ISDT ESC70 - Bit of a fail in my experience

[Cuiken 225]

Not wishing to start a pile on here but curious about other people's experience of the ISDT ESC70.

Currently available for £23 on Amamazon, and claiming some useful features along with suitability for all brushed cars (not just crawlers), I thought I'd gove it a shot.

You mileage may vary but I could not get it to work for a few reasons:

1. Connectivity to the phone is comically bad. It usually connects initially but, more than 50% o the time, when you try to update a parameter (drag brake etc), it will report a 'time out' and you'll need to restart the app. At this point you'll find that it has sometimes failed to update the parameter, sometimes succeeded and sometimes set it to a random value. It took me over 30 minutes to update four values.

2. Calibration. When you first turn it on, the ESC won't let you run the motor. Checking the app you'll find that it wants to calibrate the ESC to the Transmitter. Esat peasy, nice little routine that asks for a neutral, FWD and BRK input. Then it goes off to do some stuff and 50% of the time will report a successful calibration. Otherwise, you'll need to restart the app and try again. Unfortunately, even after a successful calibration, the next time you start the app, 50% of the time it asks for a calibration again or reports a motor error (requiring a fresh calibration) before you can run the motor.

3. I did eventually get past this setup hassle and installed it in my TA03F for a quick test. What immediately became apparent is that you can't (at least on my particular ESC) disable the drag brake. Or you can, but only sort of. If you disable the drag brake (after a few attempts) and then go from full throttle to zero throttle, the car will coast to a standstill. If however, you go from full throttle to 20% throttle (for example) it will rigidly force the wheels to rotate at 20%. So basically a drag brake. I tried everything and it could not be disabled. The upshot is that, if you ease off the throttle going into a corner, the car would just immediately spin out because the wheels have basically been dramatically decelerated up by the ESC.

It's really annoying because the feature set of the ESC is great and the car ran with plenty of 'punch'. It just required constant reprogramming to get it to work and, even then, has this weird drag brake behaviour. Maybe the latter is okay for a crawler but it didn't work at all in my TA03.

Has anyone had a better experience?

 

[alvinlwh 5894]

Replied to your other message before seeing this. OK my experience, 50% failure rate, or 2 out of 4 that I bought went bad. 

But first response to your points before my own experience. 

1. Never really had a problem with connection problem. HOWEVER, on one that went bad, I deleted the ESC from the phone and can never re-pair it back, ever again. I suspect this was due to problems with its switch button, as reported by a number of users online. Personally, I never encountered the timeout problem. Updating values is slow, but I suppose that is a Bluetooth limitation. 

2. Again, never had a "lost" calibration problem. HOWEVER (again!), on one that failed, I simply cannot recalibrate it as part of my trouble shooting leading to 1. above where I deleted it from the app. It simply will not confirm signals being received. 

3. Not sure about this, I personally had not encounter this, but it could be me adopting to different ESC/chassis/motor, etc... HOWEVER, question is do you use profiles (like road, off road, etc) as I find using profile will override some settings. 

Now, the real problems, one of mine lost reverse, and as part of my troubleshooting, I tried to reset the end points. No joy as it refused to show it actually received the signals. Then, after deleting it from the app, it refused to be paired again, effectively turning it into a brick. 

This problem first started by not having reverse, but when reverse signal is sent, the motor make some sound like it it trying to go, something like 5% reverse throttle, trying to turn but not quite going. Sometimes it may suddenly decide to go full speed at reverse with no input! 

One of my replacement from Amazon also has this reverse problem out of the box and I just returned it for a refund. 

I really do like this ESC as it has nearly as much options as a brushless ESC but on a brushed motor. Sadly, QC and firmware has too much problem. My advice is to buy from a easily refundable seller (like Amazon, not Ali) and test it immediately upon receiving it. One of mine had been sitting around for too long, passed its return time frame. 

Now, what do I like about it? I love its ability to adjust dead band, helps to keep my car stationary in neutral on my dodgy controller. Also like it's BEC allowing me to use HV servos. Able to adjust lipo or NiMH on the fly (Bluetooth works for me) is also good. 

[Cuiken 225]

Okay, from the sound of it then, I might have had a dodgy one and could be worth buying a replacement when my refund comes through.

Connection issues aside, I think the issue with the drag brake put me off most of all. Seemed like a fundamental issue with the design but maybe, again, a dodgy part. The issue was simply that you can't coast into a corner because the car actively brakes as you ease off the throttle.

If you happen to have one of these ESC in a car or buggy (probably not crawler) could you take a look at the behaviour described below and see if yours does the same?

1. Set drag brake to 'disabled'

2. Sit the car on something to keep the wheels of the ground

3. Give the car 100% throttle and then immediately release to 0% throttle. Do the wheels 'coast' down to a standstill (as you'd expect with drag brake disabled)?

4. Give the car 100% throttle and then quickly reduce to ~25% throttle (or any low value above 0%). Do the wheels 'coast' down to the new speed? On mine they would be 'braked' down to the lower speed by the ESC rather than being allowed to reduce their speed gradually. This behaviour was actually ore evident with the motor removed from the car.

Cheers.

[Willy iine 18805]

Drag braking is harsh especially on mod brushed motors as it burns up the comm and brush.  You'd have to cut the comm frequently.  Silver cans can withstand it better because they have hard brushes.  I believe drag brake is most effective on crawlers and some trailer type trucks.

When I drive my brushless cars it feels like it is drag braking as throttle input mandates the rotation speed of the motor even if the wheels are over spinning the motor beyond the throttle input.

For example if I coast from 100% throttle, car is traveling near max speed and give it 20% throttle before a turn, the motor forces itself to rotate at the 20% rotation speed, hense the drag braking sensation.   That was one of the first things I had to get use to when I started running brushless about a decade or so ago.  It felt unnatural and digital.. Perhaps more modern brushless motors are different.  My ThunderPower motors and ESC (HW XR10 JustStock) are pretty old..   I'm more a brushed motor antique guy, so..

[Cuiken 225]

2 hours ago, Willy iine said:

I'm more a brushed motor antique guy, so..

Totally! The nice coasting behaviour of a brushed car is part of the charm.

The ESC70 (or at least the one that I had) appears to ape the 'braking effect' you describe where the wheels can't overspin the motor when there is any throttle input. It's extremely pronounced too, like a HW AXE system.

Clearly this is great for a crawler but it's not what I'm looking for in a general purpose ESC. I'm just curious if anyone else has noticed it.