1515 2Y on 6S???
 

Thinking about trying this as a test. I am running now the MMM with a 1515 1Y (2200KV) on 3S 5000mah (10000K total) parallel. I am getting around 23mins with that setup and runs fairly cool. I am thinking about dropping down to the 1515 2Y (1100KV) and going 6S 5000mah. Would I gain anything from this swap? I am thinking I might gain some runtime and drop in heat......it will be geared for the same 36mph. I am trying to get as close to 30mins as possible without a swap, but weight is a major concern. Our races keep getting longer and the pro classes are minimum 30mins and I their is a 45min race coming up later this summer. I would like to keep it down to 1 stop and still have some breathing room.

You are keeping the same total energy in batts, so you cannot expect a big % gain in runtime on such a swap (considering the 1Y is quite eff in the first place.)

To increase runtime, you will have to increase batt size (and weight.) The energy has to come from somewhere. You may get a min or so at most, but can be easily negated by driving style or pile up of mud/dirt on the car.

jzemaxx,

I run the same motor in my MBX5T truggy and with 8S 3200mAh 25C packs (2 4S packs) I constantly get 30 minutes and my packs have over 100 cycles on them. I did a few 45+ minute runs, but I got bored after 30 minutes. My truggy is geared for 36mph (rounded out) without tire ballooning added (as always using BrianG's awesome speed calculator). I still haven't tried my Enerlands and you can go as high as 3700mAh without adding much weight. With the new 30C and 40C packs, I don't see a problem with a efficient HV set up going 45 minutes straight.

23 minutes? That's it? That seems awfully low for the battery specs.

You need more voltage for that motor, running 4 or 5s I'm pretty sure would be more efficient than swapping motors and running 6s...

These Neu motors I think need more, and like a little extra voltage... imo, from personal experience. ~24,000rpm what you are running now is just not ideal at all for that motor, you should be up in the 32,000+rpm range, I'm pretty sure 40,000rpm is the sweet spot for Neu's.

I figured the gain would come in the form of alot less amp draw.

If you double the voltage and retain the same overall vehicle and motor speed the amp draw will half. But seeing that you have not changed your overall battery capacity, just reconfigured it, you will not notice much benefit. You may pick up a little runtime, and the motor may run a bit cooler seeing you have halved the current passing thru it. Plus you will stress the esc less, and you could go to smaller wires to save some weight (not really worth it IMO.).

Do the wires and connecters get warm on your current setup?

Having half the current will save three fourths of the ohmic losses. This should be noticable.

I would agree to run higher revs. That motor has to pull looooong gearing.

Yes the motor and wires do get a little toasty. I think the amp draw loss will be noticeable in the runtimes...but I could be wrong.

Why don't you just reconfigure those batteries as a 6s pack 5000mah pack? You will have lot's of power, but as long as you have throttle control, you will have great runtimes, I'm sure up to 30 mins... that's what ppl here get, and that's what I get on a 1512 3D (1700Kv.)

And gear down of course, I am 100% certain you will have a cooler running setup, longer runtimes, and loads more power available.

I plan to series them to 6S instead of running 2 3S's parallel. I figured a KV of around 1100-1500

Nay, around 1500-1700kv for 6s lipo is far more common and widely used with great results. I myself run a 2000kv motor on 5s lipo for around 35,000rpms- gearing tall on low voltage with a high kv (relatively speaking) will cause much greater current draw compared to gearing down on higher voltage with the same kv. I would suggest running 6s on your 1515 1y and gearing down before you concider getting a new motor; a 1100kv item would need more like 8-10s to run well from what I've seen- that 30-40k rpm is the magic number to aim for.

Yes, Niel is right on. Don't waste money getting a different motor like I said before.

As long as you gear for a moderate speed (~40mph?), it's not going to be overpowering, you can easily manage it... might be a surprise and a grin on your face at first.

I personally ran 5s A123 on my 1512 3D and it felt like poop, and motor ran just as hot too compared to running 7s A123, IIRC.

Are you running 3S in a monster truck? It seems like that may be what is killing your run time. If you ran 4S or 5S then you would get TONS more run time since you would drawing much less amps to get the same power.

I can only imagine what kind of amps are being pulled on 3S...

Probably high average, but it wouldn't be able to pull a whole lot for power, because you need more voltage to get more amperage... that's why you get exponentially more power available when increasing the voltage.

I too think your runtime sucks as you are spining the motor too slow, and having to prolly pull a tall gear to get speed. Your runtimes should be quite a bit longer for that much batt.

6S, then use a 1300-1600 kv. I had a 2Y on 8S, and really that's the min you'd want to run. I don't like to run high rpms (~40K+) but its better than running too slow (<25K.) My 2.5D on 5S is quite fast enough and gets good mileage. A 3D on 6S 5000 packs should run quite a long time, more than 23mins for sure.

I've tried racing 3s on the 1515 1y as well. I was probably geared a couple of mph's slower than you, but I was pretty happy with it, everything ran really cool after 15 mins. 15mins is the longest I've ran it like that, but I used ~6000mah out of 9800 total, which means 24-25min max.
When I use that motor on 4s 4900 the most runtime I will get from it is about 12mins. Most of the guys I race with are using about the amount of power as mine, sometimes more.
I used to race 5s 4900mah with the 1515 2.5d, and that would get between 16 and 18min racing.
I haven't done an actual race with 6s in it, but geared to the same speed as my 4 and 5s setups, I would only expect 22 or 23 min.
From all the setups I've used and all the setups I've raced against I just don't see much more than about 25mins possible in a truggy, on 6s 5000, in a race, with a good driver, unless your car is somehow super light or it's geared to be super slow. For bashing sure I could do 30mins plus, but I've always found racing runtime is always less.

Yeah looking at this more and more, it looks like 3S is still the way for me to stay. Maybe just look for larger MAH batts that will fit and keep going.

I still think you are better off using 6s and practice some throttle control... afterall it takes X amount of power to get the truck around the track or bashing for a given driving style... and higher voltage will do that better.

Sticking with 3s with a 2200kv motor flies in the face of conventional wisdom- if its running hot now, its only a mtter of time before something expensive goes pop. I seriously recommend usng 6s and just gearing down, that will reduce the load on all the electronics and lower temps too, along with improving runtime.

Spoke to Steve at NEU yesterday. He told me the motors run their best efficiency at 25K-35K rpm. Running a 2200KV motor at 6S would be a little much as far as rpm is concerned. I think the 3S setup with the gearing I'm running has been great no complaints other then some added run time that I was looking for. Looks though as ll the other setups and suggestions will not really get me much more if any. Running twin 4's would be to heavy in parallel, and running a single 4S even a 6000mah would only get me 88.8a/h. With twin 3S I have 111a/h and the C rating doubles to 40C. Now a single 6S with 5000mah would also get me 111a/h, with possible less amps, but the higher motor rpm with a 2200KV motor maybe negate any gains and I would need a high C rating to keep the batt temp down. I think maybe something in the 1350KV range with 6S would work well though. I plan to explore more options and pretty much just start buying motors and trying them instead of theory. Need some concrete proof myself.

What about overall efficiency? Yeah, the motor may be at max eff at 30krpm, but the ESC and batts might be working hard depending on gearing. Remember that efficiency is a curve; the max may be at 30k, but there is still very acceptable eff numbers at a decent range above and below that.

I could see setting it up for 30krpm in a plane where you know the speed you want to run at and it's fairly constant. But in cars, there is a lot of stop and go (except maybe top speed runs), so you have to look at it a little differently.

If designing a setup for high speed runs, the extreme gearing needed would necessitate higher rpms - maybe well into the 50k range. That will give off the line snap AND high top speed. Yeah, it's hard on all components, but that's what top speed is about, and you generally go into it knowing that. If you gear too high with low motor rpm, the chances for ESC-damaging cogging are much greater at startup since the motor has to push the vehicle further for each rev.

If designing a setup for racing, gearing is more moderate. You don't hit top speed very often, so setting it up for 35-40k is fine. That still gives good acceleration off the line and decent top speed. And since you'll only hit max rpm rarely, like on straights, the motor is actually in the 30k rpm ballpark most of the time. If you set up for 30k rpm, that means you will typically be in the 20-25k range.

Same idea with bashing. Just a matter of analyzing the usage and tailoring the setup for best performance. So, there is no "one setup" that will work for all cases.

jzemaxx,

One of my truggy is running 5S2P (TP V1 extreme packs, similar to the High Performance series http://thunderpowerrc.com/html/high-performance.html) with the Neu 1521/1Y and I get over 30 minutes easily without stressing anything geared for 34mph (46mph on radar with tire ballooning) and I can also go with 6S without changing gears, but run time is still over 20 minutes with 5000mah packs. This truggy weighs over 15lbs. with the 5S2P set up. Now the 2200kv motor would be good with 4S or even 5S and you gear to the speed you want. You will eventually go with a smaller pinion which will help with the torque. Now a 1515/1.5Y would be the hot ticket for 6S in a truggy and gearing it for the speed you want might even net you 30 minutes if you use a smooth trigger finger.

**pulls funny face**

There used to be an awesome thread where hundreds of different setups were posted (vehicles/voltage/motor type & kv/gearing etc etc), and 99.9% used the 4-6s setups that we've been suggesting; I doubt that many people would be using setups that were wrong. Even Castle themselves suggest 6s lipo with the MMM&2200kv system, and gearig for a reasonable 40-50mph. All I can suggest is try it for yourself before buying a new motor and running it on a dodgy setup (again) :neutral:

IF you really can't resist getting a different motor, then the 2.5D is just right IMO for 6s lipo.

I am currently running 7s and 7s2p packs on my Revo with a 1512/3D(1700kv). That's equivalent to 6s lipo for top speed wise, geared for between 40 - 45mph and it runs just warm, has plento-power, and I get 15mins runtime on a 7s pack and 30+ mins on the 7s2p pack... 2300mah, and 4600mah respectively. The 7s2p pack has as much usuable energy that your 3s 10,000 pack has, maybe more.