Total Wh drained from the battery

[Danislav Kostov]

Guys, 

is there a way to add "Total Wh drained from the battery" with an option to reset it after a recharge?

What do you think?

This way we can see actually how many Wh juice is giving our battery.

[Chriull]

6 hours ago, Danislav Kostov said:

Guys, 

is there a way to add "Total Wh drained from the battery" with an option to reset it after a recharge?

What do you think?

This way we can see actually how many Wh juice is giving our battery.

Very very very theoretically yes - but practically no. The wheels return some numbers somehow correlating to mostly motor current, some newer wheels to battery current. Most report battery voltage (with reported deviations of +/- 1.5V), some "process" voltage somehow and update very irregurarly. In the best case values are reported with a sampling frequency of 10 or 5 Hz - most presumably not the average values. Beside all of this noone really knows the timely "coordination" of the voltage and current values acuisition.

So if one invests much time, brains sweat and tears one could get some ballpark numbers not worth any mentioning.

Ahh - and efficiency of regenerative breaking is quite unknown, too...

So - a very definite no to implement something meaningfull in wheellog. Maybe for one individual wheel if one invests enough time to "explore" the specific pecularities and "calibrates the reported inaccuracies".

But there exists a quite easy way - by charging with something like chargedoctor one gets the Wh put into the batteries (with unknown efficiency - ?maybe something in the 9x%?  but much more accurate than with anything possible with wheelog) or just any power meter before the charger! (And assume some 7x-90% efficiency for the charger and again some battery efficiency)

Like doing average milage statistics with a car - petrol put in and distance driven...

Edit: PS: Announced Wh of the battery packs are also just numbers never to be reached with EUCs - the capacities are only valid for some discharge current in the range of ~0.5C from 4.2V downto 2.5V (for exact specifications see the appropriate datasheet). While with wheels with "huge" battery packs driving at moderate speeds the "low" currents could be reached most wheels just discharge until 3.3V (the KS18XL downto 3.0V?). Higher currents greatly decrease usable capacity, there is not too much energy between 2.5V and 3.0V but more than enough to be neglected...

Edited March 4, 2019 by Chriull

[Seba]

7 hours ago, Danislav Kostov said:

Guys, 

is there a way to add "Total Wh drained from the battery" with an option to reset it after a recharge?

What do you think?

This way we can see actually how many Wh juice is giving our battery.

@Chriull explained all the limitations and technical difficulties very well. But I have to add that this is not completely hopeless thing. Currently I'm extending WheelLog with some additional features and one of them is an experimental "coulomb counting" feature that is available with KS-18L/XL (which reports current flow direction, required for coulomb counting method to work). I just wanted to see if anything valuable can be obtained and... I get very interesting results  Although it cannot be used to precisely measure energy flowing from/to the battery, I think it may be a good value to be fused with standard battery level metering. This way it could be possible to obtain much more real battery level that just voltage-to-percent mapping.

PS. Seems that we're overrating regenerative braking in terms of energy recovered. My data shows that only about 5 - 10 % of energy is returned back to the battery during regular ride.

[pico]

11 minutes ago, Seba said:

. My data shows that only about 5 - 10 % of energy is returned back to the battery during regular ride.

Wow! I expected much less, like 2-3%.

One of my rides involves going uphill and then downhill (return to the same level). I would be curious to see if those percentages hold...

[palachzzz]

On 3/5/2019 at 1:41 AM, Seba said:

Seems that we're overrating regenerative braking in terms of energy recovered. My data shows that only about 5 - 10 % of energy is returned back to the battery during regular ride.

If you brake really carefully, it will be much less. But regenerative braking it is only one option which is possible for braking on EUCs

[Marty Backe]

On 3/4/2019 at 2:56 PM, pico said:

Wow! I expected much less, like 2-3%.

One of my rides involves going uphill and then downhill (return to the same level). I would be curious to see if those percentages hold...

When I go on rides in the mountains, I regularly get about ~30-percent more range compared to flatland riding. It's noticeable.

[Seba]

31 minutes ago, Marty Backe said:

When I go on rides in the mountains, I regularly get about ~30-percent more range compared to flatland riding. It's noticeable.

Ok, but if I understand correctly you're riding downhill more than uphill, right? So not only there is no current draw from the battery, but the battery is being somewhat charged by regenerative braking. Because it's rather impossible to have a better range when riding up and down compared to riding on flat. Of course assuming the same speed.

[Marty Backe]

32 minutes ago, Seba said:

Ok, but if I understand correctly you're riding downhill more than uphill, right? So not only there is no current draw from the battery, but the battery is being somewhat charged by regenerative braking. Because it's rather impossible to have a better range when riding up and down compared to riding on flat. Of course assuming the same speed.

No, I start at the bottom, ride up into the hills, up and down all over the place for a couple of hours and finally return to where I started. The wheels get more range.

I observed this years ago and have consistently noted that my wheels will get more range when ridden in the mountains (starting and ending at the same location).

[Jerome]

2 hours ago, Marty Backe said:

No, I start at the bottom, ride up into the hills, up and down all over the place for a couple of hours and finally return to where I started. The wheels get more range.

I observed this years ago and have consistently noted that my wheels will get more range when ridden in the mountains (starting and ending at the same location).

That has been my experience. The reason for the above, I believe, is that speed is the biggest killer of the battery unless your climbs are significantly greater than the descents. I did a ride climbing and descending (slowly) some of the steepest hills in Philly and nearby suburbs. There was also a lot of small ups and downs. The flat sections of the ride were at speeds 25 - 30 kph.  My range was the same as when I did a 20 mile sprint on basically flat terrain at speeds of 34 - 45 kph. We are big sails on our EUCs and speeds over 32 kph take their toll. 

I am planning a 100 mile Dawn-to-Dusk ride this summer with a KS18L (not XL sob..sob). I will spend 6 hours charging. That means I must execute the right ratio of speed to time, or I won't make it. It will be very hard, early in the ride, with adrenaline flowing, to ride at an even, conservative pace. We shall see. 

 

Edited March 6, 2019 by Jerome

[meepmeepmayer]

@Jerome is right. Wind resistance is the #1 power draw of EUCing. You're slower on mountains, so you get more range. Just think of the incredible range you'd get riding at 10mph or less.

[Seba]

1 hour ago, Jerome said:

I am planning a 100 mile Dawn-to-Dusk ride this summer with a KS18L (not XL sob..sob). I will spend 6 hours charging. That means I must execute the right ratio of speed to time, or I won't make it. It will be very hard, early in the ride, with adrenaline flowing, to ride at an even, conservative pace. We shall see. 

1. Good, fast charger is a must (at least 5 amps).

2. You can use wheel speed alerts to help you keep speed within planned limit.

3. Charge your wheel at every possible opportunity.

[jas3]

1 hour ago, Jerome said:

TI am planning a 100 mile Dawn-to-Dusk ride this summer with a KS18L (not XL sob..sob). I will spend 6 hours charging. That means I must execute the right ratio of speed to time, or I won't make it. It will be very hard, early in the ride, with adrenaline flowing, to ride at an even, conservative pace. We shall see. 

 

Want company?

jas3

[Marty Backe]

1 hour ago, meepmeepmayer said:

@Jerome is right. Wind resistance is the #1 power draw of EUCing. You're slower on mountains, so you get more range. Just think of the incredible range you'd get riding at 10mph or less.

So you think reduced speed is the reason for increased range, not regenerative charging?

[Jerome]

1 hour ago, Seba said:

1. Good, fast charger is a must (at least 5 amps).

2. You can use wheel speed alerts to help you keep speed within planned limit.

3. Charge your wheel at every possible opportunity.

Hi Seba,

You are one of the people I feel a kinship with as I love endurance riding challenges. I know you are going to take an even bigger challenge riding across your country. I thought about starting a thread for "Long Distance" riders where we can post ideas, experiences, suggestions, etc.  I will respond to your suggestion in the new thread as oppose to hijack this one.

[Jerome]

1 hour ago, jas3 said:

Want company?

jas3

Let's talk! lol!  I will hit you up with email, but I will also start the Long Distance thread.

[Seba]

2 minutes ago, Jerome said:

Hi Seba,

You are one of the people I feel a kinship with as I love endurance riding challenges. I know you are going to take an even bigger challenge riding across your country. I thought about starting a thread for "Long Distance" riders where we can post ideas, experiences, suggestions, etc.  I will respond to your suggestion in the new thread as oppose to hijack this one.

I think that "Long range riders" thread or even a forum section may be a very good idea. I see more and more riders interested in longer rides. Gotway Monster, Gotway MSuper X, King Song KS-18L/XL - these wheels made it possible to ride for hundred miles and even more. I'm pretty sure that progress in battery technology will allow to ride for even longer distances. I'm with you, pal!  Start this thread and I'll keep supporting you in this effort!

[meepmeepmayer]

10 hours ago, Marty Backe said:

So you think reduced speed is the reason for increased range, not regenerative charging?

Yes. You can't regenerate what you didn't use to get up the mountain in the first place. Otherwise you have a perpetuum mobile.

I'd wager 99% of your tours are round trips (from home or the car). So while mountains are surprisingly cheap because of regeneration (you get part of the lifting energy back), if you don't start higher than you end, it can't be the regeneration giving you extra range. Speed is the only thing left.

Anyways, what counts is that you never have to worry about range on challenging mountain trips, because it's at least your flat land range (at higher speeds there, of course). Which is pretty amazing if you think about the insane amount of energy needed to lift the average rider onto something like Mt. Wilson. In short, EUCs are awesome (but we knew that already).

[Chriull]

20 hours ago, Marty Backe said:

No, I start at the bottom, ride up into the hills, up and down all over the place for a couple of hours and finally return to where I started. The wheels get more range.

I observed this years ago and have consistently noted that my wheels will get more range when ridden in the mountains (starting and ending at the same location).

 

17 hours ago, Jerome said:

That has been my experience. The reason for the above, I believe, is that speed is the biggest killer of the battery

Just put this in my excel sheet:

Going up a hill with 17% incline with 15km/h for 15 km, driving on top (flat) around 40km with 15 km/h and then going down again leaves ~31% of the battery (1kWh of 1,5kWh used) without any regenerative breaking (efficiency 0%).

Riding the same distance (80 km) with 35 km/h leaves 20% battery charge. (1,2 kWh of 1,5 kWh used)

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
15	10	17,6%	33,9	40,9	709,8	784,5	100%	15	784,5	715,5
15	0	0,0%	33,9	40,9	0,0	74,7	100%	50	249,1	466,4
15	-10	-17,6%	33,9	40,9	-709,8	-635,1	0%	15	0,0	466,4
							Total:	80	1.033,6	466,4	31%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%

 

Assuming 30% efficiency for regenerative breaking changes the 31% vs 20% to 44% vs. 20%:

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
15	10	17,6%	33,9	40,9	709,8	784,5	100%	15	784,5	715,5
15	0	0,0%	33,9	40,9	0,0	74,7	100%	50	249,1	466,4
15	-10	-17,6%	33,9	40,9	-709,8	-635,1	30%	15	-190,5	656,9
							Total:	80	843,1	656,9	44%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%

 

Edit: Have just seen a post regarding Mt. Wilson and so i looked it up in google maps: That's about a 14 km ride up with ~1.200 height meters? So "just" an incline of 1,2%... Redid the numbers - and had to increase the speed to 30 km/h, so some battery is used

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
30	0,7	1,2%	270,8	81,8	99,9	452,5	100%	15	226,2	1.273,8
30	0	0,0%	270,8	81,8	0,0	352,6	100%	50	587,6	686,1
30	-0,7	-1,2%	270,8	81,8	-99,9	252,7	0%	15	0,0	686,1
								80	813,9	686,1	46%
10	0	0,0%	10,0	27,3	0,0	37,3	100%	80	298,2	1.201,8	80%
20	0	0,0%	80,2	54,5	0,0	134,7	100%	80	539,0	961,0	64%
30	0	0,0%	270,8	81,8	0,0	352,6	100%	80	940,2	559,8	37%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%
40	0	0,0%	642,0	109,0	0,0	751,0	100%	80	1.502,0	-2,0	0%

 

BTW: @Marty Backe - are these numbers somewhat realistic or totally off?

Edit2: Looking at the Wh/km the numbers have to be very off... The ~3.8 Wh/km are not possible (At 10km/h speed on flat ground)

Maybe there is still some more friction missing than just the tire on the road.

But imo the "big missing part" are the accelerations needed for selfbalancing?! Just tried a bit with the numbers - accelerations of 1m/s² for 40% of the time would result in a burden of ~11 Wh per km... (This values of 1m/s² and 40% are not interesting at all since they are just a statistical mean for a specific rider, if at all. But i think a like the idea of adding some more or less constant Wh/km amount just for the balancing)

 

 

Edited March 7, 2019 by Chriull

[Smoother]

Regarding regenerative braking efficiency:  If you ride down a hill with App in hand, observing the current meter, you will see that differences in the way you descend, create differences in the current produced.  So two people of the same weight riding identical wheel descending the same hill can produce vastly different amounts of regen.  I won't try to explain what I remember experiencing when I last did this (last summer).  What I suggest is you try it and see if you can find the regen sweet spot for your hill.  I was able to produce a variable 4 to 5 Amps on the hill I measured.  That's 2 to 2.5 times a standard 2 Amp charger.  Unfortunately I didn't remember to measure the current going up the hill, but I would assume it would have to be more than that, efficiency losses and all that.

[Seba]

Here are some numbers acquired from my KS-18L using custom version of Wheellog, that also logs energy flowing from/to the battery during ride in Wh and Ah. Same route, similar riding conditions but different weather conditions. About 9.2 km done in 25 minutes, keeping top speed at 30 km/h. Rider weight about 95 kg including gear. It's my daily commute to work and back home. Route, speed and terrain profile is shown on the image below the table.

Date         Morning ride to work    Evening ride back home
             Km     WhD      WhR     Km     WhD      WhR
-------------------------------------------------------------------
2.03.2019    9.1    134.5    10.5    9.6    147.6    10.6
4.03.2019    9.3    125.9    12.9    9.2    149.9    9.8
5.03.2019    9.2    135.3    18.2    9.3    138.0    10.6
6.03.2019    9.1    141.5    12.3    9.3    134.6    7.8
7.03.2019    9.3    121.6    14.4

-------------------------------------------------------------------
Average      9.2    131.8    13.7    9.3    142.5    9.7
 

Legend:
Km - GPS distance
WhD - watthours discharged
WhC - watthours regenerated

[Chriull]

20 minutes ago, Seba said:

Here are some numbers acquired from my KS-18L using custom version of Wheellog, that also logs energy flowing from/to the battery during ride in Wh and Ah

Did you ever "double check" this numbers with "charged Wh"?

[Seba]

19 minutes ago, Chriull said:

Did you ever "double check" this numbers with "charged Wh"?

Yes, but I need few days more bo say something more conclusive. Seems that values got from Wh calculation are slightly underestimated (by a relatively constant coefficient), but repeatable and this is very interesting. It seems that we assumed prematurely that these data will be worth nothing  I'll keep you updated when I acquire more data.

[Marty Backe]

6 hours ago, Chriull said:

 

Just put this in my excel sheet:

Going up a hill with 17% incline with 15km/h for 15 km, driving on top (flat) around 40km with 15 km/h and then going down again leaves ~31% of the battery (1kWh of 1,5kWh used) without any regenerative breaking (efficiency 0%).

Riding the same distance (80 km) with 35 km/h leaves 20% battery charge. (1,2 kWh of 1,5 kWh used)

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
15	10	17,6%	33,9	40,9	709,8	784,5	100%	15	784,5	715,5
15	0	0,0%	33,9	40,9	0,0	74,7	100%	50	249,1	466,4
15	-10	-17,6%	33,9	40,9	-709,8	-635,1	0%	15	0,0	466,4
							Total:	80	1.033,6	466,4	31%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%

 

Assuming 30% efficiency for regenerative breaking changes the 31% vs 20% to 44% vs. 20%:

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
15	10	17,6%	33,9	40,9	709,8	784,5	100%	15	784,5	715,5
15	0	0,0%	33,9	40,9	0,0	74,7	100%	50	249,1	466,4
15	-10	-17,6%	33,9	40,9	-709,8	-635,1	30%	15	-190,5	656,9
							Total:	80	843,1	656,9	44%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%

 

Edit: Have just seen a post regarding Mt. Wilson and so i looked it up in google maps: That's about a 14 km ride up with ~1.200 height meters? So "just" an incline of 1,2%... Redid the numbers - and had to increase the speed to 30 km/h, so some battery is used

Total Capacity	1500	Wh
Weight	100	kg
v	Incline		P AirDrag	P Friction	P Potential	P Tot	Efficiency	Distance	Energy Used	Capacity Left
km/h	°	%	W	W	W	W		km	Wh	Wh
30	0,7	1,2%	270,8	81,8	99,9	452,5	100%	15	226,2	1.273,8
30	0	0,0%	270,8	81,8	0,0	352,6	100%	50	587,6	686,1
30	-0,7	-1,2%	270,8	81,8	-99,9	252,7	0%	15	0,0	686,1
								80	813,9	686,1	46%
10	0	0,0%	10,0	27,3	0,0	37,3	100%	80	298,2	1.201,8	80%
20	0	0,0%	80,2	54,5	0,0	134,7	100%	80	539,0	961,0	64%
30	0	0,0%	270,8	81,8	0,0	352,6	100%	80	940,2	559,8	37%
35	0	0,0%	430,1	95,4	0,0	525,4	100%	80	1.201,0	299,0	20%
40	0	0,0%	642,0	109,0	0,0	751,0	100%	80	1.502,0	-2,0	0%

 

BTW: @Marty Backe - are these numbers somewhat realistic or totally off?

Edit2: Looking at the Wh/km the numbers have to be very off... The ~3.8 Wh/km are not possible (At 10km/h speed on flat ground)

Maybe there is still some more friction missing than just the tire on the road.

But imo the "big missing part" are the accelerations needed for selfbalancing?! Just tried a bit with the numbers - accelerations of 1m/s² for 40% of the time would result in a burden of ~11 Wh per km... (This values of 1m/s² and 40% are not interesting at all since they are just a statistical mean for a specific rider, if at all. But i think a like the idea of adding some more or less constant Wh/km amount just for the balancing)

The Mt Wilson route that I've taken multiple times is a 4600-ft climb.

I'm afraid looking at all these numbers is making my head hurt 

[meepmeepmayer]

All these numbers, while the tendency may be clear, are just unreliable. GW's voltages, wattages certainly are more like a rough estimate what is going on than precise measurements. Off by 2x and the like. So believe what they say in principle, just don't look at anything past the decimal separator (at best). Or anything but "smaller or greater than some other number from the same wheel"

[Seba]

2 hours ago, meepmeepmayer said:

All these numbers, while the tendency may be clear, are just unreliable. GW's voltages, wattages certainly are more like a rough estimate what is going on than precise measurements. Off by 2x and the like. So believe what they say in principle, just don't look at anything past the decimal separator (at best). Or anything but "smaller or greater than some other number from the same wheel"

Don't bury hope