Gotway 18 msuper2 US

[maryland]

i am 32 yearsy old and living in Maryland ,US. I really want to buy gotway18 but i do not know where to order in safe.(no scam). anybody in US own gotway18?? if so, where did you get it?? 

[esaj]

Here's (an incomplete) list of resellers, there are many that sell Gotway, but I don't know of any in the United States (although that doesn't mean there couldn't be one or more in the US). Might have to order abroad.

Edit: I know that at least many people here have ordered both from Jane Mo (the Gotway factory representative here in the forums) and Kevin Lee, and apparently everything has went well. Also I know at least one Finnish rider who has ordered a 14" Gotway from funnybike.fr , and had no problems with the order. Can't say much about the others, probably legit, but not 100% sure.

 

[Sam Clegg]

Yeah, you pretty much need to order from aboard, and have it shipped to you.  I've used Kevin Lee and Donald Lin and they have both been problem free.  Both times I used PayPayl to pay and got a recommendation (much like this one) before I made the payment.

[GQS]

You are free to shop around, but I like how easy Kevin Lee is to get a hold of (as he is based in Hong Kong and not mainland China).  Also he is the most technical (who can explain to me and make recommendations) out of the vendors I've talked to.  We just had a recent issue and Kevin sent out a whole new wheel minus the battery.  I think there is no problems from a warranty standpoint. 

I like the mainland vendors but recently the great firewall of China has caused some communication issues with my contacts there.  They need VPN in order to reach out.  While WeChat still works, emails such as gmail do not always get through.  Hong Kong has been exempt from that.  Hence for simplicity for someone who is as close to the vendor as possible, but not within mainland China, I like Kevin Lee. 

[Gimlet]

I tend to get fairly quick responses from Jane Mo via Facebook so that seems to get through ok. She sent me a second M10 minus the battery when there was a small mechanical problem which I later fixed. She then supplied me with a battery to get both wheels up and running.

I have now dealt with both Kevin and Jane and found them both reliable.

[Donafello]

i am 32 yearsy old and living in Maryland ,US. I really want to buy gotway18 but i do not know where to order in safe.(no scam). anybody in US own gotway18?? if so, where did you get it?? 

I know JOHNC415 has a few 18in msuper fast verisons in stock. He's a great guy and straight up. he'll take care of you. pm him

[Ben Wilson]

Guys, I'm interested in buying the Gotway 18"  Msuper ( fast version ) I was told by seller on alibaba site to choose a 680 over an 840 battery. Which is better? I also want to buy from Donald lin. Still waiting for email reply. 

[MetricUSA]

Just curious what the shipping cost to US from Hong Kong is like... Yes, I'm considering buying local w/ john, but my heart was set on 850 wh battery...

[Donafello]

I would say close to $200-$300. There is a memeber here from new jersey that has some msuper HS version avaiable I think. Johnc415

[h00ktern]

Guys, I'm interested in buying the Gotway 18"  Msuper ( fast version ) I was told by seller on alibaba site to choose a 680 over an 840 battery. Which is better? I also want to buy from Donald lin. Still waiting for email reply. 

I'm interested in this answer. My reading here over the past few days seem to indicate having a larger w/hr battery (capacity) is a good thing to help avoid cut-outs.

Safe trips

[DiasDePlaya]

Guys, I'm interested in buying the Gotway 18"  Msuper ( fast version ) I was told by seller on alibaba site to choose a 680 over an 840 battery. Which is better? I also want to buy from Donald lin. Still waiting for email reply. 

I asked the same, and the answer was only one: For many reasons the bigger is better, the information is in the forum, you just need to look for it.

[esaj]

Guys, I'm interested in buying the Gotway 18"  Msuper ( fast version ) I was told by seller on alibaba site to choose a 680 over an 840 battery. Which is better? I also want to buy from Donald lin. Still waiting for email reply. 

Apparently, the 680Wh version is 4 packs of 174Wh -batteries at nominal 60V voltage, so 696Wh actually (they've probably used the rounded 170Wh -value to calculate the capacity). 850Wh should then be 5 packs of 174Wh (5 * 174 = 870Wh, 5 * 170Wh = 850Wh).

In a nutshell, not only do more packs give you extra range (mileage) per charge due to higher total capacity, they also affect the voltage sag (more packs = less stress per pack = less voltage sag), which is the main reason for cut outs (either the mainboard or the BMS can cut the power due to too low voltage). Another thing is the continuous and maximum currents the packs can give. Cells in series do not give more capacity or higher currents, they just raise the voltage, so 16 cells in series gives out roughly between 40V and 67.2V, whereas a single cell gives out 2.5-4.2V. Cells in parallel do not raise voltage, but they raise the capacity and continuous/max current. This article probably explains the effects of serial and parallel connections better than me:  http://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

Most wheels work at 60V nominal voltage (LiFePo-versions of Solowheel are closer to 51V (16S-LiFePo), Ninebot One 55.5V (15S)), so 16 cells are needed in series, but multiple 16-cell packs can be connected in parallel to increase the capacity and discharge currents. High current is needed for high torque and high voltage is needed for high speed. Torque is needed to keep you balanced and especially when hitting potholes / bumps or climbing steep hills. During "normal" riding on flat & level ground, very little power is needed, even on a slightly declining street the power can be at or near zero, or even negative (regenerative power). But then, even in "not that steep"-hills, the power required to haul ass can be in the kilowatt (kW) range, and in more steep hills, even more power is needed (depending on your total weight (you + gear + wheel), speed & hill gradient). 

When I tested vee's Gotway MCM2s (680Wh, 4 packs) and was going up a short, very steep hill (about 25 degrees at steepest point, that's about 45% grade), I found out that I needed around 1.5-2+kW continuous power at the steepest point, and spikes over 2.5kW with my weight around 60kg + wheel:

Spikes going closer to 45A at best, as the voltage drops and more current is needed to provide those around 2.5kW spikes. Still not that much voltage drop, with single pack, you'd probably see it really dive, here it just nudges a few volts downwards. It's not seen that well in the graph, but the mainboard temperature also went up a couple of degrees fairly fast during the climb, so longer steep climbs like that will probably overheat the components. The X-axis values are seconds, so the actual climb-part took about 10 seconds or so, right hand y-axis is power in watts, the rest of the series use the left-hand y-axis scale (km/h, volts, amperes, celsius). The first short spike at start is getting going from stationary, the actual steeper climb begins around 6-7 seconds, gradually steepening from around 10 degrees up to 25 degrees and then leveling out fast around 15-16 seconds.

1.5-2.5kW at 60V would be at least 25A continuous and over 41A current at spikes, and more if the voltage is lower (current = power / voltage)! If a single pack has continuous rating of 10A and maximum rating of 20A pulse discharge current, that's more than double over the "safe" limits at spikes, and can possibly burn the BMS, cause a cutout (overdischarge protection triggering, either because of voltage dropping or high current) or damage the battery cells. Probably the high current draw would also drop the voltage of the cells, so even more current would be needed to provide the power. The voltage also drops the less capacity is left, that's how at least most wheels measure the remaining battery, just by measuring the voltage.

But if you have for example 4 packs, the required current is drawn from all of them, and then single pack "only" needs to provide between 25A / 4 = 6.25A and 41A / 4 = 10.25A per pack, which is still within safe limits, and the voltage sag won't be nearly as much as with a single pack.In that sense it's a safety issue, because the wheel won't cut out on you at least as easily. Of course when the packs are closer to empty, the voltage will be lower and the sag will be deeper, so you still have to be careful with wheels that have BMSs which will cut-out "too early" in low voltage-situations. Typically the cut out is caused by sudden high current draw on low battery (fast acceleration, hitting a bump, climbing a hill), where the voltage suddenly drops a lot (or the current spikes so high that the overcurrent-protection triggers). You maybe have the time to hear some form of low battery warning, if the wheel has one, but the protection triggers right after that, before you have time to react. If the voltage drop/current raise is sudden and steep enough, it will just suddenly cut out on you without any warning.

[zentype]

Great info. Now that I'm actively considering the Gotway Msuper 18, this post really helps narrow my decision to the 860wh version. Thanks.