I think my problem right now is transmission. I have 16T to 30T and I need 6000rpm to get 167km/h. But the problem is that over 3200rpm controller is exchanging torque to rpm.Hillhater wrote:Thats a damm good Result for a kart.
Karts dont go well on 1/4 mile runs. Not enough rubber for good traction off the line and poor aero due to the sit up seating position down the the end of the run...Normally , very little speed increase after the 1/8 th mark.
Its is actually 32S2P A123 20Ah pouches, I will add 2S2P to the pack this winter to get voltage a little higher.eTrike wrote:Excellent build and 1/4 mile result A few questions for you please:
Is your battery 28S3P?
No, 1/4 mile was just for the fun, I intend to use kart in race track where max speed is around 130km/h.Are you planning aero mods?
Cells were 100% charged, just LiFePo4 voltage is 3,3V when resting, 3V when under normal load and 2,6-2,8V when under heavy load.In your video it looks like your cells are near 50% DOD. Have you been able to try with a full charge?
yeah, it seems nr 32 cell pair has some issues. Actually they sit at the end of the pack facing rear wheel. I'm replaceing them if I add 2 more cell pairs this winter.eTrike wrote:Thanks for your reply. I've got a 27S3P pack here which will see only 10kW in next build. Previously used in 30kW peak setup. They have an easy life compared to yours.
I typically charge to only 3.45V/cell but they'll rest at 3.55+V if I charge fully. Once it drops below 3.375Voc the voltage drops fairly slowly to ~3.15VoC near the LVC cliff.
Is there an issue such as greater resistance in your endmost cell (far right on vid?), or is that cell facing forward and exposed to cold airflow?
For my need it delivers well. I already bought 3 more unit for my second pack.catacon wrote:nuxland,
Have you been happy with the ZEVA BMS? I'm considering using it for a similar pack.
nuxland wrote:Was racing this sunday with retro karts again
Big thanks to Craig for selling me Zero 75-7 motor and Biff for helping me out with the config when I was stuck and all hope were lost
Had to configure sevcon "profile 1" to 4400rpm limit, because thats when field weakening starts. And with it the motor will heat up more quickly.
I also had 48% torque demand on that profile. But as I have a little button on wheel from what I could trigger "profile 2" where torque demand was 100% and rpm limit 6000 then it was fun using it 4 times in the race. But as you can see each using of it raised motor temp for 7 degrees instantly.
Here is video with data. I struggled with the motor conf in first 2 races, thats the reason I was easy on first two laps with the throttle in final race.
I have two extra temp sensors that are measuring motor external temp and controller extra heatsink temp. I have covered the motor sensor with foam tape so it does not gets cooled. Does anybody know why Sevcon's motor temp is 10 degrees higher than controller one when both are not used and should be at ambient temperature?
I have it configured as KTY84 in combobox as it should.
Total weight of the kart including me on board was 234.8kg, so its should be little lighter that zero motorcycle?
I'm using 3kw elcon charger and it takes about 50 minutes. Depends how much I use up the battery.LuigiDesing wrote:Hi nuxland,
How long does you take to charge the batteries?