Can you run 3s on the 7700 - RC-Monster Forums

slash_48 · **Can you run 3s on the 7700 -** 12.20.2008, 09:36 PM

I would like to know want you think about running the 7700 on 3s lipo's. Not that I will try but some over on rc universe did and destroyed a lipo battery. He had it geared 23/83 in a slash. I told him he was way over geared. What do you think?

magman · 12.20.2008, 09:43 PM

Only 2s is recommended....on 3s, you will exceed rpm for motor and possible shatter the magnet. You can run the 5400kv on 3s.

SpEEdyBL · 12.20.2008, 09:45 PM

Not very smart imo. You'll risk damaging the bearings. Not only that but there is a certain rpm where efficiency starts to drop very very rapidly. I bet a 5700 on 3s isn't that much slower unless your using 200 amp continuous rated packs to begin with.

Metallover · 12.20.2008, 10:03 PM

You can run 4s with the 7700.

http://www.youtube.com/watch?v=46ssLpgky5E

slash_48 · 12.20.2008, 10:17 PM

How long do you think it would last in a slash. He has stated that it is shutting down the esc. from to much heat. he said the gearing before this happened was 29/86. I went to the speed calc. and it said the car would do 100 with this gearing. Way over geared imo.

Metallover · 12.20.2008, 10:21 PM

If you disable the BEC and gear it really low, it might be OK. I'd go with 2s or a better motor.

slash_48 · 12.20.2008, 10:31 PM

It's not mine. I would never run it with that high of gearing or on 3s. The person who is doing this is on a another forum rc universe titled smoked a lipo.

SunnyHouTX · 12.21.2008, 02:31 AM

And I run 7700 motors on 3S in my dragsters, as do a lot of other RC drag racers. And the extreme class guys run them on 4S.

http://www.youtube.com/watch?v=SPMbT2X2ZEQ

slash_48 · 12.21.2008, 11:54 AM

I'm sure it's fine for short runs like that. But in a slash bashing not to good. All I'm saying is it won't last long in endurance races on 3s.

Maciolus · 12.21.2008, 12:47 PM

You should suggest your friend to try 9000kv on 3S with bigger pinion

12.24.2008, 08:53 PM

That guy was running a very small lipo. It's hit or miss running 3s, it could break down after a while, or last for years that way. It's probably not good for it, it's not recommended, but you can do it and probably get away with it for a while. Having a 7700 in a slash, regardless of the number of cells probably isn't a good idea to begin with, so he'll see heat and may or may not ruin the motor.

slash_48 · 11:36 PM

Most of his problem is he is over geared and drawing to much current 23/76 is to much for this motor. He also stated that the esc. was shutting down do to heat. The small lipo did not help either. If he keeps running this way something else will go. I run 17/86 with my 5700 and on 3s temps get to 140 to 150 in my slash. Can't wait to test the 9000 after the snow melts. This motor will probably end up in a drag car. I know it not a good choose for a slash but someone has to try it out on 2s maybe 3s in the drag car.