Search found 112 matches

by Username1
Apr 26 2020 9:26am
Forum: Motor Technology
Topic: Low Power, High Regen?
Replies: 20
Views: 702

Low Power, High Regen?

I'm considering to build an LTO (lithium titanate oxide) ebike using 40ah cells... Since the energy density kind of sucks, i want to keep the power low (around 20mph). But seeing as these cells can take a massive 10C (400a), i want to take advantage of regen braking. I don't mind using an oversized ...
by Username1
Apr 26 2020 8:56am
Forum: EBike Technical
Topic: Does acceleration affect range?
Replies: 14
Views: 575

Re: Does acceleration affect range?

So is the idea that you will always use the same amount of energy to accelerate to a certain speed (regardless of power level used), but if you do so quickly (high power) you will have traveled less distance, therefor reducing your total range compared to slower acceleration?
by Username1
Apr 26 2020 8:29am
Forum: EBike Technical
Topic: Does acceleration affect range?
Replies: 14
Views: 575

Re: Does acceleration affect range?

Simple answer, yes, acceleration is something that drains the batt. faster, much faster than a ride with much less acceleration. Absolutely. On 20A, I get 40 miles... but on 100A, I get 15 miles..but the acceleration is stupid fun. Same top speed. Would this be the case even on a completely flat ri...
by Username1
Apr 26 2020 7:57am
Forum: EBike Technical
Topic: Does acceleration affect range?
Replies: 14
Views: 575

Does acceleration affect range?

So obviously your speed greatly affects range. But i was thinking, does your acceleration make much of a difference? Using high power to accelerate obviously draws more energy (per second), but the acceleration also ends faster. Then the opposite is true for low power acceleration. Assuming you had ...
by Username1
Apr 26 2020 7:16am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

Alright i'll start checking out real power supplies properly as you suggest then. I didn't get too deep into the searching since i didn't quite understand what i needed. Now i have an idea of what i'm looking for, thanks.
by Username1
Apr 25 2020 1:14am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

So i know used Ex telecom and server room type power supplies were recommended for their reliability compared to lower quality chinese stuff... But what about car audio battery chargers, like the one i linked? These are made for powerful (i'm assuming high end) car speaker systems. Are they really c...
by Username1
Apr 24 2020 6:07am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

Oh i didn't mean like what's going on in detail with what parts it's using and all that. I just wanted to understand how a cc/cv charger works and how it interacted with the battery (basic principles). Seems like i'v got the gist of it finally.
by Username1
Apr 24 2020 3:46am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

I actually am trying to understand what happens inside the black box. So from that perspective... It seems like with cc/cv charging, you start by setting max Amp and Volt limits. The charger will then monitor it's Amp output and adjust (raise) output Voltage as needed to maintain that max Amp limit....
by Username1
Apr 24 2020 12:40am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

@sunder Amazing explanation. I think i'm understanding way better already. So basically if you took a discharged battery and began charging it at it's maximum voltage, the battery would (on its own) suck in massive amps, because the difference in voltage between the charger and battery is high. This...
by Username1
Apr 23 2020 4:05am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

Didn't realize there wasn't a hardware difference. I did look up those companies you recommenced but i didn't find anything high enough amp. I know you can stack them in parallel but it think it required too many to be practical or cheap enough. I was editing my last post when you replied... What do...
by Username1
Apr 23 2020 3:04am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

This isn't for anything too crazy. It would be used in a scooter type ebike, so size/weight is not a big deal. My main reasons for LTO are because it would be used both heavily and in subzero temperatures. After looking at my space option further, i think i'v decided on 10s 60AH yinlong cylindrical ...
by Username1
Apr 22 2020 4:05am
Forum: Battery Technology
Topic: Questions about CC charging
Replies: 12
Views: 659

Re: Questions about CC charging

I just don't understand the purpose of the CC phase. Why not just use CV mode, aka set the voltage to maximum battery voltage, provide a constant amount of amps, and let the battery draw what it wants? Then either disconnect when maximum voltage is reached (for fast charging), or let it continue cha...
by Username1
Apr 22 2020 1:25am
Forum: Battery Technology
Topic: Questions about CC charging
Replies: 12
Views: 659

Questions about CC charging

So i learned that a constant current method varies the voltage applied to the battery, in order to maintain a constant current. My question is what does constant current mean? Does this mean constant amps or constant watts? Also, regardless of the answer to the above question, why would you need to ...
by Username1
Apr 20 2020 5:58pm
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

So i realized i would actually need 10s (not 12) due to space. This means 24v nominal, so i looked into lower voltage chargers/power supplies some more, and found there's some very high amp ones in 12v... I found this 12v 250a battery charger. https://www.taramps.com.br/en/produto/procharger-250-amp...
by Username1
Apr 20 2020 12:49pm
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

Yeah but other than the size/weight, it's almost the holy grail of batteries. The density isn't even that bad, i mean it's a lot better than lead acid. For my use 1kwh with that size/weight is totally fine and in exchange i get a super battery. - not affected by extreme temperature - lasts basically...
by Username1
Apr 20 2020 10:56am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Re: Charging LTO at Max Speed?

Yeah but you gotta use less to not trip the 40a breaker. In my example you only need 6,900 which is fine i think.
by Username1
Apr 20 2020 10:16am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 118
Views: 8581

Charging LTO at Max Speed?

I recently learned about LTO and and i'm really impressed with it, so much so i'm considering making my own battery... But my question is about the possibility of charging at full speed (10 minute at 6c). I didn't see any examples of people trying this, so i'm wondering is there anything preventing ...
by Username1
Apr 18 2020 3:00am
Forum: Battery Technology
Topic: Advice for homemade 13s8p pack? (low power)
Replies: 1
Views: 208

Advice for homemade 13s8p pack? (low power)

I want to build a bigger battery for my (stand up) escooter using 18650 cells. The power would be just 500w with 48v, so the purpose is longer range... I'm thinking of using 13s8p (104 cells). From what i understand, the higher capacity cells are around 3.4ah and must be used with low c rates? So th...
by Username1
Apr 18 2020 12:22am
Forum: Stand-up EScooter/ESkateboards
Topic: Upgrading scooter from 36 to 48v?
Replies: 1
Views: 622

Upgrading scooter from 36 to 48v?

I have a 350w 36v scooter which goes about 25kph. I am planning to build a much bigger battery for longer range, but i would also like a little bit more speed. I'm thinking of increasing the volts to 48 (500w), which should give about 32kph i believe. Some questions about this... - Would i be able t...
by Username1
Jan 04 2020 12:28pm
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

Sort of. But when the iron is closing in on the magnets, there is a force that is advancing the wheel. When the iron is receding from the magnets, there is a force retarding the wheel. These make you feel a torque ripple, but the NET (average) torque over time is zero. However, as the magnetic fiel...
by Username1
Jan 04 2020 1:02am
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

@spinningmotors Just one thing you may have missed, is that this is not a conventional axial flux motor with axial (side) rotors poles. The rotor poles are actually radial (right in the middle of the stator). Easy to miss as this is a very unique design.
by Username1
Jan 04 2020 12:04am
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

@billvon The way i understand it (I could be wrong here), "drag" happens when the magnets pass by the iron stator poles while the motor is off. Because iron is attracted to both negative and positive magnetic fields, there is no counteractive force. This attraction simply causes "drag...
by Username1
Jan 03 2020 10:00pm
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

@sn0wchyld I guess i was not only comparing this specific configuration to others SRMs, but also pointing out the benifits of SRMs in general compared to BLDC motors which have a monopoly in small EVs. When talking strictly about this specific design over a normal SRM, it seems we both agree that it...
by Username1
Jan 03 2020 11:53am
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

Taking the novel aspect of the construction as a given, im not seeing a huge benefit here (though I have to state I'm not a motor expert so I could easily be missing the forest for the trees). One HUGE benefit i see is 0 drag when not powered (applies to SR and induction motors in general). With th...
by Username1
Dec 31 2019 10:09am
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

Re: Homopolar Switched Reluctance Motor

Not sure what you mean by "actual article". I linked the full scientific paper discussing this motor with all the info included. Clicking your link brings up a blank page for me. But it's definitely not an induction motor, it's a switched reluctance motor (says so right in the paper's titl...