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Do you use a backpack battery?


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I have to agree. This kind of battery setup did cause strange problems while riding, like inaccurate battery level indicator and uneven battery power consumption.

Well, but still, this is their decision. If this kind of configuration will damage the batteries or board, they wouldn't have done it, right?

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My option is suitable for those who are ready to ride with a backpack weighing 12-15 kg, the kit includes:
Two 800 VA 84 V units (e.g. from the old Gotway MSuper or Monster), switch on in series, provide direct current in the operating range of 135-166 V;
double voltmeter or other way to control battery discharge down to 67-68 V each;
two standard Gotway charges (driving on the backpack belt), switched in parallel;
charging wire "doubling" with extension and easy release in case of jumping off the wheel.

Adapter can be made for any connector, the main thing is that the EUC wheel supports charging on the go.

As a result, we get - 4-5 hours of charge on the move with dual charger (2.5 - 3 A) - I add about 40-45 km of mileage to 70 km from the wheel Monster.
If there is a power socket on the way, you can either charge the wheel directly from 220 V or backpack batteries, for this there are a couple of adapters. Sometimes I drive a 5A extra charger and charge the wheel in the parking lot together with the batteries. Two hours of such charging give the total mileage of 160-180 km.

Compared with the purchased bank, in which the built-in converter for 220 V, is obtained about three times better power in the calculation of kg extra weight.

 

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3 hours ago, Виктор Гаранин said:

provide direct current in the operating range of 135-166 V to two standard Gotway chargers

Wow, creative!

Everyone else reading- please remember not to connect DC to your charger's AC input, until you've taken the time to understand how your exact model of charger works. If there's an isolation transformer at the input, you'll melt it.

160V is also electrocution hazard territory :/

Edited by RagingGrandpa
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12 minutes ago, RagingGrandpa said:

Everyone else reading- please remember not to connect DC to your charger's AC input

I think he meant 2x84v = 168v then use a buck adapter to drive it down to 67v. After all he has been doing it successfully. Dangerous high voltage, but riding a unicycle itself is kinda risky, right?

If it were up to me I would have just connected the two packs in parallel. 84v down to 67v should have higher efficiency than 168v to 67v. Also I can have higher current to charge those 84v batteries.

 

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18 minutes ago, Philip W said:

If it were up to me I would have just connected the two packs in parallel. 84v down to 67v should have higher efficiency than 168v to 67v. Also I can have higher current to charge those 84v batteries.

Efficiency and charge current depend (as good as) only on the used charger/dc-dc converter.

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1 hour ago, RagingGrandpa said:

Wow, creative!

Everyone else reading- please remember not to connect DC to your charger's AC input, until you've taken the time to understand how your exact model of charger works. If there's an isolation transformer at the input, you'll melt it.

160V is also electrocution hazard territory :/

So true. I haven’t seen an isolation transformer used in light weight switching power supplies that look like laptop computer supplies. The inputs are normally full wave bridge rectifiers and high voltage smoothing capacitors to produce high voltage DC. This DC then gets switched at a high frequency and through a high frequency small transformer inductor to produce the desired voltage. If this is your charger, then DC on the input is fine because it just passes through 2 of the full wave rectifier diodes. 

Edited by Hal Farrenkopf
isn’t fine to is fine
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On 8/19/2020 at 12:59 AM, Azzias said:

As a side note my mten3 is not my only experience with euc. I do have a modded ninebot c+ thats modded to 20mph that I use for training others (my first wheel) and a Mcm5 that I only use off-road or yak rustling as it has a bmx nobby Tire.. I am a new Ridder with only 3 months experience.  

video please :blink1::roflmao:

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On 9/11/2020 at 9:21 PM, RagingGrandpa said:

Everyone else reading- please remember not to connect DC to your charger's AC input, until you've taken the time to understand how your exact model of charger works. If there's an isolation transformer at the input, you'll melt it.

160V is also electrocution hazard territory :/

Absolutely right - you should check everything properly before making adapters and connecting batteries to chargers. 
If in doubt, it is better to have a specialist to help and check. 
Modern battery chargers have an operating range of 100-240 volts of AC voltage, but the circuit allows you to work from DC, too.

Battery-to-chargers efficiency is 80%. The battery is charged in more than five hours and discharged in less than 4 hours.

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Now here is an update about my little investigation of why my previous EUC is bad.

Recently I purchased a battery charger/tester from Amazon:

https://www.amazon.com/dp/B07ZSHFFHF

Then I used it to test some 18650 batteries taken out of a bad power bank. Out of 4, 3 batteries are bad. They can only provide 20 to 50 mah power. However, after they are charged, they still show 4.12v of voltage. Even after the battery tester dropped their voltage below 2.6v, they still are measured at 4.0v individually.

This is exactly the symptom my EUC displayed. The voltage was good after charge: 67.2v, but after just a short time riding, it started to drop rapidly. Once it reached 58.2v, the EUC was un-rideable. A little move will send the whole wheel down to the ground losing power. I was convinced it was EUC board's fault. Now after seeing those bad batteries' behavior, I think it was the battery pack.

Now I am more interested in building an external battery pack which will allow me to freely replace the bad 18650 batteries. Here's a setup I really like. It's 17s, but I think it will fit my purpose.

https://www.aliexpress.com/item/4000351397635.html

I will get two or three 17s board and the BMS. They probably will give me 125wh power each. Though this cannot go long range, I love the fact that I will be in control of each battery cell.

 

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  • 4 weeks later...

@RagingGrandpa

ks16s_external_battery.thumb.jpg.4067834e5a4f9a4e7ae72514730e7092.jpg

This is what I was using on my KS16S. A 7S 2kWh battery + step-up to 67V (3d printed) + a long wire. Everything fit in a big backpack, total weight about 20kg.
67V was connected directly to the internal battery of KS16S.
It extended my range from 35km to 110km.

If I wanted to extend the range of the MSX, I'd charge it through the charging plug. Both MSX and KS16S can be charged during riding.
Why did I connect it directly to the battery? One of the batteries failed (so only 420Wh left...) and I had a group ride the next day so I had to improvise... :D

PSA - don't ride KS16S with one battery. It will cut out on you.

Edited by atdlzpae
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On 10/18/2020 at 1:37 PM, atdlzpae said:

2kWh battery
Everything fit in a big backpack, total weight about 20kg.

Whoa, huge pack! Really 44lb?!

Could you share details on the backpack you chose? Making a 15lb brick on my back feel comfortable is a bit of a puzzle... I can't imagine 40lb+

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@The Dude What's your use case for the battery? What do you want to connect to it?
Looking at capacity (150Wh), it may power your laptop for 5h or so... Or a unicycle for 5 km.

What's your use case for solar panels? 40W is almost nothing, why not charge your phone from a unicycle or the car?
The only use case I can think of is if you're doing multi-day hikes far away from civilization...

Edited by atdlzpae
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37 minutes ago, atdlzpae said:

@The Dude What's your use case for the battery? What do you want to connect to it?
Looking at capacity (150Wh), it may power your laptop for 5h or so... Or a unicycle for 5 km.

What's your use case for solar panels? 40W is almost nothing, why not charge your phone from a unicycle or the car?
The only use case I can think of is if you're doing multi-day hikes far away from civilization...

Everything that I'm acquiring at this point is intended for potential use away from civilization. If that's what the kids are calling this heap.

Edited by The Dude
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@The Dude That's not specific enough. "potential use away from civilization" can mean a sailboat, a homestead, a survival situation, an RV, a yacht...
Anyway, I don't think these particular items are good in any of those circumstances. Even for a survival situation "on foot" it will be cheaper and lighter to have a big USB power-bank.

Some good YouTube channels:  CheapRVliving, Will Prowse, juehgarcia.

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13 minutes ago, atdlzpae said:

@The Dude That's not specific enough. "potential use away from civilization" can mean a sailboat, a homestead, a survival situation, an RV, a yacht...
Anyway, I don't think these particular items are good in any of those circumstances. Even for a survival situation "on foot" it will be cheaper and lighter to have a big USB power-bank.

Some good YouTube channels:  CheapRVliving, Will Prowse, juehgarcia.

Sorry I didn't provide you you with ample specificity. Gracias for the recommendations. 

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On 10/19/2020 at 4:37 AM, atdlzpae said:

@RagingGrandpa

ks16s_external_battery.thumb.jpg.4067834e5a4f9a4e7ae72514730e7092.jpg

This is what I was using on my KS16S. A 7S 2kWh battery + step-up to 67V (3d printed) + a long wire. Everything fit in a big backpack, total weight about 20kg.
67V was connected directly to the internal battery of KS16S.
It extended my range from 35km to 110km.

If I wanted to extend the range of the MSX, I'd charge it through the charging plug. Both MSX and KS16S can be charged during riding.
Why did I connect it directly to the battery? One of the batteries failed (so only 420Wh left...) and I had a group ride the next day so I had to improvise... :D

PSA - don't ride KS16S with one battery. It will cut out on you.

Love my ks 16 s and never had a cutout.I always rode it under the suggested 35kmh .Really solid,stable machine that just keeps going.Only bought a Sherman because of the range anxiety.Looked at add on batteries but not really feasible.Thats all gone now.Still use the 16 s as a skills, practice tricks machine.

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@RagingGrandpa The battery itself is 12kg, a 22cm cube. It fits into a normal 60-70L backpack.
Weight is not a problem for a 120kg fatass like me - I sometimes carry way more groceries than that.B)

#############################

@Daley1
You misread my sentence: PSA - don't ride KS16S with one battery.
KS16S by default has 2 batteries, each 420Wh. If you have only one of them:
1) If you try to climb a 45° slope, you'll break a fuse, crash and will have to walk home.
2) The safe-speed tilt-back & alarm assumes that you have 2 batteries. So it can cut-off if you try to ride as fast as possible on 30% battery.
Both of those happened because of my own stupidity (after all, I knew that one of the batteries was dead). But it doesn't change the fact that with one battery KS16S is unsafe.

Solid and stable - it's advertised as 150kg wheel... IMO it should be advertised as a 100kg max.
I destroyed mine after 1300km.:D The problems started at about 600km - pedals started to tilt, then started scraping the motor, then broke off completely.
MSX is way more solid, a real 150kg wheel. I imagine Veteran is even sturdier...

Edited by atdlzpae
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On 10/18/2020 at 1:37 PM, atdlzpae said:

@RagingGrandpa

ks16s_external_battery.thumb.jpg.4067834e5a4f9a4e7ae72514730e7092.jpg

This is what I was using on my KS16S. A 7S 2kWh battery + step-up to 67V (3d printed) + a long wire. Everything fit in a big backpack, total weight about 20kg.
67V was connected directly to the internal battery of KS16S.
It extended my range from 35km to 110km.

If I wanted to extend the range of the MSX, I'd charge it through the charging plug. Both MSX and KS16S can be charged during riding.
Why did I connect it directly to the battery? One of the batteries failed (so only 420Wh left...) and I had a group ride the next day so I had to improvise... :D

PSA - don't ride KS16S with one battery. It will cut out on you.

Wow, that looks like speaker wire. The jacket of that wire is not very strong - I know you said it was a rush for the next day ride but hope you replaced it. 

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2 hours ago, Hal Farrenkopf said:

Wow, that looks like speaker wire. The jacket of that wire is not very strong - I know you said it was a rush for the next day ride but hope you replaced it.

Yes, I replaced it with MSX which has a decent range by default.
IDK, speaker wires never failed me... Except for that one time I tried to push constant 30A through one. :P

Edited by atdlzpae
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