Size maxx for LIPO on CRT.5 Pro conversion

[rexasso]

Hi guys,

I would like to build a new CRT.5 Pro model with eltrci part. I will buy the latest CRT.5 Pro kit with extened chassis (the stock one from Jammin, not from RCM).
Can you tell me which is the biggest Lipo pack I can put on it (it will be 3s with a HV Pro Novak 5.5). These will determine Lipo capacité 3000 or 5000.

Is 145 mm x 45mm Ok ?

Is 155mm x 50mm Ok ?

Thanks for your help

[magman]

First, welcome to RCMonster!


I personally am not a fan of the novak set up. In both of my crt.5 conversions, I run a mm esc w a 50 series 3300 Medusa and a 1509 Neu ( 3300kv )in the other. Both are plenty fast. The one w/the 1509 neu I run a zippy 3s. The other w/the Medusa I run a 2s TrueRc 5k pack. The 2s truck is my daughters.

You should be able to fit the 5k pack in there w/a custom battery tray.

For my crt.5 I made my own chassis which is 3/4" wider than stock to accomodate the larger batteries. Mike sells trays here and everything else you need to do the conversion

[BrianG]

Don't know if this will help, but these are the dimensions for the shorter CRT.5 chassis (not extended):

[rexasso]

Hey guys,

First of all, thanks for your help.

About Novak: I had a HV Pro kit on my Emaxx and the ESC has burnt, so I have a spare 5.5T Motor. I will use it to start the CRT with a Hobby 150A ESC. This config will go back to the emaxx later and I will install a medusa (70 series probably) on the CRT

Ok so Yes I will go 5000

[magman]

A 70 series is serious overkill in a crt.5 IMO. The 60 series would do nicely and reduce weight and should run nice and cool.

When you upgrade your electrnoics, the mmpro is the ticket for a esc.

[BrianG]

lol, even a 50mm Medusa is plenty for a CRT.5. I have a 36-50-3300 Medusa on 3300mAh 3s lipo and it runs perfect. Stays cool, decent runtimes (~20 minutes), and has enough torque to flip it on its lid if I'm not careful. Any motor larger will just stress the drivetrain IMO.

hi rexxo.I have been down this exact road on and off all this year.the HV only seems to like two pack 4 or 6 s batteries in a two plug four wire setup,on 3s one plug two wire you over heat the internal BEC fairly quickly and it shuts down like its in thermal shutoff mode. Novack claims if you install an external switching BEC it will fix this shortcoming,unfortunatly in my set up after the BEC (installtion checked by Bob N. himself at the track)it would only Cog!So now my HV is alive and well in my1/8 scale buggy 4s ,HV, 7.5 and it hasnt missed a beat.As to your .5 an MM or MMpro is the way to go. the mm pro will run your 5.5 HV motor but i cant see it doing anything well except breaking and wearing out parts at an astonishing rate,although speed run should be entertaining.When i was running Novack/3s/7.5 combo it was very drivable at 90% throttle EPA and worked well until it started shutting down as mentioned.I run an RCM chassis w/1/10 truck sized tires so im running MM/3s/36-60-3100.I strongly recomend you consider an MM/MMpro with a controlable KV motor from mamba it will save you money start to finish

[muck]

i am running the MMPro and the 4600kv on 2s in a stock STE and it is plenty fast. The MMPro fan makes the esc too tall for the lid though.

[rexasso]

In fact my HV ESC has burnt, so when I say HV 5.5 it is for the motor only.
HV Pro 5.5 motor is a 36x72mm with 3700kv motor, so I think it could take place of a medusa 36-70.
For sure it will be a lot of power, but I planned to use exponential parameter for curve on my 3PM radio
About the ESC, I think I will try the HobyCity 100A
It will be in 3s 5000mah lipoly.
Should I use 2s ?

What do you think with this configuration ?

[E-Revonut]

I initially ran a Novak HV 4.5 motor on my CRT.5 and it ran great with my MM esc, I also fried the Novak esc. The Novak motor may have the outside dimensions of a 70mm Medusa but trust me that it means nothing! I run a Medusa 36-50-4800 in my CRT.5 now and even geared for 40MPH everything stays very cool and it has TONS of power.

[rexasso]

Ok thanks for this detail

Do you think it is better
1. a Medusa 36-50 4800kv in 2s => 35.000 rpm
2. a Medusa 36-60 3100 kv in 3s or 2s
3. a Medusa 36-60 2200kv in 3s => 24.000 rpm so with a bigger pinion

And what aboit the gearing : pinion/spur gear ?

Thanks again

[BrianG]

Personally, a 36-50-3100 on 3s would be the best option. The 60mm version would simply be overkill unless you plan to gear really high. I run the 36-50-3100 on 3s (Elite 3300mAh 30C) and it stays cool no matter what with lots of power. Let me put it this way: I need a new lid from it being worn down. I'm geared for around 30-35mph, which is plenty for off-road running in this little thing.

[ta_man]

Originally Posted by E-Revonut

I initially ran a Novak HV 4.5 motor on my CRT.5 and it ran great with my MM esc, I also fried the Novak esc. The Novak motor may have the outside dimensions of a 70mm Medusa but trust me that it means nothing! I run a Medusa 36-50-4800 in my CRT.5 now and even geared for 40MPH everything stays very cool and it has TONS of power.

Unfortunately, it is getting harc to find new Medusas.

I've got a CRT.5 running a Novak HV7.5 on 3S using a Havoc 3S speed controller and an external BEC. It is plenty fast enough for racing and the motor barely gets more than 10 degrees above ambient temperature. The speed doesn't get warm at all. It is geared 14:46 and I could probably go up 1 or 2 teeth, but then it would be too fast for my track.

I think a HV5.5 will be fine.

[stum]

I don't know if anyone mentioned this but you can get the Ofna Hyper Mini STe for 160 shipped and it's a better product iMO. I've seen both up close... again iMO there is no comparision.

I run a MM w/ Medusa 4800kv w/ 2s lipo with mine and I can keep up w/ 1/8 buggies w/o issues :)

[rexasso]

Yes I have seen the STe and really love it.
But my main concern is that only Nitrohouse proposed parts for the STe. No hop up as cnc parts for instance
But maybe the STe is too young and some parts will be created later ?
Why do you say STe is better then CRT.5 ?