Search found 6106 matches

by john61ct
May 02 2021 8:42am
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 320

Re: Which geared hub for BBSHD in a full-fat tandem trike?

Why is Rohloff not in consideration?

Just too pricey?
by john61ct
May 02 2021 8:33am
Forum: EBike Technical
Topic: 48v Battery with 60v e-motor.
Replies: 2
Views: 101

Re: 48v Battery with 60v e-motor.

The top speed will be lower, and you won't get full power/torque at low speeds, or rather, you will hit the heat / current limits sooner.
by john61ct
May 01 2021 7:13pm
Forum: Vendor Relations Corner
Topic: Trying to buy a PowerVelocity Controller
Replies: 13
Views: 291

Re: Trying to buy a PowerVelocity Controller

Have you searched for others' experiences with this vendor?

Maya Angelou: "When someone shows you who they are, believe them the first time."
by john61ct
May 01 2021 6:11pm
Forum: EBike Build Threads
Topic: Titanium Fatbike - Bafang Ultra and Phaserunner
Replies: 57
Views: 16779

Re: Titanium Fatbike - Bafang Ultra and Phaserunner


robrob3141 wrote:Please help. Me…
I'm at wits end.
Probably best to start your own new thread.

Also give your location in the title and ask for reco's for local bike shops.

by john61ct
Apr 30 2021 12:56am
Forum: E-Vehicles General Discussion
Topic: 3.7v vs 4.2v
Replies: 5
Views: 428

Re: 3.7v vs 4.2v

As stated, you need to charge per-cell to Full (4.10 - 4.15V, not 4.2V) in order to get close to the Ah capacity (range) you paid for. If your use case dictates a particular pack level voltage, that determines your series count. Usually very little wiggle room there, between not getting the speed yo...
by john61ct
Apr 30 2021 12:46am
Forum: Items for Sale - New
Topic: Sold out
Replies: 17
Views: 1443

Re: Sold out

Yes. These mumbers are consistent for all "li-ion" chemistries in the 3.6 - 3.7V range, physical size makes no difference But be aware there are no "bright lines" black and white Everything affects longevity in a grey-scale curve So everything is a judgment call. 0.1C is gentler ...
by john61ct
Apr 29 2021 3:50am
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 80
Views: 2703

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?


neptronix wrote:The current limit of a geared motor is it's ability to shed heat
Unless the torque limit of the weakest gear is sooner right?


by john61ct
Apr 29 2021 3:44am
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 1651
Views: 220903

Re: bluetooth BMS?

Likely EMI issue
by john61ct
Apr 29 2021 3:24am
Forum: Items for Sale - Used
Topic: 3 Sevcon Gen4 Size4 80V PMAC BLDC
Replies: 3
Views: 294

Re: 3 Sevcon Gen4 Size4 80V PMAC BLDC

Sorry I wasn't more clear. Finding the hardware + software required (properly licensed or not) is difficult without spending as much as what the controller is worth. Finding knowledgeable / skilled / experienced help with the process is a scale of magnitude harder, even if you are willing to spend t...
by john61ct
Apr 29 2021 3:19am
Forum: Battery Technology
Topic: Is it possible to upgrade battery packs?
Replies: 36
Views: 1180

Re: Is it possible to upgrade battery packs?

Yes that would be best
by john61ct
Apr 28 2021 1:11pm
Forum: E-Vehicles General Discussion
Topic: 3.7v vs 4.2v
Replies: 5
Views: 428

Re: 3.7v vs 4.2v

There will be very low Ah capacity at that low a voltage.

And the pack will get murdered very early.

Use a lower series count instead.
by john61ct
Apr 28 2021 12:41pm
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 80
Views: 2703

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

I don't think money is the barrier to getting a bigger motor

it's those looking for "fun" use cases, cycling for sport,

looking for high power at light weight.

500# cargo bikes are unlikely to get involved in this topic until reliable solutions have been proven by the zoom-zoom crowd.
by john61ct
Apr 27 2021 1:25am
Forum: Battery Technology
Topic: Is it possible to upgrade battery packs?
Replies: 36
Views: 1180

Re: Is it possible to upgrade battery packs?

That is asking too much.

You aren't trying for cheap are you?

Top notch brand new grade A cells, all from the same production run.

And also bring the C-rate down by going to bigger Ah capacity.

by john61ct
Apr 27 2021 12:39am
Forum: Battery Technology
Topic: Is it possible to upgrade battery packs?
Replies: 36
Views: 1180

Re: Is it possible to upgrade battery packs?

Ah is about range more than power.

Even a tiny pack can get up to high speed,

in fact lower weight, less load to push

you just don't get many miles.


The quality of the cells used is the key to power capacity, and longevity.
by john61ct
Apr 26 2021 12:45pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13701

Re: 40T, neodymium magnets, plasti dip cycle test

Also for a mobile application the possibly extreme, and certainly constant shock and vibration needs to be taken into account
by john61ct
Apr 26 2021 2:15am
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13701

Re: 40T, neodymium magnets, plasti dip cycle test

This is the standard for ESIR from the battery testers at RCgroups

https://www.progressiverc.com/lipo-esr- ... rk-ii.html

for repeatable accuracy, temperature, current rate and SoC%

must be held constant.
by john61ct
Apr 26 2021 1:24am
Forum: Items for Sale - New
Topic: Sold out
Replies: 17
Views: 1443

Re: New Original LG 21700 5000mAh Cells

If you want good cycle lifespan, 0.4 to 0.5C rate. Going higher, longevity hit is reduced by ensuring the cell is at warm to hot temperatures first. Obviously if the other care parameters are "abusive" (not conducive to good lifespan) like high **discharge** rates, or high average DoD% the...
by john61ct
Apr 25 2021 9:25am
Forum: Items for Sale - Used
Topic: 3 Sevcon Gen4 Size4 80V PMAC BLDC
Replies: 3
Views: 294

Re: 3 Sevcon Gen4 Size4 80V PMAC BLDC

How did you overcome the programming challenge?
by john61ct
Apr 24 2021 2:08pm
Forum: Battery Technology
Topic: Is it possible to upgrade battery packs?
Replies: 36
Views: 1180

Re: Is it possible to upgrade battery packs?

Yes, build a new pack.

Doing so from used cells requires much more knowledge and testing gear than using new cells.
by john61ct
Apr 22 2021 2:46pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206460

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

So apparently 2500A peak is too much, reco maximum is 2000A. Presumably that is for a **very** short burst. The Odyssey PC series apparently works well, the little 28Ah version is discussed above but presumably the bigger G31 100Ah, being lead, would also not risk discharging too fast. So long as a ...
by john61ct
Apr 22 2021 12:24am
Forum: Motor Technology
Topic: Did I blow a fet?
Replies: 10
Views: 301

Re: Did I blow a fet?

Or the battery pack failed, if not the BMS (if any) then cells themselves
by john61ct
Apr 21 2021 11:36pm
Forum: Alternative Energy
Topic: Stationary Charging a battery
Replies: 16
Views: 2273

Re: Stationary Charging a battery

Whoops sorry did not recognize this as a resurected zombie thread
by john61ct
Apr 21 2021 11:34pm
Forum: Alternative Energy
Topic: Stationary Charging a battery
Replies: 16
Views: 2273

Re: Stationary Charging a battery

If only rivers were portable. Seriously, even with a truck or van pulling the trailer, wind power wojld not be practical. Nor hydro. Solar in very hot and sunny conditions, anything under 1000W will only give a couple hours' propulsion per day at slow speeds. Fossil fuel is the only practical energy...
by john61ct
Apr 21 2021 10:51pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206460

Re: kWeld -

Note I asked these related Q's a while back
john61ct wrote:
Apr 11 2021 12:18am
So what are the pack specs to get top output power?

Voltage range?

Actual peak vs continuous maximum amps drawn?

What are the specs that might get to be "too much"?
by john61ct
Apr 21 2021 10:49pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206460

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

Would a better quality LiPo (with lower discharge resistance, say 150A continuous real-world) possibly trigger that overcurrent condition?

So maybe choosing LiPo that can "only" handle 80-100A discharge might be a better fit?