Search found 6705 matches

by john61ct
Oct 17 2021 10:13pm
Forum: Battery Technology
Topic: Molicell P42a 20s13p Build
Replies: 6
Views: 289

Re: Molicell P42a 20s13p Build

EIG are lithium, li-ion

as are most cans

You just mean pouch format in general as opposed to cylindrical?
by john61ct
Oct 17 2021 11:23am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1479
Views: 224190

Re: kWeld - "Next level" DIY battery spot welder

nice looking work there!
by john61ct
Oct 17 2021 8:16am
Forum: Battery Technology
Topic: BMS needed on four 12v batteries in series?
Replies: 2
Views: 69

Re: BMS needed on four 12v batteries in series?

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club.

NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

by john61ct
Oct 17 2021 8:15am
Forum: Battery Technology
Topic: BMS needed on four 12v batteries in series?
Replies: 2
Views: 69

Re: BMS needed on four 12v batteries in series?

no only for lithium

But going to bigger Ah, lower voltage units would be much better

2 strings max, maybe three
by john61ct
Oct 16 2021 8:07pm
Forum: EBike Non-hub Motor Drives
Topic: new cyclone 3000 w mid-drive kit?
Replies: 3546
Views: 476946

Re: new cyclone 3000 w mid-drive kit?

john61ct asks, . Does anyone think the difference gives any real-life advantage other than say 2-3 mph higher top speed? Dear John, Likely anyone that can do the simplest of energy calculations can figure going from 18s to 21s is a 16.67% increase in watt hour capacity. If you do not squander this ...
by john61ct
Oct 16 2021 4:03pm
Forum: Battery Technology
Topic: Hot Swappable Battery - 1000A @ 12v or 24V?
Replies: 13
Views: 288

Re: Hot Swappable Battery - 1000A @ 12v or 24V?

Thomas and Betts or Panduit make. Flexibar. Ect. Are these specifically for Hot Swapping modules in and out while the Mecha is operating? That's what I meant. > EV packs have a much lower fire risk than you think. I do not mean anything to do with externally inflicted ignition. And I do not think t...
by john61ct
Oct 16 2021 3:36pm
Forum: EBike Non-hub Motor Drives
Topic: new cyclone 3000 w mid-drive kit?
Replies: 3546
Views: 476946

Re: new cyclone 3000 w mid-drive kit?

That voltage range matches up exactly with the Nucular usage feedback,

de-rated 21S for those willing to push the limits

20S for those wanting to not worry about the issue at all.

Does anyone think the difference gives any real-life advantage other than say 2-3 mph higher top speed?
by john61ct
Oct 16 2021 2:31pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1479
Views: 224190

Re: kWeld -

And where is it written about 3kA? This is my personal experience Could you link to, or post a thread with HowTo details? I am particularly interested in spotwelding copper to cans, using nickel or plated steel as required I use super capacitors capable of delivering more than 3 kA. Idm IRFS7430 is...
by john61ct
Oct 15 2021 10:46pm
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 128
Views: 9087

Re: True FOC: definition and examples

No I'm not looking for credentials just practical knowledge and establishing my own understanding. It is not convenient to go physically browse in uni bookshops, sounds more archaic than recommending Napster for music 8-) Full online courses as you say even MIT level lectures, everything of course i...
by john61ct
Oct 15 2021 8:16pm
Forum: Battery Technology
Topic: Hot Swappable Battery - 1000A @ 12v or 24V?
Replies: 13
Views: 288

Re: Hot Swappable Battery - 1000A @ 12v or 24V?

Those EV packs look fantastic, but besides the high fire risk, will likely not be available reliably in the future harder to integrate with third party or your custom management / monitoring / protection circuitry or temperature management systems Also, maybe not as flexible in giving you the voltag...
by john61ct
Oct 15 2021 8:04pm
Forum: Battery Technology
Topic: Hot Swappable Battery - 1000A @ 12v or 24V?
Replies: 13
Views: 288

Re: Hot Swappable Battery - 1000A @ 12v or 24V?

Those CALB are as good as gold, just go to bigger cells to get more power. Unless the weight density is a critical factor. With EV packs based on li-ion 3.6Vnom cells, you have 100x higher thermal risk and your cycle lifespan is a tenth that of LFP. As far as the hot swapping, need to do that in par...
by john61ct
Oct 15 2021 1:06pm
Forum: Battery Technology
Topic: Large Charger for 21700 cells, 50-100 cells simultaneously
Replies: 4
Views: 178

Re: Large Charger for 21700 cells, 50-100 cells simultaneously

OK, lots of bits to untangle here, as your understanding grows you will learn how to properly phrase the right questions which of course is 90% of the way to the right answers. And you may change your design along the way. IR testing is very nebulous, not just accurate gear required but very strict ...
by john61ct
Oct 15 2021 12:36pm
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 128
Views: 9087

Re: True FOC: definition and examples

Many moons ago i done a 3 year industrial installation engineer course OK I'd never heard of "installation engineer" seems to be a type of mechanical engineer, but courses are not necessarily focused on electric motors. Maybe a UK specific term? Some googling leads me to "Power Elect...
by john61ct
Oct 15 2021 11:52am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1479
Views: 224190

Re: kWeld - "Next level" DIY battery spot welder


myxomop wrote:
Silvaticus wrote:
Oct 15 2021 9:38am
And where is it written about 3kA?
This is my personal experience
Could you link to, or post a thread with HowTo details?

I am particularly interested in spotwelding copper to cans, using nickel or plated steel as required
by john61ct
Oct 15 2021 11:47am
Forum: Large EV General Discussion
Topic: Students’ solar-powered camper van turns heads on 1,800-mile road trip
Replies: 0
Views: 78

Students’ solar-powered camper van turns heads on 1,800-mile road trip

Dutch team designed and built two-person van with kitchen, bed, shower, loo and range of up to 450 miles a day

https://www.theguardian.com/environment ... -road-trip
by john61ct
Oct 14 2021 9:23pm
Forum: Battery Technology
Topic: Hot Swappable Battery - 1000A @ 12v or 24V?
Replies: 13
Views: 288

Re: Hot Swappable Battery - 1000A @ 12v or 24V?

That 1000A rate by itself is a meaningless spec C-rate is a better unit, current compared to what Ah capacity? Running for how long? 1000A for half a second, with continuous only 50A? Allowing for how much destruction of the cells? Or (same thing) how much temperature rise? 12V would mean 12kW, 24V ...
by john61ct
Oct 14 2021 9:11pm
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 128
Views: 9087

Re: True FOC: definition and examples

I prefer to spend a few months going through course materials, following a well planned curriculum ideally from well recognized universities.

I just don't even know what kind of courses teach this stuff.
by john61ct
Oct 14 2021 10:06am
Forum: EBike Non-hub Motor Drives
Topic: new cyclone 3000 w mid-drive kit?
Replies: 3546
Views: 476946

Re: new cyclone 3000 w mid-drive kit?

Then don't mess around for no reason.

Rule of thumb should be only go up to the voltage you need for your desired top speed.

Cheaper controllers, safer for circuits and humans, better efficiencies when average speeds are way below peak speeds needed.
by john61ct
Oct 14 2021 8:07am
Forum: EBike Non-hub Motor Drives
Topic: new cyclone 3000 w mid-drive kit?
Replies: 3546
Views: 476946

Re: new cyclone 3000 w mid-drive kit?

Well ultimately, your throttle control determines the voltage

if you're willing to risk burning the motor, add motor voltage & temp sensors to watch and

just take it slow?
by john61ct
Oct 14 2021 7:48am
Forum: Motor Technology
Topic: FLIPSKY new 20s 100A tiny controller (vesc based)
Replies: 80
Views: 2750

Re: FLIPSKY new 20s 100A tiny controller (vesc based)

Could an over temp de-rating or cutoff control be added to help test for real-world ampacities?
by john61ct
Oct 14 2021 7:10am
Forum: Items Wanted
Topic: Sourcing 21700 cells from Korea, Japan or China, 10,000 cells
Replies: 15
Views: 253

Re: Sourcing 21700 cells from Korea, Japan or China, 10,000 cells

I would assume the pricing issue requires self-importing from close to the source. Certainly the US market is near non-existent at this point, IMO due to our torts law liability issues. At that volume level, there are few suppliers that are reliable/trustworthy across a huge selection. So I believe...
by john61ct
Oct 14 2021 7:03am
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 128
Views: 9087

Re: True FOC: definition and examples

I taught myself this mid 2020 from scratch. LOL we have a skyscraper's worth of difference of meaning of "scratch" I did not even mean understanding FOC itself, I am a near complete noob with motors and controller basics, barely remember any high school math I just meant the 101-level und...
by john61ct
Oct 14 2021 6:38am
Forum: Battery Technology
Topic: Large Charger for 21700 cells, 50-100 cells simultaneously
Replies: 4
Views: 178

Re: Large Charger for 21700 cells, 50-100 cells simultaneously

Cell count alone does not help. Unless you mean at 1S voltage? Are they LFP at 3.2Vnominal, or the 3.6-3.7V li-ion type? If at a higher voltage, do you need a balancing charger, or will you use other circuitry to handle that? what is the series count? e.g. 16S LFP is 48Vnom, 7S li-ion is 24V Do you ...
by john61ct
Oct 13 2021 9:21pm
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 128
Views: 9087

Re: True FOC: definition and examples

Wow, yes thanks for trying, but I did not grok any of that, at all. If I were to try googling for textbooks and courses that would get me started not necessarily MIT level stuff but at least approaching understanding the jargon what are the course / program keywords / names? Besides electrical motor...