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Ninebot E+ for 250 pound rider up 10 degree hills


DaveThomasPilot

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I'm trying to decide which cycle would be best for me.

I weigh 250 pounds in typical clothing. 

I have no desire to got fast or for long cruises.  Bbut have a workshop located about 1500 feet from my house, down an 8 - 10 degree slope.  I'd like to hop on the EUC to fetch something from the workshop, and return at something faster than a walk, maybe a jogging pace.

Same thing for cruising around our subdivision.  It's hilly, with the same (approximately) 10 degree hills around 1/4 mile up, down.

I figure battery internal resistance will limit the current delivered to the motor going up the hill, and consequently, the speed I can get.  But, perhaps motor overheating will be the more critical factor in the hot, NC summers (90 - 95 degrees F isn't uncommon).

I could wait for the Pro version to be more generally available, or go with a King Song 840 wh instead to have more power for my heavy body uphill in hot weather.

However, if the Ninebot E+ can get my up and down these hills at a reasonable pace, it should be more than enough for my first cycle.  It's available now.   I figure it could become my wife's cycle if I later decide I really like doing the EUC thing and want to get a bigger wheel.   I figure availability will improve in six months, especially for bigger battery motors.

Thanks for any advice!

 

 

 

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Dave, i have limited experience with Ninebot but my 14" kingsong handles hills pretty well. I am similar to you in weight (224 lbs) and probably 240 with clothing and backpack. and the wheel still does the job pretty well. I am pretty sure kingsong with 840 batteries will be mire powerful than the ninebot P. It can even go at a high speed on 10 degree slopes. Someone around 250 lbs coukd really benefit from a stronger wheel, and honestly having tried kingsong i will never go back to the ninebot as it will lack the piwer and speed that i am now used to.

About overheating - this was my problem with the previous generation kingsong, it is also possible that my previous wheel was faulty, but the latest wheel i got has absolutely no issues with overheating even when i go uphill or ride aggressively. So i dont think you will have any issues with the latest 14" Kingsong.

i bought my wheel from @Jason McNeil who is a local distributor based in Florida and a forum member here. He sells several brands, i believe he sells ninebot too, and as such he will not be hard pressed to sell you any particular brand, rather he will be able to advise which works better for you. He has these wheels in stock, responds fast, and provides excellent and fast service. He actually even helped with the wheel that i didnt buy from him. You might want to contact him, especially if you are looking for a strong 840wh wheel like kingsong. His website is  wheelgo.com. There is also several other distributors / forum members who can help you get the right wheel for your needs. Good luck

 

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I was about 235 and had no issues with the E+ going up hills.  I don't think you would have a problem there.  

The potential problem I see is that if you keep the EUC at your house and charge it there, you will be getting on with a full battery and going down a slope.  Since the EUC is regenerative (puts power back into the battery to brake), I would be concerned about triggering the overcharge protection on the BMS and it will shut down resulting in a faceplant.  

 

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very good point about going downhill after taking off charger! That would be my normal thing to do. 

I'm an electrical engineer--maybe I could design an early charger " cut-off" mechanism to terminate charge when the battery is  higher than 75% capacity, for example.

But, with your comments I'm definitely now leaning toward the KS 14C,840 Watt hours.

Also, on a different subject,  it seems to me, all things being equal (battery and motor windings), a smaller wheel would do better uphill.  Bigger wheels will travel more per revolution, but would require more torque.

So,  I'd think a 16" wheel would by 18/16, or 12.5% better uphill than an 18" wheel, if uphill , heavy rider speed is limited by the internal resistance of the batteries, the motor winding resistance, or motor thermal constraints.

Is this a generally accepted observation?

Thanks!

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54 minutes ago, DaveThomasPilot said:

I'm an electrical engineer--maybe I could design an early charger " cut-off" mechanism to terminate charge when the battery is  higher than 75% capacity, for example.

I'm doing something that would have that capability now.  I bought a Chinese high power lithium charger and figured out how to adjust output voltage, max current, and the shutoff current level.  I also built a charging data logger to record charging data.  As an electrical engineer (I'm merely a self taught hack), any input you can provide to better the end result would be appreciated. :)

But the charger alone would work fine for your needs if you wanted to have the charging cut off after it switches from constant current to constant voltage mode which should give you about 80% charge and leave enough buffer for going down a hill.

 

 

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Hmm.  We've a Ninebot E and I would say it's at the edge. If you like to have fun go ahead for Kingsong or Gotway. With that weight go for the Gotway with real parallel batteries to have the capacity for steep inclines. Don't waste your time and money with an EU with single battery and not enough power. Just my 2 Cent.

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Cranium,

I was thinking of something much simpler which would use the existing charger and just terminate the charge early

Probably just terminating when the battery voltage reaches a voltage threshold.  This assumes I can live with the charge in the battery at the charge voltage slightly below where the charger transitions from constant current to constant voltage mode.

Thanks!

 

 

 

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11 minutes ago, DaveThomasPilot said:

Unfortunately, I don't see Gotway for sale in US, at least from a dealer So, it would boil down to waiting until they become available, or buy a KS, I think.

With your weight an d trust me I know what that means ;) you should go for an EU with parallel battery. You asked for the incline. Do you've one incline which is heavy or do you live in an area with many inclines? If not go for the Kingsong.

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18 minutes ago, OliverH said:

Hmm.  We've a Ninebot E and I would say it's at the edge. If you like to have fun go ahead for Kingsong or Gotway. With that weight go for the Gotway with real parallel batteries to have the capacity for steep inclines. Don't waste your time and money with an EU with single battery and not enough power. Just my 2 Cent.

I'm not sure it is the batteries that would be the limitation here.  The batteries in the Ninebot are rated to maintain 1,100 watts of power output continuous (20A at 55V nominal) whereas the motor is rated for 500W.  So any limitation would be more likely be imposed in the motor controller from heat dissipation.  That being said, I agree that the Ninebot would heat up and if repeated back to back trips up and down the hill were needed, the Ninebot temperature would mostly likely get too high.  

When I ride my Ninebots (E+ & P) around pretty hard at a University Campus (at tilt back speed with lots of slowing down and speeding up), I get the temperature up to near cutoff temp with my weight and I only get about 10 miles of range riding it this way.  My son weighs about 35lbs less and doesn't have the same temperature issue riding with me.

 

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" As an electrical engineer (I'm merely a self taught hack), any input you can provide to better the end result would be appreciated." :)

There are more considerations that you might realize when  charging large capacity batteries, especially at higher currents.  For example, the battery voltage while under charge isn't a very accurate way to judge state of charge, since the resistance of the individual cells varies significantly with temperature and other affects.  The variation in voltage due to the resistance variation would mean you'd have to stop charge early to prevent over charging the cells.

Als, the BMS used in EUs needs to be understood to make sure a different charging method makes sense.  Maybe that's all in the thread you referenced--I just don't have time to read it until tonight.

 

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3 minutes ago, Cranium said:

I'm not sure it is the batteries that would be the limitation here.  The batteries in the Ninebot are rated to maintain 1,100 watts of power output continuous (20A at 55V nominal) whereas the motor is rated for 500W.  So any limitation would be more likely be imposed in the motor controller from heat dissipation.  That being said, I agree that the Ninebot would heat up and if repeated back to back trips up and down the hill were needed, the Ninebot temperature would mostly likely get too high.  

When I ride my Ninebots (E+ & P) around pretty hard at a University Campus (at tilt back speed with lots of slowing down and speeding up), I get the temperature up to near cutoff temp with my weight and I only get about 10 miles of range riding it this way.  My son weighs about 35lbs less and doesn't have the same temperature issue riding with me.

 

O I forgot. Temperature is a major issue. I don't drive the 9b1 (the current EU of my wife => KS16) very often. But I got it to the limit on a sunny (not really hot day) close to the maximum by cruising at 12-14 km/h and soft inclines. Not build for real (heavy) mans

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4 hours ago, DaveThomasPilot said:

Unfortunately, I don't see Gotway for sale in US, at least from a dealer So, it would boil down to waiting until they become available, or buy a KS, I think.

@johnc415 was selling Gotways in US at least earlier. I think he's located in New York, you could ask him.

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Anyone know what the double beep means on the King Song while climbing and descending hills?

I'm 230 lbs have the 14C 800/680 after riding today I was down two four bars - a little under half a battery.

I was leaning full back on my heels to keep the speed down while going down a hill about as steep as a staircase.

On the way back up I was also getting double beeps but couldn't have been moving faster than 8 mph.

Maybe a overheat alarm?

I live in the foothills and this street is the steepest one around.

 

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28 minutes ago, davek said:

Anyone know what the double beep means on the King Song while climbing and descending hills?

I'm 230 lbs have the 14C 800/680 after riding today I was down two four bars - a little under half a battery.

I was leaning full back on my heels to keep the speed down while going down a hill about as steep as a staircase.

On the way back up I was also getting double beeps but couldn't have been moving faster than 8 mph.

Maybe a overheat alarm?

I live in the foothills and this street is the steepest one around.

 

When did you buy your wheel?

basically there is two types of occurances when you have the beep - either exceeding high speed or exceeding the power the wheel needs to contnue keeping you upright under load. You experienced the latter. Going up on 4 bars with 230lbs - the wheel was telling you you were putting too much load on it. Going slower probably would have gotten rid of the beeps. I iften rode with these beeps with no problem as i knew the next level of protection would be tiltback.

let me know when you got the unit - they changed the way beeps/ tiltback works

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I've had it 3 weeks now.

I ordered it from ElectricUnicylceReviews.com in Dec '15. It was delivered 2 1/2 weeks later in January '16.

I've only heard the rapid two and three beep alarms for maximum speed. Today is the first time I attacked the hills.

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The user manual says "Continual beep when low power battery protection activated".

It also says the battery sets are: 340 wh Panasonic, the 520 wh and 680 wh are LG, with equilibrium, overcharge, over-discharge, over-current protection.

The speed alarms are three levels, 25, 28, and 39 Km/h.
I hit all three today.

No mention of overcharge / discharge alarms so that must not have been it.

Their website doesn't have any newer info.

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bigger battery capacity does NOT mean better performance!!!

 

It's all about the motor and the electronics and what they are capable of drawing.

 

Also, if the battery is fully charged, going down hill will not cause the battery to "overcharge"  It does not work like that.

 

Think of your car battery.  When it is dead and you go to jump it, you get BIG sparks, because the battery is drawing a bigger load.  If you put the same cables onto a battery that is full charged, there will be no sparks as the battery will not be drawing any current.

 

--- if you battery is charged already, those extra electricities just go away...

 

pzv5j7l.jpg

 

In general, if any of you have questions about how things work, I have probably built a robot for it already haha....  Here is one I did with an Intel Edison!

IMG_0436 (1).MOV

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22 minutes ago, davek said:

The user manual says "Continual beep when low power battery protection activated".

It also says the battery sets are: 340 wh Panasonic, the 520 wh and 680 wh are LG, with equilibrium, overcharge, over-discharge, over-current protection.

The speed alarms are three levels, 25, 28, and 39 Km/h.
I hit all three today.

No mention of overcharge / discharge alarms so that must not have been it.

Their website doesn't have any newer info.

Ok, well, it is not the lower power battery protection, it is still the alarm saying the wheel is under a lot of load. Was the wheel stable or did it give out a bit? Did you feel any tiltback? In any case i dont think there is anything to worry about, your wheel seems in working order

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2 minutes ago, Cloud said:

Ok, well, it is not the lower power battery protection, it is still the alarm saying the wheel is under a lot of load. Was the wheel stable or did it give out a bit? Did you feel any tiltback? In any case i dont think there is anything to worry about, your wheel seems in working order

Thanks for the feed back,

Wheel was strong and stable, no tilt-back.

I was curious about the beeps and wondering what it was trying to tell me.

Usually it's just saying "slowdown dummy!" :)

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1 hour ago, chriscalandro said:

 

Also, if the battery is fully charged, going down hill will not cause the battery to "overcharge"  It does not work like that.

--- if you battery is charged already, those extra electricities just go away...

I would like to know more about how you think this works. I studied physics in school and it is my understanding that if the wheel is braking for you as you go down the hill that wheel is generating energy, and if the energy isn't going into the battery as potential energy, it must be going into heat. Is there a resistor in there heating up as you descend a hill?

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2 minutes ago, Shoe73 said:

I would like to know more about how you think this works. I studied physics in school and it is my understanding that if the wheel is braking for you as you go down the hill that wheel is generating energy, and if the energy isn't going into the battery as potential energy, it must be going into heat. Is there a resistor in there heating up as you descend a hill?

From what I've gathered so far (but I'm an amateur in electronics and physics), there doesn't seem to be anything else except regenerative braking. So if it isn't going to batteries, the energy must be burned off as heat, although I don't know where (motor/half-bridges/battery/wiring?). AFAIK, there aren't any power resistors or such which could be used to burn it off. Most (if not all) BMSs also don't have overcharge protection in the discharge side (over which the regenerative braking charges the batteries), so they will happily let the wheel overcharge the batteries during regenerative braking (in the models that do shutdown/warn off overcharge during braking, the logic is probably in the mainboard?).

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I believe in regards to Kingsong and Ninebot, both of which use the SH367004 Lithium battery protection chip package, overcharge protection and overdischarge is present in all operating modes.  In the google translation of the IC spec sheet on page 5 it defines what the "normal operation state" is.  Item 1 states:

  1. All batteries are between overcharge protection voltage threshold voltage (Vcv) and over-discharge protection threshold voltage (Vdv)

This implies that it is active all the time.  I couldn't find anything that supported otherwise in the spec sheet.  I also reference the Chinese spec sheet (attached) since it has the graphics and formatting preserved.

If I'm mistaken, please correct me.  I'm having to make some interpretations of interpretations from Chinese so there could be inaccuracies. :)

 

SH367004.pdf

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That chip looks like its a 3.3/5v chip. So that can't be right... Maybe I'm looking at the wrong one. (I had to Google it so I could translate the data sheet.)

 

I don't have time right now to explain batteries and charging, and I don't have the drawing for the board, but you can bet there are some large capacitors to help control incoming voltage generated from the motor, and that probably goes into a voltage regulator...

Most motor commercial motor controllers have regenerative circuits built into them, but I think ninebot has their own motor controller. 

It's probably built into it, but I don't know without the drawings. 

 

I'm assuming a lot here, and i could be totally wrong, but my assumptions are based on experience. It seems one day someone made the assumption that if their battery was full, and they went down hill, regenerative breaking would overcharge the battery. 

-which unless you have designed one of the worst motor controllers in the world, isn't the case. 

A lot of people like to just assume they know how things work, and that can be very dangerous...

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5 hours ago, chriscalandro said:

I don't have time right now to explain batteries and charging, and I don't have the drawing for the board, but you can bet there are some large capacitors to help control incoming voltage generated from the motor, and that probably goes into a voltage regulator...

Wouldn't the capacitors charge up fairly fast though? Of course if the voltage is regulated towards the batteries, that wouldn't be a problem, I guess...

As a somewhat related question, do you know how the battery voltage dropping is handled, ie. if the voltage would go lower than the back-EMF (during acceleration for example), my understanding is that the motor would start to brake. Do they somehow boost it then, or is the maximum speed of the motor limited so that the back-EMF cannot go above some voltage that is below the usual minimum voltage of the batteries?

 

Quote

I'm assuming a lot here, and i could be totally wrong, but my assumptions are based on experience. It seems one day someone made the assumption that if their battery was full, and they went down hill, regenerative breaking would overcharge the battery. 

-which unless you have designed one of the worst motor controllers in the world, isn't the case. 

A lot of people like to just assume they know how things work, and that can be very dangerous...

It seems to be the case at least with Firewheel. I went downhill with fully charged custom batteries (like I've done with the originals many, many times), and they cut out as the BMS was the kind that has both discharge and charge over the same wires. After some figuring out what happened and testing, I noticed that it happens only with fully charged batteries during braking (my trips start with a couple of hundred meters of downhill, as I live on top of a hill).

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