Search found 6100 matches

by john61ct
May 06 2021 8:39pm
Forum: Battery Technology
Topic: "Copper/nickel sandwich" buses for series connections
Replies: 40
Views: 3831

Re: "Copper/nickel sandwich" buses for series connections

Remember copper is **so** much more conductive, no need to go thick. I really would love to find a way to make or get copper sheeting or strips that are thickly enough **plated** with nickel to give higher surface resistance. Has anyone with Kweld tried welding a flattened segment of fine-stranded *...
by john61ct
May 06 2021 7:26am
Forum: Battery Technology
Topic: WTB Battery Relay Controller 100V 20S
Replies: 6
Views: 111

Re: WTB Battery Relay Controller 100V 20S

BMS functionality does not always include per-cell balancing. But then you should be balancing via other means, at least periodically. But HVC and LVC should be based on the first cell/group level to reach the setpoint, and yes that is the core definition of a protective BMS. That said, it certainly...
by john61ct
May 06 2021 7:19am
Forum: EBike Technical
Topic: Battery questions
Replies: 5
Views: 190

Re: Battery questions

Real life Ah will be lower. Even those top shelf marques that underestimate capacity om the nameplate base it on drawing down to the spec sheet minimum (often 2.5V) and at a crazy slow rate like 0.1C The generic lower quality makers routinely exaggerate even then. 20Ah might be a safer assumption fo...
by john61ct
May 05 2021 3:23pm
Forum: Items for Sale - New
Topic: Prismatic lifePo4 cells 50ah Sale
Replies: 11
Views: 244

Re: Prismatic lifePo4 cells 50ah Sale

That's a great price even if they last half as long as CALB Winston et al. For use cases that don't need top density Go to a higher Ah capacity, lowers the C-rate, reduces the sag and extends lifespan. Ideally well below 1C except for short peaks. Also for normal cycling, stop charging at 3.42 - 3.4...
by john61ct
May 05 2021 10:50am
Forum: EBike Technical
Topic: Battery questions
Replies: 5
Views: 190

Re: Battery questions

Yes good example of the curve slopes

but actual numbers look like LFP, a scale of magnitude longer lasting than li-ion and much lower energy density

each chemistry even model battery will be different
by john61ct
May 05 2021 10:43am
Forum: Items for Sale - New
Topic: Prismatic lifePo4 cells 50ah Sale
Replies: 11
Views: 244

Re: Prismatic lifePo4 cells 50ah Sale

Not sure about the location thing..Im from Glencoe Ontario. Thats about 40 Mins from London. As for people buying these, will sell to whomever ...shipping is up to the buyer.. ;) Sorry I assumed the original London. LI packs being Hazmat goods may complicate things if you want to be sure of avoidin...
by john61ct
May 05 2021 10:33am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

The assumption that a hub drive has no gearing is the over generalization

as is the idea that 500W is enough power
by john61ct
May 05 2021 2:22am
Forum: Items Wanted
Topic: Prodecotech 51.2V, 12 Ah LiFeP04 battery - Don't need one now
Replies: 28
Views: 2872

Re: Prodecotech 51.2V, 12 Ah LiFeP04 battery - Don't need one now

See what A123 offers - avoiding their NMC pouches of course
by john61ct
May 05 2021 2:07am
Forum: EBike General Discussion
Topic: Maximum allowable size disc rotor on NuVinci N171 hub?
Replies: 5
Views: 105

Re: Maximum allowable size disc rotor on NuVinci N171 hub?

Yes, I really want to explore the idea of doing regen with the N171. The IGH goes backwards, with "some resistance". Would long term regen "drag braking", say downhill from Donner Pass, do damage? Think tandem / cargo 500+ lb load, kids' life at stake, so keeping it slow, trying ...
by john61ct
May 05 2021 1:55am
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 309

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

Good stuff thanks!
kiltedcelt wrote:If I could find another N171 32 hole that *might* be an option
I've heard rumours Chalo might have an old one just sitting around [emoji6]

by john61ct
May 05 2021 1:28am
Forum: EBike Technical
Topic: Battery questions
Replies: 5
Views: 190

Re: Battery questions

Truly accurate measurement of the correspondence between Voltage (isolated at rest) and SoC% is both very challenging both in skills and kit required, and not really necessary, just use voltage. For those li-ion chemistries with 3.6 - 3.7 Vnominal charge to between 4.05V and 4.15V, lower the better ...
by john61ct
May 05 2021 12:52am
Forum: Items for Sale - New
Topic: Prismatic lifePo4 cells 50ah Sale
Replies: 11
Views: 244

Re: Prismatic lifePo4 cells 50ah Sale

Might want to mod the title with your geographic restriction, e.g. UK/EU only
by john61ct
May 04 2021 10:34pm
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

In places where 3kW is "small" especially my use case where 500+ pound loads need to get up long steep mountain roads this thesis is obvious mid-drives just don't cut it on their own. Yes extreme gearing will help you get rolling when at a standstill facing up hill but powerful hub motors ...
by john61ct
May 04 2021 10:29pm
Forum: EBike General Discussion
Topic: Maximum allowable size disc rotor on NuVinci N171 hub?
Replies: 5
Views: 105

Re: Maximum allowable size disc rotor on NuVinci N171 hub?

How about regen braking on the rear?

Put the panic-stopping up front, use rear for drag braking down big hills and to help prevent flipping over handlebars
by john61ct
May 03 2021 7:55am
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 309

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

Good stuff, don't care about a few pounds extra, hoping to support a 500# tandem/cargo total I guess for strength heavier is better! I assume rating for kW is going to be more oriented toward load at speed, as opposed to standing starts pointed up a steep hill, where the peak Nm is more relevant? My...
by john61ct
May 02 2021 10:01pm
Forum: EBike Non-hub Motor Drives
Topic: new cyclone 3000 w mid-drive kit?
Replies: 3507
Views: 465597

Re: new cyclone 3000 w mid-drive kit?

Most FOC controllers use sensors.

viewtopic.php?t=105139
by john61ct
May 02 2021 9:58pm
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 309

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

Rohloff isn't as robust as NuVinci N171. Its rating for gross power is the same as the later, lighter Nuvinci/Enviolo hubs. Wow yes 130Nm peak! So despite both being rated the same, what makes the Rohloff "less robust"? I've seen advice limiting Rohloff to 90Nm continuous are you saying t...
by john61ct
May 02 2021 5:17pm
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 309

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

Also check out Kindernay XIV from Norway, apparently a close copy of the Rohloff.
by john61ct
May 02 2021 5:14pm
Forum: EBike Non-hub Motor Drives
Topic: Which geared hub for BBSHD in a full-fat tandem trike?
Replies: 12
Views: 309

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

I visualize the Rohloff as a must-have for heavy tandem/cargo scenarios using mid-drives. Especially if hills are in the picture, and **most** especially if human power is anything more than an afterthought. As for the cost issue, just like spending thousands on excellent battery packs my rationaliz...
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: 309

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: 99

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: 280

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: 16752

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: 422

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: 1438

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 ...