Need some battery advise

Hey guys,

I'm getting ready to order a couple of new batteries and I am now rethinking my methods.

I'm doing some parking lot drag racing with trucks. One is an 1/8 scale buggy with a truck body and the other is a Losi 8ight T. The purpose is to cover 132' as quickly as possible.

What I'm thinking about doing is running a Neu 1515 1700kv motor on 6S lipo using a Compro controller and gearing up for speed. What I had originally planned to do was to run a 1515 2700kv motor on 6S, but when I tried that, my esc went up in smoke. I'm still trying to get to the root of why that happened. It may have been a bit much for the controller.

So, my choices are either the 2700 on 5S or the 1700 on 6S. Any thoughts?

My main question is this. What packs do I get? I'm either going to go with Flightpowers or Neu packs. What I need to know is what capacity should I go with to get a good balance between weight and enough runtime to get some good runs without dropping so much voltage that it really affects performance. Right now, I'm really looking at the 3700 evo25 flightpower packs. These should be nice for running the 1515 1700kv motor with some tall gearing.

Any advise is appreciated.

[What's_nitro?]

Get a nice high-capacity LiPo with the smallest C rating you can find. Put it in a metal cylinder with one end blocked and a small hole in the other end facing the rear of the vehicle. Use a relay actuated by the radio to short out the battery inside the metal cylinder.

That should get you to 132' pretty quick.

[What's_nitro?]

But seriously, since you're only running in short bursts, high capacity cells aren't a necessity. A high peak discharge would be more important than a continuous rating for drag racing, although if you get one you usually get the other. The 3700 evo25's should be plenty I would think.

[zeropointbug]

Originally Posted by What's_nitro?

Get a nice high-capacity LiPo with the smallest C rating you can find. Put it in a metal cylinder with one end blocked and a small hole in the other end facing the rear of the vehicle. Use a relay actuated by the radio to short out the battery inside the metal cylinder.

That should get you to 132' pretty quick.

I don't think getting a high cap lipo and low C rating is a good idea, this seems to go against logic here?

I agree with the 1700kv motor on 6s should be really good, and not over powered like the 2700kv on 5s would be!

AAngel, even a 1512 for drag racing would be enough to be honest, these motors all have enough torque flip the truck over at speed, so you are basically limited by the trucks center of gravity really, up until the very high speed end of things. Unless, of course you are using a wheelie bar, which will be another story...

[zeropointbug]

Also, whether you are using a wheelie bar or not, moving all the weight to the front end of the truck will make a huge difference in acceleration ability.

[What's_nitro?]

ZPB, what typically happens when you short out a LiPo? Now, what would happen if you were to short it out in a confined space with only a small hole to vent through? You may need to inject oxygen, I'm not sure if the container would have enough for a continuous reaction...

BTW, I'm just kidding around. Although, it might be fun to try...once.

zpb, I'm just toying with the 1700 and 2700kv motors because those are what I have. I just got the 2700kv 1515 and really don't know what I was thinking when I got it. I should have ordered the 1512 2600kv motor. We're running a 1512 in an XT8 with good results.

[glassdoctor]

I bet those 3700 packs are a good choice... punch without dragging too much weight.

Hey you might try that 2600kv motor in a 1/8 buggy if you still have one. The guys on another forum swear that they are running Neu/MM with NO cogging. They are using 2600kv and 3200kv, and gearing @10/46. They say it starts cogging if they gear up... but none on a low gear.

Their efficiency is down from what I get but they seem very happy with the setup.

Kinda makes me what to try it....

GD, I have the 2700 1515 and it does put a bit of a strain on the MM. I suppose that the 1512 might go a bit easier.

Just as a point of interest, I did run my 1515 1700kv motor in my Monster GT this weekend, just to play around with. I used a MM running 4S. The gearing was the largest spur that I could get (52T I think) and an 18T pinion with the tranny locked in first gear and 40 series Moab tires. VERY mild gearing. Not fast at all and clocked at around 35mph. Cogging was almost non existent.

Since my brand new Neu 4100 5S pack got chewed, I have the replacements narrowed down to two choices. OK, the choices are these...

1. A flightpower evo25 3700 5S or...

2. A flightpower evo30 3200 5S

I'm hoping that either of these will give me about 15 minutes of runtime while holding enough voltage to remain fast.

If anyone has a better suggestion, please let me know.

[zeropointbug]

I would just go for the 3700 pack, that should be light and powerful, and should give you 15 mins runtime for sure I think.

Are you going to get the 30C packs?

EDIT: oh, nvm... i see the C rating you typed there... still, I would get the 3700's, why not?

Well, I really saw the difference in packs last Saturday night. When running the 5S 5Ah maxamps pack, the truck was running really well. When we went with the Neu 30C 4.1Ah pack, you could really see a difference.

I hate indecision. What I really need is a 4Ah 30C pack. I just need it by this Saturday night. Neu takes forever to ship.

[zeropointbug]

So which was more powerful then? the maxamps, or the Neu pack?

The Neu pack was more powerful. It's actually a very nice pack for the money. It cost about the same as the maxamps pack, but had more punch, although it had 900mAh less capacity.

[What's_nitro?]

Hey for another $24, I'd look into the NeuEnergy packs. 240A peak on the NeuEnergy, 192A peak on the Evo30. But where time is a limiting factor, the Evo30's might be it. Could you shoot Neu an email and see about expedited shipping?