To add or not to add fuse !

[yoos]

14 minutes ago, Chriull said:

Afaik internal resistance calculation is already in testing/?one of the latest versions?

Yes, it's called "battery circuit resistance" and is shown on the "Live" part of the second tab. It agrees with R derived from the data I/V data from my tour logs: in my case it's 0.3 Ohm.

However, I don't know how often this value is updated and I don't think there are any kind of warnings triggered by it.

edit:typos

Edited November 16, 2021 by yoos

[Planemo]

Ah yes sorry I remember now, there isn't a direct battery current reading for GW/Begode/Sherman wheels.

[conecones]

23 hours ago, yuweng said:

According to my dealer friend, begode/ gotway has recently introduce a self-resetable fuse in all of their wheels, lets see if fire will be a thing of the past for them 

  Reveal hidden contents

 

I've asked a few sellers about this and they are all saying that this new fuse that can be installed across all their 100V wheels that did not come with it previously, and also can replace the older inline fuses that did not come with a board.

At only $30 CAD each, I think it's a worthwhile addition for an older 100V gotway.

[yoos]

59 minutes ago, Planemo said:

there isn't a direct battery current reading for GW/Begode/Sherman wheels.

Is there a power reading though? You can derive current from power and voltage. Very roughly speaking Power = V I. There are caveats due to capacitors storing energy to deliver short-time power bursts, but this could be filtered out (I guess) by analyzing the W(t) vs V(t) curves on a long enough timespan. Of course the sensible solution would be to finally bring the controllers up to date so they start reporting battery currents, but that's up to Begode.

[Chriull]

6 minutes ago, yoos said:

Is there a power reading though?

Begode wheels report some stupid value they call power, but this is battery voltage times motor current...

6 minutes ago, yoos said:

Of course the sensible solution would be to finally bring the controllers up to date so they start reporting battery currents, but that's up to Begode.

Motor current is very nice as mosfet burden indication - many riders rely on this!

[yoos]

 

38 minutes ago, Chriull said:

Begode wheels report some stupid value they call power, but this is battery voltage times motor current...

Still, if this is indeed a meaningful power, e.g. true motor power, then by virtue of energy conservation that power ultimately comes from the battery. There are some losses on the way but they are typically a fixed fraction of the total power. E.g. motor power = 90% battery power. Of course this is complicated by capacitors which can store and release some energy to handle burst demands. To eliminate them from the equation you just have to take measurement over a time long enough that the total energy consumed over that time is much larger than what the fully charged capacitor can provide.

I don't know the intricacies of Begode wheels and the specs of their capacitors, but as a ballpark figure let's take the capacity of aftermarket capacitors from EUCyou. That's C=7500μF corresponding to a max energy at 100V equal to E=1/2 CU² = 37.5J = 0.01Wh. Assuming typical cruising power around P=500W we find that drawing such power from the capacitor would deplete it in t = E/P = 0.07 secs. This exercise shows that over any significant amount of time (e.g. 1 second or longer) the contribution of capacitors towards motor power would be negligible. 

Disclaimer: this is all educated guessworks and I haven't seen logs for power vs voltage on begode wheels. One look at them should be sufficient to see if there is linear voltage sag behavior.

[Chriull]

22 minutes ago, yoos said:

Still, if this is indeed a meaningful power, e.g. true motor power,

No - multiplying battery voltage with motor current does not result in any meaningfull power. It's just a number.

As the pwmed inverter with the mitor coil's inductance acts as step down converter. So this is like multiplying the input voltage of a (switched mode) power supply with the output current. Absolutely senseless.

[RagingGrandpa]

20 minutes ago, yoos said:

if this is indeed a meaningful power, e.g. true motor power

It's not.

The error is the voltage assumption: their "power" value is battery voltage multiplied by motor current.

The motor phase voltage is always changing with its commutation cycle, but this RMS voltage is much, much lower than battery voltage. Alas, we don't know the motor RMS voltage, so we can't calculate a true power value directly from the signals Gotway provides.

23 minutes ago, yoos said:

I haven't seen logs for power vs voltage on begode wheels

Feel free to study mine (logs in worksheet tabs)

 

[Seba]

5 hours ago, yoos said:

Yes, it's called "battery circuit resistance" and is shown on the "Live" part of the second tab. It agrees with R derived from the data I/V data from my tour logs: in my case it's 0.3 Ohm.

However, I don't know how often this value is updated and I don't think there are any kind of warnings triggered by it.

Battery circuit resistance is calculated dynamically and how often this value is updated depends on riding style and conditions. There are no warnings triggered by this value, as it was included "by the way", as BCR is mainly used by battery level algorithms to improve its reliability. Anyway, I plan to add some warnings based on this value in the future. I just wanted to make sure that BCR calculation algorithm works reliably and wanted to gather enough data to determine which BCR is good and which is bad for all supported wheel models.

[thendless]

Looks like you can purchase the replacement for the inline gotway fuse: US $25.00 | Original GotWay Begode Unicycle New Verison Fuse Protector battery Short Circuit Suit for GotWay Nikola RS EX EXN Monster pro
https://a.aliexpress.com/_msVawzq

[vladdark]

Is there any feedback from users for this "Short Circuit Suit"?

[RagingGrandpa]

I'll... just leave this here