6S CRT.5 Neu motor question

[jhautz]

Originally Posted by VintageMA

Jeff - that was an awesome idea with the reconfiguration of the LMT - thank you very much!!

A little tricky reconfiguring the solder joints but I got it done and made sure the solder was nice an thick to avoid creating a fuse as per your old thread from last summer.

Went back up to a 17/46 (~39mph) gearing and with 4S pack measured peaks around 30 Amps just boogying around the house (whereas I would hit high 40s with the previously described config).

I probably won't get out for a real run until the weekend, but I am very excited with a setup that may work great and save me ~$500+ in the long run.

The big bummer is that my order for a Neu 3900mAh 3S pack just came in - don't know what I am going to do with it now, but maybe hang onto it for some ~30mph running around - probably get some long runs with it now.

Once I get a full run and can check the amp peaks and am sure this setup will work I then ned to find a nice 4S pack that will balance out well with the vehicle. The motor (230g), servo (60g) plus heat sink and fan come out to ~300grams. I had gotten the Neu 3.9Ah 3S pack cause it weighs in at 306grams and almost balances out the motor side of the vehicle perfectly. Maybe a NEU3200XP 4S (337.5g) or a TP3300 eXtreme V2 4S (351g) - both rated 25C.

Cool. Hope it all works out well. Let us know.

[Finnster]

The only limitation going HV on a CRT.5 is that the small mah batteries tend to really suffer considering power to weight (mah/g) ratios. The p/w ratio in lipos is not linear, so you end up having to use a much heaver (and bigger/taller dimensions) batt to get the runtime and current capabilities you need. My 4S 2500 batt from Neu seems about as big as I'd want to run. 5S may be doable w/ 2100 cells.

[VintageMA]

I agree completely as I have moved towards trying to get batteries that balance out the motor side of my vehicles lately (at least to within 50grams) if possible.

Right now the receiver and MM are mounted dead center, so i don't count them. The motor (LMT1930 is 230grams) and servo is ~60 grams. So my weight for batteries is ~300grams to keep things mostly in balance.

That puts the exact cell you are talking about - Neu 30C 2500's at 278g right up there with the other ones I am looking at TP eXtreme V2 4S 25C 2600 a 277g. http://www.rctoys.com/rc-toys-and-pa...BATTERIES.html

Both look good, but is this new setup works I'll probably try out the TP packs as they are a little longer and it'll be easier to bias the front/rear weight distribution - and not quit as tall.

[VintageMA]

Weekend update - Finally got a chance to run the new setup today. Ran it for 11:45 min with a MaxAmps 4S 4000mAh pack (god I can't wait to get rid of all my MA's and replace them) and drained 2.17Ah from the pack with a max Amp pull of 62.56Amps (830 Watts). And I ran the car HARD!! Lot's of fast high speed runnig with gearing back up to 17/46.

That is excellent news - with the max amp draw where it was I should have no problem running the TP 2600mAh 4S packs (to lighten weight) and still get at ~15 minute runtimes.

[lincpimp]

We need pics!

We need pics!

We need pics!

[VintageMA]

Here ya go. Snapped a few with Anaconda's on Traxxas 2.8 rims. I don't like them as much as the Proline 30's with the Jato offset, but it was raining today and I couldn't run on the grass so I had to put a good parking lot tire on.

[lincpimp]

Looks good, do you really need the fan on the motor?

[VintageMA]

Probably not anymore - but it can't hurt, right? I only threw he fan on the MM recently to make sure the MM would be happpy with 4S running through it. Maybe I'll try doing some runs with the fans unplugged and see how the temps on the motor and esc are.

But, like I just posted in another thread. I ran my XB8EC on 5S for the first time on a MM and w/fan the temps never got over 130* putting out a max of 1250watts - not sure right now why I preordered a MMM at the moment ;)

I really can't wait to see what the caps on the MMM are rated at, then we'll know if we can push them to 8S.

[lincpimp]

I have a MMM coming and plan to give it a try on 6s in my hyper st truggy. Will be spinning a 10xl for now as it was super cheap! I may step up to a 1515 2.5d if the 10xl does not work out.

I am interested to see how my 8s 14xl savage will compare to the 6s 10xl hyper truggy. I have had excellent success with the 8s setup, the 14xl does not get much over 150 in that truck, with hardly any airflow over it. Hope the 10xl will be as good. The hyper should be lighter when assembled than the savage, the battery is and the truck should be too.

It would be nice if the MMM will work on 8s, but then you will have to run an external bec, which is one of my favorite parts of the MMM. Imagine how neat the wiring wil look with the MMM!

[VintageMA]

Just a quick update on the results of this test:
Got a chance to run the CRT.5 with the TP2600 pak for the first time. It was kinda drizzling outside so was running a lot of wet grass so that gave a bit of rsistance, but I was very excited about the fact that with the left and right side of the buggy almost completely balanced within about 20 grams the buggy tracked prfectly straight accelerating and braking hard - no more pulling to the left or right because of a neavhy battery pack. With the lighter pack buggy weight was almost .25 lbs lighter - max Amp draw dropped to 53 Amps.

I think because of the think wet grass overall amp draw was up a bit so runtime was a bit shorter - only 9 minutes running very hard.

I'll have to try the exact same setup I did with the 4000mAh pack over the weekend and see what runtime is like.