Happy New Years All!

AlexLTDLX

AlexLTDLX

Administrator
Staff member
May 2022 be better for all of us! That said, I know a lot of us are being held up for various reasons - weather, waiting on parts, etc. I will confess that the last few years have been tough for me. But things are getting straightened out and I'm hoping to see a lot of progress not just from myself, but from all of you guys - the "early adopters." I believe this technology will do nothing but continue to grow, and I'm in a position to say there's a very good likelihood that my own progress will accelerate dramatically.

Cheers, y'all!
 
Happy New Year, All!

Thanks Alex!

The ripple effect of Covid is still having effect on all of us, either directly or inderectly. I personally am looking more "aggressively" into 2022 trying to "fix, recover and improve" on many fronts too.

As for this project: like with other tinkering projects the prep phase is taking some healthy time and this is GOOD! Since many engineering disciplines are involved here and I am not expert in all of them it helps immensely digesting the different experiences and evolving/innovating in part solutions and details!

There were times in the last month where I regretted going with the TP Power 1KV model ... too quickly. (well ... it is not too far off for the first baby steps, but a LMT3080 2 pole with 14kW continuous would have been better! Reason: 6poles need 3 times the compute power for FOC then 2poles ... and the smaller power rating of the TP I have most likely will produce some thermal bottlenecks)

Then ... I was just an inch from ordering an APD esc ... after finding out that the VESC compute platform is saturated with 150k eRPM (which it would see with a 6pole TP motor!).
Then ... Alex melted both APDs ... and had some more in depth conversation with Frank@Trampa which has moved the VESC one more place up (again, I hope the 75/300 holds up ...).

Regarding battery chemistry: not only is it hard to ship "anything battery", but somehow I was not impressed with the bulkiness (low energy density) of the LTOs ... and confused about the different/inconsistent results people were getting with Yinlongs e.g. (only that particular Lishen cylinder was good?).
So ... after digging further I started to prefer the "compromise" lifepo4 ... but not just any, but the most innovative. There is something to A123s nanophosphate advantage (and to the next evolutionary ultraphosphate!).
And I came to the conclusion that rolling the layered substrate mats to cylinders is in fact introducing more challenges for the manufacturers to be overcome (and more potential inconsistencies!). So the A123 pouch cells (with automotive history!) came into spotlight for me ...

(EVE and CATL have some bulky and quite expensive (and reportedly very good!) lifepo4 prismatic modules whith HIGH capacity which can be discharged nicely at 1C (but would need 2-3p to feed our demands)... but really bulky and expensive!)

And now ... after Alex trying to get the varying internal resistance (voltage drop) of the cells for high discharge rates under control ... I feel even more relieved to not having stressed out to get the Lishen cylinders. (well, they were fun though 🤣)
(The trick is in the p!!! find a setup which distributes the load accross multiple cells!)

I am still horrified thinking of overstressed LiPo cells in the trunk ...

Next on my list:
- cell testing, grouping, top balancing, battery build.
- mechnical stuff like beltdrive fixtures which pulley (underdrive?) and mounting brackets
- final decision re ESC
- Jikong (JK) 600A active smart BMS
- my Odroid super all in one controller build and programming
- all the cabling and "termination hardening"
- (for later if all turns out good: onboard Sterling Power Ultrabatt charger)

crap ... loads of work ... if everything goes as slow as with the batteries 🤣
 
Lol... I hear you. Frank now brought up the point that "6 pole motors" can be tricky with VESC... we'll see, I guess. I've been screwing around with my load tester the last two evenings trying to get the resistance of it as an assembly as low as possible - turns out, the 3d printer leadscrew/brass nut are pretty torque limited. I may have to switch over to a more conventional threaded rod. I'm having a hard time getting it under .3 ohms (I can get it under .1 ohm, but with inconsistency and difficulty with the current lead screw. The most current I've been able to draw from 1 LTO cell at 2.4 volts has been about 80 amps. Even that math doesn't even work right - that should be .03 ohms, but somehow I can't seem to get that on the milliohm meter.

My resistance test function on the one charger I have that has that feature seems to vary a lot. I'd rather just have a direct voltage drop reading under load.

To top it off, it's been raining the last 4 days so I can't even finish the LED headlight test video I've been trying to do for a while now. Such is life. At least this is WAY better than commuting 3 hours a day to go 28 miles combined - that's just no way to live...

To a better (and more productive/fun) 2022!
 
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