Medusa Afterburner V2 BL motors

[highflier]

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.

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.