mrkelkel
1 mW
- Joined
- Feb 17, 2019
- Messages
- 17
I got this e-moped last year as a village runabout for my dad, as his ride was getting a little long in the tooth.
It's a Segway-Ninebot N90C, which had a list price of about 5500RMB (860 USD). It came with a 72V 35Ah SLA pack, with an advertised range of 150km. That figure was of course BS, as we saw a max range of around 80km when cruising at its top speed of 60kmh. Energy consumption at full tilt with one rider, a pillion box and dual pannier bags was 30-32 Wh/km, which wasn't bad for a bike weighing almost 200kg.
Eventually Dad got bored with it, claiming that it was a bit too slow for his tastes, and it ended up back in my hands. I could deal with the mediocre top speed (patience is a virtue after all) but the range did leave something to be desired. I wanted a moped-cruiser thing for countryside trips and jaunts to the coast, and it had to be quiet, efficient and cheap. Thus came the modifications
One of the greatest attributes of cheap Chinese e-mopeds is that they use standardized SLA batteries for energy storage, which makes pack replacement a relative breeze. Another plus was that the Segway-Ninebot bikes sold pretty well across China (probably due to their connection with Xiaomi), which meant that there were many lithium pack-builders on the Chinese Internet selling packs with brand and model-specific connectors and mounting points. No more fiddling with soldering irons and building custom wire looms; everything was now plug-and-play. Supposedly.
6400RMB (1000USD) and two weeks later, my pack arrived!
Its a 74V (20S) 120Ah (8.88Kwh) pack utilizing CATL cells rated at 3C discharge, with an ANT BMS rated for 300A. A Powerpole 50A connector links it to the controller though, so that might need to be swapped out if I ever decide to go for a bigger controller.
It's been split into two parts for "plug-and-play" installation. The bigger pack takes the place of the four 35Ah SLA units under the footrest (floor? cargo area?), while the smaller pack goes under the seat, replacing the two 35Ah SLA units. Its acting as a single complete pack, with 7 cells in the small pack and 13 in the big pack.
Stripping down the front-end of the bike. The big pack won't fit without removing the plastic bits supporting the seat, and removing those bits require the removal of all the body panels and inner supports on the front end.
The big pack is now in. It's sized specifically to utilize the existing SLA mounting clamps and trusses, so mounting it wasn't a big deal.
What was a big deal was mounting the small pack within the seat assembly, which presented itself as a chicken-egg dilemma. To wire up the small pack to the rest of the bike, I couldn't have the seat in the way. But to secure the seat assembly to the frame, I had to remove the small pack first, as the mounting bolts had to be screwed in at the bottom of the assembly, and they couldn't be accessed when the small pack was above them.
Eventually I came up with a workaround. The seat assembly was bolted in place, and the small pack placed within the assembly. The pack wires were fed down the frame through factory grommets in the seat assembly, making sure they were protruding from the bottom of the frame. I ended up using a fibre optic routing kit, as guiding the wires down the chassis by hand and luck was a colossal PITA.
The pack wires were linked up, and I made a small "wiring burrito" from an old bathmat and velcro to protect the BMS signal connectors from the elements. The Powerpole connector is half-exposed, but they're good with ingress protection so it shouldn't be a big deal. I could end up making a bigger burrito down the road, but it works for now. Its attached high above the swingarm, so impacts wouldn't be an issue.
And it's done! The lithium pack weighs almost the same as the six SLA units, and energy consumption is virtually identical at 30-32 Wh/km. Theoretical range figures for the 8.88Kwh pack are thus 296-277Km, and real-world testing is backing up those values. Not bad for a bike that costs 11000RMB/ 1700USD in full.
Checking the remaining capacity and cell voltages on the ANTBMS app. A quick stint to a nearby mountaintop resulted in a 60km trip and a max altitude of 750m. I started the trip from sea level, and with regen braking activated, the trip ended with the pack one quarter empty. So with some heavy climbs and moderate regen braking, I could get a max range of 240Km. I hope my calculations aren't wrong, because that sounds very promising for long (<300Km) flat sea-level trips.
Taking the corgi out for a spin. She seems to love the new pack as much as I do!
This isn't your typical ES scratch-built masterpiece, but I do think this build proves that building a big-range electric scooter can be a relatively straightforward job. I might end up swapping out the stock 72V 35A controller for an 80A Fardriver, but that's neither here nor there. So for now I'll enjoy my 300Km(-ish) e-moped-cruiser at 60kmh
It's a Segway-Ninebot N90C, which had a list price of about 5500RMB (860 USD). It came with a 72V 35Ah SLA pack, with an advertised range of 150km. That figure was of course BS, as we saw a max range of around 80km when cruising at its top speed of 60kmh. Energy consumption at full tilt with one rider, a pillion box and dual pannier bags was 30-32 Wh/km, which wasn't bad for a bike weighing almost 200kg.
Eventually Dad got bored with it, claiming that it was a bit too slow for his tastes, and it ended up back in my hands. I could deal with the mediocre top speed (patience is a virtue after all) but the range did leave something to be desired. I wanted a moped-cruiser thing for countryside trips and jaunts to the coast, and it had to be quiet, efficient and cheap. Thus came the modifications
One of the greatest attributes of cheap Chinese e-mopeds is that they use standardized SLA batteries for energy storage, which makes pack replacement a relative breeze. Another plus was that the Segway-Ninebot bikes sold pretty well across China (probably due to their connection with Xiaomi), which meant that there were many lithium pack-builders on the Chinese Internet selling packs with brand and model-specific connectors and mounting points. No more fiddling with soldering irons and building custom wire looms; everything was now plug-and-play. Supposedly.
6400RMB (1000USD) and two weeks later, my pack arrived!
Its a 74V (20S) 120Ah (8.88Kwh) pack utilizing CATL cells rated at 3C discharge, with an ANT BMS rated for 300A. A Powerpole 50A connector links it to the controller though, so that might need to be swapped out if I ever decide to go for a bigger controller.
It's been split into two parts for "plug-and-play" installation. The bigger pack takes the place of the four 35Ah SLA units under the footrest (floor? cargo area?), while the smaller pack goes under the seat, replacing the two 35Ah SLA units. Its acting as a single complete pack, with 7 cells in the small pack and 13 in the big pack.
Stripping down the front-end of the bike. The big pack won't fit without removing the plastic bits supporting the seat, and removing those bits require the removal of all the body panels and inner supports on the front end.
The big pack is now in. It's sized specifically to utilize the existing SLA mounting clamps and trusses, so mounting it wasn't a big deal.
What was a big deal was mounting the small pack within the seat assembly, which presented itself as a chicken-egg dilemma. To wire up the small pack to the rest of the bike, I couldn't have the seat in the way. But to secure the seat assembly to the frame, I had to remove the small pack first, as the mounting bolts had to be screwed in at the bottom of the assembly, and they couldn't be accessed when the small pack was above them.
Eventually I came up with a workaround. The seat assembly was bolted in place, and the small pack placed within the assembly. The pack wires were fed down the frame through factory grommets in the seat assembly, making sure they were protruding from the bottom of the frame. I ended up using a fibre optic routing kit, as guiding the wires down the chassis by hand and luck was a colossal PITA.
The pack wires were linked up, and I made a small "wiring burrito" from an old bathmat and velcro to protect the BMS signal connectors from the elements. The Powerpole connector is half-exposed, but they're good with ingress protection so it shouldn't be a big deal. I could end up making a bigger burrito down the road, but it works for now. Its attached high above the swingarm, so impacts wouldn't be an issue.
And it's done! The lithium pack weighs almost the same as the six SLA units, and energy consumption is virtually identical at 30-32 Wh/km. Theoretical range figures for the 8.88Kwh pack are thus 296-277Km, and real-world testing is backing up those values. Not bad for a bike that costs 11000RMB/ 1700USD in full.
Checking the remaining capacity and cell voltages on the ANTBMS app. A quick stint to a nearby mountaintop resulted in a 60km trip and a max altitude of 750m. I started the trip from sea level, and with regen braking activated, the trip ended with the pack one quarter empty. So with some heavy climbs and moderate regen braking, I could get a max range of 240Km. I hope my calculations aren't wrong, because that sounds very promising for long (<300Km) flat sea-level trips.
Taking the corgi out for a spin. She seems to love the new pack as much as I do!
This isn't your typical ES scratch-built masterpiece, but I do think this build proves that building a big-range electric scooter can be a relatively straightforward job. I might end up swapping out the stock 72V 35A controller for an 80A Fardriver, but that's neither here nor there. So for now I'll enjoy my 300Km(-ish) e-moped-cruiser at 60kmh
