Ahh the long awaited 70 mm motors are finally almost here! The 80s are a surprise tho, I had no idea they were doing them. Also, the 2 new 60mm ones are a nice addition too.

Wasn't sure if I should make a new thread or in here. Its a motor question, so I opted to put it in here, so I apologize in advance if it should have gone in a new thread.

Anyway, I have a question for you gents. I have the following packs and run this setup:

2 x 4s1p A123 packs, and 2 x 3s1p A123 packs

Kyosho Inferno ST-RR
MMM v1 - still going, fingers crossed
15/50 gearing with a Feigao 8XL 2084kv
4s2p A123

This setup currently lasts about 13min of race style driving. This was excellent when my club was running 6min heats and a 10min main. Having now switched to 10min heats, and 20 or 25min finals, its now a pain in the ass.

With only 2 4s packs, I can only do about half the final and then run out of packs. I was thinking that if I can run 7s1p packs and get 13-15 min out of them, then I can have a pack to change for the 2nd half of a 20min race. A 7s1p 2300mah A123 pack is equivalent to a 6s LiPo (same charged voltage, slightly higher nominal voltage).

Which 70 (or 80)mm Medusa should I be looking at to achieve my goal of getting 12-15min (or higher) run times from a 7s1p pack. Also, what gearing should I be looking at? I've got pinions from 12t - 17t.

I was thinking the 1600kv or the 2000kv 70mm.
Any thoughts would be greatly appreciated, thanks guys.

Oh yea, does anyone have an idea of when they'll be shipping the pre-orders?

The 1600 KV 70mm sounds like it's what you're looking for. I'm not sure how long 2300 mAH will last you, but if you keep the 15T pinion on there you should be able to keep amp draws down. That motor is rated to pull up to 102 amps burst and 85 continuous, but with the voltage you're running I'm not sure that it will hit that kind of amp draw. In theory, with the rated wattage of the motor and the voltage you're putting to it you should be getting around 47.6 amps but don't take my word for it. If you can keep the amp draw down, that 7s1p pack should last you 15 minutes or better. If you don't mind going lipo, a 5s-6s 5000 mAH lipo might do you a little better.

No idea when they're shipping, I got my order in fairly early so I'm hoping to get mine before the white stuff is here to stay (it keeps snowing and melting, before too long it will actually stick :no:).

Again, I am not positive about the numbers I put above, just some quick math that works out on paper but could be completely different in the real world.

Hi Cdis,

I don't have any experience with the Kyosho Inferno, but I will help as much as my insight will allow.

First thing to consider, What kind of track are you running? A bunch of tight turns or long straighaways?

What top speed are you looking for? I'm sure the 70mm motors will be real powerhouses. I plan on getting a 70mm AND a 80mm myself. But in the meantime, I've been bashing around with a 36-60-1500kv version. I'm very pleased with it. I've been playing around with 22/40 Mod 1 gearing in an E Revo. It works well on 4S 20 5000mah Lipo. This yields about 23 minutes of runtime. I know this setup would be competive on the track. On 6S, it runs too hot for continous use.

I just switched the gearing to 18/40. We'll see how that does and what the temps are like. This may be the good 6S setup I've been looking for, or perhaps 5S.

If you want more runtime, pack some Lipo in there. You'll also lose some weight by doing so.

On the Monster Mamba that you have, please go to the Castle Website and update your firmware. Castle has came out with the a new version to make them live. The problems the Monsters were having has been linked to the old firmware version.

I hope this helps.

It's like comparing Apples to Sour Grapes, cdis. My v2 60mm was surprisingly efficient. They said something like mid November.

+1. Medusas are FAR more efficient than a Feigao, even if you got a Medusa the same size and KV rating as your Feigao you would notice an increase of run time and power.

I am running Medusa 60-1600kv with MMM and 6S1P A123 in my buggy. It is HB Lightning 2 Pro Evo, 14/46.

http://picasaweb.google.co.uk/Maciej...htning2ProEvo#

I have recorded 1804W and 164A spikes with ET. Runtime is around 8-9 min. 1P A123's have realy hard time in my buggy :intello:

If you want to run 70mm Medusa in your truggy you need IMHO 6S2P A123.

3.7 X 7 = 26 volts
1600KV X 26 = 41000 RPM
2000KV X 26 = 52000 RPM

Now your packs will sag based on you amp draw. Plus your looking for long run time. All that said. The 2000 will be close to the limit and the 1600 will be more in the sweet spot.

I don't know anything about the gearing but I would say that the 1600 with the right gearing is a better option.

Highflier
PS. Keep in mind you might be on the very edge of your ESC voltage.

Since I am in this thread anyways. Can any body comment on how a wanderer 2000KV 70MM can will compare to the Med 2000KV 6MM can (V2)?

Would be used in a E-maxx under 6s1p A123's (44000 RPM not accounting for Voltage sag)


Highflier
Wish I woudl have waited for the 70MM version. Funny thing is I never got around to installing the MED yet :(

Thanks for the replies guys.

The track is pretty twisty with 1 fairly long straight. Its about 340m in length - the faster truggy drivers are pulling around 48-49sec lap times.

As for top speed, at the moment, if I can just get it to keep up with the nitro truggys on the straight, but have enough juice to run for 12-15 min I'd be happy. I was figuring the same as you Unsullied_Spy, if I gear to keep the speed the same, the 7s1p packs should give me lower amp draw and similar run time to the 4s2p. Top speed is really only useful on the straight. With my nitro ST-RR I hardly ever hit WOT anywhere else on the track.

I'm attempting to use the batteries I have on hand and not purchase a LiPo at this stage as the missus has banned them from the house.

Highflier, A123 cells are 3.3v nominal, and 3.6v charged. Lipos are 3.7v nominal, and 4.2v charged. As you noted tho, A123's sag quite alot when in 1P at amp draws over about 50A. The MMM is rated for 6S Lipo so max voltage of 25.2v (4.2x6). The 7S A123's are also exactly 25.2v (3.6x7). So with the voltage sag, they should be much lighter on the ESC than a 6S Lipo.

I'm currently running 4s2p as the setup is pulling 80A peaks and the voltage sag was huge; unfortunately, the car is pretty heavy with all 8 cells in there. About 200g heavier than my nitro. 7s1p saves on some weight, and so hopefully with the higher v and lower A, the pack should last around the same time :D

I think that Wanderer is the same as my Feigao 8XL which is 2084kv. If it's the same motor, just rebadged, the max RPM is 30,000. I think the newer ones come with 50,000 max RPM bearings, but I'm not sure. With 6S A123 you'll be wayy over that. That's the other reason I was running a 4S A123 setup - I found the 5S was making the motor seriously hot.

If you want tho, you might consider swapping out the bearings in the wander to these, which are rated to 70k RPM. I was going to do it, but I figure the motor will be more inefficient than a Medusa anyway, so I may as well just get the Medusa lol.

Anyone got their 70/80mm cans yet? I put in the order almost a month ago and the suspense is just killing me :)

Still waiting on my 80mm, ordered 10/13.

Ordered a 70mm and an 80mm in late Sept. or early Oct. and haven't seen or heard a word from them. I'm hoping that it'll be here within 2 weeks.

Anyone got yet? :o I need a new motor now, and was looking at these, would be perfect. Im using the 36mm teknorc mount so neu is out of my options.

Are those Wanderers poorer than Feigaos/chinamotors?

looks like ill be getting a 80mm 2200kv for next spring. ill demote the 8xl to a winter motor since its sealed tight with high temp rtv silicone