1515 2Y on 6S??? - RC-Monster Forums

jzemaxx · **1515 2Y on 6S??? -** 06.10.2009, 09:49 AM

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.

Finnster · 09:56 AM

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.

lutach · 06.10.2009, 10:06 AM

Quote:

Originally Posted by jzemaxx

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.

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.

zeropointbug · 06.10.2009, 10:52 AM

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.

jzemaxx · 06.10.2009, 11:14 AM

Quote:

Originally Posted by Finnster

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.

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

lincpimp · 06.10.2009, 11:54 AM

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.).

Thomas · 06.10.2009, 02:16 PM

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.

jzemaxx · 06.10.2009, 02:24 PM

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.

zeropointbug · 06.10.2009, 02:35 PM

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.)

zeropointbug · 06.10.2009, 02:37 PM

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

jzemaxx · 06.10.2009, 02:40 PM

Quote:

Originally Posted by zeropointbug

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.)

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

suicideneil · 06.10.2009, 03:52 PM

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.

zeropointbug · 05:26 PM

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.

BP-Revo · 06.10.2009, 05:40 PM

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...

zeropointbug · 06.10.2009, 05:59 PM

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.