gonggongboy

IVE BEEN HEARING SOME PEOPLES OPINION ABOUT THE KB45 BEING BETTER THAN A LEHNER MOTOR. I KNOW FOR THE PRICE YOU JUST CANT BEAT IT BUT WHY DO MORE PEOPLE CHOOSE LEHNER OVER KB45'S. THE KB45 IS 45-77MM COMPARED TO THE SMALLER LEHNER WHICH I BELIVE IT AROUND 36-75MM AND THE BIGGER LEHNER 2250 NO CLUE DEMINSIONS BUT I BELIEVE THERE THE SAME SIZE. IM GOING TO USE KB45'S FOR A CAT BUILD BUT I JUST WANTED TO SEE WHAT PEOPLES OPINION ON THE KB45 OVER THE LEHNER.

CadillacDTS2001

not certain who told you that a Kb was better then a Lehner , However they are quite dead wrong. there is a reason why a one is about 400% more in price then the other.
also the same reason why a Cadillac is more money then a Kia.
i have owned about 8-12 Lehners and only 1 Kb motor.
also if you are comparing the 3 motors the only one that would be mildy competative with the KB would be the 1950.. the 1950 is the same rough size of a 540 brushless XL motor such as a hacker 540 XL or a fireago
the 2250 Lehner is alot of power. especialy if you are running two motors.
I would suggest you stay with the Kb motors.
Just to calify that again. the Kb motors can not hold a candle to a Lehner

Got RPM

There is a reason why people don't buy the KB motors. Taylor is right, compared to the Lehners the KB is pure junk. Club members who had them sold them right away - they would not even hold up to sport use. They are very inefficient - meaning they heat up fast. Their build quality is poor and balance stinks. Offshoreelectrics.com used to carry them but stopped due to problems. You certainly can "beat it" for the price. Buy a KB and you won't have a motor nor will you have your money - and you'll have to buy another, better motor anyway. Save your money and get a 'real' motor.

The Feiago 580L motors are far better than the KBs - but they also cost more. They would be my recommendation for someone wanting more power than a Feiago 540 but not wanting to spring the bucks for a Lehner or Neu. Actually if you are building a twin cat you may be able to use the Feiago 540XLs rather than the larger 580s.

norbique

OK I understand your opinions but how do you explain then, those videos on Youtube, that show some German guys having excellent results with both the L and XL versions of the KBs? Should I link in some? How are those KB's running so good?

CadillacDTS2001

there are a couple ways.. Maybe the replace them every couple runs. which i would totaly see. considering they are so cheap they are disposable.

norbique

What "couple of ways" are you referring to? Please explain to me a bit more detailed! Replacing bearings? Taking out shims? Drilling cooling holes in the front and black plates? Casting voodoo spells on them?!
I wouldn't say ~50+ bucks + shipping is cheap, at least not as cheap as to replace them (or should I say dispose them off?) every couple runs...

doby

My Feedback: (1)

Check out Offshore Electrics,,,motor section. They list them there for sale

gonggongboy

Great one on 6s http://www.youtube.com/watch?v=Racm4M3KyF8

And the power of 8s lipo http://www.youtube.com/watch?v=7CPuH5NVAGs

And two more great ones http://www.youtube.com/watch?v=zFlthkiWCQY

http://www.youtube.com/watch?v=rd7LQ6GXfWI

sundogz

I own 2 of the KB's - a 1000kv and a 2300kv. I had the 2300 in a 28" Batboat jet drive conversion running on 6s (briefly) when it caught air (jumped out of the water!). I ran it up the river (10 seconds?) and it blew the caps in a new Seaking 180A esc, and melted the 4mm bullet connectors (that came on the KB). When the boat floated back to me 15 minutes later the motor was so hot spit sizzled on the case! I was using 2 coils of alum tubing for cooling - should have been a full water jacket. Live and learn. There's no telling how many amps it was pulling at the time - the Seaking is rated for 360A surge. The motors magnets are fried and it spools up slowly now. You're welcome to it if needed for parts. These things are amp hogs to be sure. Spend a little more and get the Feigao's. You won't regret it. Sdg.

Got RPM

Okay, we are all trying to help you, to keep you from wasting your money. It is your right to ignore our help and plunge ahead, believing people you have never even communicated with. But remember this:

1) Don't believe everything you see on the Internet. YouTube videos only show you a few seconds of a boat's performance. Was the motor burning hot when it was brought in? Did it burn up on the next run? A club member did this, only posting the good runs to impress everyone. He soon sold all his cheap KB motors - the ones that weren't soo badly scorched that is.

2) Vendors like OSE take care of their customers. OSE stopped carrying this motor due to so many problems with it.

3) If you don't have enough money to enter the hobby correctly, wait until you do. A great many prospective boaters (and airplane flyers and car guys) get caught like a fish by the low prices of chinese junk - oh shiny!! - and buy it. Then when it burns up they say that the FE hobby sucks and only fools buy a boat (or plane or car).....



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sundogz

Let me ad that if you end up liking the hobby, and you started out buying the cheaper (parts, boats,etc.), you will have spent double or triple the money getting there. But if it's the only way you can afford to test the waters, ask lots of questions, and takes yo' chances, and may God bless. Sdg

gonggongboy

Im not all that new to the hobby i have about 10 cars brushless and nitro and a 44in mono. Im currently building a rigger and i already have a feigao 12xl and a ETTI 150A esc. I may get another 12xl and then buy two different esc from hobbyking. Yea those youtube videos are probaly miss leading.

norbique

I aggree with Got RPM, too bad I already ordered one, for a friend. the KB-45L 1800KV.
So what do you recommend me to do, I mean how to power it not to fry it. 4S Lipo shouldn't be too rough on it right?!
My friend doesn't want insane speed, just nice and easy hobby use.

Got RPM

The safest route will be to use a small prop to keep the amp draw down. Not knowing the boat it's going into, I can't make a recommendation besides perhaps an x445 to start. Just be very conservative. 4S is going to be plenty hot - you wouldn't want to go to 6S with any 1800 Kv motor anyway.




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kevinle

i owned all those motor myself 2250 is the best on the list, 1950 serries is powerfull but running hotter than 2250 because smaller size, its would be great for smaller size boat with massive power, KB is completely NO NO...., its powered ok when its still alive but its running super hot and die on me less than 1 week, its completely out of balance and very bad quality.

norbique

Got RPM, thanks for the reply! Sorry I could have been more spoecific. It will go into a Super Hawaii mono. The boat currently has a Speed 700 with a 1:1.5 gear reduction which can accept the KB, so there is possibility to either use the KB with the gears or without them as well. Water cooling jacket will be used for best cooling possible and maybe with dual water inlet & outlet, just to make sure.

Another question is, how much AMP ESC should my friend consider buying?Is the 100A mystery OK or should he go for the 200A version? Either way it's going to be modified, added watercooling and some extra low ESR caps.

sundogz

That KB45 1800 will pull over 100A when called for, so the 200A esc is the way to go. And the longest water jacket you can find that will fit it. Gear reduction is not necessary with that motor, but adequate cooling is paramount.

norbique

Thanks sundogs for the reply! I was thinking the 100A would be weak for this monster. The 200 will probably handle it better. We're making our own water cooling jackets so that will not be a problem. Here's a pic of the CF water jacket I made for the Feigao 540LX.

sundogz

Good looking jacket Norbique! Now don't make the mistake others have by putting the intake and outlet on the same side of the motor. For best results, put one on one end/side and the other on the opposite end and opposite side thereby allowing complete circulation around the motor. I've seen this rule ignored (for the sake of convenience?) even by commercial manufacturers. Ya gotta keep the KB45 cool for performance and longevity.

norbique

Thanks for the advice, but I knew that already. Here's the first jacket we've made. Not exactly 180 degrees off one another but the inlet and outlet here had to be made this way, since it was put in a very narrow space.

Got RPM

Unless the jacket outlet is at the very top of the can, you will have a trapped air pocket that will not get adequately cooled. Your jacket will work fine as long as the inlet is near the botom and the outlet is at the top of the motor. Not having full coverage of the top of the can will reduce cooling efficiency quite a bit - that is the hottest part of the can.


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sundogz

[quote]ORIGINAL: Got RPM

Unless the jacket outlet is at the very top of the can, you will have a trapped air pocket that will not get adequately cooled. Your jacket will work fine as long as the inlet is near the botom and the outlet is at the top of the motor. Not having full coverage of the top of the can will reduce cooling efficiency quite a bit - that is the hottest part of the can.
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[/quote

I concur with Got RPM about trapped air.

Von Ohain

well, i have had a share of both chinese and quality motors (hacker).
i have burned both too.

truth to be said, the chinese isnt really that hopeless, performancewise.
What determines your motors efficiency and internal resistance, wich in turn plays a huge role in heat buildup, is the quality of the wiring, and strength of the magnets.
since high grade copper wire is dead cheap, and the same is ultrastrong neodymium magnets, there is no reason the chinese cheapies shouldnt be able to perform. and they are.
quality brands are still better, of course, but not by so much as you guys want to have it.

the most noticeable difference between my hacker, and my similary sized kd (pretty much the same as kb), is the mechanical build quality. it doesnt affect performance at all, but it does affect your motors strength against wear & tear.
for example, the hacker has a thicker shaft through the motor itself, than the output shaft. this protects it against bent shafts if abused. the hacker also has one-piece rotor magnet, wich makes it able to withstand ludicrous rpms.
the latter isnt really a shortcoming of the chinese, because many other qualitybrands also lack a one-piece rotor magnet (for example mega inrunners).

for competitive performance i still recommend a quality brand motor.
but for recreational performance and just fun, a chinese can do without any problems.
its just to remember than you dont absolutely have to run your system to 100% all the time.
i build mine so i take out between 70% to 80% , and when doing this, the chinese stuff is plentiful.
the last 30%-20% can be made up for with buying slightly bigger equippment. it would still be far cheaper than quality brands.

BACKEMF

from what I have heard, of the KB type motors the shorter of the 2 cans, the "L" is more balanced and stays cooler.

I owned one XL can for a bit. Honking motor but somewhat hungry on amps.

I have read that they like higher voltage and it's a bit of a mental hump to get over. It would not seem right to run a 1800kv motor on 6S and a small prop but, maybe they just work better in the higher voltages.

gonggongboy

I saw a forum on Offshorelectrics, were a guy rebuilt his kb45. His problem was that the shims in the motor were to tight causing play and poor effeincy. And simply as by buying new shims of different size he increased the effiency alot more than it was. Now he has no problem with keeping it cool and its has little at all play.