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Cranium

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Cranium last won the day on December 28 2015

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About Cranium

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    Advanced Member
  • Birthday 04/26/1968

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  • Gender
    Male
  • Location
    Central Florida, USA
  • Interests
    Besides riding EUCs, I am an electronics enthusiast, road cyclist, computer gamer, RC racing quad flyer, and am learning to fly Paramotors.

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  1. The limitation of Charge Doctor is that it will not show you the internal resistance of the cells or if there is an out of balance situation in a pack. This would be, in my opinion, more important to find out rather than showing voltage and current for the entire battery. Especially when the pack viability is in question. When I had an issue with my battery, I took my battery heatshrink off and checked then charged pairs of cells individually. I say pairs of cells since the battery configuration is a 15S2P (15 cells in series and 2 of these in parallel) for the Ninebot so I was only able to isolate a pair of batteries at a time for charging without having to desolder the battery pack. The charger I used was an RC charger which would also provide the IR (Internal Resistance) of the cells. While the accuracy of IR value could be questionable and the value of any set of cells may not be actionable alone, the value is great to use to compare to the other cells. For example, if most of the cells showed an IR of 15 ohms and one cell showed 25 ohms, this would indicate an issue in that pair of cells. If you have cells with a higher internal resistance, it will affect their charging and discharging characteristics and lead to an out of balance situation more rapidly. So doing this will allow you to see if your pack is balanced when you check it and allow you to see if you have cells going bad. A charge doctor, buying a charger that has an 80% charge function, or modifying a charger to only charge to 80% is a great thing to do if you want to baby your batteries and get longer life out of them. It also provides a built in buffer if you do have some cells starting to go bad since all cells will never be at 100% or close when you brake or go down a hill right after you take it off the charger. And with the charge doctor data logging, you can do a trend analysis of charge cycles. This would give you a peak inside the chemistry of the battery as it's changing over time without having to open up the pack. So a new battery, for example, may take 1.5 hours to fully charge and only 1 hour to go from constant current to constant voltage mode. After 6 months, this time would be expected to gradually increase as the internal resistance of the batteries slowly increase. But if you see a sudden change, you have an issue. I retired my Ninebot One P after I fried another controller while trying to test out the battery pack to see if it was having issues. So I didn't get to fully test if my pack had an ongoing issue or if it became out of balance due to my poor charging habits (I would keep it 100% and charge after every ride which didn't give it time to balance properly). I had even bought some LiPo alarms to use for testing which would alert me if any pair of cells started going low before the BMS shut down.
  2. Cranium

    Ninebot One Z : Z6-Z8-Z10

    Yes, if modeled after the Segway there would be parallel systems which can communicate with each other. If one fails, there is an error generated by the operating board which can then alarm and force the user to come to a stop (tiltback). In the motor, each board controls a separate set of coils to ensure the failure of one board doesn't cause a motor failure. There would also be redundant hall effect sensors (one set for each board) in the motor.
  3. Cranium

    Ninebot One Z : Z6-Z8-Z10

    If only we could get the safety and reliability of the Segway electronics in our EUCs. That would be a winning combination albeit a more expensive one.
  4. Cranium

    Adding "Reverse Diodes" to the Charger Port

    I don't know if every EUC would be obviously colored red and black. But since you have your multi-meter and if you determine there is no diode, you also know which pin is the positive side and can look for the wire attached to it. Or just check polarity where it attaches to the circuit board.
  5. Cranium

    Adding "Reverse Diodes" to the Charger Port

    Multi-meter will work well for testing. If your's doesn't have one, it's easy to add. Get a pin diode with a current and voltage rating above what you need. Cut one of the charging port wires and solder the diode inline with the stripe on the diode away from the charging port.
  6. Cranium

    Paging Dr. Rehab1, another rider down!

    Sorry to hear about your accident! I'm surprised you have no pain from it. Perhaps adrenaline is preventing it and you will start feeling it soon! I've had a serious tear of a calf muscle playing racquetball and it wasn't very painful either so it isn't unheard of I guess.
  7. Cranium

    Age Thread

    I would guess that it is more prevalent among older people because we have more disposable income along with more time. Many 20-30 somethings are developing their careers and/or are raising a family.
  8. Cranium

    how to enjoy riding slow speeds?

    I bring a good book or do some crochet to maintain the fun level while riding slow. There's nothing more fun or rewarding than to complete a new cat scarf while riding. Honestly though, while riding fast is a adrenaline rush, minimizing the risk of injury is more important to me. So I just try to tune in and enjoy my surroundings more. Carving on the EUC can help wake up the brain a bit if it becomes too monotonous. I travel about the same speed as I go when I'm riding my bike (18-20mph) and I'm perfectly fine with that.
  9. Cranium

    Dream Electric Unicycle

    Comeon now....let's play nice. This isn't a battle to see who can top each other on insults. lol Changing each cell would actually be possible. Just like with changing batteries on a remote control or larger battery operated device with AA batteries. And they don't have to be at the same voltage in the series....just at the same voltage for cells in parallel. So it isn't an impossibility. You could add in a battery that is a lot lower than the rest in a string and would just have to balance out the whole string before use. But what I think @exoplanet does not understand is that with proper balancing, the batteries are not likely (barring manufacturing defects) to have single cells failing prematurely since all of them are new when assembled and all of them experience the same load over time so they all wear down the same. Very small differences in internal resistance is why we have balancing to compensate for different cell charge/discharge characteristics. There is also the issue of having a larger battery pack to accommodate cell swapping. To make it very safe, it could require parallel cells to be swapped together in a pre-assembled pack before adding it to the string. But again, it would have to be a larger, battery pack which may not offer a return in value versus increased cost and increased space requirements.
  10. Cranium

    ninebot e+ tried to kill me

    @exoplanet, your reputation on the forum is quite bad (-17 as of this post). If you are actually seeking help with your EUC many people are here to help and take your questions seriously. But if you follow it up with something that is obviously stupid, people will feel you are just trying to troll and will stop even trying to assist you. I won't try to help you again until your reputation improves.
  11. Cranium

    Tesla First Day Fun! - Motor Cutout at 34.3 MPH

    For this type of activity, yes. You will have more data being recorded so a more accurate representation of your results for review. "Smart" recording is more for very long events like a century ride or something longer. It will adjust the recording frequency to conserve battery so the results if you are changing speed or direction may be not represented as well. 1 second recording will always provide consistent results. I use a Gamin 1000 and Fenix 5X for tracking activities and have never needed Smart.
  12. Cranium

    Tesla First Day Fun! - Motor Cutout at 34.3 MPH

    Looking at the graph, your speed spikes up quite a bit from your average speed then down to zero. Were you doing something to increase speed quickly right before the fall? Is your Garmin set to 1 second recording interval or 'smart' recording interval? I think it is amazing you took a fall at speed and walked away with no injury to yourself! Good job on wearing all the protective gear.
  13. Cranium

    ninebot e+ tried to kill me

    It would work for discharging but that is not a very controlled method since you have to have something to set and hold the wires a certain distance apart to set the current discharge rate and monitor the voltage closely. But before you discharge, you really need to check the balance of the cells. If one is already low, you have to get it back up before you would be able to discharge the pack because the BMS will just cut off the whole pack when a single cell gets too low.
  14. Cranium

    ninebot e+ tried to kill me

    yes. A charger used for LiPo and other types of batteries popular in the remote control hobby. If you don't have one and want to purchase one, I would recommend one that is good for multiple battery chemistries (LiPo, LiFe, Pb, etc) and multiple cells (ie 1-6s) I had good luck with this one while I owned it (before getting something bigger): https://www.amazon.com/gp/product/B00466PKE0
  15. Cranium

    ninebot e+ tried to kill me

    I had an issue with my battery pack where one of the cells was out of balance. I was continuously topping off the charge rather than letting the battery get down in voltage very much due to just going on short rides. Over time this appears to have allowed one of the cells get out of balance due to a difference in internal resistance of the cells and not giving it enough time during charging to balance. This resulted in the BMS cutting out on me on a ride. I opened up my pack and checked the balance of cells. Then with an RC charger, I charged individual cells to get it all back to about 4V/cell. At this point I did a discharge test down to about 3.4V then did a full charge with the charger and all cells balanced perfectly. I wouldn't worry about it damaging the other cells from this if it's only a single cell really low. For example, if one cell was at the cutoff voltage of 3.2V the remainder of cells would only need to be at 4.27V to indicate a fully charged battery.
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