use of 4S or 5S vs using 6S
 

Hello all, im new to this electric thing, and have been reading trying to decide which way to go to convert my Mugen mbx5 over to electric.

I think i'm set on the new CC mamba monster 1/8 combo, but trying to figure out which batts to get and why is confusing me.

I see some run 2 x2S packs and others 1x4s pack and others still a 1x5s pack.

what are the pro's -cons of using dual packs over single.

If more voltage is the way to go, why are drivers not using 2x 3S packs or 1x 6S pack with less mah in there 1/8 buggies?

Generally using 2 2s, or 2 3s packs is for balancing a truck out or in the case of the E-REVO or E-MAXX thats what it was designed for. It balances the truck out side to side. The reason for higher voltages is to reduce current (Amp) draw to get the same power output (Watts) Watts = Voltage x Amps If you increase the Voltage the Amps needed are less, therefor things will run cooler as current produces heat. As far as using 6s in a buggy, IMO I think we don't see this because of a lack of room on a buggy chassis for 2 packs and there is only so much room under the body to fit a pack. 5s has been run on them though. IMO buggies are much lighter and have A LOT less rotating mass than a truggy or MT and can easily survive on 4s

I have a mbx-5 converted.....here are the pics...The first 2 pics. are my new set up

http://i271.photobucket.com/albums/j...e/DSC01625.jpg
http://i271.photobucket.com/albums/j...e/DSC01627.jpg

In the last pic...it shows a 5s batt....I no longer run a ccbec or the 9xl...I am running a 1512 1.5YF and a MGM 160 esc
http://i271.photobucket.com/albums/j...e/DSC01493.jpg

WELCOME TO THE FORUMS!!...:yipi::yipi:

Some people use two packs to balance the car, but the vast majority of the racers are using one pack. 4s is adequate for a buggy, but it seems that many of us who have been racing the cars a while tend to settle on 5s. Just a more efficient setup in terms of run time than 4s.

4s 5000 = 5s 4000 = 6s 3300

which way you go really depends on your track, how long you need to run, etc.

Here is my 8S MBX5T:

http://i260.photobucket.com/albums/i...h/DSC01434.jpg
http://i260.photobucket.com/albums/i...DSC01346-1.jpg

lutach,
is that MBX5T a custom fab job or some kit? looks good. 8s?! wow. the thing must fly. how is it to drive? i am building a new RC8T right now and custom fabricating the chassis. i have alum and cf and not sure which to use. i want to use the CF but some think it will not be strong enough. what are your thoughts? how has your mbx5t chassis held up? is it cf or alum? looks like cf under there.

you can use 4,5, or 6s on your buggy. i used 4s on my losi 8b and 5s on my losi 8t. just make sure you go with the right KV motor according to your battery. all the guys at Tekno RC use 6s on their setups for the cooler temps and longer run times. 4s is easier to fit in the buggies though. sometimes you have to shop around and just buy the battery that will fit in your setup. you are more limited with 6s. visit this link for some good info and products.
http://www.impaktrc.com/product_info...oducts_id=3276

The only real reason for running 4s on a setup, is really if you only want a certian power or you are limited by rules. For instance, RC Pro allows electric to run with nitro in Nitro MT, but they are limited to 4s power. I am limited to 5s by esc's myself, I have a quark 125/Neu 1515/2.5d in my G2R and a quark 80/lehner basic xl 1200 in my RC 10GT conversion. The quarks are rated for 6s, but they are finiky on a fresh charge, why risk it. I want a few MMM's to go 6s though and get away from UBEC's.

I wouldn't go that far..

I will say in a given amount of weight and space it seems the 4s 8000mah give you the longest run time of any typical setup. I run my erevo on 4s every day and it's MORE than enough voltage.. and it is more than enough for any truggy as well. The difference between 4s, 5s and 6s is in reality very little.. the difference between 4s and 8s or better on the otherhand is a bit more worthwhile. I ended up with a Neu 1515 2.5d by error and decided to keep it, the motor was nice but it ran too hot on 4s racing due to the low RPM's so I HAD to move that motor up to 5s just to keep it cool and effecient (in my 8ight-t). My Neu 1515 1.5d can however run on 4s at speeds from 40-50mph w/o heat issues in my erevo which is the same size as the truggies. I gear the 1.5d for 40 and it's very low temp but I do that because I race and 40 is MORE than enough on a track.. at 50 it's just way too fast and causes slower lap times due to less control. I can run it geared for 50 all summer though with temps on the hottest never exceeding 180.

So what does it all mean? Just pick the right voltage for the motor you want... LOL it's pretty much that simple in this voltage range. PS the 2s lipo's are in hard shells for racing and super durable so you may want to lean that way for that purpose alone. I will also say running a pair of 2s 5k, 6k race lipo's also keeps your options open for running your packs in a larger array of vehicles. Many Many good packs out there now... and if you want single packs Losi even makes a hard packs 4s as well (not many of those out there yet).

my2c

It's a Mr. C conversion and that's the version 1. He has a version 2 that looks good too. I have the set up for efficiency and not speed. It sure has a lot of torque and it's very easy to drive. The chassis has withstood head on collision with the curb 2 times when I lost signal. Carbon fiber done right can be very strong in every direction and Mr. C did his job. The hole chassis is carbon fiber, but the front kick up is aluminum and that was bent in the collision and it was easy to bend it back.

Thanks everyone for all your answers.

I am looking to get the most play time out of the set up, but still keep the temps down; hence the 6S question.

Lutach, that truggy of yours just makes me :surprised:

Generally speaking one should go as high in volt as warranted by the manufacturer(an know to be reliable) as volts help to make amps go "through" and hence power by the same token circuitry easier.

Keep in mind the ohm law:

i = v/r

i = amps
v = volts
r = resistance in ohm

Meaning for example that if a Tamiya connector is good for 20 amps at 7.4(2s) volt then at 44.4(12s) it should be able to hold at 120 amps!

Now if you keep in mind that watts(power which is a direct measurement of work or for us how fast you can go)= volts X amps...

7.4v X 20 amps = 148 watts. So that connector could let pass 148 watts continuous a 7.4 volts.

Now at 12s, 44.4 * 120 = 5328 watts. So in theory Tamiya is probably okay for HV setup.

Basically it's a square law. If you double the voltage you can pass two time as much current for a total of four times as much power.

Of course a too high voltage will short-circuit your material...

If you aren't bound by rules it's generally better to run as much voltage as possible.

Moral of the story? It's harder on a controller to to run 150 amps at 4s than 100 amps at 6s if it support it. It might even be harder to run 150 amps at 4s than 150 amps at 6s. I say might because controller are complex device that might have more limitation than simple Ohm law and that i want to cover my ass. :na:

Don't forget the currency laws ($$$) and the more importanly any laws that may apply if you are racing. Current laws remain in effect limiting 4s lipo as max voltage racing reguardless of the amount of resistance you provide to the powers that be :lol:

C= 4s = v = ~r
V * x = $$

The MMM can handle the amp load 1.5d on 4s racing in a erevo geared at 50mph so you can forget all you worries and just pick what you want. PS the again in the given space and weight most people want to be in a 4s 8k config typically will net you the longest run time.

14.8 * 8000 = 118400
18.5 * 6400 = 118400 (can't usually fit over 5k) hard to find anything over 6k even if it will fit..
22.2 * 5333 = 118400 (can't usually fit over 4k) hard to find anything over 5k even if iit will fit..

As long as your motor is in the sweet spot don't expect much difference in run time.. the 4s8k setup is the lightest and the cheapest. in the bunch. Again if you go for 8s and up it's another story but that story involves a lot of $$$$$.

good formulas?

That totally depend on what he want to do.

With a MMM, it would sure be better to attempt speed run on 6s instead of 4s.

For racing, yeah most place probably ask for 4s.

On a pure price basis 6s 5000 mah is pretty much the same price than 4s 8000 mah and 1/15 more energy isn't much energy difference in favor of the 4s lipo.

So i still stand on my previous advice. 6s if there is no rules forbidding you to run it(racing).

I'll agree for speed passes to be at 6s lipo... you will get the most by a longshot w/ the highest voltage possible. But if you bash or expecially race voltage is less of an issue from 4s to 6s, just make sure your motors RPM's are in the sweet range 30k-40k and other than making sure you stick to track rules or proseries or event rules you'll be good. It's funny in theory 6s is a lot superior as Oppressor states but when it comes to real life application trust me my 4s erevo can run faster and longer on a Neu 1.5d (120amp) vs my losi 8ight truggy on 5s or 6s with a Neu 2.5d (80amp) both running 5k packs.. drop in the 4s 8k packs in the erevo and it's not even close....

VVVVVVVVVV Works fine for me. Long run times too.