Do you use a backpack battery?

[atdlzpae]

If it's connected directly to the battery you may risk faceplanting from a short-circuit... Or maybe you have some way to prevent it?
Maybe you can connect the external battery through the charging port?

Also, how did you guide the wire outside of the unicycle's shell?

[xiiijojjo]

Read halfway through the thread but had a great idea regarding evolution of eucs and batteries. 

What if all eucs were sold as the bare machine without batteries at all.

Then the user can choose the size of their battery backpack in volts and watthours (or build one yourself) 

This way most wheels would start having similar prices because the components are virtually the same (minus the smaller wheels which would be similarly priced in their end of the spectrum) so no longer would users forgo getting the better wheels in regard to speed and other aspects and opt for cheaper solutions because of insufficient funds or impatience. This way anyone could get any wheel they'd desire within reason 

 

But not only that. Imagine a catastrophic high speed crash/cut-out. Under normal circumstances the wheel would go flying at 40mph+ potentially launching into pedestrians whereas the rider will only crash and slide a few meters . With the wheel tethered to the battery backpack with a much stronger locking mechanism than the GX connectors for charging while being really really thick. That way if a crash happened the wheel would be on a tether and that should limit its destructive potential. Also several kg of battery is removed from the wheel making it lighter and therefore less dangerous, but also more easily maneuverable but maybe even more exciting is the fact that the size of eucs can go waaay down (perfect for making space for far better Gen 2 suspension now that space for batteries is not needed) 

The more I think of this the more this seems like the next step in euc evolution but I don't think any of the companies making eucs are interested in that...or maybe they are I saw kingsong might be making a battery backpack so it might have already started... 

 

But to make it clear this idea is not to charge on the go, which is fine I guess. I want to redesign the euc so the battery goes into a separate backpack. When I get my rs 19 I will make this upgrade. 

I will move all 1800wh battery into a crash resistant backpack and add more wh. Maybe I should buy better cells all together and start from scratch on the battery.

Great flippin thread it's got the old gears spinning. 

Edited October 29, 2020 by xiiijojjo

[atdlzpae]

2 hours ago, xiiijojjo said:

several kg of battery is removed from the wheel making it lighter and therefore less dangerous, but also more easily maneuverable

Less maneuverable and more dangerous - it's easier to maneuver with 15kg in the wheel than with a 15kg backpack.
Also, it's easier to disconnect during riding and faceplant.

2 hours ago, xiiijojjo said:

Then the user can choose the size of their battery backpack in volts and watthours (or build one yourself)

Everybody will just buy a battery in the same order and will have to assemble it. Makes about as much sense as buying a phone or a laptop without a battery.
And nobody will build their own batteries - even though I have skills to build my own battery, I'd rather pay someone (the manufacturer) to do it better.

2 hours ago, xiiijojjo said:

Imagine a catastrophic high speed crash/cut-out. Under normal circumstances the wheel would go flying at 40mph+ potentially launching into pedestrians whereas the rider will only crash and slide a few meters . With the wheel tethered to the battery backpack with a much stronger locking mechanism than the GX connectors for charging while being really really thick.

Do YOU ride your unicycle tethered to yourself today?

2 hours ago, xiiijojjo said:

I will move all 1800wh battery into a crash resistant backpack and add more wh.

Riding without a battery is like using a phone that needs to be connected to a powerbank all the time.
I'll bet you a $1000 you'll get bored before 1000km. Especially when you'll want to go shopping.

Also, you'll probably lose your warranty on your RS19 if you drill the shell to connect a 100A-capable wire through.

Edited October 29, 2020 by atdlzpae

[GoGeorgeGo]

11 hours ago, xiiijojjo said:

Read halfway through the thread but had a great idea regarding evolution of eucs and batteries. 

What if all eucs were sold as the bare machine without batteries at all.

Then the user can choose the size of their battery backpack in volts and watthours (or build one yourself) 

This way most wheels would start having similar prices because the components are virtually the same (minus the smaller wheels which would be similarly priced in their end of the spectrum) so no longer would users forgo getting the better wheels in regard to speed and other aspects and opt for cheaper solutions because of insufficient funds or impatience. This way anyone could get any wheel they'd desire within reason 

 

But not only that. Imagine a catastrophic high speed crash/cut-out. Under normal circumstances the wheel would go flying at 40mph+ potentially launching into pedestrians whereas the rider will only crash and slide a few meters . With the wheel tethered to the battery backpack with a much stronger locking mechanism than the GX connectors for charging while being really really thick. That way if a crash happened the wheel would be on a tether and that should limit its destructive potential. Also several kg of battery is removed from the wheel making it lighter and therefore less dangerous, but also more easily maneuverable but maybe even more exciting is the fact that the size of eucs can go waaay down (perfect for making space for far better Gen 2 suspension now that space for batteries is not needed) 

The more I think of this the more this seems like the next step in euc evolution but I don't think any of the companies making eucs are interested in that...or maybe they are I saw kingsong might be making a battery backpack so it might have already started... 

 

But to make it clear this idea is not to charge on the go, which is fine I guess. I want to redesign the euc so the battery goes into a separate backpack. When I get my rs 19 I will make this upgrade. 

I will move all 1800wh battery into a crash resistant backpack and add more wh. Maybe I should buy better cells all together and start from scratch on the battery.

Great flippin thread it's got the old gears spinning. 

I can see the use case for this.  Either for super long range riding so you can have a ridiculously large battery capacity, or on a trick wheel that you want as light as possible to do tricks with.  The backpack would need to be designed to be form fit with the rider so as not to shift around much while doing tricks.  

[SixteenX]

I am also in the process of building one small external battery for my 16x. A 20 cells of 42V with boost current limiting converter, I don't know if I'll use a bms (18650 are new) or a cell voltage display. 

[RagingGrandpa]

7 hours ago, SixteenX said:

20 cells

Only ~250wh? Go bigger!
 

7 hours ago, SixteenX said:

boost current limiting converter

If you see sparks anywhere on the board when connecting its input to your 42V pack... you'll likely destroy it quickly and may need to modify it to reduce the inrush current. Worth a try as-is; if it blows up, ping me for details.
 

7 hours ago, SixteenX said:

I don't know if I'll use a bms

Nice that there are fuses in the converter, and the converter itself has an undervoltage shutoff (be sure to test that it shuts off at 25V and adjust if it doesn't).

How will the 10s pack stay balanced?

[atdlzpae]

17 hours ago, SixteenX said:

I don't know if I'll use a bms (18650 are new)

Without a BMS, how will you charge it? How will you make sure it doesn't destroy itself (by discharging below 3V) or catches on fire (by charging above 4.3V)?
Use a BMS, house fires are usually more expensive than a BMS.

"New" doesn't make it any different - every single battery pack on earth was new and balanced at some point. Including the ones that caught on fire.

Edited November 6, 2020 by atdlzpae

[Surfling]

Thread resurrection:

On 10/29/2020 at 10:57 AM, atdlzpae said:

it's easier to maneuver with 15kg in the wheel than with a 15kg backpack.

Nah, I feel the exact opposite. More control w/ a lighter wheel. On the EUC and on any of my bikes. With a heavy backpack, I use the extra weight to aid maneuvers but YMMV. Tho, if I was going on long, straight rides, I'd do the opposite.

@SixteenX I'm very interested in the specifics of your ext battery project.

[RagingGrandpa]

In the Sherman age, my 900wh backpack has been getting lots of use. Feels worth the effort now

https://euc.world/tour/597550054414044

In reality, I never use the backpack for a partial ride, or for recharging while stopped. The real usefulness is just being able to complete a 40 mile distance at 30mph. Backpack and EUC will both be depleted within 90mins. Fun!

Edited August 5, 2021 by RagingGrandpa

[SixteenX]

@Surfling the project is on hold, I have all the components but need the time to get down to the bottom of it, before summer since I 'm planning a road trip. I' ll let the community know when I done and provide explanations 

[thendless]

Just finished my external battery pack. I plan on using it on my 60V scooter and 84V (72V) EUC. I have lots of experience building battery packs so this was one of the items on my radar after getting my first EUC.

Specs:

Cells: Tesla 3 21700 5000mAH 10A continuous (Panasonic)

Arrangement: 16S4P (60V, 20Ah) + 4S4P (12V, 20Ah) --> 72V (84V) 20Ah --> 1440Wh 

BMS: Each pack has its own 40A continuous BMS using common ports

Weight (including back pack) --> 21 Pounds

Total Capacity: EUC (MCM5 V2)+ Battery pack --> 800Wh (technically 756Wh) + 1440Wh = 2240Wh

Enclosure --> I built a solid enclosure using cutting boards and high density foam, the battery is safe from any hard impacts that could happen.

Other Notes: I have a 40A fuse/fuse holder at the battery outputs. I have 20 spare cells left that for potential future use if I get a 100V wheel 

 

I did a 50km test run yesterday and I must say it is liberating to be able to go hard most of the time without worrying about potential cut out. Also having no range anxiety is so  liberating as I don't have to plan out routes anymore and can go wherever I please! Also regarding the weight, I have experienced hiking before with heavy back packs (30+) so this really isn't much. I also felt the weight less when I was moving so its definitely doable long term I think.

Edited August 4, 2021 by thendless

[Hal Farrenkopf]

On 8/4/2021 at 6:55 PM, thendless said:

Just finished my external battery pack. I plan on using it on my 60V scooter and 84V (72V) EUC. I have lots of experience building battery packs so this was one of the items on my radar after getting my first EUC.

Specs:

Cells: Tesla 3 21700 5000mAH 10A continuous (Panasonic)

Arrangement: 16S4P (60V, 20Ah) + 4S4P (12V, 20Ah) --> 72V (84V) 20Ah --> 1440Wh 

BMS: Each pack has its own 40A continuous BMS using common ports

Weight (including back pack) --> 21 Pounds

Total Capacity: EUC (MCM5 V2)+ Battery pack --> 800Wh (technically 756Wh) + 1440Wh = 2240Wh

Enclosure --> I built a solid enclosure using cutting boards and high density foam, the battery is safe from any hard impacts that could happen.

How are you connecting it to the wheel? Through charging port or parallel to batteries and then how do you handle equalizing the charge/voltage differences when you connect it?

 

Edited August 12, 2021 by RagingGrandpa
(fixed bug in quote function)

[thendless]

7 hours ago, Hal Farrenkopf said:

How are you connecting it to the wheel? Through charging port or parallel to batteries and then how do you handle equalizing the charge/voltage differences when you connect it?

 

The battery pack is connected in parallel. I had to add another set of wires and connectors in the wheel to allow for the 3rd parallel connection. I came out under the handle using the same path as the lift switch wires. Both external and internal packs must be charged to the same voltage prior to connecting.

Edited August 12, 2021 by thendless

[peddiparth]

I am working on a parallel but separate setup for MCM5v2.

The idea: have a plug to disconnect the -ve for internal battery pack, and connect the external pack in parallel.

I am still waiting for the motor+hub to arrive, so cant test yet.

[dycus]

I just finished a parallel-connection backpack battery for my Molicel S18. It uses a magnetic quick-disconnect tether I designed and pogo pins for the electrical connection. Currently the tether supports one extra S18 pack (360Wh) but it will support up to 3 in the future.

I was able to go from getting 24.8 miles (at 33.7 Wh/mi, 900Wh) to today doing 37.3 miles (at 34.3 Wh/mi, 1260Wh). Great result!

Check out more details and a bunch of photos:

 

[marc]

A big innovation in EUCs would be EUCs without internal battery where you carry your battery in your backpack that is coupled to your EUC with a cable.

Advantages: 

 - since battery is the most aged part, it can be easily replaced

- authorized in airplanes, hire a battery in your destination (like Gogoro in Taiwan)

- reduces EUC weight: imagine a 2500W EUC of 10kg!

[Robse]

A very good idea.  And the first rider to have a cutout because of bad battery connect can blame it on.... himself, usage,  or the company?

[Funky]

Fast (Connect) exchangeable batteries would be better idea. You can simply exchange empty battery, to full one from your bag. (No need to connect and have dingling wire.. Imagine you fall and you tear off that wire, so bad.) Don't forget what power is going true that wire. Any damage to it and say hello to bonfire.

 

Best thing in in future will be "solid" state batteries. Maybe in 3-5 years... Fast rechargeable 1-100% in 30 mins. 2x the range of same weight. Or 2x lighter batteries for same range. Better fire protection as they don't burn.

First thing when solid state batteries become a thing in euc, i will buy new wheel right then.

Edited August 8, 2022 by Funky

[Mono]

An external battery is most likely a no-go from the safety perspective. Even a swappable battery, which looks like an attractive alternative, hasn't succeeded in the market so far. The KS-14B and the Uniwheel both had a swappable battery.

AFAIK, EUC are not authorized in airplanes even with the battery taken out.

Edited August 8, 2022 by Mono

[litewave]

A better solution would be an easy-access battery compartment that would make swapping batteries easy. This would limit liability for the manufacturers and resellers but enable riders to exploit the design.

This has been done before by @SuperSport and myself. I have five spare batteries for my Ninebot One E+ and swapped them out hundreds of times with absolutely no issues for more than five years.

 

 

Edited August 8, 2022 by litewave

[Funky]

Quick connection - which doesn't involve manual messing with wires, would be much better ordeal. Same mechanism as on e-scooters/e-bikes slide the battery in/out. Some kind of pins at the end of battery, or something.

Edited August 8, 2022 by Funky

[Tawpie]

I think the bigger problem is the the extra battery costs so much that it's just not worth it.

[Robse]

how about riding with 7-10 kg batteries dead weight in the rucksack? + the other stuff?  IzNogood.

[Funky]

Yeah it's cheaper to buy new euc, than replace 2 batteries. (If you need to replace both the same time..) Example 1 battery pack cost 600-700$. Wheel cost 1900$.

Sure 1900$ is more expensive. But you get extra motor/tire/shell/everything. 1200-1300 vs 1900. (Simply ride new one and old one goes into reserve parts.)

 

That's why having small battery (Multiple small packs) is better than big one..(4 small vs 2 big ones) If one pack dies, it's cheaper to "repair" the wheel.

Edited August 8, 2022 by Funky

[Hellkitten]

Induction roads..........