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Nominal Battery Capacity & Actual Range


Jason McNeil

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Posted

A couple months ago I did some controlled range testing with the Ninebot E & the IPS132. Although both units have similar nominal battery capacity—the IPS 132 has 260Wh, while the Ninebot has 240Wh, the results where surprising in that the IP132 had 20% better range in actual range than the Ninebot with identical cruising speed, track conditions & rider weight. This is accountable, because many cells nominal capacity is rated with a load that is less than the cruising speed of an Electric Wheel. 

With high-power cells, like the Sony US18650V3 that are found in the IPS132, offers a similar energy output across a wide-range of loads, from 1A to 10A. Other cells, however, may loose a substantial % of their rated capacity as the load increases. How this translates in Wh/Mile, is that the best performer (out the the three units tested) is the IPS132 at 20.68Wh/mile, with Ninebot One E managing only 22.84Wh/M. At first sight, 10% may not seem like much, but practical experience demonstrates that this increments make a big difference for range planning in the real-world.

Another related consideration is how the control board manages 'limp-home-mode', the condition where the battery is low, usually about 25-33% capacity. Some control-boards are setup very conservatively (with pedal-tilt-up action), where it is difficult to exceed 5MPH—those last couple miles home are never as enjoyable. With others, you can still maintain a fairly respectable 7-10MPH  until the battery is finally exhausted. 

Ninebot One E: 22.84Wh/M
IPS 132: 20.68Wh/M
IPS 121 (T350): 21.88Wh/M

 

 

IPS132 Range Test.png

Ninebot Range Test.png

IPS 121 Testing.png

Posted

Having used my two IPS132'S to go into town and back loads of times now with my son we have found that although they don't climb quite so well when we are getting near the end of the long climb out of Bath City centre once they reach the flat on the top they are happy to go on another mile to the racecourse and back again before dropping down the hill to my house.

Imagine our surprise when we took both the M10'S with their 340Wh batteries on the same trip and only just made it back up to the top of the hill with one light left on and loads of warning beeps from both.

They did both recover to two lights going down to my house but with 80Wh more power to begin with I was expecting a little better than that despite the less efficient 10" wheels.

  • 2 weeks later...
Posted

Hi, Jason, Hi, Gimlet.

First, nice post Jason.

I'm quite new in the forum and not fluent in English.

I just bought a Unicycle fiew weeks ago and had some problems with the battery.

My battery made of no brand cells (or fake cells) can't handel the power and the internal switch in the battery PCB turn the battery of to protect the battery. At the beggining i tought it was my way of using the unicycle then i realise that the battery can't handel the need and the battery PCB turn the battery of for the cells not to burn or whatever, this is very dangerous, no alarm i just fall like a pancake. And it wont turn on, you need to plug the battery to the charger for the battery PCB switch to desconnect and to use the unicycle again.

So i've been searching for new battery cells. With a good discharge rate. I realise that they are a lot of fake battery in the market. 

And i realise that most of the battery cells that reach 3000mAh can't really handel a 10A need. Only the fake Chines cells can do that but it's just writen on the box. (It's like buying a 1 litre bottle but it's writen 2 liters, you will never be able to add more water).

So maybe i will replace them with the samsung 25R that will give me a 150wh battery with 20 A (max Curent discharge). I can also go to the Panasonic NCR18650PF but they have a C rate of 3 so they can't handel more than 10 A. And i'm not sure if in the top of a hill for exemple the unicycle won't aske for more ? In theorie it shouldn't

Do you have any recommandation ? Or experience ?

Gimlet maybe it's because it's a small wheel, small wheel mean more revolutions....

thank for your help.

JL

PS : I have a 350w unicycle so it shoult take less than 6A (with 60v 16s cells battery) 

 

 

Posted

I realise that a smaller wheel has more rolling resistance, especially on rough surfaces and we do have several sections of badly laid flagstones on our route, but the number of revolutions shouldn't make much difference as the power required to carry our weight over a set course is always going to be roughly the same.

Posted

My battery made of no brand cells (or fake cells) can't handel the power and the internal switch in the battery PCB turn the battery of to protect the battery. At the beggining i tought it was my way of using the unicycle then i realise that the battery can't handel the need and the battery PCB turn the battery of for the cells not to burn or whatever, this is very dangerous, no alarm i just fall like a pancake. And it wont turn on, you need to plug the battery to the charger for the battery PCB switch to desconnect and to use the unicycle again.

 

"​Fall like a pancake", lol (lol for the expression, not for the accident, of course). It's the BMS cutoff problem, already described in this forum and over there : http://trottinetteselectriques.heberg-forum.fr/ftopic870_solution-probleme-bms.html

I've have searched for a made to order battery solution in the past and I've found it's too much hassle to make it yourself from indivdual cells (except if you have tons of scrapped 18650 cells from laptops and infinite spare time to pair them). Not counting the fact you must have a point-soldering system to avoid heating the cells.

If you want good batteries with cells made from reputable brands (Samsung or Panasonic), order them from Gotway. Firewheel use good batteries too but theirs won't fit in a 350W generic wheel.

Posted

@JLG Paris

Oh I forgot, this wheeler has good battery packs with Samsung cells for sale, 120€ : http://trottinetteselectriques.heberg-forum.fr/sutra19515_batterie-interne-externe.html#19515

A nice guy (he just bought me a Charge Doctor :P) with a product at reasonnable price, what not to like...

Posted

Gotway aren't the only company to package good quality cells. Ninebot, King Song, & IPS also possess top grade 18650 cells from reputable manufacturers with probably better overall reliability.

@JLG Paris, you're quite right that there has been relationship between very high-capacity cells & their sustained current. I agree that the Samsung 25Rs offers great capacity/power spec's at a incredible price. It's a good choice, obviously please use precautions if creating your own pack, there's a lot of energy in these things (I read somewhere, that these cells are capable of bursting to 100A for 1sec!, yes 100A).

Eventually, I think the 132Wh/350 Wheels will ultimately be banned on safety grounds, for most western riders, there isn't enough power safety margin to prevent brown-outs/cut-outs.   

Posted

Eventually, I think the 132Wh/350 Wheels will ultimately be banned on safety grounds, for most western riders, there isn't enough power safety margin to prevent brown-outs/cut-outs.   

​I think I understand what you're saying, the Chinese tend to be smaller and lighter so the small wheels are not a problem. However, my 14-inch wheel is fine for me at 70kg and my wife is smaller. It would also be fine for kids. So I think it's more a problem of making sure that people know what they need for their weight and cruising range. There is just no decent info out there to help you choose except forums like this.

Posted

Eventually, I think the 132Wh/350 Wheels will ultimately be banned on safety grounds, for most western riders, there isn't enough power safety margin to prevent brown-outs/cut-outs.   

IMHO there is no need to ban them but they should reduce the max weight from 120kg to maybe 60kg in the specs. I bought a TG-T3 for my son (45kg) and he is riding it a lot with no issues. When I drive it (90kg) I have to be very careful to prevent it from stalling out. 

When we drive together, he on his TG and me on my X8 (170wh battery), we have close to identical range and performance :)

Posted

Hi, thank's for all the answer.

I was out for the day and what a nice surprise to see all that answers. Thank you.

@hobby16 thank you or merci pour les link, it's exactly my problem. And that's great to have the solution.

@Jason yes the 25R are maybe to powerfull. I dicided to look more at my battery and one cell is at 3.2volts (don't know why) any way they are generic battery cells. Good for a cell phone bank maybe. So i'm going to replace them.

My plan is to buy new cells and to turn off the safety cut off.  (maybe panasonic or sony cells some have tags and i found them at a good price + shipping from Nlkon.com to France) 

I think that the panasonics NCR18650PF 2900mAh is a good choice that's make a 170wh battery. Like Lorents said.

I was also looking for turnigy battery from hobby king.

the problem is that the 14inch wheels don't have a lot of place for battery so it' impossible (or difficult) to have more than a single 16s 60v 170wh battery.

@ hobby16, if it don't work i think that i will ask your guy. "Encore Merci"

thank you

PS : i will make some pictures

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