Hi everyone, so I went to bunnings today to check for some cheap drills and I came across 2. The XU1 18V drill, which I know there is a tutorial for using in robowars robots, and a Ozito Power X Change 18V Drill Driver. I decided to try the Ozito because it has a very high torque rating (40Nm) and I'm intrigued by the speed switch (0-370rpm/0-1200rpm).

I have been attempting to remove the chuck housing with no success.
I removed the chuck screw in the middle (which took another drill to remove it) and that was fine and then I tried removing the housing by unscrewing by hand, that didn't work so I tried the alan key in the chuck method and knocked it counterclockwise which I believe is correct... Nothing, it won't budge at all. I've tried so many different things now that I'm pretty sure the gearbox is stripped at the last stage and have still failed to remove that damn chuck housing.
Has anyone else had this issue with this specific drill, or did I just get a dud? I did buy two so I might try and hand unscrew the other and if that doesn't work, give up and return it to get the XU1.

I went with the Ozito because it claims to have 40Nm of torque, which I assume is at the slow setting (380RPM) which essentially is just a switch on the gearbox itself to add another stage at the motors end (I'll need to glue that to make sure it doesn't switch mid fight). I was going to use this for my weapon system and then for the drive motors use the fast setting (~1200RPM) which I only assume cannot provide the full torque but rather just the extra speed.
Another interesting thing I came across is the motor and the gearbox is not secured together, it can actually come apart between the motor and gearbox so you can see the gear attached to the motor shaft and the first stage of the gearbox. I'm not sure why that is or if it's normal?

So final question, how much torque can the XU1 output and and what motor is it inside (RS550?) I saw 16NM thrown around somewhere. Also what's the max current?
I would really like to use the Ozito because of it's two settings and the better specs than the XU1, but if I can't get the freaking chuck housing off, then I obviously can't do that and I'll just have to go with the ZU1 for drive motors and a much more expensive worm drive motor for my weapon (needs around 20Nm of torque).

Thanks This is really really frustrating I've been working on it for 3 hours!!!

EDIT: XU1 is 50 dollars with battery, Ozito is 40 without battery, so the better specs might make sense. Also for the record I didn't run out the motor in the drill with a battery to flat since i don't have one, I was going to do that with a different battery once the motor was out

So I managed to get someone to help my out with the drill and managed to get the chuck housing off, there was a small clip I didn't see when trying to remove it. I will post photo's a bit later for reference if anyone else has the same problem.

The motor the Ozito Power X Change uses is an RS-550S, I assume this is the 18V version and not the 12V considering it's an 18V drill. So I just need to find out what the max/stall current. From my searching online I found RS550s 12V has a max current of 85A but the RS550s 18V has a max current of 8.5-10A, does that sound about right if anyone can confirm? Because that would be a huge improvement; 10x less current for only a little more voltage.
I'll be testing out the gearbox soon!!!

Thanks everyone

Honestly for a first bot it won't matter which one you use. Main thing is if you use a 12V motor use 3-4S don't exceed it and if you use the 18V version can probably get away with up to 6S (maybe).

Less hot winds are better and worse... Really a 18V 8.5A motor sounds a little limp if thats the stall current. But I wouldn't trust any motor specs you would need to test them. Just pick the voltage you want to run and pick motors based on that and get a pair of these. http://botbitz.com/product/botbitz-30ampv2-electronic-speed-controller/
Anymore thought is wasted on drills.

When you get the shits with drills buy a pair of these.
http://botbitz.com/product/banebots-p60-161-gearbox/

And when you get the shits with brushed motors buy a pair of these.
http://botbitz.com/product/banebots-p60-rs700-5mm-pinion/
http://botbitz.com/product/botbitz-30ampv2-brushless-firmware/
With a pair of little brushless motors to add to the gearbox.

Basically the progression everyone makes.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Thanks for the info Steve!
I've been gradually learning that's what people tend to do. I'm not so worried about the drive motors now, like you said I can just use a botbitz 30A ESC. But I now believe that the motors will use ~60A @ 18V because they should be 1000W. I can see that would be fine if they were brushless but considering botbitz 85A ESC seems to no longer be being made for brushed motors, that's a little bit of a problem.

I really need the extra current for my weapon (not really the drive) so it can produce enough torque.I was looking at potentially replacing the brushed motors on the gearbox with brushless, but most around the same size (same mounting hole position) are only half the power (500W) (I was looking at the Propdrive 3536 1400kv since I think it may have mounting holes the correct distance apart?). I was looking at potentially trying to modify an ESC with higher amperage but could just get messy and blow motors and electronics. I was looking at maybe seeing what the XU1 has in it, hoping it's an RS555 lol but figured that's probably not the case.

In terms of price using a botbitz brushed ESC and drill motor vs drill gearbox with brushless motor attached and a brushless ESC, comes out to around the same price.
So I'm kind of stuck at decision right now.
For drive motors just the brushed drill motors and botbitz ESC or gearbox, brushless and brushless ESC but half the power.
For the for the weapon I'm not even really sure now, I'd need a 1000W brushless which I may not be able to mount well or to get hold of a botbitz 85A brushed ESC.

And last simple question, is it fine connecting a 50A motor to a 30A ESC?

Thanks again for the tips Steve!!
Any advice is appreciated

For the drives stick with brushed drills. 30A will be fine on a RS550 whatever the variant. It will roast long before the ESC does.

For weapon what is it? Probably worth buying the P60 and a little prop drive motor with a Brushless ESCs.

My advice would be not to put a brushless motor on a drill gearbox. They are too fragile and mounting will be a bitch. I dont have any more of the brushless ones for sale on BotBitz but if you need a reversible Brushless ESC I may have something else if you get in touch when you make choices.


Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

I didn't realise RS550's roasted so quickly, lol
The weapon is a pincer using linear actuators I'm making myself.

I think the propdrive 35xx series should be able to mount to the drill gearbox because the spacing between where the screws go should be the same?.
The reason I was thinking drill gearbox is because the P60's are quite expensive (for my budget) compared to the drill gearboxes. The Ozito appears to be a 16:1 and 64:1 gearbox in one.
Also aren't the P60's configured to mount an RS500 motor? So shouldn't a propdrive that fits on a P60 also be able to mount to a drill gearbox that fits an RS500 or did you mean mounting in terms of the actual gearbox to the chassis?

Regardless I think I will be using brushless, getting brushed ESC's will end up costing the same (or more in the case of the weapon) as switching to complete brushless.

I was thinking of trying to design and make a custom brushed ESC just for fun, might post on here if I ever get that working successfully

Also didn't realise you were part of Botbitz! Nice to meet you

There is a number of issues with putting a brushless motor on a drill gearbox. First is the mounting. Yes the mounting holes should be the same but if they aren't you can't modify it. P60 just drill some more in it.

Secondly is power. Drills are already at the limits of their construction gears/pins start shearing under high load. If you put a brushless motor on it, it will easily exceed the forces the gearbox can handle and be destroyed.

$60 for a new drill vs $95 for a P60 isn't too bad when you throw away the drill after you realise it wont work anyway.

And while you can build an ESC it will be for fun you won't do it cheaper but it will be a learning process.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Oh another reason is the pinion. P60s the 775 gear fits straight on some motors.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

I do like the look of the P60's and will inevitably use them at some point, sooner rather than later is probably better!

In terms of the brushless exceeding forces how different could a 1000W 18V 60A 20K RPM brushed be compared to a 1000W 15V 70A 26K RPM? At higher RPM the torque would be less? I thought it was more of a performance to weight ratio thing rather than power or do the brushless have a higher stall torque? I haven't really seen stall torque values for brushless motors anywhere.
Haven't really looked into brushless until very recently so I'm still learning.
And yeah, building an ESC would be of just personal interest.

I've decided I'm going to stick with the 4 drill motors+gearbox for the drive but for the weapon, since I need that added performance I'll go with the 2 P60's and brushless motors, I've just got to decide on the ESC's once the appropriate motor is chosen. I would love to go with all brushless and P60's but it just can't fit my budget unfortunately, even for a 2-wheel drive system.

I'll go with all brushless and proper gearboxes in my next robot/version of Armistad!

I've been trying to calculate rough torque for brushless motors based on Wattage and RPM relation, since I need at least 15Nm of torque for my weapon, is this roughly an appropriate method of calculation?

Thanks again!!

Hey hows it going, sounds like you're onto a good start.

Drills are good to get you going, can use the cheap botbitz brushed esc's to keep things simple. I haven't seen the two speed types but they are generally a bit nicer than the single speed versions. Don't get too hung up on the specs, if its in a drill it will drive a robot IMHO!

P60s are much much nicer but to be expected for the price - unless you buy the wheels and hubs to match you will need to machine your own for the p60 so be aware of that. Drill gearboxes you can generally make your own wheel hubs without too much fuss as its just a threaded shaft.

As for brushless it is still an emerging technology and there's no real standard. Many are using small outrunners and inrunners to match the p60 with success. Both the controllers people were using (ztw60 and TZ85) are now end of production so that makes things tricky!

Putting them on drills is a bad idea as stated - they produce too much torque and would wreck the gearbox, the drills generally have a 1/8 inch shaft too which not many brushless motors share. although Jules and Miles on the forum i believe managed to find some.

Hopefully get to see your creation at icra
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Thanks for the info Glen!
I have decided to keep going with the drill motors and stock brushed motors with 30A botbitz ESC's. Brushless for the next one

Since I "found" (not much info on these quiheu chinese motors) the brushed motors must be 60A max at 18V, they will obviously be at half power which should be fine for the drive, unfortunately botbitz has no more of the 85A in stock so I'm looking for a solution to that for my weapon which I want to use at full power or close to it, but it's proving difficult to find a brushed ESC rated for 18v and 60A, I'm running out of ideas! I've even considered a motor controller with a high power motor driver between the receiver and motor, which right now is looking like my best bet right now unless I can find a low power brushless to attach to my drill gearbox that won't break it (at least instantly) like said.

Right now I'm deciding on directly connecting motors to wheels or using a v-belt drive with Nylon 3D printed pulleys, I assume timing belt drive is probably not the best idea to use for my robots drive system.

I'm thoroughly enjoying this and hope to see you at icra too!!

Timing belt would be totally more ideal for 3d printing - quite a few featherweight robots do that with HTD 5m 9-15mm wide timing belts. V belt is generally better for spinning weapons and that sort of thing. Of course the small ESCs and drills are relatively cheap so many just use 4x independent drives for redundancy

So with your current talk - the current rating on the ESCs is how much they can output constantly without overheating or failing, they aren't current limited (i.e. output an absolute maximum of 30 amps and no more) except in the high end ones (VEX BB and ragebridge can do that). A 30A botbitz could output as much current as whatever motor you attach to it demands until either the motor or controller fails so be conscious of that.

For your weapon, bb 30A is still probably okay, you said you are making your own linear actuators, i guess from drill motors/gearboxes also? In that case just leave the clutch active on the gearbox then you can't stall them at the end of their travel which will absolutely burn the motors up.
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Thanks for the quick reply Glen.

I'll take your advice on the timing belt. Depending on weight of everything I may or may not go for 4-wheel drive.
It's also good to know about the ESC's not having current limiting I wasn't aware of that. I just assumed it peaked to the ESC's limit and stopped there.

I have already decided to leave the clutch (and potentially chuck) in place for the weapon. I know all the tutorials around on youtube generally say to remove the clutch and insert grub screws to achieve maximum torque from the gearbox but would it be more beneficial for me to just leave the clutch in place for the wheels as well (if I do direct drive)and make sure the clutch setter can't come loose. Because if the robot is pushing into a wall for some reason then the motors will stall and burn out fairly quickly unless I have something like a timing belt that will probably end up slipping and prevent that? I guess this is also assuming I'm ramming my robot into a wall for more that a few seconds!!!

Thinking about it, why do the tutorials suggest to remove the clutch? Since the torque setting device takes basically no room, what's the point. Is it to just avoid it gradually loosening or is there some slight added torque from doing it?

Thanks again

I have run these motors on the 30A fine. http://ranglebox.com/product/775-18v-motor/ Like I said doubtful will have any issues with 550s.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com