heres the lithium
OwnerMatthew Lacey
Owner's Other EV1987 Toyota MR2 AW11
LocationPerth, Western Australia Australia map
Email email image
Vehicle2006 e-max sport
Motor 1500 watt synchronus hub motor 3-Phase AC
2000-2500 watt continuous, very high max theory 7000watt highest usage. currently does 6.3kw when batteries are fully charged.
Controller standard emax controller
was 48v when stock. i now run it at 60v. current limit has been increased to 125A (6000w)
Batteries15 Thunder Sky lfp40AHA, 60.00 Volt,
15 cells 40AH LiFePO4 with two 20AH 12.8v YESA batteries wired in series/parrallel.
System Voltage60 Volts
Charger kipoint 48v Lead acid charger 8A + 7.5A charger fo
The bms is wired so that it is compatible with any standard lead acid charger.
A 7.5A charger is used for the 2 YESA packs.
Heaterlol its a bike....its also Perth
InstrumentationDrainBrain: volts, Amps, AH, Whr
instrument panel: speed, voltage
paktrakr: Amps, vpc, volts, battery failure warning, data logging
V3 data logger: Volts, Amps, AH, data logging.
Top Speed45 MPH (72 KPH)
when run at 60V with fully charged batteries, will do 70kmh on a flat under own power
Accelerationawesome now that I've shed 30kg (25%) weight and upped power by 70%. I used to get in the way of they get in the way of me.
Range25 Miles (40 Kilometers)
in theory goes 60km (40miles) with booster pack. furthest i have ever gone is 57km draining 36AH from the pack. Now its winter the batteries sag more under load so winter range is 40-50km depending on weather. due to reduced capacity in one or more cells, range is now 40km. the addition of a paktrakr will let me determine it this is an outlier.
Watt Hours/Mile68 Wh/Mile
bikes pulls 45whr per km from the pack on my commute from Welshpool to Thornlie at 60-70kmh. Based upon what AC kwhr counter tells me so far (only used it for 3 charges) im getting 55whr/km from the mains.
EV Miles
Current:9,000 Miles (14,481 Kilometers)
Seating Capacity1 adult
Curb Weight250 Pounds (113 Kilograms)
will have to weigh some day. I've read somewhere that these bikes weigh 150kg in stock form. I have removed 8 batteries (6.5kg each) and replaced them with a LiFePO4 pack that weighs 23kg.
Conversion Timeshould be none since OEM build, but kinda did some mods...well lots of 25 hours
Conversion Cost$3300(bike and helmet and registration)+$3000(Thunderskys)+$200(Drainbrain and shunt)+$100(new caps)+$600(paktrakr)+$3000(various failed experiments kinda related to this bike).
blew up my stock emax charger by doing something stupid, so had to replace with a charger bought from kipoint off ebay.
Also ordered a paktrakr for measuring and logging voltage sag of the lithiums under load. will use to measure internal resistance to see how believable thunderskys 10C claim is. Will be using these cells in my car conversion later this year.

much has happened since the last update.
passed 8500km on my thundersky batteries.
killed one cell...then it raised itself from the dead right before i was going to cut it open.
turns out corrosion on the terminals was causing large voltage drop under load.
Tip for young players:
1) tin your copper inter-connects with solder to prevent oxidation of the copper and to lower junction resistance.
2) dont let water get anywhere near everything

as usual i break my own rules.

overdischarged the pack till every cell was less than 2.5v. It recovered and has been operating fine ever since.

this pack is in for an early death, though as a evaluation and learning pack, this is to be expected.

i found out the Paktrakr was no good to use with my BMS.
The paktrakr draws its operating current from some of the cells but not all, resulting in slight imbalance.
unfortunately my BMS was never designed to balance more than 0.05AH/charge, whereas the Paktrakr pulled my batteries out of balance by 0.25AH/day.

just fixed the speedo cable, that was broken for 1-2000km or so.

discovered the hub motor has no torque arm.
as a result of increasing the power output, the hub motor turned over relative to the chasis.
had to reinforce the mountings to take the extra torque.

increased battery side current limit to 125A.
max power going to the controller is now 125A@48v = 6kw.

added this data logger:
WebPage /> will soon have logged voltage and current for the TS pack.

speedo isnt working again, this time its the speedo unit itself.
after changing the rear hub motor for my spare due to a flat tire, i have developed a shudder at 60khm.
the last time i had this i had eggs in the front tire.
checked both tires, neither are abnormal, so my indicate an imbalance or mis-alignment in the rear wheel :S

just reinstalled the paktrakr, this time with a switch to turn it off to avoid the balance issues it caused me last time.
it immediately indicated the second cell in the string was reaching full charge, which might explain my loss of range. further investigation will be needed.

in the next few months i will upgrade my bench tester:
WebPage /> with the 500w booster, so i can bench test the cells at higher currents.
the one cell i have tested, that i have previously thought to have failed, appears to be fine, and within specification.
this might suggest the failure mode of LiFePO4 is more a reduction in striction point rather than loss of AH capacity. (striction point is the discharge rate at which the internal resistance increases, due to the max ion exchange rate being approached.)
meaning the cell might pass at 20A load, but not the 50-100A load it would see in the scooter.

I had a flat today.
after removing the rear wheel, i noticed that the counter torque brackets had been bent outwards.
it seems increasing power causes mechanical grief.
im having a boiler maker weld the brackets on, and increase the thickness.
hopefully this will stop any further damage.

also, after a disasterous ride, i now know that my TS pack is now only good for 30AH@100%dod.
more info later

The bike has now been decommissioned for the following reasons:
I recently found out that under the LA ADR category, this scooter is legally only allowed to go 50kmh. the new Emax scooters are LC category, meaning theres no speed restriction.

I recently aquired my motorbike licence, meaning im looking for a bike with more power.

the number of flat tyres i have had due to poor quailty tyres availiable in 10" size

I will soon own a newer model emax capable of a much higher top speed and better build quality.

code by jerry