"volt up" pros & cons

[tim the toolman]

I have a brxl in my honcho, and it's working out great for me. Running around on 3s right now with a 35 turn handwound, 80/14 gearing. No complaints really, but I have one 4s battery which I run on occasion, and it really helps out if there is mud or steep dirt climbs on the trail. So since this esc is rated to handle up to 6s, should I just start running 4,5, or even 6cell lipos? Would that shorten motor life drastically, or would there be no drawbacks other than more broken parts probably? I'm thinking of ordering an inexpensive 4 or 5 cell just to give me more options and have some more fun

[binaryterror]

More volts cause more arcing on the comms. How much is too much...well that depends on your use. In bashing motors are critical and cheaper to replace.

[Harley]

It will eat through brushes quickly. You can go to 4s and go to something like a 45t motor though. Keeps about the same speed but bumps the power way up. If you just want the speed then deal with the faster wear and have fun

[tim the toolman]

How much faster do you think? I wouldn't mind replacing brushes now & then. I recently switched from 45t to 35t, and it seems like 35 on 3s is the same as 45 on 4s

[Duuuuuuuude]

Pros ~ more fun!
Cons ~ more expensive!

[Charlie-III]

Yes, more volts will eat brushes faster. It is "almost" a linear line though. You double the voltage, you ~halve the brush life. Sorta.

Your choice.

As Holmes states, "Gear down, volt up" as long as your ESC can handle it.

[squatch71]

Originally Posted by tim the toolman

and it seems like 35 on 3s is the same as 45 on 4s

I don't think this is true either. I have both 35T and 45T, your assumption would also be like saying that 35T on 2S is the same as 45T on 3S....its not that big of a difference...60T on 3S and 35T on 2S...MAYBE more believable, but still I don't think is true...is a good thought though.

[tim the toolman]

squatch I was just going on my own recent experience, the 35-3s and 45-4s seemed very similar. Probably not exactly the same, but very comparable I thought. The motors could be a factor too maybe, I went from a standard 45 turn tekin to a 35 turn ckrc twister handwound.

[WIDELOAD]

Machine wound tekin vs. Hand wound CKRC doesnt make for an even comparison, which would explain your experience as well.

Pretty much what everyone has said is right. More volts=more wear with a brushed motor.

I've feel that the higher voltage makes things 'feel' a bit smoother as well as the obvious bump in power.

[tim the toolman]

also the higher voltage "feels" a bit funner for sure

[Duuuuuuuude]

If you knew the kv of the two motors you could see on paper how fast the 45t would comparatively spin with the added voltage.

[tim the toolman]

Hmm I've never seen kv ratings for brushed motors? All I know is those motors performance were very similar with the different batteries. I believe I will get a hobbyking 5 or 6s battery, to see how it performs and some entertainment too

[Charlie-III]

Originally Posted by tim the toolman

Hmm I've never seen kv ratings for brushed motors?

True, KV ratings are usually just for BL motors. I think Holmes Hobbies has some KV ratings on their site.
But that is limited value since neither of your motors are HH motors.
Yes, a handwound motor is typically better in all ways (except price) over a similar machinewound motor.

[Duuuuuuuude]

Originally Posted by Charlie-III

True, KV ratings are usually just for BL motors. I think Holmes Hobbies has some KV ratings on their site.
But that is limited value since neither of your motors are HH motors.
Yes, a handwound motor is typically better in all ways (except price) over a similar machinewound motor.

Its not hard to test a motor and see what the kv's are. Spin them with a drill at a known rpm and measure the voltage the motor is generating.

For example (and its a really rough example) if you spin it at 1000 rpm's and it puts out .5v, then you know that for every .5v you power it with it will spin approximately 1000 rpm's. 1v = 2000 rpm's, etc.

[Charlie-III]

Originally Posted by Duuuuuuuude

Its not hard to test a motor and see what the kv's are. Spin them with a drill at a known rpm and measure the voltage the motor is generating.

For example (and its a really rough example) if you spin it at 1000 rpm's and it puts out .5v, then you know that for every .5v you power it with it will spin approximately 1000 rpm's. 1v = 2000 rpm's, etc.

Hmmm....not sure the numbers obtained when the motor is a "generator" would be the same as it's KV rating. It would likely get you close though.

[Duuuuuuuude]

That's why I said "approximately". It may not give you lab-tested scientifically approved ratings, but it'll let you compare one motor to another.

[Grizzly4x4]

Originally Posted by Duuuuuuuude

That's why I said "approximately". It may not give you lab-tested scientifically approved ratings, but it'll let you compare one motor to another.

I have done it with my cordless Dewalt. Just make sure the battery is charged up whenever you test and the rpm should be listed on the drill. The numbers are right about what you would expect and like Duuuuuuuude says, it;s a great way to compare the motors you have.

As far as accuracy goes, I'd say it's like dyno testing a motor (1:1 gas or rc electric); results will vary from one tester to another. There is no such thing as an accurate number really, everything has some error.

[EddieO]

Thats how the plane guys and such determine KV rating for their motors......all done by spinning the motor at a known RPM and monitoring the voltage.

Some schools think you can just spin the motor up and check the RPM at 1v, 2v, etc and record the readings......

Which is right, I dunno..........I find KV a fairly retarded rating in the first place.

Later EddieO

[Duuuuuuuude]

Originally Posted by EddieO

I find KV a fairly retarded rating in the first place.

Maybe so, but its something that just about anyone can test. It may not be the best way to do it, but it makes an easy reference.

[EddieO]

Fairly easy to test yes........but its a fairly deceptive rating by itself, one that often leads to stuff going boom because people rely too much on it for things like gearing.

Example

Motor A 1500 KV

Motor B 1500 KV

Do you gear them the same? What if I told you Motor A made 14oz of torque on the dyno, while Motor B only made 9oz?

More of a factor in racing motors, but with trucks like the wraith and such popping up, along with scalers, can have similar effects.

Like I said, very deceptive rating where a customer could of had Motor A, he ends up with motor B as a replacement thinking.......same KV motor, slap it in my truck leaving all the same........to end up with a blown up motor.

Later EddieO