DaveThomasPilot

62 year old fat guy

57 posts in this topic

I purchased my 14C from Jason last winter.  Spent an hour on each of two consecutive days just getting on the wheel and riding a few yards before hopping off (couldn't turn yet).

Then I broke my back in a plane crash (N256CD).  Didn't get on the wheel again until this morning.

I'm pleased to report I got about a mile of riding in today.  I have to "cheat" on where I put my feet, so that when I get the second foot on the pedal there's a good lean forward.  That gets me going more quickly.

Of course it's not the distance--once I get going there's no problem.  It's about how many 180 degree turns I make and how tight I can make them.  So far, only cul-de-sacs.

However, once I get going it's not comfortable.  Actually gets pretty painful (feet) in a few minutes, so I guess I'll try moving my right foot back some on start up.

Which finally gets to my question...   I'm wearing hiking boots, since I was banging up my ankles quite a bit last winter getting on the wheel.  Would some other footwear be better?

 

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Talking one fat guy to another, I personally find hiking boots the most comfortable...

The ankle padding is good, as is the additional support it brings. And the stiffer soles that most hiking boots have should reduce pressure points on the feet. 

It is very different to walking though, so it will take some time for your body to adjust. But there are a few things that you can do to minimise discomfort...

Particularly when riding on a long straight, rather than just standing still, put pressure on one heel and the opposite toe. Then alternate - this will assist with the blood flow and reduce discomfort. 

If you balance the pressure, it shouldn't change your direction, but it doesn't matter if it does (on a straight), as my other suggestion is rather than riding straight to move in a long slow slalom. The slow weaving has a similar effect to the heel / toeing, once again relieving pressure. 

Being a bit heavier, riding an EUC can be more challenging. But it is very achievable (except maybe for the range that those skinny people claim). And it may help with your overall core strength and flexibility (something else I have found from wheeling).

Edited by The Fat Unicyclist
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Thanks for the replies!  I'll try the weight shifting and doing the slalom thing tomorrow.

Goal is to do the entire subdivision including side streets.  About 3 miles.

 

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58 minutes ago, DaveThomasPilot said:

Goal is to do the entire subdivision including side streets.  About 3 miles.

3 miles is a significant ride (early on). I'd suggest a stop or two partway around to stretch-out your soles. 

Other than that the key thing would be to just relax and enjoy! 

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11 hours ago, DaveThomasPilot said:

Then I broke my back in a plane crash (N256CD).  Didn't get on the wheel again until this morning.

Oh buddy, glad your are OK! I see your fly a Cirrus! What went wrong with the aircraft?

11 hours ago, DaveThomasPilot said:

 

I'm pleased to report I got about a mile of riding in today.  I have to "cheat" on where I put my feet, so that when I get the second foot on the pedal there's a good lean forward.  That gets me going more quickly.

 

Excellent! There is no cheating on technique in this field! Whatever works !?

 

11 hours ago, The Fat Unicyclist said:

Particularly when riding on a long straight, rather than just standing still, put pressure on one heel and the opposite toe. Then alternate - this will assist with the blood flow and reduce discomfort. 

Great point! That works for me as well. I just don't realize I am shifting anymore?

11 hours ago, Cloud said:

Dave , i have almost admired the peopke who dont fold in the face of circumstances, but continue to fight no matter how hard it is. Congratulations! I am sure your example will inspire many!

 

 

Fully agree! Keep us abreast of your continued progress!

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Rehab1--I lost engine power.  I headed to the nearest airport, After I broke out of the clouds I didn't think I could make it to the airport so I pulled the chute.

Broken back sounds worse than it was.  Compression fracture of T12 vertebra.  Lots of pain for a couple of weeks, but I'm pretty much ok now.  (but 1" shorter!).

I'm anxious to go riding this morning, but the wheel (KS14C) is overcharged.  That happened yesterday, but I figured it was because I left it on the charger too long.  It took over 8 hours for it to discharge down to a voltage that eliminated the three beeps and slow tilt forward/tilt back!

This morning, I took the wheel off the charger when I saw the green LED illuminate.  I might have been on the charger 10 or 20 minutes (at most) after the green LED illuminated. 

Total time on charger was about an hour.  This was longer than I expected, given the short time I rode after a full charge.

I emailed Jason this morning, but it's Sunday and I don't expect to hear back from him until tomorrow. 

I'm beginning to think the voltage reading is inaccurate.  There's a lot of watt-hours being dissipated without much voltage drop, if I believe the WheelLog app. An hour so far with the wheel turned on  Power dissipation varies from 20 to  70 watts, according to the app.

Even at the 20 watts dissipation, 20 watt hours dissipated with the voltage still at 67.69 volts doesn't seem reasonable, does it?

I'm worried that if the voltage isn't accurate, the charge state isn't known.  Maybe if I go riding the batteries could deplete so much I'd get a faceplant.

Or, is the overcharge thing normal and I'll be ok waiting until it finally discharges enough?

Thanks!

Am I safe starting at the bottom of a hill and going up to get the thing to discharge?

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20 minutes ago, DaveThomasPilot said:

I'm anxious to go riding this morning, but the wheel (KS14C) is overcharged.  That happened yesterday, but I figured it was because I left it on the charger too long.  It took over 8 hours for it to discharge down to a voltage that eliminated the three beeps and slow tilt forward/tilt back!

This morning, I took the wheel off the charger when I saw the green LED illuminate.  I might have been on the charger 10 or 20 minutes (at most) after the green LED illuminated. 

Total time on charger was about an hour.  This was longer than I expected, given the short time I rode after a full charge.

I emailed Jason this morning, but it's Sunday and I don't expect to hear back from him until tomorrow. 

I'm beginning to think the voltage reading is inaccurate.  There's a lot of watt-hours being dissipated without much voltage drop, if I believe the WheelLog app. An hour so far with the wheel turned on  Power dissipation varies from 20 to  70 watts, according to the app.

Even at the 20 watts dissipation, 20 watt hours dissipated with the voltage still at 67.69 volts doesn't seem reasonable, does it?

I'm worried that if the voltage isn't accurate, the charge state isn't known.  Maybe if I go riding the batteries could deplete so much I'd get a faceplant.

Or, is the overcharge thing normal and I'll be ok waiting until it finally discharges enough?

Chargers have internal "trim potis" which can be used to adjust to the right voltage (normaly 67,2V or for some wheel a bit higher (0,4-0,7V) in case they have a protection diode). Yours seem to be "misadjusted" to a too high voltage - a reading of 67,69V from wheellog is too much. That amounts to 4,23V per cell! (should not be over 4,2V per cell)

But leaving the wheel on the charger every x charges once the led turned green is important so the BMS can balance the cells! In your case you should not do this until your charger is adjusted again or replaced. If you use your charger be sure to disconnect early enough - overcharge is reducing the life expectation of the cells. If they are overcharged don't leave the cells like this too long (~some weeks) - try to get the charge lower by riding (uphill).

Quote

Am I safe starting at the bottom of a hill and going up to get the thing to discharge?

Going up is no problem and i'd recommend you doing this for the sake of your cells! Or just driving eights and circles on a flat space (increases ones driving skills ;) ) is a good way to discharge the battery and have fun.

Just declines and (stronger) braking could trigger the overvoltage protection of the BMS and lead to an immediate cut-out.

Edited by Chriull
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By "trim potis", I think you mean" trim pots".  Short for "trim potentiometers".  (A variable resistor.

If that's right, it's disappointing.  In modern power conversion designs (like Lithium chargers), trim pots are usually avoided.  Precision voltage references largely eliminate the need for trim, and any adjustments  required are usually done using a processor and D/A, A/D conversion.

Does a schematic exist for the K14C charger Jason ships?

 

 

 

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3 minutes ago, DaveThomasPilot said:

By "trim potis", I think you mean" trim pots".  Short for "trim potentiometers".  (A variable resistor.

If that's right, it's disappointing.  In modern power conversion designs (like Lithium chargers), trim pots are usually avoided.  Precision voltage references largely eliminate the need for trim, and any adjustments  required are usually done using a processor and D/A, A/D conversion.

Does a schematic exist for the K14C charger Jason ships?

I don't know if a schematic exists, but from what I've seen and understood, most of the wheel chargers seem to be relatively simple switching mode power supplies with adjustable constant current / constant voltage -modes. And the adjustments are apparently made just by trim-pots in the PCB.

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Thanks for the replies, ESAC.

The wheel battery is still at 67.67 volts after being on for two hours dissipating 20 watts or more, according to WheelApp.

Is this believable?

My concern is not so much that it's overcharged--I can probably fix that by going uphill first.  But, if the voltage reading is wildly inaccuracte, I'm worried it's unsafe to ride at all.  Battery charge state wouldn't be known, so the wheel could shut down without warning.

Thanks

Edited by DaveThomasPilot
typo
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14 minutes ago, DaveThomasPilot said:

By "trim potis", I think you mean" trim pots".  Short for "trim potentiometers".  (A variable resistor.

Exactly. potis is more a german abbreviation.

Just in case you think of adjusting the voltage by yourself - there are normally three of this trim pots in these kind of chargers. One for the max voltage, one for the max current and one for the shutoff("end current") (once the green led goes on):

 

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12 minutes ago, DaveThomasPilot said:

Thanks for the replies, ESAC.

The wheel battery is still at 67.67 volts after being on for two hours dissipating 20 watts or more, according to WheelApp.

20 Watts is strange - normal minimum Power for slow steady driving is around 200 Watts.

How much Wh has your battery? Something around 300, if i remember right for Ks14?

200W for 2 1/2 hours would total for an energy use of ~500Wh and should quite deplete your battery if i am right....

Or did you manage to get some fixture for your wheel and let it spin for this 2 1/2 hours? Then this 20 Watts * 2 1/2 hours would be just ~50 Wh which is not too much enery used up....

However - you should look to get enough load on your wheel to discharge the batteries below 67,2V (4,2V per cell)

Quote

Is this believable?

My concern is not so much that it's overcharged--I can probably fix that by going uphill first.  But, if the voltage reading is wildly inaccuracte, I'm worried it's unsafe to ride at all.  Battery charge state wouldn't be known, so the wheel could shut down without warning.

Going uphill should not be unsafe to ride. Just going downhills or (stronger) braking could lead to battery charging by the wheel and by this to a cutoff.

Edit: Ups - i just realized i did not read your last paragraph and gave an answer for a different content ;(. You could check this with an Volt(/multi)meter by measuring the no-load output voltage of your charger - for a first indication what could be the cause.

Edited by Chriull
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So, after going up my 600 foot (maybe 10 degree slope), uphill driveway three times and up two more hills in my subdivision I still get tiltback and three beeps even when just slowing down on a straight-away.  Forget about going down even the slightest slope.

Wheel App says still 67.63 volts.

I'm not worried about what happens if it really IS that high a voltage.  I'm very used to the tiltback now.  I'm just thinking that something's wrong in the KingSong's voltage measurement so that my battery might drain completely while the smarts in the wheel think it's got plenty of energy.

I'm going to try a few more uphills to get the voltage down.    If the voltage is still high,  then I'll open up the charger and measure the voltage while connected to KS.  I'm really impressed by a battery that has that much "extra" capacity without the voltage decaying below 4.2 volts per cell, even after lifting 250 pounds several hundred feet.  B)

Ironically, I need some sort of dolly to carry my wheel DOWN hill when my battery gets too full!  :P

I haven't read the thread you pointed me to you--still trying to run it down by riding it.  Is there a pin-out for the charge connector in there some where?

Thanks,

Dave Thomas

 

 

 

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Also, the wheel was just leaning up against the wall in a box.  Beeping, and tilting back and forth.   20 watts was the MINIMUM I ever saw.  Very jumpy current readings, maybe typical reading was around 50 watts.

My wife is going to follow me in our golf cart and give me rides down the hill. ( It's impossible for me to stay on the wheel when it tilts back so much).

I'll try about a mile of all uphill then come back and see what the app reports for voltage then measure with DVM, once I figure out the pinout.

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Ok, 3 rides, 1/3 mile each, all up fairly steep hill. 

Voltage is 67.5 volts.  Still too high.

Don't believe it.  Going to measure voltage with DVM now.

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Can you take a reading from the charger and the battery with multimeter? This will help you find if the problem is the charger, the battery or the app.

 

A few things to note when testing:

-Be very careful not to touch the probes on your multimeter together when testing live voltages. This creates a short that can destroy multimeters and parts of the wheel.

-It is normal for the voltage from the charger read to a little bit higher than advertised. Considering impedances, most chargers when not connected to a battery will read slightly higher than the 67.2 you are expecting.

-Don't test the battery at the charging terminal. It is very easy to make a mistake and create a short that stuffs up the prongs on your charging port.

-Instead, open the wheel and disconnect the battery at the clip. It is yellow on most wheels and usually has a black and red wire coming out each side of the clip. Much less chance of creating a short.

-Be very careful not to touch the probes on your multimeter together when testing voltages. This creates a short that can destroy multimeters and parts of the wheel.

^ I know I have said already this but its worth mentioning twice as it is important.

 

After you have tested this and you know where the problem lies you will know if you need to replace the battery or the charger. If its the app, there isn't much you can do.

 

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I must be measuring trying to measure battery voltage on the anode side of a series diode.  The voltage readings aren't reasonable--much too low.

I measured in the charger where the charging cable is connected to the charger board, with the wheel on but charger off.

I also measured inside the wheel on a Dean's connector that's inline with the charge cable.  Still an unreasonably low voltage.

So, I'm thinking there's a diode in series so that current can only flow from the charger into the battery.  So, you can't measure voltage at that point unless the charger is on (and sourcing some current).

I only disassembled the left cover on the KS, and I don't see a connector that's directly to the battery.  I did find the connector from something to the main board, but it's voltage is also low (with wheel off now).

I'm going to solder a couple of test wires inside the charger and monitor the charge voltage while the charger is on, unless I hear a better suggestion.

 

 

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15 minutes ago, DaveThomasPilot said:

...

So, I'm thinking there's a diode in series so that current can only flow from the charger into the battery.  So, you can't measure voltage at that point unless the charger is on (and sourcing some current)...

Exactly.

try measuring the voltage from the plugged in charger. I'd assume its too high and so overcharges your battery pack.

 

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So, with the charger on and charging, the voltage is 67.6 volts--which agrees reasonably well with what the KS thinks, according to both the WheeLog and KingSong apps.  (And it's too high)

No green light on the charger,so I need to adjust the pot to make sure it's green at this voltage--and even a little lower.  Anyone have a clue on which way to turn to set the voltage threshold lower?  And how sensitive it is?

It's still hard to believe I did that much up hill riding without getting the battery voltage down more, but at this point I'll keep doing the uphill thing (tomorrow)..

Thanks for the replies!

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34 minutes ago, DaveThomasPilot said:

So, with the charger on and charging, 

...

You should measure the charger output voltage with no load - not while charging the wheel!

34 minutes ago, DaveThomasPilot said:

No green light on the charger,so I need to adjust the pot to make sure it's green at this voltage--and even a little lower. 

The trim pot adjusts the maximum voltage, but while charging it can be (and is in your case) in the constant current phase and regulates by this to some lower voltage! So adjusting the trim pot while you charge your wheel is not in any way recommendable! 

34 minutes ago, DaveThomasPilot said:

Anyone have a clue on which way to turn to set the voltage threshold lower?  And how sensitive it is?

I'd assume turning to a higher "ohmic" value will increase the max output voltage - but thats just a guess. You'll see once you try and measure while _not_ charging the wheel.

if i remeber correctly one has to turn quite some rotations for "real" changes...

Just as precaution: be sure to remember the original state in case you changed the the max current or cutoff trim pot by accident.

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10 hours ago, DaveThomasPilot said:

Rehab1--I lost engine power.  I headed to the nearest airport, After I broke out of the clouds I didn't think I could make it to the airport so I pulled the chute.

Broken back sounds worse than it was.  Compression fracture of T12 vertebra.  Lots of pain for a couple of weeks, but I'm pretty much ok now.  (but 1" shorter!).

Wow the Cirrus came down hard even with a chute! Compression FXs generally heal well without surgical intervention. I see a ton of kids that land hard on their butts while playing sports that suffer from those type of injuries. Glad you are Ok!!

I had 2 helicopter engine out autorotations, both resulting in tip overs and major damage, one including a fire, but walked away with only a few scratches. I don't know about you but I saved some of the parts from my crashes. I have the main and tail rotor blades hanging on a wall in my barn just to remember those moments in greater detail.?

Wish I could be helpful on your wheel issues but you are in good hands with everyone that has offered advice!

Edited by Rehab1
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Sounds to me like your charger is ok but one of your 18650 cells in your battery pack has become disconnected/faulty or a fuse on the bms has gone. I had a similar problem a while back with a bad connection. Managed to fix it too with a bit if work. 

If you are feeling brave and you are comfortable doing it, I'd be opening up the battery pack and looking for a dodgy cell. Test the positive and negative of each cell. I usually test on the bms itself rather than the nickel strip or battery to make sure the connection is actually getting onto to the pcb. Hopefully it's just a bad connection because that is an easy fix with a bit if solder. If  it's the cell itself you will need to remove and replace the bad cell. Kinda tricky. Again be careful of shorts especially on the positive ends of the batteries as the side walls of each cell are negative and can be easily tripped.  Plus you will have some high voltage points in various places over the board eg. First and last cell in the series and at the charging and power switch connections to the bms. Gotta make sure all your cells are balanced too once you are done otherwise you may have 1 under charged or over charged cell. 

Quite frankly it's a lot easier and a lot safer just to but a whole new battery pack at this point.

Just my two cents.

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1 hour ago, 16bitSprite said:

I had a similar problem a while back with a bad connection. Managed to fix it too with a bit if work. 

Is it possible that a faulty cell could lead to an over-charge in the pack? I'm sending Dave a standard charger tomorrow morning as a first step.

This is the first case of over-charging on the 14C. On the 14B experienced the situation where if it's left into the charger for several hours, it can rise as high as 67.8v. Riding it out for a couple minutes with the smaller 148Wh pack usually gets the voltage below normal range.

 

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