Lipo question
 

Ok so im converting my hyper 7 to electric and i need some lipo suggestions, i will be running one pack

Ill be running mamba max esc along with the feigao 540 8l so i need either 2c or 3c lipo

my instincts would tell me to go with 3c for more run time and power although i think it would weigh more than the 2c

Do lipo's need discharging, if so can you suggest a good charger/discharger in one

and also what is a balancer and will i need one, if so plese suggest one

My buget will be around £175 - about $300

Im a complete newbie to lipo so thats why the questions will seem noobish

Cheers,
Matt

Welcome to this forum Matt!

An 8L on 3S pushing an hyper 7, that might be a current hungry setup for sure!

It is possible, but it's not a setup i would recommend in the first place.

Normally, a 4S setup in a buggy would do great. Allthough; i had great succes with a 7XL on 3S in an e-maxx. but this was truck was going about 30-35 km/h

alright cheers for the info what motor would you reconmend i was thinkin the 8xl also not sure though im new to brushless

Yeah, either a 7 or 8XL on 4S would do. The 8Xl would be the best choice.

so 4c disbaleing the BEC and Get a descent UBEC looks like what ill be doing then Cheers for the help

Will i need a discharger?

or balancer but ill only be running one 4c pack rather than two 2c to save room.

Cheers again,
Matt

Do not get a discharger for lipoly packs, cycling them is one of the dont's in the lipo rule book.

K cheers, what would i set the cutoff voltage on the MM Esc for the 4c pack then ?

It's 4S instead of 4C, the C rating stands for something different, read the sticky about brushless in general in the brushless section.

But with lipo's you can go to 3V per cell cutoff. 3.1-3.2V per cell is the way to go to be easy on the cells.

Ok cheers i use c because i think of Cell and abreviate like that, but thanks for the correction

I don't think it's so much a "correction" as making sure you use the proper lingo because other people won't really understand what you mean. The "s" is series cells if that help you visualize it better...

Well, you must also realize that referring to the number of the cells in a pack cna refer to many different types of cells.

An 8 cell lipo can result in 8S1P, 4S2P, 2S4P, or 1S8P (though the last one would almost never occur).

So, one must designate the type of wiring.

Otherwise, for a 1/8 scale buggy a 4S Lipo setup with an XL or high turn L seem to work well. Also consider a Neu 1512 series if you haven't purchased a motor yet, they seem to be a nice combo in 1/8 scales, but beware since Neu's don't seem to like Mamba Max controllers all that much (if that happens to be your choice of controller).

Right now I'm setting my Hyper 8 Pro with a Feigao 8XL (purple one), Mamba Max, UBEC, 4s 5000mah Lipo from Maxamps, and a custom motor clamp. The gearing is 18/46, and the estimated top speed is 41mph. It should be perfect for the local track.

That's dead on what my setup does... 41mph w/same gearing, @same kv, etc... it's a very fast setup but still good for a big track.

That is also going to be my set up, lol. Except that I will run an 8000mah battery instead of the 5000.

I am running a 9xl with 16/44 gearing. If you guys dont have problems running an 18 tooth pinion then it sounds like I can gear higher. I will also be running the 5000 maxamps pack, when ever it finally gets here. :)

The key is the motor kv... and at only @1750kv the 9XL should pull that gear easy. I still run a lower gear for racing but really I don't have to.

That's one of the things I want to experiment with: how temps and efficiency will be effected if I race with this taller gear, vs. the 14-16t pinion I normally race with.

Cheers for the info guys, forum is very helpful

isnt the 9xl 1864kv? its the 540c can that I am running. anyways good to know that I should be able to gear higher. I probably will do that when I go back to a 4s pack. currently I am running a 5s pack with 16/46 gearing but am picking up a 4s 5000mah pack because I dont want to puch the MM to hard.

If you're looking at the specs of the Feigao motors, I believe that they are unloaded ratings. To get a better idea of a loaded rating for a Feigao motor, look at the specs for the BK Wanderer. The Wanderers are the same motors, but their kv ratings are under a load. 1864kv is more along the lines of what the 8XL will do under a load, IIRC.

But of course, make no mistake, the 9XL is a great motor and will probably do what you need it to. You just have to gear it a bit more. I run a 7XL/MM combo in my buggy (Sportwerks Turmoil) and my buddy runs an 8XL/MM combo in his Losi 8ight and he easily gears to match my speed on the track. If I'm not mistaken, he also gets a bit better runtime, but that might be because his buggy is lighter than mine.

mine is in a losi 8ight too. I also have a 7xl motor so if the 9xl is not fast enough then I will just put that in. thanks for the info on the motors I was wondering why the wanderers and feiago c had different kv rating. seems odd that they wouldn't use the same method though.

I think that the 9XL with about an 18T pinion will do you nicely. Not too crazy on the bottom with a top to keep you ahead of the nitros. BTW, we're running a 46T Kyosho plastic spur on the 8ight. It did take some doctoring to make it fit. I had to turn the bearing standoff down by about 30/1000ths, I faced that side off by about 10/1000ths and opened up the back for the diff cup by about 20/1000th on a lathe. The whole operation only takes a couple of minutes. It's really just a matter of having the right tools.