Power choices....

[gbaileyo7]

Hey guys, I have a bomber that I'm gonna use for foff type
and need to power it. I built a wraith a couple years back and was doing the same thing with it at the time. I had a mmp and pro 4 3300 on that rig. I loved it but more wheel speed would of been nice so I'm thinking of all my options before i pull the trigger on a motor for the bomber. I already have a mmp esc and hopefully that isn't going to be the limiting factor on what I'm wanting to do here.
So I been doing lots of reading and I'm thinking of either another Pro4 3300 , a Holmes 3500 puller pro or possible a 4500 puller pro. The pro 4 4000 is not rated for 3s so that kinda puts it out of the equation unless I overlooked something. I do have a 2 speed kit awaiting installation at time of motor install for slow technical crawling when desired but I have a 2300 roc 412 powered JK for my crawling needs so the bomber won't see too much crawling but will see some I'm sure.
The terrain that I'll be foffing in will be strictly sawdust. I have unlimited supply of sawdust piles to play on....i mean 30 ft tall sawdust piles! So it won't be getting crazy amounts of traction and i run a standard 2.2 crawler tire such as a bogger or swamper.
I have and will be running strictly 3s 5000 mah 25c onyx batteries in this truck. I know heat will prob the main factor in this equation and not sure if the 4500 is just too much and will get hot too easily. The 3300 pro4 did great and if ran long enough and hard enough it would warm up but I always keep and eye on Temps and never felt that it got hot too easily by any means. I know the 4500 is a long way from the 3300 i had before but wheel speed is key in this type of terrain. So maybe a 4500 with underdrives???? Plus I have no problem letting it cool and while watching one of my buddies break something on their rig in the mean time

So any input to help on this decision would be greatly appreciated!

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[gbaileyo7]

Anyone?

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[Adamgllc]

I run a MMP and ROC 412 3100 KV in my Bomber and am pretty happy with the performance. I really wanted the 3500KV Std puller pro but they were out of stock and I'm impatient. If I was building strictly for foff I would go with the 3500 KV Puller Pro XL because the xl can size will tolerate higher gearing for more wheel speed. I would worry about the 4500KV on 3s personally, but maybe it's ok??

[WHITE-TRASH]

You want wheel speed on 3s then this will do it. I have one in my basher rig and it rips.

[gbaileyo7]

Originally Posted by Adamgllc

I run a MMP and ROC 412 3100 KV in my Bomber and am pretty happy with the performance. I really wanted the 3500KV Std puller pro but they were out of stock and I'm impatient. If I was building strictly for foff I would go with the 3500 KV Puller Pro XL because the xl can size will tolerate higher gearing for more wheel speed. I would worry about the 4500KV on 3s personally, but maybe it's ok??

I read somewhere that the XL would run a battery down considerably faster than the standard size. Any experience with this?

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[mikemcE]

Tekin 4x4 hd 3000kv the rpm version will give you insane wheel speed, I run the straight redline and no problems

[DenisLM]

I run the MMX + HH Puller Pro 540 standard 3500kV with 4300mAh 3S 40C without heating issues. I also have the 2 speed for very slow stuff.
And geared 15/64 give you plenty of wheel speed.

I'm sure you'll be happy with a similar setup...

[gbaileyo7]

Originally Posted by mikemcE

Tekin 4x4 hd 3000kv the rpm version will give you insane wheel speed, I run the straight redline and no problems

RPM version?

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[mikemcE]

The had motors have two versions.... Speed is the "redline rpm"

I may be brain farting.... My 17.5 sensored tekin has me thinking, one has a rpm version ( both motors are 3000, one is shorter)

[Adamgllc]

Originally Posted by gbaileyo7

I read somewhere that the XL would run a battery down considerably faster than the standard size. Any experience with this?

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Definitely has more of a draw than a standard, which will decrease run time, but you also get 550 size and more power!

[DenisLM]

Originally Posted by gbaileyo7

I read somewhere that the XL would run a battery down considerably faster than the standard size. Any experience with this?

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I have the XL in my Yeti and it's hard to compare because the Yeti is also heavier than the Bomber.

XL in the Bomber may not be a good idea, specially because the startup isnt as smooth than the STD.

[gbaileyo7]

That's good to know. ...i will have a 2 speed though. .... that offset the poor startup u think?

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[DenisLM]

Originally Posted by gbaileyo7

That's good to know. ...i will have a 2 speed though. .... that offset the poor startup u think?

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will help for sure, but if you want go slow just get the std and I'm sure you'll be happy. The STD already will be more torque and speed than the Bomber can handle. and that is my own experience with.
Maybe upgrade the MMP to the MMX to make it even better.

[durok]

Direct quote from Holmes Hobbies :

"we recommend 2S LiPo only for the 4500kv motor
because 3S could spin it beyond its 50,000 RPM limit. 68/11 is the
lowest gearing shown in the manual. We recommend that when running a
brushed motor. We have not tried it with a 4500kv motor, however"

[gbaileyo7]

I thought it could handle 4s :(

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[gbaileyo7]

Will the XL handle 3s?

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[durok]

Yes, They are lower kv, mostly - you multiply voltage times kv and don't end up past 50,000rpm or there will be issues.

I forgot the exact equation, let me dig for it...

Edit:

Yep, basically

"Voltage directly influences the RPM of the electric motor (brushless motors are rated by kV, which means 'RPM per Volt'). So if you have a brushless motor with a rating of 3,500kV, that motor will spin 3,500 RPM for every volt you apply to it. On a 2S LiPo battery, that motor will spin around 25,900 RPM. On a 3S, it will spin a whopping 38,850 RPM. So the more voltage you have, the faster you're going to go."

7.4v for 2S, 11.1v for 3S, 14.8v for 4S...

so 11.1v 3S LiPo with the 4500kv is about 49,950 - and when the pack is freshly charged it will have notably more voltage than 11.1, thus spinning it over 50,000rpm.

The RPM max rating on the HH PP motors is 50,000.

[gbaileyo7]

A 4600 castle motor is rated at 4s i just saw on ebay and i know the pro4 tekin 3500hd is only rated at 2s....not sure what they go by to determine how many volts they'll take. :/

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[WHITE-TRASH]

The castle 4600 is not rated for 4s by them. Castle motors will stand up to some stupidity as long as you pay attention to the bearings and don't do any sustained speed runs. The 4600 is only rated above 2s if used in a light weight 2 or 4 wheel drive buggy and then it's only rated for 3s.



Tekin rates their motors rather conservatively but they aren't totally out of line in their guidelines.

[gbaileyo7]

I'm sorry 3s!...typo :/

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