Johey Posted August 24, 2016 Share Posted August 24, 2016 I bought my KS16 from wheelgo.com which states the battery they deliver is 840 Wh. That is also confirmed by a sticker on the pedal. However, my charge measure it to about 560 Wh after charging. That's quite a bit under 840. How can I confirm the battery is really 840 Wh? Link to comment Share on other sites More sharing options...
esaj Posted August 24, 2016 Share Posted August 24, 2016 You need to run it to "empty" repeatedly. Wait a bit between attempts (so the battery voltage recovers a bit) and repeat. Ride slowly, no fast accelerations or such which could trigger the "out of battery"-alarm (I don't know how it works with KS, does it still let you ride then?). You'd need to get the battery all the way to about 3.0V per cell (48V total) to get the "full charge", I don't know if KS firmware even lets you do this. But try to ride it as empty as you can and then measure. Link to comment Share on other sites More sharing options...
Jason McNeil Posted August 24, 2016 Share Posted August 24, 2016 1 hour ago, Johey said: my charge measure it to about 560 Wh after charging. That's quite a bit under 840 What voltage did you start the charge at? Link to comment Share on other sites More sharing options...
HEC Posted August 25, 2016 Share Posted August 25, 2016 4 hours ago, Johey said: I bought my KS16 from wheelgo.com which states the battery they deliver is 840 Wh. That is also confirmed by a sticker on the pedal. However, my charge measure it to about 560 Wh after charging. That's quite a bit under 840. How can I confirm the battery is really 840 Wh? First of all - if you've got the KS-16 from @Jason McNeil I can assure you that you've received a correct battery. And as @esaj already mentioned you need to have the battery completely discharged and even then when measuring the charged capacity (I assume you're using Charging Doctor from Fred?) you'll never have full 840Wh but you'll see something around or even slightly above 800Wh. When I've got my KS-16 all the way to reported 6% capacity it took about 785Wh to recharge to "full". Also - what voltage you have selected on the 5A fast charger? Because if you have selected 64.8V (instead of full 67.2V) that will indeed further decrease the capacity charged. Link to comment Share on other sites More sharing options...
Johey Posted August 25, 2016 Author Share Posted August 25, 2016 Ah, so I cannot measure the energy without first emptying the battery? Wasn't sure about that. It was like 60 % remaining when I started charging and ran the limited setting on the charger. Just thought that if I needed to empty the battery first, it would show much less than 560, so therefore my conclusion was that the total energy of the battery is what is shown on the display. Anyway, I'll try emptying the battery (it doesn't hurt the battery, does it?) and run a full charge. Using this charge doctor, but with only one charger connector. Link to comment Share on other sites More sharing options...
HEC Posted August 25, 2016 Share Posted August 25, 2016 2 minutes ago, Johey said: Anyway, I'll try emptying the battery (it doesn't hurt the battery, does it?) and run a full charge. It's not recommended to repeatedly almost fully discharge the battery so that should be avoided if possible as it prolongs the battery life in general - the best is to keep the battery between 20 and 80 to 90% of capacity max to greatly extend battery life. But indeed discharging battery once a while is not going to "kill" it and it's also protected by both the FW of the wheel as well as BMS in battery to avoid any real damage. To understand what Charge Doctor shows under Wh or mAh value - it's amount of energy "pushed" into battery during the charging. And indeed you'd need to reset it by long push on the control button before each new charge cycle otherwise it will keep it previous value and add new charge to it as total. So it's not something which will "guess" and display actual full battery capacity as you maybe though? Read more details at http://hobby16.neowp.fr/category/charge-doctor-en/ Link to comment Share on other sites More sharing options...
Johey Posted August 25, 2016 Author Share Posted August 25, 2016 Oh ok. Then what is shown is how much fuel I have tanked since I started using the charge doctor, in both the KS16 and the X8. I'll read up on the charge doctor. It's more complicated than I thought. Link to comment Share on other sites More sharing options...
Cloud Posted August 25, 2016 Share Posted August 25, 2016 @Johey basically the charge doctor doesnt "read" your battery parameters. It only reads your charger parameters. It cant tell you how full your baattery is when you conneect it. It only can tell you the charger's voltage, current, and how many watt-hours the charger has pushed into the battery over time. Link to comment Share on other sites More sharing options...
HEC Posted August 25, 2016 Share Posted August 25, 2016 28 minutes ago, Johey said: Then what is shown is how much fuel I have tanked since I started using the charge doctor, in both the KS16 and the X8. Correct. Using your car analogy it would equal to amount of petrol tanked to your car at petrol station And if you don't reset the counter before each charge it would equal to a total "fill up" of multiply cars from the same station ... Link to comment Share on other sites More sharing options...
sbouju Posted August 25, 2016 Share Posted August 25, 2016 One precious thing to know, and this is very easy to know with the help of ChargeDoctor, is how many Wh we need for a kilometer. Currently, I am between 13 and 14 Wh/km with my MSuper2, with a weight of 100 kg. Link to comment Share on other sites More sharing options...
sbouju Posted August 25, 2016 Share Posted August 25, 2016 8 hours ago, esaj said: ...You'd need to get the battery all the way to about 3.0V per cell (48V total) to get the "full charge", I don't know if KS firmware even lets you do this. But try to ride it as empty as you can and then measure. On my MSuper2, I cannot discharge the batteries under something like 53 volts (while riding the wheel!) because of the "low battery tilt-back". And trying to go lower is not very good for the battery, no? Link to comment Share on other sites More sharing options...
Cloud Posted August 25, 2016 Share Posted August 25, 2016 @Johey if you just want a peace of mind to see that your battery is indeed 840wh, and you dont want to or have trouble discharging the battery fully, why dont you just discharge it to 50% and then charge full and see if you get 420wh or close to that? Link to comment Share on other sites More sharing options...
sbouju Posted August 25, 2016 Share Posted August 25, 2016 How do you know when the wheel battery is "at 50%"? Just trusting the smartphone app, or the lights? Link to comment Share on other sites More sharing options...
Johey Posted August 25, 2016 Author Share Posted August 25, 2016 @Cloud, That's a good idea. Given that the percentage measurement really is linear, I can do my maths. Will reset the doctor and charge it with full setting on the charger later today. Oh, I need to disable the shutdown feature of the doctor as well I suppose? Link to comment Share on other sites More sharing options...
Cloud Posted August 25, 2016 Share Posted August 25, 2016 Yes, disable shutdown Link to comment Share on other sites More sharing options...
Keith Posted August 25, 2016 Share Posted August 25, 2016 41 minutes ago, Johey said: Oh, I need to disable the shutdown feature of the doctor as well I suppose? Yes of course. Both the lower voltage charging mode on Jason's charger and the adjustable cut off current on the Charge Doctor are designed to do the same thing in different ways, that is that they prevent you from fully charging your wheel as it improves the battery's long term life. I recommend you most certainly do not do both at the same time as you will end up with an even lower charge in the battery, as you will cut off Jason's low voltage charge whilst it is still putting in a fairly high current. Also do not forget that most BMS only start to balance the cells once the voltage in the battery gets close to 67.2V so roughly every 10-20 charges you should do a full voltage and full current charge plus leave the charger on for an hour or two after the charge complete (green LED) goes green to ensure all the cells in the battery are "balanced" I.e. Every cell is at the same voltage. You don't need to be anal about this, ideally do a full charge when you know you are likely to be doing a long run. To turn off the Charge Doctor Shutdown feature, turn on the charger with the Charge Doctor connected and repeatedly press the button on the it until a flashing display ending in A (for Amps) is displayed; now press and hold the button, the display will toggle with each long press between 0.00A (full charge) and a changeable other value which, as a default, is 1.00A I.e. Cut off when charge current has dropped to 1 Amp. To reset the stored total Amps and Watt hours, just hold the button in for a long press when either is displayed. You can do this without connecting the Charger to the Wheel and connect it once you have set the Charge Doctor as you like. Fully discharging a battery isn't good for it and leaving it stored fully charged for long periods isn't either so @Cloud's suggestion of doing a full charge when the app shows a percentage you can multiply from is an excellent idea, especially as riding the wheel down to the point it reaches limp home mode isn't a lot of fun! Link to comment Share on other sites More sharing options...
Johey Posted August 25, 2016 Author Share Posted August 25, 2016 Thanks for all suggestions and explanations! Very appreciated. Can you turn off the persistence in the charge doctor? I can't really get the point of accumulating the results of previous charges. Link to comment Share on other sites More sharing options...
HEC Posted August 25, 2016 Share Posted August 25, 2016 22 minutes ago, Johey said: Thanks for all suggestions and explanations! Very appreciated. Can you turn off the persistence in the charge doctor? I can't really get the point of accumulating the results of previous charges. At the moment no - you need to reset the counter manually and after while it just becomes a habit. I actually reset it after charging before turning charger off so it's ready and zeroed next time I pop it in to the wheel. You can indeed suggest the option / new feature to Fred however it would not be possible to retrospectively add to your current CD. As to while the "electric meter" value is persistent I'd say reasoning was that if you interrupt the charging for whatsoever reason (be it manually or automatically via CD or by "accident" selecting the lower voltage on the charger) you can resume it and still obtain the total value in the end. I do agree though that for most users that would be less frequent scenario than one uninterrupted charge per one "power up" session. In regards of the 50% (or what ever other value) - it's not really that linear so you'll not get exact values there but for rough estimate it should suffice I'd say. And as already mentioned above - when using CD to cut of your charging early leave the fast charger on the full voltage (67.2V) option. Finally as you have now new version of CD (2.03 or higher) you can also set the Voltage cut off instead of Current which is more (IMO) reliable option and is independent of the battery state, size or age. I have mine set to 66.4V which results in 87% reported charged capacity by wheel / app but you can indeed set it a bit lower if you prefer but remember that the resulting actual voltage of the battery will be a bit lower than cut off value. Link to comment Share on other sites More sharing options...
esaj Posted August 25, 2016 Share Posted August 25, 2016 4 hours ago, sbouju said: On my MSuper2, I cannot discharge the batteries under something like 53 volts (while riding the wheel!) because of the "low battery tilt-back". And trying to go lower is not very good for the battery, no? Constantly discharging or fully charging the battery all the way to empty/full likely leads to faster capacity degradation than keeping it somewhere between 20-80%. The Firewheel low-battery tiltback occurs only after the voltage dips to somewhere below 48V (3.0V per cell), so it was much easier to do this testing on it... after 400+ cycles, I could still get the battery to charge 268Wh (264Wh nominal) by running it repeatedly to the tilt-back (ie. after the tilt-back, I stopped, waited a few minutes and tried if the warning starts immediately on power up, if not, continue riding ) and then charging it all the way to full (until charging current dropped to something like few tens of milliamps). But yeah, doing that all the time would probably not be good for the battery. Link to comment Share on other sites More sharing options...
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