Attack of the Clones...

[suicideneil]

Bummer.

Not suprized about the KD motors, they do only seem to last about half a dozen runs before the temps go a bit ka-ka. So, back to waiting for the 70mm medusas again....

hey neil sorry for bringing up this thread but i wanted to know what gearing would you reccomend for this motor? i just ordered the 1845 version and will be using 14 cells for now. waht gearing should i use? i have a 68 tooth spur gear. waht pinion would you reccomend? im a basher and own a 3905 (stock tires pretty much stock besides bulks and rpm stuff) and i am looking for a balance and speed and power with cool temps. i also have the MMM. thanks again if you can help.
also would you reccoemnd changing the stock connectors to the high amp 6.5 castle ones?

[suicideneil]

I'd definately say change the connectors- 5.5mm ones are more than fine, and easier to solder/ find heatshrink tubing for too.

I have the 1845kv motor (9XL), and currently run 24/70 on 5s lipo, so I think for your 3905 truck and 14 cells, something like 24/68 comes out at 35mph, which I believe is about the best you could hope for really using nimhs and a large BL motor. Depends though, the lighter the truck, the higher you can gear slightly, so 65/24 is possible, just watch the battery temps closely more than the esc and motor. Good luck.

thanks a lot neil. ill be ordering my pinion soon...i have to get more solder those connnectors reallt do use up a lot.

[suicideneil]

Final update on testing:

Killed it

Its weird, 3 trips back the motor was fine, just needed a cooling down break after 10 minutes or so to keep things under 180*F.

2 trips back I decided to gear up seeing as the batts and MMM were fairly cool, so maybe I was too conservative on the gearing and actually under geared it. Answer was no, I was just pushing to hard and got the motor upto 180-190*F in 5 minutes, so lots of coolling down breaks that session (until I killed the tranny again).

Final trip out on Saturday and I was hopeful- geared it down a fair bit and ambient temps were stupidly cold, so... Anyways, started out fine and after 5 minutes I was only at 110*F on the motor, brilliant, then a large crowd gathered round of families and kids who were in the park (who takes their kids to the park on a freezing winter's day, weirdos...), asking lots of questions like how fast/much £££/where from/ power source etc etc. I put on a little show for them; basically stupid amounts of WOT and crazy suicidal high speed passes that were rather dangerous as the crowd were stood infront and to either side of me, so I couldnt really see where I was going all that well from my parkbench/shelter location. No injuries though, just lots of 'woos' and 'wows' (massage that ego baby), until the truck suddenly ground to a halt and refused to move again, just rocked back and forth when I appied throttle. I was hoping it was a loose pinion as I now have an all metal tranny gear setup, but nay, I saw the small stream of white smoke coming from the front of the motor when I picked the truck up, and knew it was toast; temped at 242*F which is much less than the 358*F the hobbyshitty motor died at.

Upon opening up the motor I noticed the magnet was incredibley weak even though it hadnt been cooked that baddly- free spinning with zero resistance, and the windings smelt like an old ashtray again, so no saving this motor saddly. Still, I have another cool fridge magnet, and a really cool pencil holder...

Anyone know if Mike will be selling the 80mm Medusas? I emailed him about it on saturday so hopefully will hear something next week (only the 50/60/70mm motors in the store at present).

[trev3813]

Man, i wish i had a cool magnet...... Sorry to hear about the motor.

[jayjay283]

Neil man time to give up on your great Chinese hope. You are 3/4 of the way owning a Neu 1515 2d with that waste of experiment. Not too fast (sometimes) not to slow (ever) for 5s lipo or your 6s a123 perfect motor !!

[suicideneil]

Hobbycity 9Xl = $30
BidProduct 9XL = $46
Total = $76

Not quite the ~$250 needed for a neu 1515, heck, actually about the same cost as a feigao, and that would've burnt on me too probably.

Now Im just waiting to hear back from the Monster with regards to the 80mm medusas- how dare he take a christmas break like the rest of us!

[lutach]

Originally Posted by suicideneil

Hobbycity 9Xl = $30
BidProduct 9XL = $46
Total = $76

Not quite the ~$250 needed for a neu 1515, heck, actually about the same cost as a feigao, and that would've burnt on me too probably.

Now Im just waiting to hear back from the Monster with regards to the 80mm medusas- how dare he take a christmas break like the rest of us!

Add the shipping costs lol.

mine died too this christmas eve! i split the rotor right in half right after i bought my 4s pack. it was really fun on 4s but now im just going to wait for some money to accumulate and get the 70mm medusa! it was a good little motor but once i got a good battery it new its days were numbered.

[suicideneil]

Bummer, must be some kinda suicide cult...

Shipping costs werent too bad really, I think about $10 for each motor, so nothing too steep. Still, if you dont take a gamble every now and then, you'll never find out if these things are any good or not.

yeah that is true.

i think it would be better powered with nimhs. likw some good 7 cell packs not old and probally shorted packs like mine.

[himalaya]

Sounds like the rotor was de-magnetized by overheat, and then a deadly pull on your throttle sent the coils to heaven.

These motors are also known for their weak magnets, can easily fail by hi rpm, just split into pieces.

[suicideneil]

You mean the bidproduct ones specifically?

The magnet is a nice one piece item, but it seemed to de-maggetize a bit too much/easily compared to the hobbycity one I had back along.

Interesting question though for the masses: is a single piece magnet better or worse than a segmented one, all other things being equal?...

[BrianG]

Segmented is better. Splits up the magnetic eddy currents. Also, if there is a weak spot in the material, using a segmented setup increases the strength by splitting them up - kinda like how plywood is better than solid wood for the same reason.