Need advice on my temperatures and possibly suitable ESC and motor.
 

Hi all,

This is my first electric and 1/8th vehicle, it's a second hand Losi 8 2.0e, so far I have tried the following pinions 15, 17 and 19 and the temperatures were too high so below are my latest temperatures with a 16t pinion and the standard 45t spur. The motor at the 15 minute mark did get too hot to touch so I'm not sure if that is normal or not?

After 3 minutes:

Motor - 41*c
Battery - 26.2*c
ESC - 35.5*c

After 6 minutes:

Motor - 52*c
Battery - 27*c
Esc - 38*c

After 10 minutes:

Motor - 67*c
Battery - 29*c
Esc - 42.5*c

After 15 minutes:

Motor - 81*c
Battery - 39*c
ESC - 47*c

What do you guys think?

After the 15 minute mark I believe the reason for the battery and motor jumping up in temps that much was due to me not realising the battery was spent and carried on for another 30 seconds to 1 minute and the controller kept cutting out. However when I got home and connected the LiPo to be storage charged the charger was reading the cells at 3.7v each, I have set the voltage protection at 3.4v/cell so I'm not sure what was causing my car to not respond to the controller when the LiPo still had some juice left, thoughts?

Forgot to mention my LiPo is a Turnigy Nano-Tech 5000mAh 65-130C.

Thanks in advance for any replies.

It's generally recommended you keep the motor under 180F or 82C. The wisdom I've gleened over the years suggests under 160f or 71C is a much better place to be. Your esc temps are fine as they should be under 150F or 65C. Lipos should be under 120F or 49C so you're good there too.

Your motor temps are getting higher than I'd like in my vehicles but I'd really like to know more details about the motor. Manufacturer, kv, size (length and diameter) to help out more. Also what's the esc and the voltage of the Lipo, 4s, 5s, 6s?

Its perfectly normal for the voltage to read higher when you measure voltage after a run. In fact your packs reading 3.7v/cell with the LVC (low voltage cutoff) set to. 3.4v/cell is right where it should be. The esc is constantly monitoring the total voltage of the pack and then dividing by the number of cells to determine individual cell voltage. The voltage of the pack will drop under load (when on the throttle) even when the pack is fully charged. Remove the load and the voltage will rise. So take a fully charged pack at 4.2v/cell hit the throttle for a second or two and the voltage under load during that burst of throttle will be more like 3.9-4.0v/cell and when you release the throttle it'll go back up to 4.2v/cell. Same thing happens during the rest of the run. So when the LVC trips, it's actually tripping when you're on the throttle. The esc stays in the protection mode once the LVC is tripped because it knows the voltage will drop again tripping the LVC again as soon as you hit the throttle. Most esc's actually have a 2 stage LVC where the throttle is limited when you first trip it so you can drive the vehicle back to you. With limited throttle voltage won't drop as much under load and may be around 3.5v/cell while driving back to you. But if you continue driving around and voltage under load hits that 3.4v/cell the esc will cut all power to the motor.

As the Lipo loses voltage the amp draw goes up since the motor is still drawing the same wattage which explains why the temps rose faster at the end of the run.

What motor, ESC are you running?
Also, what voltage is the battery (didn't see an S rating in your post)?

Although gearing and ambient temperature are the primary sources of motor temp control, Drive train, driving style and other factors will affect motor temp as well.

Being a used buggy, what shape are the bearings (wheel bearings for sure, diffs and other bearings as well)?
Of the 20+ RCs I've bought used over the last 8 months, I don't think any came with bearings in decent shape. Rolling resistance + the weight of a 1/8 buggy will put a continuous load on the motor.

Sorry I didn't include these details earlier.

The LiPo is a 4s Turnigy Nano-Tech 5000mAh 65-130C. The ESC is HobbyWing XeRun 150a. The motor is a Turnigy Trackstar 2350kv, it is a sensored motor however the sensor is either damaged or the port is where the censored wires goes in to the ESC and so it's running without it instead. The can length is 68mm and the diameter is 42mm.

I haven't checked the bearings to be honest however I did buy a whole front end of the car which claimed it had new shock oils, serviced diff and it looks fairly decent. I have put all new gears, gaskets, and oil in the centre and rear diff myself.

I just wanted to clarify my earlier concern about the car not responding, was it actually the battery running out of juice then or something else?

Thanks.

The car not responding is the battery voltage running low and the esc's low voltage protection or low voltage cutoff (LVC) kicking in and protecting the battery. Lipos cannot be run below 3.0volts per cell otherwise damage will occur. To prevent this the esc has a LVC that will reduce power to the motor to let you know the battery is out of juice. If you keep running the car after the esc reduces power, the esc will eventually cut power to the motor completely to protect the battery. As I said before it is completely normal for the battery voltage to rise when you take the battery out of the car and measure the voltage. Battery voltage will drop when throttle is applied and the LVC will kick in during this time. When the battery is out of the car obviously no throttle is being applied so the voltage will be slightly higher.

As as for your motor temps I'm going to say it's because the speed you're geared for is too high. With the 2350kv on 4s geared 16/45 your speed is about 50mph. Your motor will be much happier with a 14t pinion for a top speed around 43mph. If you want to maintain the 50mph top speed you're going to need a bigger motor.

Also while it is possible to run sensored motors in sensorless mode, many sensored motors don't particularly like it. I'm pretty sure it has something to do with the timing and sensored motors liking a bit less timing. If you can lower the timing on your esc that might help a bit and may allow you to run the 15t you mentioned that you had. Either way I'd say 15t is going to be the largest pinion you can run with this motor and it will probably like 14t better.

I've bought many used rcs where the seller claimed add electronics and go. Find out what size bearings you need and hit eBay. You can get them cheap there and always good to have new bearings on hand. Odds are your geared a bit high and bearings aren't the issue.

The not responding is probably the LVC as previously mentioned.
Every ESC I've had allows power to the servo when the LVC is in play. I'm guessing you can turn the steering when the motor kicks out?

For your sensor, try a new cable. They tend to be what goes before anything else

Thanks guys, I'm going to try a 15t pinion when the weather is better and also see if a new cable works on the censored motor and I'll come back with my readings.

What should I set my timing to on the ESC?

My current ESC settings are as follows:

1. Forward/Reverse/Brake
2. Drag Brake 0%
3. Voltage Protection 3.4v/cell
4. DRRS Punch Level 5
5. Brake Force 75%
6. Reverse Force 25%
7. Initial Brake 0%
8. Neutral Range 9%
9. AMTS Timing 4

I generally run 25-50 for brake force, reverse 50% and timing middle range.
Higher ESC timing narrows the power band to the higher throttle range and will generate more heat in the motor.

My ESC (could be just different wording) has reverse lock out which won't kick into reverse until the ESC senses 2 seconds of throttle at neutral (or reverse trigger, neutral then reverse trigger.
I've had issues with the forward/brake/reverse kicking into reverse on hard braking on loose terrain. Tires lock up, motor detected as stopped and bam, reverse when I wanted brake. The reverse lockout just means I double tap reverse if I need it quickly.

Right got the results from the 15t pinion today but couldn't let the LiPo finish as I had broken a lower arm running in to a post.

After 3 minutes:

Motor - 41*c
Battery - 26.5*c
ESC - 32*c

After 6 minutes:

Motor - 56.5*c
Battery - 29*c
Esc - 39*c

After 10 minutes:

Motor - 73*c
Battery - 36*c
Esc - 48*c

After 12 minutes:

Motor - 73*c
Battery - 37.5*c
ESC - 51.6*c

As you can see it's still disappointing and the motor is too hot to touch even after 12 minutes. I really don't know what to do now, shall I just get a different motor? Perhaps something around 2200kv and see how it goes? There's not much of a change from the 16t and 15t pinions but in fact the 16t pinion ran the electronics slighty cooler if anything.

Thoughts?

Try putting a fan on the motor,on and off throttle alot can cause it to heat up quick.

How you drive the vehicle can make a big impact on temperatures. As Next Exition mentioned lots of stopping and starting can raise temps pretty quick, same with driving in grass. How you drive and possibly driving a little easier with the 16t compared to the 15t could explain why the temps are similar.

I dont have have any experience with that particular motor but it should be able to support the speeds you're geared for. It's got the right external dimensions and it's a 4 pole motor, the only thing I don't like very much is the kv is on the high side. I'd try a fan or a fan/heatsink combo as the temps with 15t pinion are close to acceptable. A fan and 14t pinion should be about perfect.

If you'd rather replace the motor I'd drop the Kv to around 2000kv. At 2000kv you'll be a little more suited to 1/8 and the pinion selection you currently have, I'd say 17t would pair well with it. Make sure the new motor is still a 4 pole and is the same size or larger. Longer motors have more torque and can pull a higher gear while heating up less.

Well I've been driving pretty much in the same style with each testing of a pinion. Can you guys please recommend me 2 or 3 motors from which I can choose from, my ESC is a HobbyWing, not sure if it'll have compatibility issues with the motors you guys recommend?

I was running a fan/heatsink on my ofna lx2e and can say it helps a lot.
The highest temp I could hit was 53'C running sand paws in deep grass.
If I let the buggy sit for a second or so, I could watch the temp drop.

As far as compatibility, there's no compatibility issues with sensorless, sensored can have issues at times but I'm not really familiar with any specifics. For motors there's always the ubiquitous Castle 1515 (2200kv), Tekin T8 series sensored motors (many kv's availible) at the top of the list. Hobbywing has a few choices like their 4274 1800kv sensored motor and a 4274 2250kv sensorless. Leopard has many options from 4074, 4084, 4085 in a variety of kv's and even a sensored line to go along with their sensorless line.

I'm sure some have luck with Turnigy, Toro and other brands found on Hobbyking but these are much better choices. The Hobbywing and Leopard motors aren't that much more expensive than Hobbyking stuff and you get what you pay for.

http://www.hobbypartz.com/07e-xerun-...lue-motor.html
This motor puts out 1350 WATTS.!! :eek: That's some serious horsepower. So yeah, a fansink would probably be a good idea.
Gear down another tooth.

Ive used the mamba monster(tork version)2200kv-hobbywing 2250 but the toro 42/75 2000kv x8st sensored motor I used was the best it has a fan inside the motor on its endbell and ran way cooler and grunt that seem like it never ended on rctech youll see alot of guys praising them and even rating them more than there previous tekin and castle motors,its kinda ironic how they look like the turnigy ones though maybe the guts tell a different story(4 pole 12 slot sintered rotor etc)that was on a xerun 150a esc for 2yrs running nothing but 6s.

One thing I can say from experiences, if you go big power, expect to wear parts quickly.
I was running a 1600w leopard motor in my rustler and most of the thing pins are bent, pin mounts sloppy, and changed drive shafts like underwear.
The last time I ran my rustler, you could see the rear rpm suspension arms flex and rear wheels wobble when I cracked the throttle.

I'm not so sure on the Castle motors as they are considerably more expensive than ones such as the Turnigy or the Toro one and I'm not certain if their price will is justified by how long they will last because even they can fail right. It seems HobbyKing are out of stock on the 1/8 Turnigy motors. From eBay shipping can be up to 1 month for China. It's shocking that there are no suppliers in Europe that are stocked.

The internals tell the story with brushless motors. Btw it's not the rotor that's slotted and sintered. It actually refers to pieces of sintered iron wrapped in the windings of the stator that amplify the magnetic field generated when power is applied to the windings. Slots refers to how many pieces of iron are in the stator. When you open up a motor and remove the rotor you can actually see them and the "slots". I haven't kept up with the various motors on Hobbyking. Their descriptions don't always tell the whole story and users are generally fairly new who rave about them until they burn up. There's also lots of stories similar to the one above where temps are too high. It is nice to see them advancing and getting better though.

Umm, of course a Rustler on 4s is going to wear and break stuff pretty quick! 1/8 buggies are a lot tougher though and the amount of extra wear is hardly noticed. Besides 4074 or even 4085 on 4s isn't exactly big power, it's actually the "standard" 1/8 power level. I ran my LX1e on mostly 5s, some 6s with a Castle 1518 (4282 1800kv) geared for almost 60mph for years. I went through god only knows how many tires and never broke a single drivetrain part or had excessive wear. I would inspect the diffs and refill but never had to reshim them at all either and the LX gears aren't as good as most other 1/8 buggy diffs. The OP should get the aluminum rear bearing/diff insert for his 8ight if it doesn't already have them though, then it's ready for just about anything you can throw at it.

only highlighting words instead of the big description like this,which is 2800watts at 23volts 121amp draw 45,000rpm max.

Im not sure what you're trying to say exactly with your post. But thanks for the cutaway pic, I've never seen one before.

If you're trying to convince me of the motors merits I already conceded they're getting better, lots better. But I'm not going to recommend or buy one myself when I still see threads like this one around. The OP's motor is a 1/8 motor yet it can't push a 1/8 to 45mph and stay under 160F without a fan on it. The more expensive motors can do it and this thread isn't the only example of Hobbyking type motors running a bunch hotter. I'm not condemning those who chose these motors and live with the hotter temps, fans and/or lower top speeds either. But for my money the more expensive motors are worth it. The Castle 2200kv I bought 6 or 7 years ago is still going and has never been rebuilt. I also run Tekin and have run Leopard as well.

I found this on eBay, it's 200kv less than my current motor so that should be good. Shall I buy it? Would it work with my ESC/programming card?

http://www.ebay.co.uk/itm/360694228388

I found this on eBay, it's 200kv less than my current motor so that should be good. Shall I buy it? Would it work with my ESC/programming card?

http://www.ebay.co.uk/itm/360694228388

http://m.ebay.co.uk/itm/321399202303 Same motor you linked but a little cheaper.

If you're going to go with one of these motors see if you can find the Toro X8ST 2250kv. It's a little longer at 74mm which means it'll have more torque (for lower temps) and it's also a 1Y wind. Wye or "Y" winds are more efficient than the Delta or "D" winds like the 2150kv 2D wind you linked. I couldn't find any compatibility issues with your esc.

I'd also like to point out that the Toro X8S 2350kv is really similar to the Turnigy Trackstar 2350kv. They have the same Kv, same exact outside dimensions, they have the same number of fins on the can, I've even seen versions of the Toro with the same style lettering, in the same spot as the Turnigy. The out of stock at HobbyKing Turnigy motor is about $20 USD cheaper than the Toro. Maybe the Toro has better internals, maybe not, I don't know. I also found some Toro X8S motors that list an internal fan and some that don't. The ones that do list a fan aren't sure of it's location as one vendor says it up front, another says in the rear. Either way there are no holes in the can for air to get in and out. How effective can an internal fan be if air can't get in or out of the can? From where I'm sitting the Toro doesn't really look like an upgrade from the Turnigy Trackstar you already have. Just saying.