Search found 1391 matches

by Hummina Shadeeba
Mar 21 2019 12:13am
Forum: E-Vehicles General Discussion
Topic: Motor kv and efficiency
Replies: 5
Views: 143

Re: Motor kv and efficiency

With the 100 pieces of copper in parallel being each fed with a 10 amp supply then the total current before split into the parallel strands would be 10,000 amps to get the same torque as the single 100 turns of the single wire doing 10 amps. The motor constant km. Same ohmic loss to torque. I guess ...
by Hummina Shadeeba
Mar 20 2019 1:33pm
Forum: E-Vehicles General Discussion
Topic: Motor kv and efficiency
Replies: 5
Views: 143

Motor kv and efficiency

It makes senses that a lower kv would be more efficient as it will have less switching in the esc maybe but would it be any less efficient in the motor? It seems the grim simulator incorporates the whole system and not possible to isolate the motor. while it’s said a motor will have the same km rega...
by Hummina Shadeeba
Mar 20 2019 1:17pm
Forum: E-Bike Technical
Topic: MeanWell Mods - S-150-24
Replies: 51
Views: 16972

Re: MeanWell Mods - S-150-24

I’ve got many meanwell copies I got off amazon or alibaba that are broken and wondering if someone around the bay are would want them or help me fix some. Is it possible to alter some of these similar power sources for a lower current output as I imagine they would be able to survive longer. Ive got...
by Hummina Shadeeba
Mar 18 2019 8:44pm
Forum: General Discussion
Topic: using voltage sag as indication of bad battery
Replies: 11
Views: 179

Re: using voltage sag as indication of bad battery

Mark I guess with that method you would be comparing the voltage by eyesight of the different p groups. that would work and be pretty simple but I figured a computer that knew what sag to expect and incorporated the temperature effects and the cycles of the battery would be better than me looking at...
by Hummina Shadeeba
Mar 18 2019 3:52pm
Forum: General Discussion
Topic: using voltage sag as indication of bad battery
Replies: 11
Views: 179

Re: using voltage sag as indication of bad battery

the bms and even the vesc will typically shut down when the whole pack gets to a certain low voltage but it doesn't take into account the amp discharge that's being done to hit that low voltage cutoff so I could go up a mountain with a crappy battery and have huge sag and the vehicle will shut down,...
by Hummina Shadeeba
Mar 18 2019 3:30pm
Forum: General Discussion
Topic: using voltage sag as indication of bad battery
Replies: 11
Views: 179

Re: using voltage sag as indication of bad battery

it seems a simple program (to someone who doesn't know how to program). If it were to work it would save space, time, money possibly replacing a bms if it were good enough, no? No. The primary reason you need a BMS on a li-ion battery is to monitor for cell imbalance, not for remaining life. it wou...
by Hummina Shadeeba
Mar 18 2019 12:34pm
Forum: General Discussion
Topic: using voltage sag as indication of bad battery
Replies: 11
Views: 179

Re: using voltage sag as indication of bad battery

it seems a simple program (to someone who doesn't know how to program). If it were to work it would save space, time, money possibly replacing a bms if it were good enough, no? surprised no one has tried making it or probably someone has. what happens with current and voltage in the WHOLE battery wh...
by Hummina Shadeeba
Mar 18 2019 12:18am
Forum: General Discussion
Topic: using voltage sag as indication of bad battery
Replies: 11
Views: 179

using voltage sag as indication of bad battery

can cells be relied on to perform consistently enough that a software program could pick up on an increased voltage drop under a given current draw from a complete battery and indicate a problem? It would first have to get to know how the battery behaved then if a cell or cells were damaged or disco...
by Hummina Shadeeba
Mar 16 2019 8:05pm
Forum: General Discussion
Topic: Discharge unbalanced battery
Replies: 7
Views: 190

Re: Discharge unbalanced battery

Say toaster is 1000w. 1000w / 115vac = 8.69 amps 115v / 8.69a = 13.23ohms 4.2v / 13.23 ohms = 0.313a So discahrge will be pretty slow for a big back, but fairly quick for a single small cell. parallel more loads for faster discharge. would you use the full 115 in the equation or would it be the roo...
by Hummina Shadeeba
Mar 14 2019 10:26am
Forum: General Discussion
Topic: Discharge unbalanced battery
Replies: 7
Views: 190

Re: Discharge unbalanced battery

Aha. There’s the math. Thank you.
by Hummina Shadeeba
Mar 13 2019 8:50pm
Forum: General Discussion
Topic: Discharge unbalanced battery
Replies: 7
Views: 190

Re: Discharge unbalanced battery

I hooked the overcharged pack up to my toaster! Nothing happened that I noticed and don’t think they were discharging, maybe they were. 4v. And then I tried to hook it up to a couple different bulbs and nilch. Is the voltage too low? I’m surprised. Maybe need a much higher wattage bulb? Thanks Luke....
by Hummina Shadeeba
Mar 13 2019 7:24pm
Forum: General Discussion
Topic: Discharge unbalanced battery
Replies: 7
Views: 190

Discharge unbalanced battery

I’m forgetting. Can I hook an incandescent bulb (or something that will discharge faster than leds) directly to my p groups to balance them? I’m
Remembering a toaster. Can I directly hook the toaster up to the 4.2v pack to get it down to 3.9?
by Hummina Shadeeba
Mar 06 2019 2:38pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

Galvanic corrosion would be possible between the indium and the nickel plated steel of the motor case but the copper wouldn’t be in contact as it would of course be insulated. Supposedly nickel will cover with oxides which should be removed for best thermal transfer but that seems nitpicking. Indium...
by Hummina Shadeeba
Mar 04 2019 1:38pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

But what short? There’s no short I’m finding indium easily gotten on Amazon and not tooo expensive but strangely all the indium stores I’ve called haven’t heard of using it in this way and seems Ill have to do it myself to find out zamac3 I see. There’s a bunch of options it seems with indium maybe ...
by Hummina Shadeeba
Mar 03 2019 9:19pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

The tin alloys would be cheap and maybe straight tin would work with a melt temp of 400f, soft, thermal expansion less then indium at least, great thermal transfer. 400f is no problem for the amount of time the coils would be at that temp with the cast metal around it and can use standard 200c wire....
by Hummina Shadeeba
Feb 27 2019 1:02pm
Forum: Stand-up E-scooters and E-skateboards
Topic: AT-One electric inline skates (quick update Feb 2019)
Replies: 211
Views: 31765

Re: AT-One electric inline skates (quick update Feb 2019)

Id like having a tiny battery so less weight. I see panels for sale today are able to capture about 22% of the sun energy and the best panels designed capture about 44%.
by Hummina Shadeeba
Feb 27 2019 12:50pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

No spinning stator so no added spinning mass.
by Hummina Shadeeba
Feb 26 2019 9:15pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

Those resins if any good are expensive. I think the best thing u could do, and it would be easily stripable if it fails, as apposed to resin, is solder. Or some other metal. https://www.google.com/amp/s/www.electronics-cooling.com/2006/08/thermal-conductivity-of-solders/amp/ https://www.engineeringt...
by Hummina Shadeeba
Feb 26 2019 5:46pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

https://www.elektrisola.com/us/magnet-wire/magnet-wire-types/nema.html Essex wire has a good graph demonstrating how the wire is temp rated at 20,000 or maybe 40,000 hours use and for shorter periods of time will take higher temp. The link above has a “cut through temperature.” It’s 752f for the 240...
by Hummina Shadeeba
Feb 26 2019 12:00pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

You can see the mild steel wall beside the stator here that i would cast to and through then contacting the black aluminum hanger Mild steel is maybe half as conductive as zinc. There’s also a bunch of low melt alloys of aluminum and other metals I linked above and I haven’t found their thermal cond...
by Hummina Shadeeba
Feb 25 2019 4:49pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

I've had a think about what's going on. There's two frequencys, the pwm frequency that has a duty cycle to control the amount of voltage the coils see. Then there's the erpm, the voltage that the motor sees from the pwm signal will spin the motor at a certain rpm that is then calculated by the amou...
by Hummina Shadeeba
Feb 25 2019 3:24pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

Getting 100% slot fill is not possible with cyclindrical wire and filling the voids is very doable with cast metal

I’d rather transfer heat to the motor hub or straight out than through the rotor w ferofluid.

I haven’t been able to find anyone who has done this
by Hummina Shadeeba
Feb 25 2019 1:13pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

Du. Yea skin effect FROM eddy currents. But if the frequency were high enough to produce substantial Eddys in the windings I think the skin effect would be more of an issue than the losses beside in the zinc due to Eddys I’d have thought with an ironless motor and low inductance it would need a high...
by Hummina Shadeeba
Feb 24 2019 12:13am
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 50
Views: 1338

Re: Why never see metal cast around wound stators?

interesting the core only directs the field produced by coils. I understood the use of litz wire would be for high frequency. Higher than on a bike or skateboard hub motor. And in the case of a high electrical frequency the main benefit of the litz wire reducing skin effect. I’m instead reading abou...