully have the same fitting as the stock chassis. I went to McMaster Carr and picked up a slab of 3"x12"x1/32" and 3"x12"x1/16" carbon fiber (http://www.mcmaster.com/#standard-carbon-fiber-sheets/=w8j0hu), a Dremel Workstation, and some carbide tips.

I put some masking tape on the carbon fiber to draw up some dimensions. I'm making a layout for cutting some trenches to place the cells, to lower the profile of the chassis/cell assembly.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2481.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2481.jpg.html)

Then I use a carbide cutting wheel to make some initial cuts where the cells will go, which are the black lines, the red lines are to mark where I want an angled cut to go, to make the cell trench.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2482.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2482.jpg.html)

It took me a while to get the right tooling method down, to remove material efficiently and try to stay in the lines, which included a lot of filing and 55 gallon drum of elbow grease.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2485.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2485.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2486.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2486.jpg.html)

Every so often, checking the fitting of the cells...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2487.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2487.jpg.html)

But I finally got the trenches deep enough to where the cells are flush with the bottom surface of the main chassis component. This was a far as I wanted to go.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2491.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2491.jpg.html)

So now I need to firm it up a little bit, fill in the gaps, and make the chassis form fitting for my cells, so I made a mold.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2493.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2493.jpg.html)

I placed a sheet of saran wrap on top of my other slab of carbon fiber, and then my main chassis component on top of the saran wrap, and clamped them together. Then wrapped 6 cells in a thin layer of saran wrap.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2494.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2494.jpg.html)

I then put some epoxy in the trenches and laid the cells in the trenches.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2501.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2501.jpg.html)

When the epoxy cures, I will then pull the cells out and file off the excess epoxy and hopefully have my main 6-cell form fitting chassis component.

This is as far as I've gotten so far. I'm waiting until tomorrow for the epoxy to fully cure and begin machining the front and rear linkages.

imxlr8ed
2015.03.09, 03:04 PM
I hope you're wearing a mask when you're cutting that stuff... you do not want to get that stuff in your system!

imxlr8ed
2015.03.09, 03:09 PM
I hope you're wearing a mask when you're cutting that stuff... you do not want to get that stuff in your system!

http://www.rcgroups.com/forums/showthread.php?t=311845

Jshwaa
2015.03.09, 03:37 PM
Aw, so it wasn't a good idea of me to do up a line of the stuff? Man.....cough!

byebye
2015.03.09, 09:07 PM
Pretty cool.

Jshwaa
2015.03.12, 12:31 AM
So the cell mold worked out pretty good. With minimal hold-down, the cells should be nice and snug...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2515.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2515.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2516.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2516.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2517.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2517.jpg.html)

Now to make up the 6-cell pack...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2521.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2521.jpg.html)

I roughed the surface of the cell contacts with a file then added solder flux. This makes it where you only have to apply the heat from the soldering iron for 5 seconds or less, so as to not allow the heat to penetrate into the cell and cause damage.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2528.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2528.jpg.html)

Now add some header to make the connections....

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2523.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2523.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2540.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2540.jpg.html)

I also dotted the joints between the cells with super glue to add strength to the pack.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2539.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2539.jpg.html)

Now to work on the rear chassis...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2541.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2541.jpg.html)

There's a couple of annoying plastic nubs on the back of the chassis that kept me from placing it on the carbon fiber for tracing, so I drilled holes for them to fit in which held the chassis in place for tracing, so it worked out...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2544.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2544.jpg.html)

reached my pic limit for this post...

Jshwaa
2015.03.12, 12:36 AM
After cutting out the back piece, I routed a notch in the main chassis component for it to fit and then epoxied in place.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2550.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2550.jpg.html)

Now I can check to see whether it's going to fit and that the body will grab it correctly.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2553.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2553.jpg.html)

TheSteve
2015.03.12, 01:20 PM
Pretty shocked to see you soldered the cells - you clearly have the skills so you should have assembled yourself a spot welder. Any soldering heat does a little damage to the cells, especially ones as delicate as the Eneloop XX/Pro series.

Jshwaa
2015.03.12, 02:56 PM
Pretty shocked to see you soldered the cells - you clearly have the skills so you should have assembled yourself a spot welder. Any soldering heat does a little damage to the cells, especially ones as delicate as the Eneloop XX/Pro series.

If you've seen a spot welder at work compared to what I did, you'd think otherwise, besides you're talking some cost with one of those.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2529.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2529.jpg.html)

Anyway, right after I built the pack, I cycled it, and from the data I couldn't tell that I degraded it any. The pack should actually get a little better with a few cycles, but we shall see. However, I did this years ago with the lithium-ion cylindrical cells, and those are even more sensitive to heat extremes, and I got my money's worth out of them for sure.

TheSteve
2015.03.12, 03:16 PM
It doesn't have to be that expensive or huge, nickle battery tabs aren't tough to spot weld. Here is something we threw together in the shop in an hour for fun. We even made a foot pedal out of a some acrylic and a big game switch.

Jshwaa
2015.03.12, 03:39 PM
It doesn't have to be that expensive or huge, nickle battery tabs aren't tough to spot weld. Here is something we threw together in the shop in an hour for fun. We even made a foot pedal out of a some acrylic and a big game switch.

Whoa, that's cool. That looks like a little project in itself.

With spot welding though, you effectively bring both metals you are connecting to their respective melting points and fusing them at their surfaces, making a 'third' metal in between that is an alloy of the two. Depending on the thermal mass of the two things you are joining, that could require quite a bit of heat to get a good bond. With soldering, you only heat up to the solder's melting point, which is a LOT less than nickel (nickel's melting point is 2651F, lead solder is 651F). Using flux, the soldering time is quickened dramatically, and you don't need to heat either items to the solder's melting point but for a few seconds and it's a good bond. It isn't like you would imagine, where the cell gets hot to the touch after soldering.

I like the spot welder though. How much power can it deliver?

DMALMAD
2015.03.12, 03:57 PM
How are you going to fit a t-plate holder in there.... doesn't look like you left yourself enough room for any rear suspension

Jshwaa
2015.03.12, 04:24 PM
How are you going to fit a t-plate holder in there.... doesn't look like you left yourself enough room for any rear suspension

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2564.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2564.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2561.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2561.jpg.html)

I measured how thick of a t-plate I normally run with and it's over half the thickness of the bottom plate, but as long as I got something, the carbon fiber is pretty tough, whatever else isn't anything a little dab of epoxy can't take care of, but I will route out a notch underneath for the t-plate, and hopefully have enough room on the top side of the main plate to embed some 2-56 nuts for the 2-56 screws to fasten the t-plate to from underneath.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2565.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2565.jpg.html)

The stock hardware are clunky button head self tapping screws, but I plan on using beveled machine screws for a near flush surface underneath. Mcmaster Carr is good for that.

TheSteve
2015.03.12, 04:25 PM
16 volt 68000uF caps x 7 in parallel, bunch of parallel SCR's to fire it. Usually use between 8 and 12 volts. The probes are super cheap soldering iron tips. When you weld the connection point does get hot(obviously) but there is no heat transferred to the rest of the cell.
If you actually want the absolute best/lowest resistance solder connection I recommend using solder paste(I prefer leaded).
No matter how good/quick you are at soldering, spot welding is always much kinder to the cell then any form of soldering. I have also soldered many cells without doing any damage but unless I need massive current(100 + amps) spot welding is the way to go.
Just another project for you to work on on one of those Friday nights...

Jshwaa
2015.03.13, 11:04 PM
How are you going to fit a t-plate holder in there.... doesn't look like you left yourself enough room for any rear suspension

Left a little, but now every fraction of a millimeter is starting to count...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2594.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2594.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2587.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2587.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2589.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2589.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2602.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2602.jpg.html)

Jshwaa
2015.03.22, 02:21 AM
http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2623.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2623.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2622.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2622.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2619.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2619.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2626.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2626.jpg.html)

mleemor60
2015.03.22, 07:29 AM
Looks like you are making some good progress.

Jshwaa
2015.03.22, 09:12 AM
Yes, the pieces fell together pretty nice. My heart dropped a little when it came to fitting the steering mechanism in. I super-glued the servo motor to the steering mechanism and it dropped right in where the servo motor is 'just' resting in the recess between the two middle AAA cells. I couldn't have planned that if I tried, and if it didn't fit it would have been a show stopper....

I'm waiting until I see if these li-po cells fit before I trim down the sides. I may need to create a 'hold down' for the pack which would require a couple holes drilled into the flanges hanging off the side. They fit in the body anyway, so no biggy leaving them I don't think...

Then a lil' wiring and we'll take 'er for a spin....

Jshwaa
2015.03.29, 02:54 PM
Gaaaaaaaahhhhhh!!!!

Made a costly mistake...:mad:

The exposed metal casing of the servo motor caused a short in the receiver circuitry, and my board is no longer responsive.... :mad: I never even got to open it up... :mad::mad:

Lesson learned. Ordered another set of elecs, and shrink-tubed the motor for insulation....

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2650.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2650.jpg.html)

Board is coming from Hong Kong with estimated delivery between 4/7 and 4/20...:(

Aw well, time to get back on the research project I guess...

byebye
2015.03.29, 03:03 PM
Well that sucks...

Jshwaa
2015.03.29, 03:30 PM
Ya, time and money...

Should have seen it coming, but I got happy and powered up foolishly. Did a couple test forwards and reverse and noticed it just stop, and a little tiny puff of smoke emerged, and the LED was off... The short took out the 3.3V regulator, which powers the main controller that lights up the LED... Swapped that from a set of elecs that mleemor gave me which restored the 3.3V and blinking LED, but then noticed that every time I power up the receiver IC gets hot and the LED just blinks regardless of my transmitter. So I'm sure I took out the receiver. :(

JesseT
2015.03.31, 01:28 AM
Have you checked what is regulated and what is not? There might be something that just goes pop every time with 9V input. I haven't heard anyone use so high voltage before for a Mini-z. 2S Lipos, 4xNiZn, and switch mode boost converters are known to be used, but they haven't produced that much voltage.
The Cypress tranceiver IC must be regulated at least because, if I remember, it was designed for 1.8V and 3.3V Vcc supplies only.

For anyone wantign to go FAST with a Mini-z, try a fast motor and 4x NiZn batteries. The car will be so fast you just can't stop laughing.

DMALMAD
2015.03.31, 10:38 AM
Yea with 2s batteries we have a hard enough time preventing the steering fets from blowing and keeping the board cool so when you go way beyond the inteded voltage it may just be that the board cannot handel the power

LED
2015.03.31, 11:19 AM
Well If you aver try this again, I suggest feeding 4 cells to the board and make a 6 cell connection right on the FET feading lines. After all, a FET is intented to switch on a higher power then the control power.

Sorry you fried your board :-(

Jshwaa
2015.04.01, 12:22 AM
Well If you aver try this again, I suggest feeding 4 cells to the board and make a 6 cell connection right on the FET feading lines. After all, a FET is intented to switch on a higher power then the control power.

Sorry you fried your board :-(

Thanks, man. I appreciate that.

It wouldn't have saved me anyhow. I hacked the isolation between the servo motor and the elecs, and Murphy's law was swift...

This is giving me some time to work on my motor collection. Mike (mleemor60) gave me a good price on these bad boys.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2655.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2655.jpg.html)

And then my own concoction of a motor that I can't wait to try....plasma dash arm in a proslot velociraptor setup with bearings and 1800 gauss neodymiums.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2656.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2656.jpg.html)

Should put some hurtin' on the FET's, however before I brain-farted my board, I had it set up for some pretty tough current flow, with a heat sink and current shunt.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2647.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2647.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2639.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2639.jpg.html)

It'll fly as soon as this barge gets here sometime mid April... :)

Have you checked what is regulated and what is not? There might be something that just goes pop every time with 9V input. I haven't heard anyone use so high voltage before for a Mini-z. 2S Lipos, 4xNiZn, and switch mode boost converters are known to be used, but they haven't produced that much voltage.
The Cypress tranceiver IC must be regulated at least because, if I remember, it was designed for 1.8V and 3.3V Vcc supplies only.

For anyone wantign to go FAST with a Mini-z, try a fast motor and 4x NiZn batteries. The car will be so fast you just can't stop laughing.

Well, the board was tested to the extent that I knew it could handle the voltage level. 6 cell comes off the charger at about 8.4V, and that wasn't an issue. My elecs were drawing a healthy 10A in spurts while just doing some very short run-times and verifying assembly of the motor and gearing, etc. It was when I put it on my dining room table and accidentally nudged the throttle and it lightly crashed into my laptop, the board jostled and touched the servo motor that was the killer. Any other part on that board could have been replaced, but the receiver module, and the main cpu...I'm not that lucky. Total brain-fart...

But yes, the receiver module runs on 3.3V, but if I dead short that through the receiver module...which is what I believe happened because it took out the 3.3V reg too and replaced to no avail... Now the receiver just draws current through the 'now permanent' internal short inside it, because that puppy gets hot when I power the board up... And regardless of my transmitter the LED just blinks away...

Jshwaa
2015.04.15, 02:08 AM
Got my board today!!! Yay!!!! :)

Decided to change up the FET configuration to a 2x2 stack of 8858's on top and a 1x2 of my DMC's with a heat sink on the bottom...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2659.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2659.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2660.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2660.jpg.html)

Just stayed up all night installing and testing, now I'm charging 'er up for a good run tomorrow.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2669.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2669.jpg.html)

Next is to fit these bad boys in place of the 6-cells, design a hold down, and trim the excess flange off of the sides of the chassis...

Tammer
2015.04.15, 09:17 AM
So wait now you are going with 2s lipos? I thought the whole point of this build was for 6 aaa NiMH batteries?

Jshwaa
2015.04.15, 09:31 AM
So wait now you are going with 2s lipos? I thought the whole point of this build was for 6 aaa NiMH batteries?

Actually, from the start it was about having the choice of 4 cell, 6 cell or lipo, but to design to fit the 6- cell means that all the other options will fit by default. However, eventually I plan to repeat this chassis build to be exclusive to lipo, and skip the laborious step of tooling out cell trenches. I'm going to have some fun with the 6-cell until I get a good feel for what it can do with a few motors and then wire in the lipos and compare. Not that it's even a contest. Just taking one step at a time.

DMALMAD
2015.04.15, 09:38 AM
Do you have dimensions and a site where those batteries can be bought from?

Jshwaa
2015.04.15, 10:11 AM
Do you have dimensions and a site where those batteries can be bought from?

at the bay

dial in the numbers you see in the pic, should come right up

doug01n
2015.04.16, 08:54 AM
Main difference will be in total weight and GC... In my opinion, you will have more control and traction with 6 cell NiMh. Please test! I'm following.

Jshwaa
2015.04.16, 09:19 AM
Main difference will be in total weight and GC... In my opinion, you will have more control and traction with 6 cell NiMh. Please test! I'm following.

Yes, you are correct. The added mass in the right place does help. When running at the tennis courts yesterday, I had some nice acceleration and top speed, but still squirrelly if I hammer on it too quick. If I can get it to a middle speed without losing it, I can hammer on it and it rips pretty good. Video to come...

DMALMAD
2015.04.16, 02:18 PM
Part of the reason why it may seem squirly is that you have to think about wheight transfer. When you add so much more mass to the rear end of the chassis you may gain some traction on power as that mass is pushing down on the tires but you will also lose that much more traction off power. When off power the more weight in the rear the more transfer there is to the front and the more there is a loss of traction at the rear. Thats why minimizing weight and keeping centralized and neutral (front back/side side) is generally the better way to go. Not only that but your wieght is all the way out to the side so therefore you have more roll. And the more roll you have the less overall grip you have. I can go into more detail but there is a video I know of that has some really good visualiations. If I can find it I will post it or if I cant find it you can pm me I can get a little more technical.

Jshwaa
2015.04.16, 02:47 PM
Part of the reason why it may seem squirly is that you have to think about wheight transfer. When you add so much more mass to the rear end of the chassis you may gain some traction on power as that mass is pushing down on the tires but you will also lose that much more traction off power. When off power the more weight in the rear the more transfer there is to the front and the more there is a loss of traction at the rear. Thats why minimizing weight and keeping centralized and neutral (front back/side side) is generally the better way to go. Not only that but your wieght is all the way out to the side so therefore you have more roll. And the more roll you have the less overall grip you have. I can go into more detail but there is a video I know of that has some really good visualiations. If I can find it I will post it or if I cant find it you can pm me I can get a little more technical.

The loss of rear end happens to the leanest of setups, with lack of throttle control and having so much overhead power for the surface you are running on and the tires giving you the traction to harness that power. You've seen the rear end on this beast, and I was running on a pretty decent tennis court with sandpaper like surface, and I can still lose the rear end easily but with some good throttle control it takes off and corners well. Right now I'm running the Atomic Chili with an 11T/53T which may just be too much but I wanted to try and burn in the elecs real good to see how well it holds up. I should try and pop the stock motor back in and see how it does....

I understand the dynamics involved, however the previous comment was about the notion of having a point of diminishing returns when it comes to adding weight in the form of increased power, at least that is what I am trying to experiment with by the 6-cell design. It's like the age old problem of adding fuel to a rocket, to lift the fuel for the rocket. There becomes a point where adding fuel can be a benefit, there's a peak, and then beyond that the added fuel becomes more of a load then added power. Mind you, I could have duck taped a couple extra cells anywhere I wanted to get that extra voltage, but I displaced that mass mid-central and as low as I could, thus having a 'potential' double advantage. Without breaking out 2nd order differential equations, which I can't stand, I think the feasibility is definitely there, but again it all comes down to control, and I gotta say it is kind of fun trying to run that line between complete control and complete loss of control, which is what the art of racing is about in my opinion...

Jshwaa
2015.04.16, 07:57 PM
Well, if it isn't one thing, it's another.... :mad:

Went to my local park, which has a crappy tennis court, in hopes of capturing some video. Probably shouldn't have...

Hit a few small rocks and/or a crack really hard and did a nice bunny hop but...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2671.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2671.jpg.html)

But I'm happy to report that the elecs hold up great. :D The car ran super hot for the duration of a full discharge, and by that time you could cook off of the motor and the cells were very hot, but no burnt FET's, so after a minor repair job I can tame down to a PN 70T and see how she does on the torque end of the spectrum.

Really didn't capture any video, other than the free wheel rev-up (http://vid83.photobucket.com/albums/j314/Jshwaa/Mini-Z/revup.mp4) before 'attempting' to. :rolleyes:

Turns out I'm a sucky camera man, and there really wasn't a shot that gave it much justice given all the debris on the court... :( Will try again when I regroup...

Jshwaa
2015.04.28, 01:15 PM
My college's Financial Aid department is soooo slow.

"Gee, Jshwaa, how slow are they?"

They are sooo slow, by the time I finally got a representative to answer the phone and not help me, I was able to install the li-po's in my mini-z.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2672.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2672.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2677.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2677.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2673.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2673.jpg.html)

Still need the hold-downs....

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/th_matts%20phone.mp4 (http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/matts%20phone.mp4)

Notice how I have to two step the throttle on the take-off in order to keep the rear end, and it does a burn-out mid-way when I am finally able to hammer on it.
http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/th_takeoff.mp4 (http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/takeoff.mp4)

Jshwaa
2015.04.29, 10:01 AM
What a dramatic difference in mass with the li-pos, and the power output is phenomenally greater. The 6-cell Ni-MH weighed over half what my entire car (without body) does with li-pos, but it was fun for a hot minute...

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2679.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2679.jpg.html)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2681.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2681.jpg.html)