Jump to content
Traveller

Gotway MCM5 Light - 900w

Recommended Posts

Has anyone got one of these yet?

I have just ordered one. 

I know the battery is only 170wh and 67v and 900w motor.  Apart from the battery it has same specs as MCM4 from what I can see.  The battery is ok with me as I can build my own additional batteries using 20a 18650's or maybe even 20700's if they will fit.  There should be room in the shell if you can fit 60 x 18650's in there for the 87v 1500w version.  I think I can add another 170wh of 20a cells for about $100 or 340wh for $200.  So as a minimum for $550 I will have 340wh of cells capable of 30 amps and 30km/h max speed or for $650 510wh capable of 50 amps.  Should be better cells than the In-motion I5, faster and cheaper.  

There is also a 340wh version available from https://www.flash-ecom.com/products/gotway-mcm5-electric-unicycle-black-340wh-67-2v-420wh-84v-800wh-84v?variant=13732898701367&currency=USD

I ordered one of these first however he couldn't ship to Canada.  Web site says in California but actually currently in China.

 

image.png.1a650deeb5d51d3972be75af884f2b7f.png

image.png

Share this post


Link to post
Share on other sites
2 minutes ago, Traveller said:

I know the battery is only 170wh and 67v and 900w motor.  Apart from the battery it has same specs as MCM4 from what I can see. 

900W motor (with higher peak burden) will definitely "destroy" a 170wh battery quite fast - takes too much current from the cells.

340Wh will still be quite borderline - to stay on the "save" side i would not use anything below 4p (4 cells in parallel) with such an EUC.

Share this post


Link to post
Share on other sites

Yes I agree. to some extent.  16s of 10amp cells is way too low.  Would only deliver 600w at rated discharge rate.  Theoretically adding another 16s of 20 amp cells should give me 1800w at rating which I think might be just enough for my kids that are lighter than me.  Ideally another 340wh of 20 amp cells gives 3kw capacity which is way over the motors ability or using 20700 cells if they will fit.

Share this post


Link to post
Share on other sites
36 minutes ago, Traveller said:

Theoretically adding another 16s of 20 amp

Theoretically, yes. Practically i've never seen "nice" discharge graphs of cells rated for 20A... :(

36 minutes ago, Traveller said:

I think might be just enough for my kids that are lighter than me

Not (too) much range and no aggressive driving (motor power is just as emergency reserve) could work out for light kids.

... but then again "normal" 10A nominal current cells could have "nicer" characteristics and would "fit better" for the already installed battery pack ...

Share this post


Link to post
Share on other sites

I wish the 1500W had the red coloring that these lower power MCM5s have. I like the red design way better.

Share this post


Link to post
Share on other sites

it was pre production wheels.

No MCM5 has red coloring ....

Share this post


Link to post
Share on other sites

Just joined the kiddie-party for US$200 new. Intend to upgrade batteries too.

Share this post


Link to post
Share on other sites

Just an update.  I put 16 Lishen 4500mah 21700 13a cells in with their own standard off the shelf 16s bms as well as the original 170wh of 10a cells with their bms.  So far have done 140kms with alarm set at 27km/h and tilt back at 30km/h.  So far has performed flawlessly - really responsive, great hill climbing. Sides are too smooth to jump easily and it is heavy.   I haven't done a range test as such but assuming 15wh/km as a guess should get about 28km range and this seems about right.  

Share this post


Link to post
Share on other sites
On 8/31/2019 at 12:09 AM, Traveller said:

Just an update.  I put 16 Lishen 4500mah 21700 13a cells in with their own standard off the shelf 16s bms as well as the original 170wh of 10a cells with their bms.  So far have done 140kms with alarm set at 27km/h and tilt back at 30km/h.  So far has performed flawlessly - really responsive, great hill climbing. Sides are too smooth to jump easily and it is heavy.   I haven't done a range test as such but assuming 15wh/km as a guess should get about 28km range and this seems about right.  

Just seeing, this. Very awesome!

If you have any pics of the custom built pack exposed, and how it fits, please post pics, thanks!

Share this post


Link to post
Share on other sites

Thank you. Today I have opened my MCM5 900W too and are looking at battery options.

Have you  put a BMS on that pack that you have made. I have just ordered both of the BMS's for each style. Of battery pack.

The only issue I have is I don't know where I connect the second BMS.

https://www.dropbox.com/sh/uymym2tko903xlu/AAAtoDGWv5CBdZgrJklz4vFpa?dl=0

Share this post


Link to post
Share on other sites
On 12/19/2019 at 4:27 PM, Traveller said:

https://imgur.com/a/udToFxs

Photos of the battery spaces on MCM5

I'm wondering how many 21700 cells would fit... I think even if there seems to be some more space, the curve of the cover may get on the way if the main packs of a 800wh MCM5 were replaced with 21700 cells, I guess it wouldn't fit. 

Share this post


Link to post
Share on other sites

Here guys.

https://pixhost.to/show/335/142427911_topbattery-32cell-20700x2.jpg

https://pixhost.to/show/335/142427912_sidebattery-32cell-20700x.jpg

 

I sourced both original BMS boards and bout 64 x Sanyo 20700b 4250mha (20A discharge) To begin with the made a pack 4S8P, brick shaped battery. At least it helps demonstrate that the battery fits in the top compartment. After we got things sorted we are building the side battery, 32 cells. It shows that you can't put 20700 batteries in an 84V as you can't put 2 extra batteries. 

I want to test performance and pedal stability with one pack..


 

Share this post


Link to post
Share on other sites
On 3/17/2020 at 7:14 AM, Jean Dublin said:

I'm wondering how many 21700 cells would fit... I think even if there seems to be some more space, the curve of the cover may get on the way if the main packs of a 800wh MCM5 were replaced with 21700 cells, I guess it wouldn't fit. 

yes but only if you have a 67V/900W you can use 16 x 21700 on pack on the side panel for sure.

I think the top compartment woudl also handle 21700's...

Share this post


Link to post
Share on other sites
Posted (edited)

I want to thanks to Traveller for posting the discount price of this MCM5 "light" ($462 with 170 wh).
It encouraged me to search for good deal and here is one I want to share : $496 with 280wh (16S/60V) & 1500W !
https://www.aliexpress.com/item/4000712073446.html from Airecho Store

In comparison, the 800Wh cost $1032, meaning $1050 the kWh of additional battery, about x4 the price of these cells (nkon.nl in europe) :w00t2:

So here I am with my first wheel, small battery is perfect to start as the wheel stay light,
Will upgrade the battery later with all the great input here.
 

Edited by Camenbert

Share this post


Link to post
Share on other sites
Posted (edited)
On 4/11/2020 at 8:42 PM, Camenbert said:

I want to thanks to Traveller for posting the discount price of this MCM5 "light" ($462 with 170 wh).
It encouraged me to search for good deal and here is one I want to share : $496 with 280wh (16S/60V) & 1500W !
https://www.aliexpress.com/item/4000712073446.html from Airecho Store

In comparison, the 800Wh cost $1032, meaning $1050 the kWh of additional battery, about x4 the price of these cells (nkon.nl in europe) :w00t2:

So here I am with my first wheel, small battery is perfect to start as the wheel stay light,
Will upgrade the battery later with all the great input here.
 

Be careful what you do with that 170Whr battery and pay attention to the low voltage beeps. Before upgrading the battery my friend decided to push it and it cut out and he fell... Only now now that I have 48 x Sanyo 20700B, 4250mha (20A)I feel it is stable. The so called 900W seems to be  the same 60V motor the use on the 84V model. I have seen my 60Vmotor/67.2v battery, pull 4000W going up a steep hill. I think your 170Whr  (10A) won't be able to do.

I think the best upgrade you can do is take that 170Whr battery pack apart and get the BMS out, buy the batteries from a trusted source and build yourself a 2P16S battery pack.... If you are not going to use 20700B, I suggest the LG HG2 the have the same capacity as the NCR18650PF, but rapid discharge.

The side panel does outward space to take more than 16S, I tried 2P16S, but it is too thick to close the side panel panel.

 

Edited by OneLeg

Share this post


Link to post
Share on other sites
Posted (edited)

Thank you for these great advises (and the all pictures you made) :thumbup:

GotWay now sale as base model "280Wh" that include 2P16S Sanyo ZL2 2380mAh 10A.
I will learn as is and upgrade later, depending on learning curve (and coronavirus), this summer i guess.

I have some genuine unused Panasonic NCR18650BD 3200mAh 10A to add 2P16S on the side panel for a total of 670Wh. That is short for 4000W but I have no big hill.

What would recommend me, to buy another BMS (any recommendation ?), or to wire 17xAWG24 from the secondary battery to the main one ? Normally there is no big current between cells in //, I can fuse these eventually.
Of course main/power cable will be AWG12 or so, going to XT60 with Y connection.

Edited by Camenbert

Share this post


Link to post
Share on other sites

Interesting I didn't know the BD doesn't have protection. Which makes it suitable for unicycle use.

One new factor to add to the mix is that the 67.2V and 84V have the same motor.... they allege that one is 900W and the other 1500W, they the voltage difference is 25% higher.... I think the 900W motor is bigger. I am still inclined to suggest that you go for 20A battery given the power it has. I am using to riding a V5, which has huge torque and responsiveness, not the power to climb wall like hills like the MCM5. If you push the MCM5 I find it can really bring down the voltage, especially if you don't have enough cells. I think 48cells is the minimum, if you want a "serious grade pedal sturdiness" without having to put it on strong mode.

BMS, the Goteway "BMS" is pretty dumb, it simplicity makes reliable if you have it working. The quality of these boards when new, unbuilt and untested is pretty poor and may find components are missing etc....  The other problem is that the side BMS board dictates the shape  of the your pack and you cant stack it 2 batteries high as there isn't the room...... now if you if you use a BMS where batteries arent soldered on it.. eg...

https://www.aliexpress.com/item/32879341603.html

Then you can make a string of batteries side by side which is flat and long so  32cm long and 7cm wide  the BMS would fit above it. you put a plastic sheet to make it rigid and absorb impact. The idea, yet to be test is whether we can put 32 cells on the side. That is a smart BMS which has lots of smarts to charge and protect the batteries and the pack, the latter may not be favourable as it may mean a cuts out...

The other problem is that making batteries is not easy. Even the guy I used and builds batteries for laptops had issues.... he shorted something whilst building the pack, the battery was deep discharged and killed....

The other huge problem is that you build the pack and have put it in the unicycle have no visibility of the status of the batteries other than the output voltage which may tell you if one of the batteries has issues.... If you put two batteries in, they are connected in parallel and one may mask problems in the other.

The other way is to open the pack and measure the voltage of each.  The Gotway BMS is not connected to the controller board like on inmotion (it is built in), and the microcontroller can't know if a battery is dead.... but don't worry the circuitry allows you to ride around with a big number of your cells dead. My friend showed me his 84V unicycle only outputing 58V.... He is an amazing rider so he manages.

So I think we need a BMS that has bluetooth and allows you to query the battery status. The other issue is we want a BMS that is not used for discharge, as I think that may force us to have a BMS with of high amperage.I believe these charge only BMS have 2 cables and not 4 other than the connections to the cells.

I am in the middle of researching all this and finding solutions that are safe.

You also need XT60 splitter and a charger cable splitter, get the right connectors so that you don't screw up and reverse the polarity from charger port. Also when you buld the pack make sure they are all in the same state.... safer to work with batteries that are not charged. Also if you put two pack together make sure the other pack is in the same state. If you money to throw at this, get Opus 3100 to verify the cells, condition and capacity. Also I am looking at a Hota D6 to be able to charge or discharge the packs...

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...