kufman

iTrader: (6)

I have seen several Losi guys doing the same thing. They tend to run the Losi 1700 motor on 4S.

brofroe

iTrader: (20)

Yes, there is a guy at our track who was running a 1700LOSI on 3s & 4S with great success. It finally gave up and he has the same 1512/1.5Y(1850kv) Nue as I do. We both love this motor. It's torquey and effiecient. Most guys on RcTech are running this motor on 5s! I've thought about it and gearing way down but it's doing so well on 4s I say leave it alone.

js058515

iTrader: (6)

I know the original thread author went with 4S batts, but I wanted to chime in on which might be more efficient with what motors are currently out on the market.

I am a low kv/high voltage guy running 6S and I like it except for battery prices. Edumakated has what I think is the best all-around setup. I can't remember what buggy he is running, but he is using the Tekin RX8/T8 1550 Truggy combo in a buggy and running 5S batteries.

From what we all have learned in the past year, a 1550kv motor is ideal for a 6S battery setup. But since the Tekin motors are underated a bit, Edumakated is getting more than enough power from this motor on 5S plus he is getting sick amounts of runtime. I wanna say over 20min. The truggy motor has the power too since it's a bit longer than the buggy motor. He even runs the 1350kv Truggy motor in his 8T 2.0! How many guys on this forum actually run the 5S/1350kv setup? Edumakated is onto something.

yfzracer912

iTrader: (6)

I am in the same boat deciding what I will run in my 8ight e. I was dead set on the MMM 2200 and 4 cell but now with the talk of 5s being more effecient I dont know. I did look at the weight of a 5s and its not very pretty. I read that for a buggy I should stay around 500g and the NEU Lipo packs are:

5S(25c) 5500mah 684g vs 4S(25c) 5500mah 546g
5S(25C) 4900mah 630g vs 4S(25c) 4900mah 506g
5S(25C) 4300mah 552g vs 4S(25c) 4300mah 448g
5S(25C) 4100mah 519g vs 4S(25c) 4100mah 417g

js058515

iTrader: (6)

It's tough to compare the weight of a 5s and 4s with the same mah as you will definitely get more runtime with the 5s. The first comparison you show is actually 5oz difference (oz being a common weight measurement we all use to show off how light are cars are or not). You could probably run a 5s 5000 or the 4900 and you may still get more run time vs the 4s 5500mah.

Edumakated

iTrader: (19)

I can't say enough good things about the 1550kv truggy/rx8 setup in my xray 808. It is the shiznit. Excellent run time and more than enough power to embarrass any nitro on a straight. I am only burning about 200mah/minute at most on a large track. JHautz runs the same exact setup in his buggy and our performance is practically identical.

Voltage is your friend. All the setups whether 3s to 6s work well, it just depends on your needs. The first step anyone needs to do is figure out how long they need to race for. If you only need to race 10 minute mains, then 4s is more than adequate. It starts getting tricky when you need 15 or 20 minute mains and you really need to look at going up in voltage and a lower KV motor.

Regarding weight of batteries. I actually can pretty much race a 10 minute main on a 5s 3300 pack. 20 minutes I can usually use a 5s 5000 pack and 15 minutes I use the 5s 4100 pack.

4s 5000 = 5s 4300 = 6s 3300

yfzracer912

iTrader: (6)

Well I think I made up my mind. I m going with the MMM esc with a Neu 1512 3d(1700kv) on Neu 5cell 25c 4900mah. Should be fast(hopefully controllable) and efficient.

Tomeygun

iTrader: (1)

as a side note to the high voltage/low kV idea -- My first motor was a cheaper 1100kv long can and it was obviously slow on 4s (A123 3.3v cells)

So one day about 5 min in to playing I figured what the heck, I got the series connector out and ran 8s A123 into my MMM for this 1100kv motor. Was as fast as a 4s/2200 combo, AND i ran forever before they dumped...

The one issue was I was really pushing the limit on the MMM esc in voltage. Any talks of a high voltage MMM?

SpEEdyBL

iTrader: (1)

Consider yourself EXTREMELY lucky that the MMM didn't puff out smoke. With that much voltage you increase the likelyhood that the battery voltage will go over the 30 volt maximum of the fets. The cause of this is called ripple current, which flows in reverse to the battery during braking, causing the battery voltage to rise. All it takes is a few milliseconds of heavy braking and your esc could become toast. And the higher the resistance of the batteries, (A123 cells have much higher resistance than lipo) the higher the voltage will go. Simply put, don't do that again. There is a very fine line between what is safe on the MMM and what isn't.