Search found 4473 matches

by john61ct
Jun 06 2020 1:49am
Forum: Motor Technology
Topic: Motor for 18ft Electric boat
Replies: 2
Views: 75

Re: Motor for 18ft Electric boat

Thunderstruck is a great source for OTS kits
by john61ct
Jun 06 2020 1:46am
Forum: E-Bike General Discussion
Topic: new eZip motor
Replies: 5657
Views: 487811

Re: new eZip motor

Covid-19 is not so easy to transmit when outdoors, especially moving around.
by john61ct
Jun 06 2020 1:40am
Forum: E-Bike Technical
Topic: Help please! I have a QS 205 v3 motor paired with a SVMC 72200 Sabvoton powered by a 72v 50ah 300a continuous BMS.
Replies: 30
Views: 516

Re: Help please! I have a QS 205 v3 motor paired with a SVMC 72200 Sabvoton powered by a 72v 50ah 300a continuous BMS.

Each cell group is at nominal 3.6 - 3.7V, max charge is 4.2V

that is 1S, only one series, a group all in parallel same as one cell

so you must be measuring every two groups to get that 8.something delta.

I agree for your level of understanding you need help, IMO in person.
by john61ct
Jun 06 2020 1:32am
Forum: E-Bike Technical
Topic: how to make a proportional regen ebrake lever
Replies: 18
Views: 675

Re: how to make a proportional regen ebrake lever

For me, I see proportional regen braking as "drag braking", preventing excessive pad wear and supporting controlled long descents and steep grades completely separate from safety in emergency stop hard-braking. I certainly would not want the latter to depend on the former nor allow any delays for an...
by john61ct
Jun 05 2020 9:51pm
Forum: E-Vehicles General Discussion
Topic: Is there any IC available to convert sensor signal to CAN signal?
Replies: 3
Views: 65

Re: Is there any IC available to convert sensor signal to CAN signal?

There are very straightforward CAN comms libraries for all the leading MCUs, especially Arduino.
by john61ct
Jun 05 2020 9:27pm
Forum: E-Bike Technical
Topic: Help please! I have a QS 205 v3 motor paired with a SVMC 72200 Sabvoton powered by a 72v 50ah 300a continuous BMS.
Replies: 30
Views: 516

Re: Help please! I have a QS 205 v3 motor paired with a SVMC 72200 Sabvoton powered by a 72v 50ah 300a continuous BMS.

Depends of course on what connection type, and what sort of gear you have. If you can disconnect the series connections charge up (or discharge down) to a bit below your desired balance point (say all within 0.05V) then get everything in parallel, and charge as one big 1S to the point then let it si...
by john61ct
Jun 05 2020 9:10pm
Forum: Battery Technology
Topic: continuous draw on harvested 18650 cells?
Replies: 5
Views: 116

Re: continuous draw on harvested 18650 cells?

Best to keep going until you get them to at least match as much as practical

ideally same brand similar age

start with capacity testing, timed CC loads

The power and resistance should be less critical at low C rates.
by john61ct
Jun 04 2020 11:55pm
Forum: E-Bike Technical
Topic: Proportional braking/regen?
Replies: 6
Views: 112

Re: Proportional braking/regen?

Virtual coaster brakes would be great, ever been implemented?
by john61ct
Jun 04 2020 9:12pm
Forum: Battery Technology
Topic: Parallel connecting high-V sub-pack modules with one (or more) BMS
Replies: 6
Views: 228

Re: Parallel connecting high-V sub-pack modules with one (or more) BMS

I am obviously not a "never BMS" guy, since the whole point of the thread is to discuss how to use one. But using a very specific limited scenario to isolate that one issue. It will be much more valuable to the community if it can remain focused. I am requesting that **this thread** not get sidetrac...
by john61ct
Jun 04 2020 6:48pm
Forum: Battery Technology
Topic: Parallel connecting high-V sub-pack modules with one (or more) BMS
Replies: 6
Views: 228

Re: Parallel connecting high-V sub-pack modules with one (or more) BMS

I guess you did not read the OP:
john61ct wrote:Note this thread should for clarity stick to **only** this above example, just discussing electrical design principles here
Please post to another thread, or start your own.

by john61ct
Jun 04 2020 3:03pm
Forum: E-Bike Technical
Topic: Where to get ORIGINAL Anderson Powerpoles for someone outside America
Replies: 5
Views: 108

Re: Where to get ORIGINAL Anderson Powerpoles for someone outside America

Well cheap Chinese knockoffs will of course make the authentic product look very expensive. And yes markets in countries outside the US are going to be much more expensive than in the US where nearly everything is more competitive, it is just too stressful to compare like that. I'm not justifying, b...
by john61ct
Jun 04 2020 10:01am
Forum: E-Bike General Discussion
Topic: new eZip motor
Replies: 5657
Views: 487811

Re: new eZip motor

It is a waste of money trying to get a good pre-built battery cheaply.

Build it yourself, or a personal relationship with a sympathetic DIY builder cutting you a deal on the labor is the only way.

Still need to pay more for the top-notch cells if you want high power density and decent lifespan.
by john61ct
Jun 04 2020 8:08am
Forum: Battery Technology
Topic: Smaller packs or 1 large battery?
Replies: 12
Views: 223

Re: Smaller packs or 1 large battery?

That sounds like the BMS were doing what they were configured to do, rather than malfunctioning.

Rather than a cutoff lower down, an alarm could go off earlier.

A wattmeter to let you know visually what DoD% you're at, even better.
by john61ct
Jun 04 2020 7:47am
Forum: E-Bike Technical
Topic: Where to get ORIGINAL Anderson Powerpoles for someone outside America
Replies: 5
Views: 108

Re: Where to get ORIGINAL Anderson Powerpoles for someone outside America

Contact Anderson and ask who their authorized distributors are on your continent, in your country many of their designs are now patent expired so there will be decent quality knockoffs buy original contacts by the 100's, then test other housings? try Mouser Digi-Key Allied Newark Edit https://www.an...
by john61ct
Jun 03 2020 10:08pm
Forum: Battery Technology
Topic: continuous draw on harvested 18650 cells?
Replies: 5
Views: 116

Re: continuous draw on harvested 18650 cells?

You may be overestimating what your kit can do wrt hills and "towing kids", you need that 30A for much longer than just a short few seconds "peak", need to plan as if that is your continuous need. Forget scrapped cells, save your money up until you can afford a quality built pack of top-notch new ce...
by john61ct
Jun 03 2020 10:00pm
Forum: Battery Technology
Topic: Smaller packs or 1 large battery?
Replies: 12
Views: 223

Re: Smaller packs or 1 large battery?

After reading some threads elsewhere today I am still at a loss as to why there is any concern at all with parallel packs and individual BMS Assuming a well built pack of quality cells in healthy condition, a BMS becomes the most likely **cause** of an early death. That risk goes up exponentially w...
by john61ct
Jun 03 2020 6:35pm
Forum: Battery Technology
Topic: safety and fully enclosed/embedded packs?
Replies: 1
Views: 73

Re: safety and fully enclosed/embedded packs?

I am not sold on these cells not requiring compression plates. capkart04.jpg So I would make that part of the heavy-plate part of the design. The other sides of the enclosure can be lighter gauge. Sealing right up airtight is IMO pointless, unless you're thinking the whole rig is going to end up sub...
by john61ct
Jun 03 2020 6:30pm
Forum: E-Bike Technical
Topic: Hi, I need help choosing a battery.
Replies: 4
Views: 79

Re: Hi, I need help choosing a battery.


caseylain wrote: As long as the pack comes with Samsung 35e cells it should be good.
Let them know if they turn out not to be genuine you'll be taking action.

And ideally be ready to cycle/load test immediately on receipt.
by john61ct
Jun 03 2020 5:57pm
Forum: E-Bike Technical
Topic: Hi, I need help choosing a battery.
Replies: 4
Views: 79

Re: Hi, I need help choosing a battery.

I would only focus on the quality of the cells and the maker's build quality ignoring the BMS as most likely rubish not worth keeping anyway. Really I would not buy from a random seller anyway, only from a source well recommended by someone I trust. Saving 50% and getting something only 20% as good ...
by john61ct
Jun 03 2020 5:38pm
Forum: Battery Technology
Topic: Smaller packs or 1 large battery?
Replies: 12
Views: 223

Re: Smaller packs or 1 large battery?

looks great! Two BMS of course. Well to me, the only reason "of course" would be because of the physical separation between the two sub-packs, and cross-wiring each cell/group together would be more awkward. > I went with a single port BMS design so I could leave them in parallel and charge in paral...