EUCWorld battery level 16XS

[Tawpie]

I've a new 16XS (yes, half a battery, it was on purpose) and at this moment EUCWorld says I have 40% remaining (34.5 miles since 100%, pack voltage 74.5). The KingSong app says 58% (55.5 km since 100%, pack voltage 74.48V). DarknessBot says 100% so it's evident DarknessBot isn't with the program.

Does anyone know if I should believe EUCWorld over the KingSong app? It seems like one is calculating the percentage remaining as if the pack was the full 1556KWH and the other is aware that my wheel only has half the X's battery capacity.

(I'm learning so I go very slowly on flat pavement, and I don't weigh much. So for the present anyway, my range is abnormally high)

[meepmeepmayer]

Both numbers are right (or wrong). They are different interpretations of the same physical battery state (the voltage). Only voltage counts.

The battery has a voltage where it is full (84V) and empty (I think that's 63V here).

The KS app simply interpolates linearly between those two states. The middle between 84V and 63V (73.5V) is displayed as 50%, and so on. So if you plug in your number of 74.5V, you get (74.5-63)/(84-63) = ~55%.
But in real life, the voltage drops faster when the battery is emptier (the discharge curve is non-linear), so at 50% (voltage in the middle between full and empty) you're quite beyond the point of no return. You don't get as much range from the last x% as you get from the first x%.

The EUC World algorithm tries to be more "realistic" and is more elaborate: battery percents should correspond to range. (Or something like that, I know no details.) So if it displays 50%, it means you have used half of your overall range and are at the point of no return, and so on. (Again, not sure if it's indeed range or something different.) That's why it gives you a lower battery percentage in comparison. You can also switch EUC World to the other algorithm (same as KS app).

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Darknessbot possibly defaults to a 67.2V wheel, so any voltage above that might count as 100%. Maybe there's a setting somewhere where you can switch what wheel type it expects (you want 84V)? Or it simply does not work at all for some other reason.

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Btw, an error from expecting a certain battery size can not happen because the wheel doesn't even see the battery size.

A wheel only sees the battery voltage. A bigger battery (like in the 16X) has the exact same voltages, they change just more slowly because the battery is bigger. So a wheel won't know how big a battery is connected (and it doesn't matter for how the wheel works). It only sees how full the connected battery is (the voltage, which counts for how it works - e.g. speed reductions at a certain low battery state).

Edited October 18, 2020 by meepmeepmayer

[redsnapper]

5 hours ago, meepmeepmayer said:

Darknessbot possibly defaults to a 67.2V wheel, so any voltage above that might count as 100%. Maybe there's a setting somewhere where you can switch what wheel type it expects (you want 84V)? Or it simply does not work at all for some other reason.

 

drkbot allows u to specify the batt capacity so u get "accurate" readings on different wheels. chk device settings and set batt to 756wh...

Edited October 18, 2020 by amelanso

[Tawpie]

Thanks, that makes good sense. Having spent time as both a hardware and firmware person in the portable power biz I somewhat naively assumed remaining charge would have been sourced from a fuel gauge (coulomb counter) on the BMU but they do cost a buck a part. 
 

Darknessbot is set to 750WH, so there’s an app problem there. EUCWorld is set to the optimized battery algorithm and I haven’t looked at what the standard algo reports. 

net net is that the apps’s view of remaining charge is “indication only”, being neither calibrated nor precise. Not a problem as long as it’s known.

(I believe the 16X has an 84V battery these days, at 77% on all the apps it’s 78.4V. If not I need to quick move the thing outside!)

[Mr Wolf]

Coming back to this topic, is it normal that on a 16X with 72.5V KingSong app says 47% battery charge and EUC World (with battery level averaging turned on) states 26%?

Ok for different interpolation methods but more than 20% of difference seems a little bit too much to me... Any comments? thanks

[Tawpie]

For EUC World I ended up switching to the non-optimized battery algorithm and it tracks the KS app better. DarknessBot is still broken and stuck at 100%. NOTE: if you have csv or tour logging 'active' in EUC World, you won't be able to switch algorithms. Stop logging csv and stop your tour, then you should have the option to switch.