Mark13i Posted June 5, 2021 Share Posted June 5, 2021 Hello. I am new to this forum. I am thinking about the possibility of increasing the security of using EUC. There is my hypothesis with two assumptions: - Total resistance of the power circuit (internal resistance battery, wires, connectors, etc.) - should be a constant value (with some tolerance), independent of the battery charge status, driving speed and rolling resistance. - Failure of the power supply circuit (power supply interruption, short circuit preceded by insulation melting, battery fire) - is always preceded by some change in the circuit's resistance, beyond the permissible limits. If the assumptions are wrong - correct me. Question for forum members more experienced than me: Having the data reported by the application (e.g. EUC.World): - instantaneous battery voltage, - instantaneous battery current or phase current, - instantaneous speed, can you calculate the static resistance of the power circuit? The "phase current" parameter worries me. Personally, the most important thing for me is the Gotwa wheel condition "prediction" algorithm. 3 Quote Link to comment Share on other sites More sharing options...
Eucner Posted June 5, 2021 Share Posted June 5, 2021 Welcome to the forum. The electrical resistance of copper is highly depended on temperature. Your hypothesis doesn't have any chances unless you know temperature in each part of the circuit. That is a lot of probes. Quote Link to comment Share on other sites More sharing options...
Mark13i Posted June 5, 2021 Author Share Posted June 5, 2021 (edited) @Eucner - Yes and no. A Δ10K temperature change changes the specific resistance of copper by only 4%. The resistance of the copper is a smaller part of the resistance of the circuit. In MSX the coil resistance R_coil = 0,3 Ohm (@Chriull wrote this somewhere :)). Temperature will change this resistance by 12 mOhm. The change in copper specific resistance is a predictable and repeatable phenomenon - the algorithm can take this into account and compensate for it. I am more interested in the temperature independent change of resistance of the plug-socket connection by 25 mOhm. Or change of internal resistance of a wrong cell by 100%. Edited June 5, 2021 by Mark13i Quote Link to comment Share on other sites More sharing options...
Eucner Posted June 5, 2021 Share Posted June 5, 2021 The ambient temperature difference can easily be from -10C to 30 C (Δ40K) and usage on top that. You can take temperature in account only if you known it. Quote Link to comment Share on other sites More sharing options...
Mark13i Posted June 5, 2021 Author Share Posted June 5, 2021 @Eucner - Inmotion V8F does not report temperature? Quote Link to comment Share on other sites More sharing options...
Eucner Posted June 5, 2021 Share Posted June 5, 2021 It does, but only one. The battery, BMS, contol, wires and motor will all have a different temperature. 4 hours ago, Eucner said: Your hypothesis doesn't have any chances unless you know temperature in each part of the circuit. That is a lot of probes. Quote Link to comment Share on other sites More sharing options...
Mark13i Posted June 5, 2021 Author Share Posted June 5, 2021 That should be enough. The temperature of the BMS, cables, etc. is derived from power and that one temperature. The test and report of the efficiency of the power circuit can be done a moment after turning on when all components have the same temperature. Quote Link to comment Share on other sites More sharing options...
Eucner Posted June 5, 2021 Share Posted June 5, 2021 2 hours ago, Mark13i said: The temperature of the BMS, cables, etc. is derived from power and that one temperature. I would look for current, not power. The ambient temperature doesn't affect the same way in all components. Don't also forget speed. It has main impact in cooling. It would be easier to add few thermal probes than build a full thermal simulation model. Quote Link to comment Share on other sites More sharing options...
Mark13i Posted June 8, 2021 Author Share Posted June 8, 2021 When I started this topic I haven't seen EUC.World v2.6 yet. Thank you @ Seba for implementing the function of estimating the internal resistance of the battery (with wires and plugs). Is there any hope that this feature will work with Gotway / Begode wheels in future EUC.World releases? Quote Link to comment Share on other sites More sharing options...
Skecys Posted June 8, 2021 Share Posted June 8, 2021 They probably COULD make EUC's safer and more reliable... But they won't cause...profits Quote Link to comment Share on other sites More sharing options...
bASKOU Posted June 8, 2021 Share Posted June 8, 2021 (edited) 1 hour ago, Skecys said: They probably COULD make EUC's safer and more reliable... But they won't cause...profits Make our wheels safer is always something we want. But I just wonder how can it be done ? Like the fuse before the motherbard, it's protect the componants inside our wheel but not us. If the fuse do it's job this is not safe for us, as our motor will no more have any current. Having temperature probes can be a good feature, but the problem is how it'll be manage by the software is another problem. Because if they reduice power output we'll fall, so they need to increase the power output for the tilt back then make us reduice our speed. But will the increase in power not be fatal depending on how much we accelerate ? If it is an alarm, EUC World already propose it for some componants. Battery would be really great, but how can we put a probe per cell, as a cell might overheat but others could be in perfect state and it won't be relevant if there is only one probe per battery pack. We alson already saw on some small wheels a battery protection, but all it did was cut power suddenly or reduice power significantly with for both the same result, a fall. We are riding dangerous vehicules. Personnally I just set an alarm on EUC World at 60°C on my MSP. Also stopped using the current alarm as it was going wild on hard braking and hard acceleration. What matters is to check your average current, and avoid to climb long hills at low speed under a burning sun. For most of time you'll be safe, but we are on electronics with our life on batteries, motherboard and wires. Just got a face plant yesterday because of bad welding on my lift switch, the extension of wire I made broke on very bumpy ride. One of the wires touched another and 90kg crashed on the floor at 25kph, thanks to my heavy protective gears, just have some bruises and smalls hematoma. I want a performance wheel, I could make my MSP HS safer and more reliable by riding it at low speed and not jumping everywhere and not going down stairs. With a tilt back at 25kph and a current alarm at 20A I am sure that it'll stay next to me until I am no longer able to drive it. Edited June 8, 2021 by bASKOU 1 Quote Link to comment Share on other sites More sharing options...
RagingGrandpa Posted June 8, 2021 Share Posted June 8, 2021 (edited) On 6/5/2021 at 6:33 AM, Mark13i said: Having the data reported by the application (e.g. EUC.World): - battery voltage, - phase current, - speed, can you calculate the static resistance of the power circuit? No... Even at a steady speed, you don't know the mechanical load on the system. Is the rider going uphill, or downhill? Is there wind? Is the surface loose sand, or polished concrete? Which tire is installed? etc Correlation of commanded duty vs measured phase current could be practical, if only the EUC reported its commanded duty. Gotway + Veteran don't (Maybe KS?) On 6/8/2021 at 4:40 AM, Mark13i said: Thank you @ Seba for implementing the function of estimating the internal resistance of the battery. Is there any hope that this feature will work with Gotway / Begode wheels in future EUC.World releases? Not during riding, because Gotway does not measure battery current But a crude estimate could be made during recharging with a plug meter while monitoring EUC voltage... perhaps even automatically if we were to turn the charger off and on periodically... Edited June 28, 2021 by RagingGrandpa Quote Link to comment Share on other sites More sharing options...
Phantom5533 Posted June 28, 2021 Share Posted June 28, 2021 Oh, nice. Good question you asked. /added this page to favs/ Now I know where to go in case something similar will happen to me. Thanks, man! Quote Link to comment Share on other sites More sharing options...
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