Search found 229 matches

by fatty
Mar 07 2021 10:44pm
Forum: EBike General Discussion
Topic: Hub motors and were they hide
Replies: 16
Views: 445

Re: Hub motors and were they hide

Thanks for all of the links. I'm increasingly concerned that the specs most of these show for a motor or wheel only there showing max speed and noise ratings but no pole pair information sensor information or even options for temp sensors...am I just asking to much? I understand that most of this s...
by fatty
Mar 07 2021 9:20pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

Of course, you might as well be right, that would depend on how I manage to pull off making of the shell, but battery emphatically is NOT a factor in air drag. Plus, by splitting the weight in a very different manner from what is real (not that I am proud of being obese, but that's one of critical ...
by fatty
Mar 07 2021 9:00pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

Now what the hell was THAT? Which orifice you've pulled that conclusion from? It takes 'less', not 'extra'. Desperate, indeed. What part of subtraction are you not following? 4080Wh - 3120Wh = 960Wh. It takes you 960Wh extra to lug around 40kg of electrification over 600km (aero). 1415Wh - 925Wh = ...
by fatty
Mar 07 2021 2:34am
Forum: Battery Technology
Topic: Charging LTO at Max Speed?
Replies: 54
Views: 6480

Re: Charging LTO at Max Speed?

This thread is an interesting mix of dangerous ideas/techniques (naked charging at 10kW) and battery/charger fundamentals... First reason is just because i want to. It's really cool and useful to charge an ebike in 6-10 minutes (and still have it last 10k+ charges). Well, it may be useful. It would ...
by fatty
Mar 06 2021 9:58pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

BalorNG wrote:
Mar 06 2021 6:46pm
As for what I'm building... does it *look* like a velomobile to you?
There isn't a formal, technical distinction. A velomobile is a streetable enclosed HPV. That's what you're building, as distinct from a streamliner (which I reference above).
by fatty
Mar 06 2021 9:54pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

I'm talking about your general conclusion that 'adding a motor to a bike is useless for long trips'. It is most emphatically not - even a simple a motor with an overrunning clutch plus a decent battery will be able to compensate much more than it's weight over VERY long distance, you just need to u...
by fatty
Mar 04 2021 10:03pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

Yes all these "ratings" are based on certain KcmIl / A. You can bend and fold the "rules" a little but not much and it will catch up wi you eventually. I expect my cut short corners to fall on me some day. For sure. I chose 5A / 20g cause I have seen alot of DIY kits that bundle...
by fatty
Mar 04 2021 1:00pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

As we discuss implementation, it's becoming clear why node charging isn't more common: At the very least, the 3A JST balance connectors would have to be replaced. Even if the chargers were hardwired with 8A-rated conductors (they aren't), the battery-side balance leads all the way back to the cells ...
by fatty
Mar 04 2021 12:51pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

As for *your* numbers... you don't seem to be as good at them as you seem to be claiming, to be frank. Haha, how do you figure? I calculated based on the very limited information you had provided (mass, velocity, CdA, and distance) -- where was the error? You solved an entirely different problem ba...
by fatty
Mar 04 2021 12:41pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

Regarding 20AWG wire current capacity, it can be given as around 10A, depending on the information source. One chart, as example: https://www.powerstream.com/Wire_Size.htm However, that chart gives different current ratings for use as "chassis wiring" (11A), and another for use as "p...
by fatty
Mar 03 2021 5:57pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

Here is a pic of my "Pole Access System" that I have been trying out. It is nice to have a easy view of the packs voltages. Plus charge at will @ desired current. Please critique. BMS shares a harness that brings them all together in 21pins to BMS, Monitor, problem? Disconnect and have cl...
by fatty
Mar 03 2021 1:41pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

" Rated". I cannot believe that "BC168 Balance Charger" shoves 8000mA through 24g wire. thats craxy . Lipo even. How idd they not burn errytag? It does tho. Definitely crazy. And they sure do burn :( Could you link me some of this 20g wire that takes 8 amps reliably? I would not...
by fatty
Mar 03 2021 1:36pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

ilu wrote:
Mar 03 2021 4:58am
From Grin's GMAC description:
"The GMAC motor without a clutch has a no-load drag that varies from 1.0- 1.5 Nm with sheel speed, which is more than a typical direct drive hub motor (0.6-1.0 Nm)."
Wow -- thanks for the correction.
by fatty
Mar 03 2021 3:14am
Forum: Battery Technology
Topic: My BC168 Charger went POOF!
Replies: 68
Views: 7286

Re: My BC168 Charger went POOF!

Looking at the differences it could be as simple as worse heat dissapation of that channel. These FETs degrade in their ratings rapidly with heat. If you look at the specs, it loses 20% current rating at 70 degrees. I would definetly use a higher voltage (VDSS) and amp (ID) part as a replacement. W...
by fatty
Mar 02 2021 11:09pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

NCC1941 wrote:
Mar 02 2021 1:07pm
The GMAC does drag, due to the locked clutch that allows it to do regen.
Chalo wrote:
Mar 02 2021 1:10pm
It definitely drags-- more so than something like a direct drive Leaf motor, in my observation.
Maybe a bit of exaggeration by Grin, but they seem convinced it is less than a DD hub. Interesting.
by fatty
Mar 02 2021 11:03pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

Well, if you want numbers… To start, what is your estimated Wh/km at 40km/h on that 170kg bike? At double your theoretical CdA, you might get down to 6Wh/km. 600km = 3.6kWh. What is your functional threshold? You'd need to hold >175W for 15 hours straight. It's just a problem of scale, and as has b...
by fatty
Mar 02 2021 9:44pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

Be lots of 12g wire connecting each Parallel string to charge. Makes things a bit bulkier in terms of size. Nah, the chemical-resistant wire I like to use is rated at 8A for 20g. The bigger problem is the JST connectors are only rated for 3A, and certainly not for the mating cycle count, but it see...
by fatty
Mar 02 2021 3:44pm
Forum: EBike General Discussion
Topic: Build pack onto and around frame tube, rather than inside?
Replies: 27
Views: 453

Re: Build pack onto and around frame tube, rather than inside?

They are a bit pricey. BatterySpace lists them for a silly $40/ea, but I've seen other listings in the low $20s, and a package deal at $20/ea would be ~2.4Wh/$ -- that's maybe double what even cheap LiPo or Samsung INR21700-50E -- super cheap. In fact, the only higher Wh/$ I know offhand is Queen Q...
by fatty
Mar 02 2021 12:25pm
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

BalorNG wrote:
Mar 02 2021 4:53am
I actually did. Multiple times. *sigh*
Post your numbers here for accurate advice.

Is that a mockup?
There's a lot of lower-hanging fruit.

GMAC hub motor with locked clutch: no drag and does regen.
by fatty
Mar 02 2021 12:05pm
Forum: EBike General Discussion
Topic: Build pack onto and around frame tube, rather than inside?
Replies: 27
Views: 453

Re: Build pack onto and around frame tube, rather than inside?

LewTwo wrote:
Mar 02 2021 4:12am
That might actually work for me ....
Nice. LFP is safe and heavy enough already -- no need to make it worse with a heavy mount. And even 40s would easily clear the crank arms.
Are you planning to use short threaded rod to get the cell ends flush?
by fatty
Mar 02 2021 3:24am
Forum: EBike General Discussion
Topic: Build pack onto and around frame tube, rather than inside?
Replies: 27
Views: 453

Re: Build pack onto and around frame tube, rather than inside?

H,mmmmm ..... just thinking .... Three rings of six would be 18S ... leave two out to make room for BMS, switch, etc. That would cut the length down to 18 inches and be a more common 16S1P=52 volt configuration. Nah, LFP 24s is nice because the ~87.6V charge voltage is just under the common 90V con...
by fatty
Mar 02 2021 3:05am
Forum: EBike General Discussion
Topic: Build pack onto and around frame tube, rather than inside?
Replies: 27
Views: 453

Re: Build pack onto and around frame tube, rather than inside?

Assuming that the down tube was 40mm in diameter then one is looking at four rings of six cells each. That would be 120mm (4-3/4 inches) in diameter by 608mm (24 inches) long with a weight of 11.52Kg (25 pounds). That is minimal without any casing or terminations, bms (24S = 76.8 volts), etc. I sus...
by fatty
Mar 02 2021 1:22am
Forum: Help wanted & offered
Topic: Anyone offer Ebike consultation for $$?
Replies: 15
Views: 553

Re: Anyone offer Ebike consultation for $$?

but i believe my situation calls for two motors to help me. but not sure. I two approx 500lbs of bike trailer and bike and me, like to move at approx 25/30 km/h and when i hit a grade of 30% higher i find it hard to get up the hill. S Probably best not to crosspost the same question in 2 forums/3 t...
by fatty
Mar 02 2021 12:43am
Forum: EBike Non-hub Motor Drives
Topic: Friction *regen brake* sanity check
Replies: 31
Views: 566

Re: Friction *regen brake* sanity check

I'm building a long-distance tourer and having maximum efficiency to get the most out of human powered drivetrain is paramount The solutions for this design goal have been very thoroughly characterized and refined over the last.. century? And they don't include unnecessary braking, but rather aero ...
by fatty
Mar 01 2021 10:44pm
Forum: Battery Technology
Topic: Why isn't "node charging" through the balance leads more common?
Replies: 24
Views: 601

Re: Why isn't "node charging" through the balance leads more common?

I would say just from a reliability standpoint, a single bulk charger plus BMS is an order of magnitude more reliable than an individual charger per cell group (I.e. node charging). I don't agree -- every second or third thread in this subforum is for a misbehaving (or incorrectly-spec'd) charger o...