Neu motors

[glassdoctor]

Quick update. (it's 3:30am... think I need to go to bed soon :) )

I have done a couple test runs with my 1512 1.5Y now... so far so good.

I put it on the track the other night during the races. Had it geared 10/46 and 4s lipos. It ran very cool but it didn't have much "rip" to it.... no top end at all. Geared too low.

So at home I tried 13/46 and it was better but still really impressed... so I grabbed the 18T gear I have from the emaxx tranny. Much better. :)

Wow... it's geared tall! But it seems to run great. I would like to try a tooth or two lower but don't have anything between the 13 and 18 right now.

With the 18/46 and 4s lipos it's fast... I didn't put the gps in it but it must be hitting low 40's, and plenty of punch. I ran a crappy 3s lipo pack and it was still pretty quick, just not as impressive, obviously.

Run #1... 6 minute nonstop street bashing (simulated racing ;) ) the motor hit 145 degrees and the Mtroniks was 115 on the case and diodes were 125 maxamps 6000s were 110.

Elogger showed peak amps of 75, average 14.6 and only 1544mah used. (I think it's conservative in the mah #'s... maybe add 20-30% ?) I did some long speed runs to see what the amps were like and it would go from 60 amps off the line down to 20-25 amps once up to full speed, FYI.

Run #2... 3s lipo pack for 6 minutes pretty hard. Temps: motor 110 esc 90 (barely warm) peak amps 67 ave 13.5

Run #3 I then did a run with a Mamba Max (w/ubec) and maxamps 6000 lipos, and got similar results to run #1. The car felt really fast on this run, but it was under street lights so that might explain.
9:22 run time minus about one minute of "down time", so about 8-8.5 minutes. Motor 145, ESC 140; 120 at caps, batts 105-110, front drive shaft 120 :) Log data: 2225mah used (over 2500mah charged back after the run) peak amps 77.5 ave 14.3

These runs are on paved street/driveway with bald tires. Peak amps and mah used will surely be higher on a high bite offroad track, but I don't know how much.

A guess would be about 100 peak 20 ave... temps we will see.... I can't wait to see what happens on the track.

[glassdoctor]

Yes... 5mm shaft. :005:

As for which one????? It's too early for me to say, but it appears you can go with a little higher kv than mine. Mine is 1900. They have a 2000 and 2600.

At this point I don't even know if the 1512 is ideal.... maybe the 1515 is better yet?

I think I'm going to get a 1515 for my truggy... so maybe I'll find out. We don't know right now... :035:

That 1515 1Y is looking really good...... :004:

[glassdoctor]

Oh... these runs were with no fans on motor or esc, and it was not real hot here today. And there are 7 smileys in the two posts above.... ha ha

[cart213]

What's with the Y and D designations on the motors? Does that signify the type of wind, and does one type have an advantage over the other?

[Serum]

What voltage did your maxamps packs reached at the 75A current?

[glassdoctor]

One run showed a min 12.1v which is not bad... I'll have to check and see what the voltage was under a sustained full throttle pass.

One run showed a 10.1 dip so I ran that pack too low. That's a very brief dip and it bounces right back up to around but you don't to run them like that.

I have been doing some reading on rcgroups about cutoffs on the newer high-C lipos and they say to keep the cutoff above 3v per cell. You want the voltage to rebound to 3.7v per cell withing a few minutes after the run.

They used to say it's fine as long as it comes back to 3.0v but with the latest cells they say higher is better... I don't know how the cutoff translates to cars though cause it's a different ballgame than planes.

I think I will start looking at what the voltage is a few minutes after running to compare to what the cutoff/ low voltage was.

On a side note, I fried my ICE last night... one of the batt leads touched the power supply case while charging and smoke rolled out the charger. Not good. :031:

[Serum]

You mean your maxamps packs dropped under the 3V per cell, with only a 75A load?

You used a balancer to charge them?

I know what you mean with the higher voltages. the cells from flightpower (www.trakpower.com) stay above 7V at 100A load. you can gain some energy from these little buggers.

[Serum]

(I think it's conservative in the mah #'s... maybe add 20-30% ?)

nope.. That's Lipo! With Nimh cells, you can charge them for 3700 and only get 3000mAh back..

[glassdoctor]

[QUOTE=Serum]You mean your maxamps packs dropped under the 3V per cell, with only a 75A load?
QUOTE]

Basicly yeah... I can't say my packs are good as new though. The graphs pretty much show 3.5v per cell at 30A 3.4v at 50A 3.1v at 70A and 3.0 at 80A.

These numbers appear to be low but 3.4 at 50A isn't terrible. They are rated 10c or 60A. I can't say they wouldn't pull that off in a constant rate discharge. I have to wait and see what other batteries will show before I complain. The #'s for other pack I ran look to be much worse.

There are variables like temp of battery. I am running them cold which lipos don't like. They produce better graphs if run hotter.

And I don't know how this type of running compares to constant loads like you see in a discharge graph or plane. Often you see a graph dip and come back up as temp rises. These packs would probably hold 3.4v at 60A once they heat up a little, base on my spike load graphs anyway.

[glassdoctor]

here's a few graph snapshots of a coupel different runs

[glassdoctor]

One more... this is a full graph about 9 minutes in te street... 2225 mah etc etc

[glassdoctor]

Don't want to stay off topic but..... :) I think we just won't see the same #'s in the truck as we see in the discharge graphs from the guys who test a bunch of batteries.

They are using heavy wires directly connected to a bare cell... no esc, no long wires, no connectors, fresh off the charger, etc etc

The maxamps 6000 packs "feel" better than any other packs I have right now, so I am sure the numbers from the others would be worse yet...

I am going to put together a big pack for the truggy for super long run time... I can't wait to see the data from those packs. I think the voltage will hold very very well with a 12000mah pack. :)

[Serum]

One thing that concerned me;

my maxamps 4000mAh packs came with thin wires; 14awg..

Thanks for the graphs, are you using the micrologger too?

[glassdoctor]

yup... new toy for me.

I think the Mamba Max comes with 14ga also. But high strand quality wires like this don't have much loss esp in just a few inches of wiring.

I know what you mean though... I have been using 12ga wet noodle for years and 14ga seems kinda small. But really, the 12ga may have just been overkill all these years. :)

[MetalMan]

The Mamba Max has 13ga. wires on the ESC, and the motors have flexible 12ga. wire.