High Torque motors on HL Leopard 2 problem
 

Hi All,

I recently bought 2x High Torque motors for HL Leo2A6. (Apparently 5x times stronger)
http://www.rcuniverse.com/forum/atta...mentid=2060031

My gears are all full metal to handle the gears.

I installed them, works fine, went fast if accelerated at full speed, etc... EXCEPT!

1. When i turn RIGHT, it didnt have much power, then the tank went dead. Then i had to restart the engine from the controller. (reminds me when you have not much power on battery and due to recharge)

2. But when i turn LEFT, it has power to turn, but not much as i expected comparing the power when your tank go forward or backward


I fully charged the battery

I tested the tank on paved bricks floor. Standard HL metal gears works fine on paved surface, but not the new high torque gears.



Could anyone kindly suggest what the problem might be? :confused:

Thanks in advance

I think this what's happening to your tank.

I don't think it's a battery discharge problem because you can move forward and back fine right?

I think it's your motors that are drawing too much current and the board just shuts down. The reason why it only happens when you turn is because one motor is basically moving the entire tank weight, so that motor is drawing much more current than when two motors are working together to move the tank. The reason why the right is more affected than the left is because your your left track is more rigid, it takes more torque to move it, hence more current being drawn by the left motor.

By any chance you're using metal tracks too? Metal tracks requires more torque to move, so taking them off might help.
Do the following test: Take off the tracks and test your motors just with the sprockets. If they run fine without the load, then it's the motors drawing too much amps than your ESC can handle.

Hi Mate,

thanks, that sorta make sense. im not good at electric stuff you see... lol!

With the tracks, i'm using Tamiya tracks. good quality Plastic + Rubber Pad. Do you still want me go ahead with the test?

Check the gear mesh - sounds like you might have one side thats a bit too tight? You can always bend the mounting bracket 'a little' to improve this, or slot one of the mounting holes with a needle file.

I assume you are using the original motor pinions? If you have changed the number of teeth this will also require adjustments to the mounting holes to compensate for the bigger (or smaller) diameter pinion.

Ok, after spending half day trial and error on me tank, i gave up.

1. I took off the gears from the hull, put back in, ensure the gear's teeth slot nicely to each other, balance them, and Greased. Test run and the results improved the speed when turning. but still, one is weaker than the other

2. Another problem arised, when cornering, or reversing, i realised my right TRACK came off slightly from the sprocket. only on the RIGHT. not left. The solution was to stretch the (left and right) Idlers forward making the Track stretch out as well. Sux, but the solved the problem at least.

3. Re-attempted to fix the point 1. problem, i swapped the so called hi-torque motors from right gear to the left and of course vice versa, test run it, it gets better. But ONE problem, my tank keeps shutting down when climbing, or turning on rough surface (e.g. sand surface). Basically, whenever it requires extra grunt/power, the tank shuts off. Even when you try to keep moving against the wall, it dead...

Oh this is the battery im using.. i think it can handle more than stock battery does.

http://www.rcuniverse.com/forum/atta...mentid=2060472


When i get a chance, i'll revert back to the stock HL metal Gears back in and see the difference... :mad:

If all is well in the gears, then it does sound like your Hi torque motors are drawing more power than either the battery or control board can supply?

For example - I have a set of high rpm 380's here that will basically move the tank about 6" before shutting down the Tamiya DMD that they are hooked up to. I did some research on the model they were intend for and discovered that it comes with a 70A ESC(!) - the DMD can only supply about 20A before it shuts down.

I agree with Pat. And there is really no easy "fix" to this.

1. If you want to run these motors, you probably have to get a better board/ESC that can handle the current. Email the people you bought the motors from and ask for what recommended tank electronic to run them. Ask for the motors continuous current and peak current are also useful to know.

2. Use old motors or get motors with current that matches your board motor controller. For example, these promax 480 motors (ACC348) draws only 12A max and they are very strong. (http://www.maxxprod.com/mpi/mpi-10.html)

By the way, what electronic are you using?

Take a look at this thread and see if you think the Leo will perform similarly to the 99A. I got two of these motors for $7, including shipping. They're marked as 360SH motors, but I'm not sure if they're real Mabuchi motors or if they're the -2885 I was looking for when I found these. The tank in the video is running on stock HL gear (RX-18) but I haven't tried some of the punishing stuff like climbing steep grades.

http://www.rcuniverse.com/forum/rc-t...uad-video.html

Just email TankArmy and ask them if they know what brand these gears are and if they are suitable for the stock HL board?
It does say they come with cable for connecting to RX18. Perhaps they can shed some more light on it for you.

I think the board is running hot, reducing sustained current delivery. It's my best guess. The HL 2.4GHz board pretty tough though because I have one here (the new one) that I used in my tank with metal tracks, idler, sprocket & road wheels. Yours might running really hot if this is the case. Temp can rise pretty quickly & the FETs can cool down pretty quickly too once there's no load.

Cheers Pat, good indication.

I emailed Tank Army on eBay (Where i bought this motors from) based on your point # 1 above.
I'm using pretty much standard board and controller. Though i do have CLARK board sitting in a box untouched, just because i take my sweet a*se time to get another controller... i think i'm more like "Use it till it dead, then consider buying another to replace" basically use it as much as i can before getting another.
Im not sure if ClarK board can handle these motors though? maybe its time?

Hey Mate, yeah i emailed them already to see what they can come up with


. i'm using Version 2 board of HL "2.4GHz Multifunction Unit For Heng Long 1/16 Tank VERSION 2"

THanks guys for your help. Will keep this post posted. Cheers!

nexusys have you checked this video posted by maxu 52 360 Hi-torque Motors in Modern Tanks (A Squad Video) you haven't mentioned it and for the $7.00 & that includes shipping sounds like the cheep way to go and get the tank running. instead of burning the rx 18 in this one out or spending money for a transmitter to use the clark board, that you still don't know if it can handle these motors either

Sounds like stall current problem with motors drawing too much current for the ESC's.

Need to compare the motor data sheet with the stock motors and 'find' a motor with better torque/RPM that does not let stall current go through he roof!

5 times the torque usually means increased current draw (especially for one motor as in turning) and thus a bigger ESC is needed. The battery is good for all types of ESC's so don't worry on that.

Yea I saw those "5x the torque!" motors and knew something like this would happen. An easy way to find out if you are pulling too much amps is to get a 5A auto fuse and hook it up between your motor and your motherboard. If you blow the 5A fuse you are pulling too much power. 5A is about max it can handle if I remember correctly.

I have found Lipo's are the battery to use in situations like this. The issue is more the battery then the ESC. If you use a lipo this issue will stop or fry your ESC if the motors are truly drawing that much amperage.

IN all the cases where I had tanks shutting down from to much amp draw( Brownout) the Lipo cured it every time, and to date all my RX18's are still fine.

Also what gauge wire are you using to supply the ESC from the battery.

That's interesting Dan, but makes me wonder how the RC car guys get high output on their batteries without brown-out, I mean they were using NiCad's and NiMH batts for years before Lipo's and us tankers came on the scene.

It's probably a combination of Battery current drain, ESC max surge and motor stall characteristics.

I'm sure a hot motor can be used if the stall current is low for his application.

Now that I think about it Dan, your point seems more valid as I have experienced some browning from batts freshly charged. In fact after running them a bit the browning goes away.

Maybe some batt types need 'warming' for the chemical reaction to surge when needed? Sound viable?

Probably because the gears on rc car is much simpler, light weight chassis & almost zero chance to stall. I've never experience brown-out issue before though, in rc stuff. If I did, I would fallback to NiCD battery because it was design for heavy duty job. I mean cordless power drill also use NiCD battery.




@nexusys, you said "new high torque gears". Can you post a picture of that gears? It's not the HL Ultimate Edition II gb, is it?

All I know is that when I am running a Benedini ,15 watt amp with a 12 volt power convertor the brown out with NiMH is almost inevitable if the tank gets into some heavy lifting. With Lipo's there is no issue. Maybe if a guy went back to a receiver batter pack might help as well and isolate your electronics from the mechanical side of things. .

Hi All,

Sent an email to the seller, i get this back from them:

"Hi

This item has been used in many heng long tanks without any problem. I suspect your 4700 mah battery has caused the problem. It is recommended to use with heng long 1700mah battery.

You can send it back for refund if you do not like it, per our return policy

Regards"


Failed to answer my question. Looks to me an easy way out for the seller. And of course arrogant. Didn't expect that at all.




Yep, i just watched them, (was at work yesterday, so no go for youtube videos). That looks good, just what i was expecting to have. I got all the speed, but not when spinning, and climbing.....




This is the problem, i couldnt obtain this information from the seller.. see above response from them... :mad:



This is what im considering.. an ESC that can handle this... any suggestion?


That will be an experiment.... good suggestion, but i think we all drawn to mainboard is the culprit..... maybe...



Hey YHR, can you confirm this? i would consider to get LIPO instead...
I dont use any other wire apart from stock supplied stuff...


Hey Kizwan, this is it... no brand or whatsover..
http://tankarmy.com/heng-long-tank/i...zinc-alloy.jpg




Thanks all for keep the topic rolling....! ;)

Looks to me like you have the basic pot metal 3-shaft HL gearboxes. I've tried the HL 2.4GHz electronics on my Bulldog, which has 4-shaft steel gearboxes and 480s in it. It browns out running in the house. The same tank runs beautifully using Taigen 2.4GHz electronics. I think that HL took some steps backwards when it moved to the 2.4 GHz setup. The same tank ran well with the old 27 MHz RX-18s. Aside from losing the proportional speed control of hte RX-18, the new 2.4GHz setup also seems to have lost the more robust FETs of the RX-18s. If you have an RX-18 tank, try the same setup in that tank with the RX-18 electronics instead...or try a Taigen. The problem isn't the battery's capacity (4700 vs 1700 mAh).

Oh...those pot metal gears have a tendency to bind if not broken in. Recommend following the procedures in the FAQ sticky in this forum to break them in.

Yes, Lipos can deliver way more current then NiMH batteries. That is why they are so dangerous. Dead short one of these and something bad will happen.

.

Oh I see, Dan

You use a 12 power inverter, I bet that's the issue with your battery browning.

From my experience building power supplies, the current draw can be excessive (and instantaneous) to maintain voltage level on the output. The recovery of battery is typically too slow for most inverters when drawing surge current from my experience.

I use the same gearboxes in my T55 tank with stock motors with no problems (and Tamiya electronics), so I suspect it goes back to the motors having a really high stall current.