Monday, 27 January 2020

Scooters as practical and ecologically sustainable transport

I love my scooter as a practical and fun transport method for shor trips. Not only that but its just bloody practical to store at home too (right at my back door).


Making it super handy for a quick trip to the shops, or up the hill to visit my elderly mate.

One of the aims of most transport planners is to encourage less trips (especially short trips) by car, to minimise the impacts of cars on both infrastructure and the environment.

Cars (generally speaking) last significantly longer and generate less pollution if used for long continuous times not shorter trips with lots of stopping and starting. Their fuel use goes up (per km) and the emissions get worse both in quantity per km and break up of what is emitted. Engines do better warm than cold.

Wikipedia has an interesting article here that goes into it, and puts walking as the standard (which is pretty efficient) and bicycles make that twice as efficient:
A standard lightweight, moderate-speed bicycle is one of the most energy-efficient forms of transport. Compared with walking, a 64 kg (140 lb) cyclist riding at 16 km/h (10 mph) requires about half the food energy per unit distance
Interestingly they find that a scooter gets nearly 25km per MJ of energy, while walking gets only 4.5. This puts the scooter at the number one spot for efficiency by a big margin (discounting the Velomobile simply because they're really quite impractical and have some real visibility problems in traffic).

 So leaving the exercise benefits aside (which perhaps you shouldn't), considering also time taken to get somewhere as part of efficiency, of all the mechanised transports a scooter is about the most efficient in particular for short journeys (which becomes clear when you compare the data in their table)

Now its interesting that the data from scooters comes from simply the claims of Xiaomi 365 based on their claimed maximum range. I know that you know that claimed ranges are not always reliable, so I have been (as you may have seen in other posts) making some measurements of energy usage on my own scooters and thought I'd do some additional tests. On this test all I did was one specific run, then recharge it. This is the run I do (discussed before here):


and so yesterday I did it twice in the following manner:

  1. fully charge the scooter
  2. do the run
  3. rest the scooter for 20 min and then recharge
I got an average of 147Wh needed, which means 15.3Wh/km or 1.53kWh/100km to use the same language used in that above table. This is not significantly different to the most optimistic claims of the much lower powered Xiaomi (which is 1.15Wh/km).

That's simply amazing stuff, and for contrast Tesla Model S is cited as being 17.25kWh/100km and the GEM NER is 10.5kWh/100 ... so 10 times less energy.

Yet (considering time) I'm sure I can walk out my back door, step on the scooter and be at the local shop (just under 2km away) in less time than I could do it in either of the above EV's

Impressive stuff.


Further, readers of my blog will note that I've done quite an amount of experimenting with small scale solar and I know that even multiple recharges per day of my Mercane from a solar system with 200W worth of panel (and controller, inverter, battery).

So in the event of any infrastructure failure I'm also covered there too.

Conclusion

Now all this is just back of the envelope stuff, but I'm sure that well treated and well maintained one should be able to get similar usage life out of a scooter when you factor in how much smaller it is, how much less you had to invest to get it, and how much less you'll pay in operational taxes. A starter for that calculation is this:

  • my Mercane weighs 24kg, a Model S weighs 2,225kg 
  • my Mercane has 78 lithium 18650 cells a model S has 7,104 
  • my Mercane cost AU$ 1400, a model S cost AU$140,000 

so about 1% of the Tesla in all cases. Interesting.

This leads me to be more confident that Electric Scooters are not just good for the environment and highly practical but they're bloody good fun on a low budget too.

Win Win

Saturday, 25 January 2020

Mercane Wide Wheel Disc Pads

Someone asked me if I could measure the brake pads on the Mercane Widewheel ... seemed a slightly strange request because if you had one you'd just measure them yourself. But it seemed like something to occupy 10 minutes, so I thought I'd post that here, and thus also have a reference myself for when that's needed (which isn't going to be any time soon looking at them).

Now I don't have the new 2020 model, so if the caliper is different, best pull them and see for yourself as its literally 5 minutes work. Its taken me twice as long to photograph and write this as it did to pull them out and look (well, and really, best pull them anyway if you're going to change them right?)

So this is the diameter of the pad back (steel)


and they're just held in with a magnet, so I just took them out with grabbing that tab with needle nose pliers and took them out.

Of course I had to wind back the outside pad to do that (but you'll need to be doing that anyway when you fit new pads (as well as the back one) because they'll have worn, and you'll have had to make adjustments over time if you still wanted your brakes to work right?

This is the amount of wear mine have had in over 6 months:


which is barely visible ... and the backing plate thickness is 1.5mm. Plenty of meat left there, and importantly showing nice regular wear (a good indicator of proper adjustment).

The pad in general looks like this from the front:


so no issues and generally in good condition all round.

Looking on ebay I found in about 3 minutes searching (key words were mtb disc pads) that they seem to be these:

TP-11C: 18.5 x 22.8mm/0.73 x 0.90"


So basically they cost nothing ... its beyond me why people carry on about using regen to save their brake pads ...

HTH

Saturday, 18 January 2020

leaning off it VS leaning it

Scooters are not motorcycles (as I've mentioned before) and so cornering technique is different, but leaning off the motorcycle is actually still a common technique (even a MTB) when cornering, for example:


In the above picture my mate has altered the center of mass of the bike (and him as a unit) to enable him to keep the bike around the corner and not run out of tyre.

This is because eventually when leaning the tyre contact patch is reduced (by the lean) and the angles that the forces are being experienced are off axis from the suspension enough to unsettle the bike more when bumps are hit.

The situation on a motorcycle is that you may weigh only one third of the system weight (you and the motorbike) but still its helpful to lean (more so in wet conditions), BUT with a scooter its usually the case you weigh much more in that ratio (of you : scooter) with you being more than four fifths of the weight. So you leaning in a bit makes heaps more sense than attempting to stay "on axis" with the scoot and its stem.

On my Widewheel this is even more easy to demonstrate.


So, lean in a little instead and have better grip and better steering dynamics ... on pretty much every scooter.

first significant rain test ride

Well it rained here a bit lastnight



I was over visiting a mate when it started, which I expected but didn't mind. I waited for it to clear, but when it was pretty clear it was set in for the night I rode home.

Scoot performed well, one corner (the usual fast one) stepped out the front a wee bit (but happily I anticipated and caught that slide) and testing the brakes down my hill showed no easily observable loss of braking.

I sit it on a couple of heavy duty "plastic woven canvas" bags in my front room where it drip dried over night.

This is a quick look over it this morning:


so, seems alls good for a little bath.

Thursday, 16 January 2020

4A Charger for the Mercane 1000W scoot

Given that my scoot has 13.2Ah battery capacity, charging it at 2A seemed ludicrous, especially given that Lithium batteries are well within safe limits at 0.5C charging (and 2A is about 0.15C) and 4Amps will still only be 0.3C.  As well my 2A charger gets rather hot on a hot day (so I wanted to get something with a fan). I got this one from Aliexpress for about $40:


it came "plugless" at the scooter side and so I added a compatible plug (no big deal) for my scooter.

Plugged it in and whop: perfect:


the astute will observe that this photo was taken before the one above because I had not got around to putting insulation on the plug ... heh

Some observations have been made about the noise of the fan, and I can say "its obvious" ... not "Commercial Hair Dryer" but not "Silent Night" either.


Naturally my battery wasn't "dead flat" so I can't provide full charging data, but I can say that normally Lithium follows 2 stages of charging:

  1. Constant Current (where the voltage gradually inflates like a baloon)
  2. Constant Voltage (where the voltage barely moves, but the final parts of the battery pack "expand" in capacity like blowing up a balloon).
So I thought I'd record the latter part of the charging and compare it to the existing data I recorded using the 2Amp charger the other day.

so basically both the 4A and 2A charger took the same time for the "balance charge" component, 1 hour 50min . The 4A charger makes it plain when its in that phase by not just making a light go green, the fan shuts off too, so it goes very quiet.

So while the 4A charger will bring up the bulk of my pack in half the time, meaning that it will charge to the start of balance charge time in 2 hours instead of 4 hours, the remaining balance stage will still take nearly two hours (for either charger).

This is actually very close to what Battery University report for charging Lithium Ion.


which is charging at 1C (while I'm charging at lesser amounts, like 0.15C on the 2A charger and 0.3C on the 4A charger. Both my results and their results show that the last part of charge takes nearly two hours.

Assuming you are doing a full balance charge (and I would at least every second or third charge) the 4A charger will bring it down a lot but no matter what higher speed charging has its diminishing return points because even with charging at 13Amps it would take 3 hours in total.

Summary:
  • 2A charger -> full charge (including balance) time = 6 hours
  • 2A-> full charge (no balance, just to green light) time = 4 hours
  • 4A charger -> full charge (including balance) time = 4 hours
  • 4A charger -> full charge (no balance, just to green light ) time = 2 hours
And of course if you just wanted a quick top up then half an hour will get you twice as much as the 2A charger.

Pretty comfortable that this is money well spent (cos sometimes I just need a quick boost and go out again)

Saturday, 11 January 2020

Mercane Battery reassembly and the problem may be fixed

Well I didn't expect this to work but it seems that it now is.

After pulling down, measuring my battery pack and individually balancing the pack (see this blog post) it seems that its now working properly (which I don't think its done since new, certainly not after the first few weeks as this video I did back in July last year shows).

After that I thought I'd clear up the ratsnest of untrimmed wires from the loom left by the battery assembler (I don't blame them too much because I bet they're not well paid).


Firstly I thought it looked a mess and secondly I wondered if it somehow contributed to the problem with balance charging because of the different resistances with really long wires (and some were not).

I manged to get it like this:


before packing it up and shoving it all back together (like a swollen suitcase).



Then once all  the stuff was back and the cables neatly arranged I put it on the charger and was greeted by -->> Balance Charge completion!  YESS!!


So now I'm sort of stuck for what was the solution, because clearly the BMS does not have a problem now, although it did before. I'm left with a few theories:


  1. Somehow the pack got out of balance at some stage and was sufficiently out of balance that it was beyond the capacity of the BMS to bring back. If this is so then my manual balance charging of bundles may have been the required solution.
  2. Although all the solder joints looked good, perhaps unplugging and replugging  the BMS (as well as point 3 below) was enough to get it working right?
  3. Because I shortened the wires (trimmed quite a lot off some) perhaps this  made a  difference too?
I really don't know, but now I'll be keeping an eye out for it.

Conclusion

Well I really would not have been able to diagnose this was a problem without in the first instance the voltmeter built into the scooter, and being able to observe the instant voltage drop when removed from the charger. Then the 150A inline monitor has really been very helpful in plotting and understanding the last phases of current draw >> after the red light has gone green << when people would think "charging is done" (see this blog post).

Either way, I'm pleased its all together and going :-)

PS: I took it for a quick spin around my usual circuit (both cycling and scooting, its a nice little run in the morning) and it returned with a good state of charge. The GPS data for it was this:


which is actually not too far away from what my Dual normally gives me:


which is pretty much what I've usually found when I initially began comparing them:

  • the dual motor climbs hills better
  • on the flats they're pretty similar, but the take off on the 500W single motor is much more even and gentle.

Post Scriptum


After charging the pack did not come back up to 54.7V, but 53.4, so something is amiss. This means I'm going to have to do some more testing and perhaps try one of my new BMS units. Also, a little web  searching revealed this test on what appears to be the same batteries. I think its reasonable to believe that they are more or less the same as the cells that are in my pack. His conclusion was:

Conclusion

The cells looks fairly good, they are obvious not for 30A, but 20A looks fine.
Post PS: this actually fixed the BMS charging issue but did not fix the issue entirely so see my post here.

: this actually fixed the BMS charging issue but did not fix the issue entirely so see my post here.

the rear kick as a useful tool on the scooter

One of the things I love most about my Mercane is that kick up at the back. Its not only a great piece of styling its a great way to brace yourself when you hit the accelerator on take off and needed for transferring weight back and rear during braking.

Here's how I use mine:


Personally I love narrow longer boards because it gives me great stability, especially where you need it front <-> rear because that's where forces come from:

  • braking forces
  • acceleration forces
  • bumps and movement
Sadly I see so many videos done by sales people who are most often business people with no history or experience in riding (either scooters, skateboards, mountain bikes or motorcycles), and its pretty obvious when you watch them


its pretty obvious who the guy with no experience on a scooter is ... the two kids are doing it naturally.


Videos like this seem to be just some sort of wankfest where they show spinning wheels (with no one on the scooter, in dirt) and proceed to influece (at least unconsciously) viewers who are newbies.

This feet together style is just bad bad bad and forces you to put all your body weight on your stem in an unexpected encounter with a bump that you didn't see. Leading to stuff like this:



I have no idea what led to this but stems are not designed to be for more than directing steering. The leverage is just too high and you'll eventually break it (or hopefully just weaken it and complain about the wobble.

I love the cosplay outfits like big motorbike boots, jackets and full face helmets that clown is wearing, where you just pretend its all going to help you ... Sadly the reality is that bad stance like this will likely lead you to this:


Even with the cosplay gear like the motocross boots and full face helmets isn't going to help much in accident at any sort of speed (even 20kmh), which will likely lead to stuff like this poor fellow suffered when fell off and broke a few things. He reportedly wasn't going "flat out" either.

Safety is in observation and technique, so:
  • don't stand like a statue
  • keep your balance
  • practice emergency braking (stop as fast as you can without locking up the rear wheel)
  • stay chill
Happy Scooting

Friday, 10 January 2020

Mercane Battery pull down (part 1)


Warning: don't do this if you don't have a clue

For some time I've felt that my 500W single motor Mercane Widewheel may not be "fully up to scratch" and the teltale to me was the display battery voltage dropping from 54.4 to 52.2 immediately after unplugging it from the charger. Further evidence was the abrupt change in charge rate (1.8 amps still getting sucked) when some particular (seemingly arbitary) voltage was reached. Note how at about the 10second mark in this video it suddenly drops to 0.00Amps (and the charger light goes green).


This suggested to me a failure of the BMS in some way ... (actually I am still not sure if its a fault or a design failure of the BMS, but I digress).

So to answer the question I decided to pull the battery out and dissect it to examine the internals. Warning, if you do this yourself be fucking careful, cut shallow and cut along the corners carefully. If you need a pry tool (I did) make it NON Conductive (an old spatula came in handy, had to get a kitchen utensil in there somehow right?). In short I found the following:

  • the Mercane battery is very well made and well sealed
  • the wiring connections are excellent and very well put together and protected
  • the critical connections seem well sealed (perhaps not the controller itself)
  • again I'm impressed with the incredible webbed stiffening around the main board

And so with the belly pan off you can see that the battery is well sealed (even more than you think here) and you can see that the connectors are actually similar to ones that are used on the Zero 9 (which hang out in the open and so one can assume are pretty water resistant), but in the Mercane they're actually shielded more from water by being inside and under the board (which is solid cast alloy). XT-60 connectors (which use gold plated terminals) are found embedded in that foam.


so removing the battery was as simple as unplugging that and removing the charger port at the front (also XT-60)

To get the battery out I needed to move the controller there too, so I could get my fingers under the battery and rip off the velcro tabs (vibration made them well held I must say).


which is as good a time to remind anyone who has an engineering eye just how bloody strong the Mercane chassis is, look at the size and thickness of the cast alloy chassis


and just how dense is that strengthened section where the stem bolts into!

So next it was to slice into the battery compartment. This is actually (inside out) first covered in sheets of fibreglass then fully shrink wrapped



nicely quality control marked ... 



 then silicone sealed at the joints even into the protrusion holes. Very impressive.


So, finally I get to the battery (or array of cells) pairing back the fiberglass sheath with my spatula (yeah - reddit approved kitchen utensil)


and finally we can see where the BMS is ...


This is where I find that (when I prise it off the sticky stuff) that its actually a well made bit of gear even if its programming may be suspect. It has 6 FETs in it while the one I bought has only 4.


fortunately I bought two (of different types) because (surprise) there is no wiring standard for these fucking things, and the even though the plug is a perfect match if I were to plug that red one in, then it would blow up because +ve is on the opposite side of the plug wire loom direction. These are the two BMS I bought 


and the one on the right will plug right into the existing harness and need a little soldering (and I think its amenable to regen braking too).

Measurements

So now that I've got it open heart and on the slab I can take measurements and I didn't really like what I found:


Battery #V
14.19
23.97
34.18
44.21
53.86
63.98
74.06
84.01
94.02
104.2
113.93
123.97
133.95
Sum52.53

The pack was clearly unbalanced, and while the mathematical average seems ideal (to a Wanger) the devil is as always in the details.  52V would be an average of 4V per cell, which if they were all at that level it would be "ideal" for those Wangers who want to somehow preserve their battery life till well after their scoot is dead for other reasons. Basically 3.5V is getting pretty close to "don't take it there" and under load its pretty clear that some of these cells will quite likely buckle down to that, especially...


the one just above 3.75V, where the amount it can fall before likely triggering a BMS shutdown for low voltage (which has happened twice) is not far at all (while others would still have plenty of capacity). Further the ones at top charge of very close to 4.2V (one is over), which probably triggered the BMS to shut off the charging, as observed in that video, while there was still clearly some more charging to do on cells.

I anticipate this is why (pretty much probably from new because range has not changed) that my scoot has had less range than I thought it should (see here). I will be interested to see if my scoot has better range after this.

This underscores why you DO NOT want to be regularly "saving your battery" by unplugging (or turning off with a timer) your charger before it gets to some some magical number.

So I don't know if this is a malfunction of the BMS or if the BMS is a simpler one from times gone by when balance charging (as observed on the Mercane Dual motor) here:


Current state

So now I'm doing individual "parallel bundle cell" charging to bring up those which are down with my dedicated LiPo charger. I've given all the lower cells about an hours charge at 3A to bring the pack into balance.


As this is still happening (I've got a few to do still) I'm planning to simply re-balance the pack and will then re-wrap and re-install and see how it goes before deciding if I need to replace the BMS or not.

Side Note

I found that the nomenclature on the battery had INR in the name on it:


this makes me wonder if this is the newer chemistry with Nickel in it?

INR - NMC - Lithium manganese nickel

The reigning champ of the 18650 vaping world. This chemistry adds nickel to the IMR chemistry above, making it a "hybrid" chemistry. It combines the safety and low resistance of manganese and the high energy of nickel.

The resulting battery chemistry gives you a reasonably high capacity and a high discharge current. Importantly for vapers, the chemistry is very stable, meaning that you don't need expensive built-in protective circuits. 

There is extensive innovation within this chemistry as well. Sony, Samsung, and LG are all developing next-gen INR batteries with different ratios of manganese, nickel, and cobalt. 

which is very interesting.

Conclusion

I might give it a few test runs and see how long it takes to get out of balance again.

I'll keep you posted

PS: job done and charging is now behaving properly see my post here.
PPS: no job wasn't done, follow links from there.

Thursday, 9 January 2020

Air B & Beware

Public Service Announcement

This post is a bit different to my usual post it stands to offer caution to anyone who's a user of Airbnb. Now this is nothing against Airbnb but more a caution for you to take precautions to protect yourself from the subsequent accusations of Hosts.

Recently I stayed at this place, as it happens it was my first ever Airbnb experience:



It looked nice enough in the pictures but fairly quickly a few problems emerged, to summarise them it went like this:

  • place was locked and apparently empty when I arrived, so I messaged the Host via the App (always use the app)
  • Host messaged me back saying he was just down the road and would be back in 5 min
  • half an hour later no sign and I messaged again, host replied he'd contacted his sister to let me in
  • eventually someone inside let me in and briefly showed me around.
  • much later a young woman arrived who identified herself as the Hosts sister
  • I asked when the Host was going to come home and was told "he's flown out to Sydney tonight" meaning that his above message can only have been a lie.
  • She was pretty unhelpful and it was hard to find anything to cook with (the house was very weirdly arranged)
That's it ... I left after 2 nights, this was in November.

Then on the 28th of December I get a message from the host accusing me of stealing property (a laptop and a yellow bag). I confirmed back to the host "were you accusing me of stealing this" to which the answer was yes, and that they had been photographing me and had pictures (which is illegal  in the state I live in). The host then said to return it or else they would report this to the police.

So rather than reply to them "good, please do so" I decided to instead contact (or as the current wanky words are "reach out to" (FMD) ) Airbnb  and report this.

As it happens I know that I didn't steal their laptop, as I had my own, which is a Linux based system. This has the advantage of allowing me to access the data about all WiFi systems my laptop connects to, stuff like this:

[connection]
id=******
uuid=6c1d9030-b5e1-4bfa-a49d-90c090c7e113
type=wifi
permissions=user:chris:;

[wifi]
mac-address=****
mac-address-blacklist=
mode=infrastructure
ssid=****

[wifi-security]
auth-alg=open
key-mgmt=wpa-psk
psk=****


which more or less allows me to identify their router uniquely and demonstrate clearly that my laptop was actually there. This makes a pretty solid case that any (illegally obtained) pictures of me carrying a laptop are going to show me carrying my own fucking laptop.

My message then is this...

So all this leads me to where I now see pretty clearly that after you leave an Airbnb the host can wait weeks (over a month in this case) before communicating with you to make accusations, threats and attempt to extort you.

So my advice is to do your best to enable you to have something to demonstrate you were innocent of any charges. If possible record with your phone any irregularities and be prepared to immediately cease contact with the host (do not argue with them) and go through Airbnb.

As it happens I got a plain and simple reply two weeks later saying:
 "...I reach out to your Host, and he mentioned that he already received your message and leave this case."

Which was unclear and pretty bad English. I sought clarification on what that meant, and apparently it meant they were withdrawing their accusation, but I can only imagine how much more frustration would have occured had I needed  to engage more.

No apology from the host, no apology from Airbnb.

To me this sort of shit is unacceptable, and in my research I uncovered that I'm not the only one who's encountered dodgy stuff: as you can read here ...

I will be from now on protecting myself against more of this sort of shenanigans from Hosts; I suggest you do the same too.

Best Wishes