A123 M1, 7XL, Quarky E-Maxx project

[zeropointbug]

Hi there, im just posting the starting point for my BL emaxx project

Specs so far:

Fiegao 540C-7XL
Quark Monster Pro (integrated massive heatsink behind motor for cooling)
5s2p A123 battery pack
uBEC
HiTec 120oz/in servo
RD Logic Spikes tires on RD Logic rims
FastLane Machine diff cups
MIP CVD's, center RC-Monster CVD's
RPM suspension arms, and axle carries

[MetalMan]

Your project will be interesting to me, considering I will also be using 5s2p A123 cells and a Feigao 540C 7XL in my Revo. But, I'll be using it with the Mamba Max.

[Sylvester]

Very nice start! Cant wait to see some pics when the final product comes to life! :)

[zeropointbug]

Oh ya, for sure we can compare results. I just love it when i hear people using the A123 cells, it's the direction we need to go in. They are just simply better batteries.

The chassis will be a Gorrilla Maxx style design somewhat. The upper chassis will be 6mm aluminum machined (you can see a rough sketch in the pic) that will screw to the bottom chassis plate (also machine lightened), in combination, i honestly think it will be THE most rigid/durable chassis to appear in the western world ;)

I plan to use 7075-T6 aluminum Alcad, the tensile strength of this grade is 85,000 psi, common 6061-T6 Alum is about 45,000 psi. Very high strength indeed, also very high fatigue resistance, which is needed too.

[starscream]

I used my A123 6S1P setup at the track yesterday. I would have used them racing but they dump right around 15 minutes so I didn't want to chance using them in the 15 minute Main. I am running 6S1P and they don't give me the punch my 5S1P Kokam 20C 3200mAh cells do. My next project is 8S1P A123's with a 12XL. I'm just waiting for word on the esc. 8S1P should give me the Punch and run time I am looking for.

[zeropointbug]

Oh yah, the A123's you NEED to double them up, you are working them too hard running single cell (it's only 2.3Ah), doing 2p you get 140 amp cont. plus more punch from higher voltage, and more than double runtime.

8s1p running a 12XL would be a monster for sure, but i think you are better off going 6s2p running a 8 or 9XL motor. Which I should have done... i should have got the 8XL running (i got 7XL) 6s2p pack. For more power and runtime.

[starscream]

Originally Posted by zeropointbug

Oh yah, the A123's you NEED to double them up, you are working them too hard running single cell (it's only 2.3Ah), doing 2p you get 140 amp cont. plus more punch from higher voltage, and more than double runtime.

8s1p running a 12XL would be a monster for sure, but i think you are better off going 6s2p running a 8 or 9XL motor. Which I should have done... i should have got the 8XL running (i got 7XL) 6s2p pack. For more power and runtime.

I guess you can call me an efficiency freak because I'd rather get my runtime from higher voltage than running packs in parrallel. I guess I feel that if I'm going to add extra weight by adding cells, I'd rather run them in series and get the benefits from the higher voltage than waste the opportunity by running them in parrallel. 8S will significantly reduce the current needed from the batteries and boost my run time as well. 8S1P should get me well beyond the 15 minute mark for the Mains. 8S1P is lighter than 5S2P and I'd be willing to bet the run time won't be much different. I can't say for certain until I get the opportunity to actually test it. I'm waiting for the esc and I'll post my results. :017:

[zeropointbug]

it will be more efficient slightly on the motor end of things, but the batteries will be drawing alot of amps from only single cell. Maybe 8s1p will do for the 12XL, if you are racing, then i guess its sensitive....

[starscream]

Originally Posted by zeropointbug

it will be more efficient slightly on the motor end of things, but the batteries will be drawing alot of amps from only single cell. Maybe 8s1p will do for the 12XL, if you are racing, then i guess its sensitive....

I must say that I am happy with the run time I am getting from the 6S1P. They seem to deliver more mAh's than what my Lipo's are rated for.

From what I've read, the M1's drop voltage when the current exceeds 50amps or so, thus the need for 2P. My 6S1P setup has just about enough power but the power just isn't quite there. I'm pretty sure that 7S1P (with appropriate gearing) will do the trick. I'll have to wait until the phantom cell becomes available so I can add an extra cell to my soderless power tube for 7S1P.
I am certain that 8S1P will reduce the current needs to a level where the M1's can provide adaquate power because if 4S2P can provide enough current, an 8S1P should cut the current draw in half thus eliminating the need for 2P.
If 8S works well with the 12XL I will most likely go 9S1P and a neu 1515 2Y.

[Procharged5.0]

Great project! Keep us posted on developements.

I'm considering 5s2p or 6s2p A123's as well.

[Serum]

You see zero, another person here who takes higher voltage over higher current, this is not for nothing.

Projects are always nice. But if it will be the strongest designin the west? you got the 32p gears that will fail on you sooner or later.

[Serum]

About the diffcups; did you bought them already? i would not put my money on a 6061 cups, i would get a 7075 instead. the contact area of the shaft that holds the bevel gears presses real hard into/onto the aluminum, since 7075 is a harder grade, they will wear less fast.

[zeropointbug]

Serum, i am prob the biggest high voltage freak around, i was just mentioning to him my experience when using 1p or 2p. I've built a Tesla Coil, i'm sure you have no idea what it is or how it works, mine discharges at 750,000 volts @ 350KHz.
You can let the arcs stream off your hands with no ill effect.

What does 32 pitch have to do with anything!? Gears wear out, thats a simple fact 'Serum'. And when i say the best in the west, do you really think someone means it? Are you just looking for stuff to bicker about?

[Serum]

No, you are absolutely right, i have got no idea what that is, now if you'll excuse me, i need to put someone on my ignore list..

You arrogant a-hole

[zeropointbug]

Oh !? I'm an A-hole now? You know what, all i can do is laugh at ppl like you.