WheelLog & Pebble for Better Safety in Riding

[Marty Backe]

Lately I've been enabling the Maximum Current alarm in my WheelLog app. I have it set at 90 amps (for my Tesla). When the current demand exceeds this value I get a vibration buzz on my wrist.

This has been very educational in learning about where my wheel demands power.

When starting from a stop and going up a steep incline - buzz. Probably to be expected. But most interesting to me is when it occurs at high-speed. If I'm riding > 20-mph (32-kph) hit a small bump or drop in the road I will often get the buzz. This is telling me that there's an increased risk of a wheel problem occurring (I'm riding a Gotway folks ) when hitting obstacles at high speed. At lower speeds I never get the alarm to trip.

So this instantaneous feedback mechanism has been invaluable for learning the potential limits of the wheel.

Now, when I'm approaching a little tiny drop in the pavement when traveling very fast, I will slow down a bit to avoid the power surge. It's all about increasing my safety margin and avoiding potential face plants. Something for you Gotway riders to consider.

I love the WheelLog / Pebble combination.

 

Edited November 24, 2017 by Marty Backe

[WARPed1701D]

90amps! 

Holy cow. Mine is set at 17amps (20s2p V8). It hardly ever goes off. Maybe on the odd bump at speed. 90! Do you ever graph your ride data in Excel to analyze general patterns/usage?

[Marty Backe]

6 minutes ago, WARPed1701D said:

90amps! 

Holy cow. Mine is set at 17amps (20s2p V8). It hardly ever goes off. Maybe on the odd bump at speed. 90! Do you ever graph your ride data in Excel to analyze general patterns/usage?

No, but I'll do that today. It was 60-amps but that was going off too often 

These Gotway wheels have some serious power.

[WARPed1701D]

 Is this the Tesla?

 If be interested to hear the result.

Edited November 24, 2017 by WARPed1701D

[Marty Backe]

2 minutes ago, WARPed1701D said:

 Is this the Tesla?

 If be interested to hear the result.

Yes, the Tesla. I'd edit the post to clear that up, but I see similar results with my 84-volt ACM.

[electricpen]

I'm a little curious since I know you also wear the demon wristguards. Where do you wear the pebble watch? The wristguards go more than 1/3 up my forearm and I'm not sure how the watch would fit.

[Chriull]

2 hours ago, Marty Backe said:

No, but I'll do that today. It was 60-amps but that was going off too often 

These Gotway wheels have some serious power.

Imho @KingSong69 posted that tesla reports unusally high currents conpared to other wheels. Also with very low loads.

 

[Marty Backe]

2 hours ago, electricpen said:

I'm a little curious since I know you also wear the demon wristguards. Where do you wear the pebble watch? The wristguards go more than 1/3 up my forearm and I'm not sure how the watch would fit.

 

[Marty Backe]

2 hours ago, Chriull said:

Imho @KingSong69 posted that tesla reports unusally high currents conpared to other wheels. Also with very low loads.

 

Is this good or bad or indifferent?

[WARPed1701D]

3 minutes ago, Marty Backe said:

 

I have mine mounted over the Flexmeter symbol and rotated 90 degrees. I got my pebble quite soon after I learnt and looking down while lifting my arm high enough to see over my chin guard destabilized me. Turning it and moving it forward helped as i could keep my arm straight out and not lift it as high. It was more difficult to mount due to the curve of the splint and not wanting to cover the charging port on the back of the Pebble Time with Velcro. I may try moving it back to where Marty has it now I'm stable but it is another option for you.

[US69]

3 hours ago, Marty Backe said:

Is this good or bad or indifferent?

 

It are just unrealistic numbers in my opinion...i can easily get it to 90 amps, and the batterys are not able to deliver that without looking like your mten battery....

[Smoother]

If you're really pulling 90A with an 84V system (is Tesla 84v?), then that sounds high, especially in light of what @WARPed1701D and @KingSong69 said. 

I'm  reminded of our recent discussion of amounts of work for a given situation. You on your Tesla and me on my 16s going up the same hill, should consume essentially the same energy (plus minor variations in efficiency between the wheels, wind resistance,etc). Our Watts (Amps X Volts) should work out as a wash. Get one of you buddies on a different brand, to pebble up and do a controlled, repeatable test. 

I've read here several times (usually app development threads) where people are getting unbelievable energy (W,A,V, etc) out of certain machines, and concluded that the data output was not accurate. A correction factor was required)

 

PS my wheeLog stopped working ?

Edited November 27, 2017 by Smoother

[US69]

My conclusion is that the amps shown for Tesla are at least 2 times, more likely 3 times to high.

[Marty Backe]

7 minutes ago, Smoother said:

If you're really pulling 90A with an 84V system (is Tesla 84v?), then that sounds high, especially in light of what @WARPed1701D and @KingSong69 said. 

I'm  reminded of our recent discussion of amounts of work for a given situation. You on your Tesla and me on my 16s going up the same hill, should consume essentially the same energy (plus minor variations in efficiency between the wheels, wind resistance,etc). Our Watts (Amps X Volts) should work out as a wash. Get one of you buddies on a different brand, to pebble up and do a controlled, repeatable test. 

I've read here several times (usually app development threads) where people are getting unbelievable energy (W,A,C, etc) out of certain machines, and concluded that the data output was not accurate. A correction factor was required)

 

PS my wheeLog stopped working ?

 

 

1 hour ago, KingSong69 said:

 

It are just unrealistic numbers in my opinion...i can easily get it to 90 amps, and the batterys are not able to deliver that without looking like your mten battery....

I'm using a very recent version of WheelLog. Whether it's accurate or not I can't say, but I am seeing a few instances where the current exceeds 90 amps. I do see that the voltage is 67 volts max.

Does WheelLog derive the current or is this value supplied by the wheel?

[US69]

3 minutes ago, Marty Backe said:

Does WheelLog derive the current or is this value supplied by the wheel?

Amps or watts can not be derived without a second value to volts....i am pretty sure amps are supplied by wheel.

And this high values are alsothat high on all other apps i have.

[Marty Backe]

11 minutes ago, KingSong69 said:

Amps or watts can not be derived without a second value to volts....i am pretty sure amps are supplied by wheel.

And this high values are alsothat high on all other apps i have.

So you are saying that you believe that the Gotway firmware is providing inaccurate values?

Then all we can use WheelLog for is to provide relative values for the power?

[US69]

40 minutes ago, Marty Backe said:

So you are saying that you believe that the Gotway firmware is providing inaccurate values?

Then all we can use WheelLog for is to provide relative values for the power?

For the amp values?

yes, i am sure they are wrong, they are just way to high. At least when they represent the values on battery side.

if these values would be true, our battery where empty much faster :-)

example cruising....on about 20-25kmh straight road, no wind, your wheel should use about 250-400 watts (4-6 amps)....you can check that with your ks14

Gotway numbers are about 3times that high, even on normal cruise....thats much to much power consumption.

[Chriull]

3 hours ago, Marty Backe said:

Does WheelLog derive the current or is this value supplied by the wheel?

3 hours ago, KingSong69 said:

Amps or watts can not be derived without a second value to volts....i am pretty sure amps are supplied by wheel.

And this high values are alsothat high on all other apps i have.

Wheellog sends the "motor" current, the battery voltage and the multiplication of both (watts).

2 hours ago, KingSong69 said:

For the amp values?

yes, i am sure they are wrong, they are just way to high. At least when they represent the values on battery side.

if these values would be true, our battery where empty much faster :-)

Normally the wheel send the motor current. This also would make the most sense - on the mainboard (at least) two of the three phase currents are measured by the small shunts. This motor phase currents are needed for the firmware to balance the wheel.

(Battery current would be a nice to have, but seems not be measured and is not needed by the firmware. Battery voltage is measured and send. As seen in the past for the KS14?C? this values can be quite off - so this some wheels of this brand did overvoltage tiltbacks/beeps way to early while regenerative braking. Motor voltage is not needed for the firmware and by this presumably also not measured. )

And it is not known if they reported motor current it is the (true effective) average of all three phases, just one phase, some other average... 

2 hours ago, KingSong69 said:

example cruising....on about 20-25kmh straight road, no wind, your wheel should use about 250-400 watts (4-6 amps)....you can check that with your ks14

Gotway numbers are about 3times that high, even on normal cruise....thats much to much power consumption.

For the KS16C it could be by the factor 2 too low

Since there i had a quite low number of samples this could be also the factor 1,7 - the factor between the current in one phase and the same in two 120° shifted phases...

If this is right KS (and older GW) could report just the current in one phase, the new Tesla the "whole" motor current (1,7 higher). 

And imho accuracy for this shunts and the motor current is not important for the wheels/firmware - the values "just" in a feedback loop (pid)...

Once temperatures get nices again in spring time maybe i'll try some logs going up a known incline (known energy needed) at different speeds and compare it to the whellog logs... Imho by now my only simple idea to get some "feeling" of this values...

[meepmeepmayer]

I think there's 2 points to consider here:

• The Tesla seems to report unrealistic values, or at the very least not seriously applicable values. 90A continuous current is not going to happen on 4P with 10A max or 15A max or whatever the right number is per cell parallel pack.
• A current spike of X Amperes is more or less worthless information without its duration. You can probably get as high current numbers as you like if only the time is short enough (like a millisecond). So 90A is just the current for minimum time resolution of whatever is monitoring the current and sending that info out. You get shown crazy current numbers in Wheellog when starting all the time, means nothing.

So, forget about the number, and see it as an empirically derived method of finding out when a specific wheel is at its limits. I'm more wondering how @Marty Backe came up with the 90A number in the first place...

[US69]

42 minutes ago, meepmeepmayer said:

s an empirically derived method of finding out when a specific wheel is at its limits. I'm more wondering how @Marty Backe came up with the 90A number in the first place

you can have this 90 amp easioy by just placing your feet in front of the wheel(blocking it) and pushing the wheel by hand against it...

i just come back from a ride and checked these amp numbers.....especially when relaxed cruising for me its clear....double watts\amps as my ks18s

[Marty Backe]

5 hours ago, meepmeepmayer said:

I think there's 2 points to consider here:

• The Tesla seems to report unrealistic values, or at the very least not seriously applicable values. 90A continuous current is not going to happen on 4P with 10A max or 15A max or whatever the right number is per cell parallel pack.
• A current spike of X Amperes is more or less worthless information without its duration. You can probably get as high current numbers as you like if only the time is short enough (like a millisecond). So 90A is just the current for minimum time resolution of whatever is monitoring the current and sending that info out. You get shown crazy current numbers in Wheellog when starting all the time, means nothing.

So, forget about the number, and see it as an empirically derived method of finding out when a specific wheel is at its limits. I'm more wondering how @Marty Backe came up with the 90A number in the first place...

Why I chose 90? I picked a number that rarely caused my watch to buzz. 60 happened too much, so I tried 90. Very scientific.

Edited November 25, 2017 by Marty Backe

[Smoother]

Oops

Edited November 27, 2017 by Smoother

[Herbas]

On 11/24/2017 at 11:37 PM, WARPed1701D said:

Mine is set at 17amps (20s2p V8).

Any reason why 17A for V8? Just a hunch or have you seen some data from logs with cutoffs which indicate this is an optimal threshold?

[WARPed1701D]

@Herbas The max rated discharge rate of the LG MH1 cells in the V8 is10A. The pack is a 2 parallel configuration meaning max current draw within specs is 20A. Getting a wrist buzz at 17A means I am approaching this limit (85%) and should back off. I know that momentary surges above 20A are fine in most cases but it helps me stay in the safe envelope of operation. Because i live in a flat and warm area i only ever get the odd buzz during acceleration or if i hit a bump. These are almost always momentary draws above spec which are generally ok. The alarm would be much more useful on a hill where the draw would be continuous and could exceed the battery's abilities to supply sufficient power.

Edited November 26, 2017 by WARPed1701D

[Marty Backe]

3 hours ago, WARPed1701D said:

@Herbas The max rated discharge rate of the LG MH1 cells in the V8 is10A. The pack is a 2 parallel configuration meaning max current draw within specs is 20A. Getting a wrist buzz at 17A means I am approaching this limit (85%) and should back off. I know that momentary surges above 20A are fine in most cases but it helps me stay in the safe envelope of operation. Because i live in a flat and warm area i only ever get the odd buzz during acceleration or if i hit a bump. These are almost always momentary draws above spec which are generally ok. The alarm would be much more useful on a hill where the draw would be continuous and could exceed the battery's abilities to supply sufficient power.

I prefer to play it safe. When I'm cruising at 25-mph and hit a bump large enough to cause the watch to buzz, I need to slow down on future bumps of that nature. I prefer not to experience a face-plant like that Tesla rider, so I'm learning where I need to be conservative.