Lehner Basic XL 2800 on 24 volts?

[extremexmods]

I know the Lehner Basic XL motors are limited to 65,000 rpm. The rpm/volt quoted for the Basic XL 2800 is 2800 on the Lehner website. With 24 volts this works out to be 67,200 rpm. If this is the unloaded speed, would the loaded speed in a dual brushless powered e-maxx with this motor on 24 volts be less than 65,000 rpm? I was thinking about BK Electronics 12020 Warrior Controllers, 2 Lehner basic XL 2800 motors, and 20 cells. I would parallel wire the 2 speed controllers to get the full 24 volts with out having to use a total of 40 cells. Would this work, geared 20 or 21 tooth pinions and 66 tooth spur?

Speed chart for idea of speed

http://qcda.com/emaxx/speedchart.asp

[MetalMan]

Why do you want to do it that way? 20 cells to a single Wanderer XL motor like a 10XL would be a very powerful setup, and would be well within the specs of even a 9920. 20 cells total would not be enough to supply dual Lehner 2800s, unless you did 10 cells to each motor. You could run 28 cells total, 14 to each motor, though.

Overrevving motors is not a good practice, and in the case of the Lehner 2800XL, 2800 is the loaded kv. You can assume that the unloaded kv would be about 200 higher, so unloaded with the full battery voltage would yield a RPM of about 72,000, which is much too high. At that point you risk damaging the motor by way of the magnet coming loose. It's also possible that the bearings would seize, causing a huge current to be pulled by the motor(s), which could kill a controller (potentially).

[maxxdude1234]

There's no way you could reliably run 24v through the 2800XL. I run 21.6v on the 2000XL and the motor is already pretty toasty at the end of a run, wouldn't consider putting 24v through it. I agree with what metalman said, dual brushless in an emaxx is a waste of time (and money :D). A wanderer 10XL on 20cells is a lot more than fast enough in an emaxx

[coolhandcountry]

I fried a xl2000 on 18 cells for heat build up. If you going all out for that may i suggest a bigger motor on the 40 cells you planning on putting on the truck with one esc. You could drop back the cells size to a gp2200. It would be a crazy ride.

I run a Lehner 2800xl in my Ofna 9.5 buggy and it's hot after a run, gonna get a heatsink in addition to the fan it already has because of the heat it makes. I've got it geared 12/51, but think I might go to 14/65 instead which would be a little lower and drop the heat down a little. Problem with the Lehner Basics is the 1/8" shaft, limits the mod1 pinion selection and sometimes makes them fly off.

[extremexmods]

Thanks guys.

What about dual lehner Basic XL 2400 motors, geared 23 pinion, 64 spur, with 20 cells? And do the cells really put out a full 1.2 volts? I thought they put out a little less, making 20 cells on a Lehner Basic XL 2800 possible. If each cell only puts out a max of 1.16 volts under load, the rpm would be only 64960 rpm. I am running new GP 3300 cells, in a side by side racing configuration, not stick packs. I want the lehner because I insist on a screwed, not a pressed on motor endbell, and my friends all say Lehner makes the best motors for the price, $150 per motor is the most I want to spend, and I insist on the awesome look of dual brushless, I refuse to run single brushless. I just want to know if my set up is safe. I though if the batteries never put out more than 1.16 volts, the rpm would be safe. And I would not run the motors without a load. What other websites sell brushless motors?

[extremexmods]

Thanks guys.

What about dual lehner Basic XL 2400 motors, geared 23 pinion, 64 spur, with 20 cells? And do the cells really put out a full 1.2 volts? I thought they put out a little less, making 20 cells on a Lehner Basic XL 2800 possible. If each cell only puts out a max of 1.16 volts under load, the rpm would be only 64960 rpm. I am running new GP 3300 cells, in a side by side racing configuration, not stick packs. I want the lehner because I insist on a screwed, not a pressed on motor endbell, and my friends all say Lehner makes the best motors for the price, $150 per motor is the most I want to spend, and I insist on the awesome look of dual brushless, I refuse to run single brushless. I just want to know if my set up is safe. I though if the batteries never put out more than 1.16 volts, the rpm would be safe. I should have said 20 cells, not 24 volts, because I know the cells would put out less than 1.2 volts each. And I would not run the motors without a load. What other websites sell brushless motors?

[Sneeck]

Actually a full pack put's out more volt's than it's rated. Like 18 cell's would be 18 x 1,2 volt = 21,6 volt's. Wrong. Matched pack's when fully charged put's out more volt's. Like a 6 cell pack is around 8,4 volt's fully charged, instead of the 7,2 volt's it's rated at.

Do not forget this, it could blow up the controller.

[extremexmods]

The controller states for 4-20 cells, wouldn't the manufacturer consider this?
if the cells put out 1.2 volts, then 19 cells on the Lehner Basic XL 2800 would be 63,840 rpm and 18 would be 60,480 rpm. Is this safe?

[coolhandcountry]

I am not sure why you want so many rpms and such a small motor. It is your money though. What are your plans? You just going for a all out speed record. I wouldn't want to try and bash a xl2400 around on 20 cells. I am not sure i would want to bash a truck with 40 cells on it at all.

[extremexmods]

Originally Posted by coolhandcountry

I fried a xl2000 on 18 cells for heat build up. If you going all out for that may i suggest a bigger motor on the 40 cells you planning on putting on the truck with one esc. You could drop back the cells size to a gp2200. It would be a crazy ride.

Would 2 motors heat up less because they could share the load?

[squeeforever]

yea, kinda. but the fact of the matter is that you shouldnt put that much power through a hot motor like that. i had a xl3100 on 12 cells and i fried it probably because it got really hot...and your setup will do exactly that. have you ever even owned a brushless setup? 2 is not only overkill, for less money you can have a better setup... i run a 10xl on 16 cells and soon 6s lipo and its plenty for me. actually, its to much for a race track. my point is, if you really want to run dual brushless, go with a wanderer with a rcm heatsink/clamp. the can wont pop, L would run alot cooler, and i personally think there better. the lehner basics arent all that. your friend is right and wrong, lehner does make the best brushless motor but not all of them are the best. the basics are made in china and the others are hand made in germany. the german ones are the best, but the feigao/ wanderers are just as good if not better than the basics. probably better since there larger and disappate heat better. keep in mind that the basic xl is only about the size of a feigao or wanderer S...

20 cells is way to much on such a small motor. if i was you i would go with a good single setup instead of 2. Its your money though.

[Sylvester]

I think the can would pop open 5 mins into the run!! :P

its just way to much for such a small motor