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Manufacturer prospect - help evaluate their honesty


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Hey guys! So I'm evaluating a manufacturer, trying to find more safe and high quality options for beginners. I asked them to provide:

Motor sizes available
Wheel sizes available
All available battery options and battery brands utilized
Shell construction material and durability testing
Pictures of all circuit boards and battery designs
Low battery behavior (very detailed)

So, I have quoted their response below. Obviously not all information was given that I requested. Do you guys have any opinions, based on what we have here?


Dear Will,

Really glad that we can have a good partner like you.
You gave a professional conclussion that many factory offers dangerous battery when they produce it. The battery type named : 18650 battery.  
This kind of battery has capacity memory, and heat themself very sharply so the battery some times exploit, and will often power off suddenly.
Please read the picture of battery:
1, It is made of Li-Polymer material. No matter you full charge it or not, it will still keep the original capacity as 190WH. Never reduce even if you often less-Charge it.
2, Its currency will be always stable for different working circumstance. High speed, low speed, will calculate the balance capacity automatically. If battery low, it will alarms and then four LED blinks at the same time.
3, When you turn on it, if four LED lights, means more than 90% full.  The the LED lights will turn off one by one during your riding and the battery exhausting.  The last LED lights indicate 40% capacity. So, when people see only the last LED is lighting, they will still have enough time to find somewhere to charge it.
4, This kind of battery also is a Cell phone and tablet PC and other electronics charger, when the battery is full, it can full charge 25 Iphone 6. Very good for outdoor sporting. 
Other parameters, please read below, if any questions, please feel free to let me know. 
[Model offered:]
Smart & High Speed
BT 4.1
BT Mini Horn Built-in
triple mineral Polymer Lithium battery
    67.2V/1.75A (1.5H+)
Triple protection: Over-charging protection, Over-temperature protection, Over-voltage protection;
Support 110V / 220V input        
67.2V 17.5A
Upon 2000 times charge, capacity decrease 15-25%;
Environment temperature<10℃, capacity decrease by 20%.
14 inch 2.125 Standard pneumatic tyre
30 degrees(Max)
Black, White, Yellow(PT Yellow C), Green(PT 368C)
As partner, we must give you the best support. SuppliedBatteryPicture.jpg

Thanks for your help everybody, there are so many smart people on here and without you guys I'd be lost.


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I don't accept that no matter how long you charge your batter you get full charge?  If that were the case why would you charge your batter atall?


The biggest point is do you have the time to try different batteries, which at The Self Balancing Scooter we have done as we have been selling these since the beginning of 2014 and have had to out of necessity, source a decant battery.  We have found that the only batteries which are really worth your whicle are the branded Li-Ion batteries such as SAMSUNG, LG or SONY.  There may be the odd one which comes close but in out experience they dont and they are hardly going to be better.  It has been our lively hood and we still cant get better batteries than Samsung 

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Li-Pos are outside my "comfort"-zone, as I've mostly just researched stuff related to 18650-format Li-ions... I do know they have higher charge- and discharge rates, but they also are more easily punctured, guess that's why the hard plastic casing. From the battery safety point of view, they're probably among the most dangerous options, but could be wrong... I don't know if they last any longer than "normal" Li-ion, I do think they age similarly if deeply discharged or heavily used. I think F-wheel Dolphins actually use Li-Pos instead of Li-Ions, don't know any other wheels that do though.

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LiPo batteries have higher discharge rates than Li-Ion (easily up to 45C, much more is possible), but lower energy density per gram (which is not necessarily a problem in a EUC, a batter pack that weighs 20% more won't "break the bank", even if not desirable in general). Their discharge rate is also much flatter, and discharging below 3V results in reduced lifespan at best, disaster at worse. LiPo also like being fully charged for long periods less than LiIon.

LiPo are a much for low voltage systems, where the only way to get a lot of W is to use high currents (i.e. in a 3S, 1.1V drone with a 3Ah battery, you can easily see >1200W spikes, more than 100A, requiring a 35C battery to safely handle that much load. There would be no way to do that with a Li-Ion, hard pressed to get above 20A loads. As a matter of fact, long endurance flight drones use super big Li-Ion packs, using massively parallel configurations to achieve the necessary capacity and current handling ability, yet have much lighter battery packs (which matters a lot when flying). Electric skateboards also seem to use mostly LiPos, and have lower voltages, too. EUCs, with their high voltages, can get away with lower currents

LiPos are easily built with much bigger capacities in a single cell, but that's more to do with the lack of a standardized format compared to Li-Ion. Bigger capacity means that a single damaged cell can do a lot more damage. Lack of standardized formats means that if your custom-made LiPo pack has a wonky cell after a while, you won't find a replacements. With Li-Ion packs, if there's a single wonky cell, you can easily find a single 18650 replacement

LiPos seem to have a more dangerous chemistry than Li-Ion (this is a hard claim to prove, since there are so many different chemistries both for LiPos and Li-Ion, so you could have a more dangerous Li-Ion than a safe LiPo; but, in general, it's valid statement, especially considering that LiPos can have very big single cells)

Lastly, LiPos discharged below 30% have shorter lifespans than lightly discharged packs, making it hard to use the full stored charge (or, better, making it more expensive, since your battery life will be shorter). Going down to 10% of the pack, makes things even worse. 

All in all, I would say that Li-Ion are a superior solution to LiPo in a 16S, 67.2V pack: better, more linear discharge cycle, lighter, safer chemistry, better ability to be stored fully charged, longer life when abused. Obviously if you are a LiPo manufacturer, you will know your product well and know how to build a better pack with LiPo tha nLi-Ion :) it's a bit like asking my barber if I need an haircut (the answer is surprisingly always "yes"). But their claim on the poor safety of 18650 is a bit misleading: it's true that Li-Ion, if the system is not designed properly, can easily be overloaded (too much current) and burst. LiPos with their higher C ratings, do so less easily (but you don't want to see what happens when a LiPo goes above their C rating: they overheat and puff immediately, and doing so inside a rigid pack like theirs would be catastrophic... clearly, given the much high C, it's unlikely).

Their claim not to suffer reduced life when over-discharged flies in the face of every other LiPo in the world and their manufacturer's data

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