Brushless cogging

[justo316]

Ok, I know good batteries are the *best* fix for cogging in brushless systems (Mamba), but I just read about a 'band-aid' fix for cogging for people without GP1100s or lipos.

Basically castle creations suggest adding a capacitor to their setup. I've read a lot of responses from people who have stated that this has improved their performance by a huge amount. I have yet to try it, but first thing tomorrow....

Anyway, the capacitor needed is a 470uF 35V one, and it needs to be attached to the esc side of the power wires. Easiest way is to solder it directly to the Deans connector you should have installed. The -ve side (has a little stripe) must be soldered to the negative power cable (black).

Sorry if everyone knows this already, this is just in case someone doesn't.

[BALISTC]

All I did was set the take off power to "low" on the Mamba 25, and there is no cogging whatsoever. I get cogging with the high take off power setting, and I havent tried medium yet.

[justo316]

What's your take off like? Do you pull wheelies from a standstill?

[justo316]

Oh, and I'm sure it's only a couple bux for a cap, so worth trying. I think it not only is supposed to minimise cogging, but it also gives better throttle response. Worst case scenario, you waste $2 and get a bit more practice soldering.

[justo316]

A problem you are gonna hate if you get a brushless.

Basically, the motor gets starved for power when you try accelerate too quickly and put a lot of load on it. It ends up not going anywhere fast and stutters like it doesn't know what to do. You have to really apply throttle very lightly to get it moving and then you can go nuts. But even so, if your batteries aren't great, or they've rundown a bit, if you try driving through grass (for example) it will stutter and not move.

You *should* be ok cos you got GP1100s which are so far the best nimh batts at the moment. They can handle a motor drawing a lot of amperage. However, I've heard mambas can sometimes pull 200A, so you're still not safe really.

Another quick fix as pointed out by Balistc, is to turn the power settings down on the esc. This can help, but as many people agree, they shouldn't have to. The esc settings should be for tuning how you want to race, not for minimising cogging.

[justo316]

I emailed Shawn at Castle Creations about this capacitor. I just wanted to know whether I HAD to use his ones or if I could just buy one here. He replied back asking me what 'cogging' problems Im having and that people usually use 'cogging' as a generic term for anything that goes wrong.

Well.....I have just been reading about cogging all night.....so I kinda let rip. I wasn't rude at all. I just stated the facts (basically, you need good cells to not cog. Simple). So I implied that any form of 'help' that he was gonna give me via email would just end up with the fact that I need to buy new batteries.

Don't get me wrong, I knew I was gonna need new batts in the first place. I just didn't think it would suck this bad without them! And from all the marketing material, it was NEVER stated that decent cells were required. I did notice the instructions recommended KAN cells, but nowhere else was it mentioned.

Anyway, I'll post back when I get a response. I wrote a huge email, may take him a while to get through.

[BALISTC]

Hahah, nice one Justo...let us know how it goes! If you can, post the email up here.

Justo, my Mini-t pulls huge wheelies from stand still and if I'm not careful it flips onto its roof...it also pulls very nice rolling wheelies ;)

[danhfvcsd]

are you gonna install em on your setup then? - can you get a pic of the install if you go through with it please? - i'm a bit unsure about where u solder it to hehe

[James]

I fitted my mamba 6800 last night and tested it quickly out on the lawn, which was wet. it wouldnt wheely (coz of wet lawn) but it hoons like hell. havent experienced cogging and didnt set any settings, just plugged it in, setup throt/brake, and drove it

[justo316]

As requested...I rebutted his argument again. He is the marketing guy, and was doing most of the testing. He should have tested on average equipment like average people would have.I told you he would end up saying I need new batts ;)

Hi Justin,

I appreciate your reply, and wish I had time to be on the boards more to
fully explain to everyone why the Mamba does what it does with "stock"
batteries and connectors.

I agree with you fully that we need better info on the website, in the
instructions, and perhaps even right on the box in big red letters that
top-quality batts and connectors are necessary for top performance with
these high-power systems. To be totally honest with you - we made a WRONG
assuption that when the consumer purchased a system capable of 5x the power
and speed of the stock one, they would then know to upgrade the one part of
the system actually SUPPLYING that greatly increased amount of power. The
motor simply uses the power applied to it - it can't "make" it's own - the
ESC is just a gateway from the batts to the motor and can't "make" power
either - the only part of a high-power system the whole thing hinges on, is
how capable the batteries and connectors are at transmitting their power out
to the rest of the system to use. Our main background was in aircraft, and
thus - cutting edge top-level equipment is highly sought after with the
power levels needed for flight, and the above type of thinking comes with
the territory. We realize now - that the car market is very much not that
way, and we need to be FAR more explicit with instructions and
recomendations than we have been. The abovementioned changes to the website,
instructions, and box are my responsibility, and are being worked on as we
speak.

I fully realize the pifalls of informing our customers, who have already
spent $150+ on the system, that "you need to spend yet more money to fully
realize the capabilities". I wish I could do something to change that, but I
can't by force of will make batteries more capable of high-level discharge,
so the alternative is to educate the consumer of the importance of upgrading
their battery packs, if they expect to see the full increase of power the
Mamba sytem is capable of giving them.

Thanks,
Shawn Palmer
Marketing/Support Dir.
Castle Creations
shawnp@castlecreations.com
785-883-4519 direct ex 115

[BALISTC]

Not a bad reply from Shawn actually, at least you got a decent reply out of him...most companies would have sent you a crappy generic email saying "we appreciate your comments".

Good batteries should be at the top of your list anyway...not only to reduce cogging, but to get more speed ;)

[justo316]

My point was, yes we all know the benefits of good batteries. However, with normal brushed motors, if your battery is crap, you can still play at least. With brushless, it's all or nothing. There should have been plenty of warning from castle creations directly.

Went dick smith to get a capacitor. Couldn't find one. In Shawns previous email he said the newer ones didnt need it. I will still try it though when I can find one. In the meantime, I bought a new soldering iron, so I'm gonna try build a battery pack.

[BALISTC]

True that.....many people dont expect to fork out so much on a motor and ESC, then have to find out the hard way about having to buy good battery packs...they should know beforehand before they drop the money on the table!

[justo316]

With the whole move to brushless (in cars) over the past few years, I'd never have assumed that good batteries were a must. It was always pushed as super fast, powerful and EFFICIENT, which I took to meaning it could make the most of your battery.

[James]

I've read enough. I'm honestly not going to waste my time and money on nimh batteries for the mamba.

It's lithium polymer batteries or nothing. I'll have to wait a while because it's a large purchase for me at the mo, considering I'd need to shell out $250'ish for a charger that can support lipo's. So it will have to wait a while.

I'm thinking Duratrax ICE, and two or three 2-cell lipo packs.

I've found I'll never have performance with the battery pack I have. It just doesnt cut it. well, it does for like 1 min. then, pfft.

I've not managed to get my mini-T to wheel stand yet.

LIPO or die.

[danhfvcsd]

still tho - $80 max for a lipo charger - $35-40(depends on exchange) for 1500mah 2cell lipo battery.
so around the $150 mark is pretty good i'd say for 2 lipo batts and a charger ;)

i suppose the batts are from the states tho at that price -lol-
but like i've said before, my lhs sells prolux lipo charger for $50 :)

[BALISTC]

Thats weird James, mine is ridiculous with an 8 cell.......its lightning quick, to the point that its so much quicker than my RR Evo, even when your babying the throttle to prevent it flipping on its roof, then BAM...full throttle and it pulls a massive rolling wheelie!

This is on grass too, not bitumen ;)

[BALISTC]

Oh, and when I mean quicker, I mean quicker...but obviously top speed isnt the same as my RR Evo was ;)

[justo316]

I'm relying on you Balistc....I'm hoping there is this magical increase in power with good nimh cells.

I've done my reading. It's all to do with current draw and certain cell's abilities be a slut enough to put out.

[BALISTC]

I'll SHOW you mine on the 8 cell if you want Justo before you take it home, you'll see for yourself ;)

I'm sticking with my 6 cell packs from now on.....the 8 cell really is too much for me to handle, and I keep flipping the car every time i get on the throttle!

I've got another GP 6 cell on the way, so it should be all good for racing ;)

If I want to go stupid, I just set EXTREME timing and it does huge wheelies either way!