Knowing the life span of an electrical unicycle that would lead us to....?

[Scubadragonsan]

Like us, the life of an electric unicycle will one day meet its fate. But when? Some say it's around 5,000 miles or 8000 km. We might never know exactly when because not all wheels are made the same. When it happens it happens kind of thing. But having an idea would lead us to plan ahead as if for someone's funeral. If we knew, we'd plan to sell/give it to a new learner, plan for a budget to revive it if possible, plan for its funeral (where to dump it)...etc.  Is it worth the investment besides just to have one for fun. But most of all, back to the question: roughly when? What are the stats out there? Anyone wants to share the stats or thoughts for their short-lived or long-life wheels due to "natural deaths?" I have several of my wheels (KS18XL, KS18S, KS16) already in the 5000 mile range. Hopefully, they will last for another 5000 miles, wishful thinking? Whenever they die, no funerals, but upgrade is my plan! 

Edited March 31, 2023 by Scubadragonsan

[chanman]

If you're willing to replace parts the lifetime is basically infinite, as long as spare parts are widely available, although you have a ship of Theseus situation going on.

Personally I draw the line at battery pack replacement since that's quite expensive, and the lifespan of them is well studied and is measured in cycles, generally accepted to be a few hundred cycles before significant range loss, although you can usually continue to ride for quite a while longer on reduced capacity. Thus bigger battery pack wheels have longer battery pack lifespans in miles, and is on the order of 10k miles for a 30 miles range wheel you see significant range loss, but again can continue afterward for some time.

Other parts you're most dealing with stress induced or random failures, which is harder to predict and isn't always consistent across models, but the replacement is generally much lower cost.

Edited March 31, 2023 by chanman

[drader]

A few youtubers have gotten about 10,000 miles and then the main bearings need to be replaced, and that motivates them to buy something new. You can almost double the life of the battery by charging slow and not to 100%.

[BKW]

I have 8K on my Sherman Max and still going strong, so I'm not sure of the lifespan of these things yet. I haven't noticed any difference in the battery either

Edited March 31, 2023 by BKW

[Scubadragonsan]

Oh, I really like these feedbacks, thank guys, especially the predecessors who are still riding! It tells not only me but everyone else and the soon-to-be EUC enthusiasts that these wheels are really a worthy investment, fun and made well that will last for a lifetime! 

[Phonoman]

Pretty sure I've seen people saying they've got wheels over 15k still going strong, just some tire changes and bearings at some point. 

Edited March 31, 2023 by Phonoman

[BKW]

17 minutes ago, Phonoman said:

Pretty sure I've seen people saying they've got wheels over 15k still going strong, just some tire changes and bearings at some point. 

i haven't even changed the knobby kenda tire on it in 8K miles either. It's still good. AND I ride on pavement most the time where it should be wearing faster.

Meanwhile, the last ebike I had I was getting multiple different flats a week, and the maintenance seems constant

[Murdomeek]

i got over 22,000 on my OG sherman and still going strong.

Only replaced tires and tubes.  And a rollbar from a crash.

- The batteries have 500-2000 cycles life before they degrade to 80% capacity.  That means my sherman has 50,000 - 200,000kms before it degrades to 80% capacity

- The direct drive motor technology are solid and will last well over the above limit unless you overheat them intentionally

- The electronic controllers can also last much more kms if protected from water and dust.

- The tire lasts 5000-20,000kms depending on your terrain and psi

- The tube gets punctured every now and then

- the bearings need to get oiled/replaced every now and then

- The shell gets scuffed up from drops and falls every once in a while.

 

 

So realistically, the only 'limiting factor' is to not crash so bad you destroy it, ruin it with water, or being too lazy to replace a tube/tire/bearing. 

The main limiting factor will actually be a new and shiny EUC model with more features gets released and you replace it.  

[Hellkitten]

I currently have almost 12,000 km on my v11. Stock tire is balding, but still going. I’ve done zero maintenance and only changed the pedals to spiked versions and added pads. I balance my cells regularly. 

Edited April 1, 2023 by Hellkitten

[mrelwood]

 

6 hours ago, drader said:

You can almost double the life of the battery by charging slow and not to 100%.

Incorrect. By not charging to 100% you can shorten the battery lifetime down to a tenth of what you would otherwise get.

 

I sold my MSX at 14k km, in a decent condition. Battery was practically as good as new, since I had charged it to 100% + a few hours for balancing every time I charged the wheel.

Before that my 16S battery died at 4k km, and the second pack at 8k km. Possibly because I balance charged them only about every tenth charge. Pedal bracket bolt also snapped at 8k, but with new bolts it was good to go again. The battery repairs were a chore though.

 So, where do you measure when the time has come? If you expect that zero maintenance must be involved, the lifetime will be a fraction of those who regularly maintenance and take care of their vehicle. So based on what I’ve seen and experienced, I’d say that the normal lifetime expectancy for an EUC is 4k - 20k km, depending on where and how you ride, and how you take care of your wheel.

Edited April 1, 2023 by mrelwood

[Tawpie]

12 hours ago, Scubadragonsan said:

Like us, the life of an electric unicycle will one day meet its fate. But when? Some say it's around 5,000 miles or 8000 km. We might never know exactly when because not all wheels are made the same. When it happens it happens kind of thing. But having an idea would lead us to plan ahead as if for someone's funeral. If we knew, we'd plan to sell/give it to a new learner, plan for a budget to revive it if possible, plan for its funeral (where to dump it)...etc.  Is it worth the investment besides just to have one for fun. But most of all, back to the question: roughly when? What are the stats out there? Anyone wants to share the stats or thoughts for their short-lived or long-life wheels due to "natural deaths?" I have several of my wheels (KS18XL, KS18S, KS16) already in the 5000 mile range. Hopefully, they will last for another 5000 miles, wishful thinking? Whenever they die, no funerals, but upgrade is my plan! 

My 16XS.LR is at 4000 miles, seems to be fine but I need to go in and re-fasten the motherboard (I didn't really know what I was doing when I took it out to troubleshoot an issue with my add-on battery pack and didn't understand that the nuts were kaputer'd (whatever that white pucky is called) in... I should have cleaned and redone the white stuff). Battery seems fine.

S18's battery suddenly stopped charging at 74V (fine one day, not fine the next) and got molicel replacements. It had about 1600 miles on it. All 4 packs were degraded as it turned out, not 1 with a broken weld as I had suspected. I was the second owner responsible for the last 1000 miles and was religious about charging to green + 1-2 hours every time it was charged. So that wasn't nearly as good.

S22 is too new to count, MTen3 doesn't get enough use to count.

I suspect I shall continue to replace parts until the batteries fail—then they will be parted out. I like them all, and resale value is so bad these days that it's easier for me to hold on to them and ride them occasionally than it is to give them away. Each has its own sweet spot.

[Begodecrashtestdummy]

4500 miles on my new rs19 highspeed since last summer .I shall be needing a tire very soon 

[drader]

On 3/31/2023 at 6:09 PM, mrelwood said:

 

Incorrect. By not charging to 100% you can shorten the battery lifetime down to a tenth of what you would otherwise get.

mrelewood, you are absolutely WRONG on this, and laughably so. Every brand cell and chemistry used in our EUCs has been studied to death and an easy source for info is reading about Teslas (the car). You can accurately predict the life of your car's battery based on charging habits (hint: tesla taxis die soonest). While you are correct that EUCs use some of the dumbest management systems and cells will "eventually" go out of balance that doesn't mean you have to balance your cells every single time you charge. And charging from 60% to 80% doesn't use up one charge life, as if it was a stamp on your diner card.

[mhpr262]

What really matter is not letting the battery SIT for a long time when charged to 100%, and if you dont charge the battery to 100% often then the more important it becomes to not discharge it fully each time you go for a ride, because li-ion cells HATE being deep discharged.

[mrelwood]

On 4/6/2023 at 8:25 PM, drader said:

mrelewood, you are absolutely WRONG on this, and laughably so. Every brand cell and chemistry used in our EUCs has been studied to death and an easy source for info is reading about Teslas (the car).

… Which has a very different BMS mechanism and technique, making it completely irrelevant for EUCs. What I’m talking about has got nothing to do with the battery chemistry, only about how the EUC BMSs function. For single cell battery applications and proper non-EUC BMSs (and now V13 and S22), 80% charging will absolutely prolong the battery life, because then we are comparing the behaviors of the battery chemistry. With a passive top balancing EUC BMS though, imbalance kills the pack much faster, while each individual cell is still in a good condition.

 You should watch the video I linked to in my previous post, it’s all explained there. If nothing else, you should get even more laughter out of it. 

 

On 4/6/2023 at 8:25 PM, drader said:

that doesn't mean you have to balance your cells every single time you charge.

We all form our beliefs on our personal experiences and the events we hear/read about. Besides a large amount of mileage on three different EUCs, I’ve read about battery issues and BMS analysis on this forum very actively for 6 years. I claim that I have a pretty solid understanding of how the balancing process happens on an EUC. You might want to look into the balancing current amperage to reiterate your opinion.

On 4/6/2023 at 8:25 PM, drader said:

And charging from 60% to 80% doesn't use up one charge life, as if it was a stamp on your diner card.

I’m sure you mean “charge cycle”. I think most people understand this by now.

Edited April 8, 2023 by mrelwood

[Begodecrashtestdummy]

On 4/1/2023 at 9:30 PM, Dosingpsychedelics said:

4500 miles on my new rs19 highspeed since last summer .I shall be needing a tire very soon 

I needed a tire so I decided to just go ahead and buy a master pro v2 🤣🤷🏻‍♂️YOLO 

[techyiam]

45 minutes ago, Dosingpsychedelics said:

I needed a tire so I decided to just go ahead and buy a master pro v2 🤣🤷🏻‍♂️YOLO 

If you do that, you won't be able to keep up with the Joneses.

If I am not mistaken, the average life span of a tire these days is around 5000 km's. That is way too long. 

You should be buying a new wheel either when you got a flat, or the new tire nubs got worn off, whichever occur first. 😀

 

[Begodecrashtestdummy]

9 hours ago, techyiam said:

If you do that, you won't be able to keep up with the Joneses.

If I am not mistaken, the average life span of a tire these days is around 5000 km's. That is way too long. 

You should be buying a new wheel either when you got a flat, or the new tire nubs got worn off, whichever occur first. 😀

 

7300 km on this cst knobby it’s been a helluva tire not sure why people don’t like it ..after 1000km it’s great on all surfaces 👍🏻

[techyiam]

26 minutes ago, Dosingpsychedelics said:

7300 km on this cst knobby it’s been a helluva tire not sure why people don’t like it ..after 1000km it’s great on all surfaces 👍🏻

Is it completely bald? That is a pretty long life for a stock tire.

[alcatraz]

On 4/7/2023 at 1:25 AM, drader said:

mrelewood, you are absolutely WRONG on this, and laughably so. Every brand cell and chemistry used in our EUCs has been studied to death and an easy source for info is reading about Teslas (the car). You can accurately predict the life of your car's battery based on charging habits (hint: tesla taxis die soonest). While you are correct that EUCs use some of the dumbest management systems and cells will "eventually" go out of balance that doesn't mean you have to balance your cells every single time you charge. And charging from 60% to 80% doesn't use up one charge life, as if it was a stamp on your diner card.

You're right.

Even though it's impractical to invest extra time and money on packs that can be balanced at 80%, it is still true.

I almost built myself a balance charger for my wheels to get around it. It nearly makes the original bms useless, and nearly eliminates fire risk even for degraded/damaged/unbalanced packs.

A simple balance charger is essentially 20 single cell chargers (for 84v) with separate transformers. You can build one for maybe 20-30usd by using an array of 4.2v power supplies (with end voltage that can be dialed in). Then you'd need a harness  to connect it to. Maybe a 22pin PHD2.0 connector.

[mhpr262]

11.000 kilometers on my two and a half year old V10F. This winter the battery showed the first sign of weakness when it would barely go above 24 km/h or so before tiltback when cold soaked at a couple degrees above zero. I am a very heavy rider though.

[Uras]

On 4/7/2023 at 2:55 AM, drader said:

mrelewood, you are absolutely WRONG on this, and laughably so. Every brand cell and chemistry used in our EUCs has been studied to death and an easy source for info is reading about Teslas (the car). You can accurately predict the life of your car's battery based on charging habits (hint: tesla taxis die soonest). While you are correct that EUCs use some of the dumbest management systems and cells will "eventually" go out of balance that doesn't mean you have to balance your cells every single time you charge. And charging from 60% to 80% doesn't use up one charge life, as if it was a stamp on your diner card.

ahh, ignorance. 

I'm slow to learn. After watching mrelwood's charging video, I thought that I'd charge to 80% then next charge to 100%. I thought this would be a pretty good compromise. Now I'm going to charge to 100% each time. I might get 6 to 10 rides out of a charge from 100%; with 80% I only get a few. I'll explain and perhaps you have the same thing.

Whenever I charge to 80%, my first usual 10km ride it uses 15%. Then from around 65% it only uses around 10% for the same 10km ride. I said I'm slow to learn and couldn't figure this out. It starts using more after 40%, as you'd expect. I thought it's some issue with euc world and ks app just not reading the batteries properly.

If I charge to 100% it will use about 5% for the first 10km ride - understandable because of the voltage. When it get's down to around 80% it only uses around 10% for the same 10km ride! It generally uses 10% for the 10km rides till I get to 40%, then it plummets.

To summarize:

1. if I charge to 80%, on the first usual 10km ride it uses 15% 

2. if I charge to 80%, from 65% down to 40% it uses 10% for each usual 10km ride

2. if I charge to 100% and do the usual 10km ride when it is at 80% it only uses 10%.

The only time my battery power acts in a linear fashion (taking dropping voltage etc into account) is when I charge to 100%. Why do you suppose that is?

I'm slow and it only just occurred to me today - mrelwood would have told me straight away.

Edited April 10, 2023 by Uras

[mrelwood]

1 hour ago, Uras said:

1. if I charge to 80%, on the first usual 10km ride it uses 15% 

2. if I charge to 80%, from 65% down to 40% it uses 10% for each usual 10km ride

2. if I charge to 100% and do the usual 10km ride when it is at 80% it only uses 10%.

My guess is that this is caused by the surface and core voltage difference. A Li-ion battery cell can be thought of having two separate voltages, the core voltage and what’s called a surface voltage. While you charge the wheel, the surface voltage rises some 0.2V higher than the core voltage, and the core voltage catches up slowly.

 If you disconnect the charger mid charge, the surface voltage that can be measured from the battery terminals, slowly drops down to equal with the core voltage. This takes about 10-20 minutes.

 When the charge process reaches the Constant Voltage stage, the surface voltage is held at the maximum charge voltage, which makes the core voltage slowly crawl up to the charge voltage as well. The smaller the difference between surface and core voltages, the lower the charge current drops as well.

 If you disconnect the charger at 80%, it’s only the surface voltage that’s at 80%, and it will slowly drop down to 75% or so to match the core voltage.

 If you charge the wheel all the way to full, the core voltage will reach 100% as well, so the voltage doesn’t drop.

 The surface and core voltages are explained at the batteryuniversity.com

[Uras]

9 hours ago, mrelwood said:

My guess is that this is caused by the surface and core voltage difference. A Li-ion battery cell can be thought of having two separate voltages, the core voltage and what’s called a surface voltage. While you charge the wheel, the surface voltage rises some 0.2V higher than the core voltage, and the core voltage catches up slowly.

 If you disconnect the charger mid charge, the surface voltage that can be measured from the battery terminals, slowly drops down to equal with the core voltage. This takes about 10-20 minutes.

 When the charge process reaches the Constant Voltage stage, the surface voltage is held at the maximum charge voltage, which makes the core voltage slowly crawl up to the charge voltage as well. The smaller the difference between surface and core voltages, the lower the charge current drops as well.

 If you disconnect the charger at 80%, it’s only the surface voltage that’s at 80%, and it will slowly drop down to 75% or so to match the core voltage.

 If you charge the wheel all the way to full, the core voltage will reach 100% as well, so the voltage doesn’t drop.

 The surface and core voltages are explained at the batteryuniversity.com

I don't think so. I thought it could be the bluetooth staying on, so I'd check voltage just before the ride (long after charging) and it would still read the same. I suspect that some cells are reaching 80% while quite a few still aren't because there hasn't been any balancing. The cells do seem to discharge linearly if charged to 100% and all are balanced. I'm guessing here, but it seems that on an 80% charge those cells with the highest charge get used till they are equal with the other cells - this seems to happen somewhere near 65%. After 65% everything is linear again (all cells are equal?). So I'm guessing that on an 80% charge at least one of the cells is around 65% charge, with a few others somewhere between 65 and 80.

Edited April 10, 2023 by Uras

[mrelwood]

 

1 hour ago, Uras said:

I suspect that some cells are reaching 80% while quite a few still aren't because there hasn't been any balancing.

Balancing is an extremely slow process, and very little happens during one charge. It takes something like 10 hours to bleed one cell group worth 0.05V. Same goes for getting out of balance; it’s a very slow process that happens across dozens of battery cycles.

1 hour ago, Uras said:

seems that on an 80% charge those cells with the highest charge get used till they are equal with the other cells

It’s actually the opposite; the cell groups with a lower state of charge get used more, since they are burdened more. But again, it’s very doubtful that this would have anything to do with the voltage balances.

1 hour ago, Uras said:

I'm guessing that on an 80% charge at least one of the cells is around 65% charge

I really hope not! That would make the pack very badly out of balance, which the balancing function probably wouldn’t be able to salvage.

 

 How many times have you tested this difference between 100% and 80% charging?