Search found 6244 matches

by john61ct
May 27 2021 2:59pm
Forum: EBike Build Threads
Topic: Lithium Titanate (LTO) battery pack for electric motorcycle
Replies: 16
Views: 3119

Re: Lithium Titanate (LTO) battery pack for electric motorcycle

Wow 17000km! Just shows the infrastructure for proper monitoring maintenance & protection can make a huge difference! Personally once that's in place, regular testing protocols implemented to track SoH% decline and rising ESIR over time I'd start with a new pack maybe keep two going so downtime ...
by john61ct
May 27 2021 2:51pm
Forum: Battery Technology
Topic: Using 69.4v charger for LiFePo battery
Replies: 3
Views: 116

Re: Using 69.4v charger for LiFePo battery

You can always use a charge source that CAN get up to a higher voltage than you want to terminate at. But if you ALLOW it to go much higher, you can 1. at best reduce the cell longevity 2. break other devices on that circuit 3. destroy the battery quickly 4. start a major FIRE kill people and destro...
by john61ct
May 27 2021 2:37pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1371
Views: 210275

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

So let's say a Hobby charger designed for 2S li-ion, can charge from the pack-level power pair only, no balance lead connected or you rig a pigtail harness adapter to spoof its need for 3 wires Assume one port only. What is the minimum wattage / amps output required to feed the kcaps fast enough, to...
by john61ct
May 26 2021 11:16am
Forum: EV Business World
Topic: Battery Protection System
Replies: 6
Views: 203

Re: Battery Protection System

I'd be excited to see you do a robust reliable adjustable protective BMS using a range of OTS external contactors so the BMS is only voltage-based, no need for different models limited at different ampacities that included this low-SoC limiting functionality as an adjustable option, that the user co...
by john61ct
May 26 2021 9:48am
Forum: Battery Technology
Topic: Building a large capacity battery for bicycle trailer
Replies: 94
Views: 1799

Re: Building a large capacity battery for bicycle trailer

>> Any decent battery can charge in 90min without harm. >> Better ones can charge in 45min only sacrificing a small percentage of lifecyles off the back end. > 90min for how long? I guess you are suggesting again 100km @ 25km/h. No, I am talking about refilling your pack(s) to 100% regardless of yo...
by john61ct
May 25 2021 7:01pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 52
Views: 838

Re: Compression of pouch cells, info/data

My error in using "puffing" ... as puffing is a NO NO. What i should have said is "expansion" as it relates to this post Nope, puffing is just greater expansion than should normally be allowed. Just prevent it is the bottom line, no rocket science needed unless we're talking som...
by john61ct
May 25 2021 6:58pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 52
Views: 838

Re: Compression of pouch cells, info/data

Sure but when you want major kWh fiddling with hundreds of itty bitty cells is a pain.

And honestly, all you need is metal plate and some strapping or threaded rods, really NBD.

Especially starting with the hard-cased prismatics like your Winstons.
by john61ct
May 25 2021 10:52am
Forum: Large EV General Discussion
Topic: one stop shop electric car motors plus?
Replies: 4
Views: 195

Re: one stop shop electric car motors plus?

Yes, I think the DIY process is more likely to be made illegal

before volume is ever high enough for mature distribution channels to form
by john61ct
May 25 2021 10:51am
Forum: EScooters/EMotorcycles
Topic: My new electric motorcycle
Replies: 10
Views: 551

Re: My new electric motorcycle

Cheaper shipping is slow, 4-5 months common for big heavy boxes.

Then customs may want a look at it. . .
by john61ct
May 25 2021 10:43am
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 52
Views: 838

Re: Compression of pouch cells, info/data

I suspect that keeping them fully charged all the time is in fact abusing them. True for every lithium chemistry. But when cycle life is decades, and/or the other longevity factors are "more abusive" then that one factor may not be so influential, if the use case requires it, so be it. Li...
by john61ct
May 25 2021 10:40am
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 52
Views: 838

Re: Compression of pouch cells, info/data


flippy wrote:"you dont need compression but you do need to prevent the cells from expanding".

… that is what compression does

TL;DR: you need compression.
Yes, this, that is all.
by john61ct
May 25 2021 10:39am
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 52
Views: 838

Re: Spot Welding Copper Strips to 18650 Battery Cells

PSI is not worth that level of attention in real life. No puffing is never "a good thing". The only point of compression is restraint, preventing movement beyond a few mm. Like preventing a short across terminals, basic necessary part of building your pack, that is all Nothing to do with &...
by john61ct
May 25 2021 10:31am
Forum: Battery Technology
Topic: Building a large capacity battery for bicycle trailer
Replies: 94
Views: 1799

Re: Building a large capacity battery for bicycle trailer

13s8p alone can not give 100km specially when attached with a 15kg trailer. I was talking about 2 batteries that I use when I take longer trips. The extra battery is EV battery (li-ion) but each cell is 20Ah. I have tested only ~100 km only without any additional load such as a trailer. Charging ba...
by john61ct
May 25 2021 10:22am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 93
Views: 2813

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

Fantastic stuff here! "Elegance" in the engineering sense is far from an objective goal. All depends on both the use case and what the owner values. For me, reliability / longevity and ease of repair in remote third-world locations are critical. For someone else low noise levels and aesthe...
by john61ct
May 23 2021 3:18pm
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 93
Views: 2813

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

4 maybe 5 is the most you need if motor powered only

More is needed when you still want to contribute lots of human pedal power
by john61ct
May 23 2021 12:24pm
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 93
Views: 2813

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

Just aesthetics, but you could use this to make it pretty

https://tinyurl.com/app
by john61ct
May 23 2021 12:22pm
Forum: EBike Technical
Topic: Cycle Analyst - still solid choice?
Replies: 24
Views: 1077

Re: Cycle Analyst - still solid choice?

Grin direct
by john61ct
May 23 2021 11:03am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 93
Views: 2813

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

Ianhill wrote:electric motorcycle conversion kit Triumph Arch

Top results
Aaargh

you do know everybody's search results vary based on the per user activity tracking?

I have no idea why you are averse to just pasting a link???

Image
by john61ct
May 23 2021 10:39am
Forum: Battery Technology
Topic: Synchronous buck converter - step down
Replies: 5
Views: 138

Re: Synchronous buck converter - step down

So cheap order three different ones and report back here.

But I stand by the battery pack issues, at least measure your actual draw per hour peak vs average for each load device with a coulomb counter

and ballpark your "half a day" energy budget more precisely
by john61ct
May 23 2021 10:33am
Forum: Items for Sale - New
Topic: [Sold] Nucular 24F potted for Sur-Ron
Replies: 4
Views: 439

Re: Nucular 24F potted for Sur-Ron

How does that compare to new price waiting for production to catch up?

Shipping to USA would take how long?
by john61ct
May 23 2021 8:38am
Forum: Battery Technology
Topic: Synchronous buck converter - step down
Replies: 5
Views: 138

Re: Synchronous buck converter - step down

With cheap Chinese, assume the ampacity listed is a fantasy, maybe triple what you should use it for without adding heroic cooling / heatsinking. A small portable DC fridge running 24*7 might use 30+ Ah per day, a gaming laptop much more so do your energy budget first. A pair of lead GCs at 200Ah (1...
by john61ct
May 22 2021 4:48pm
Forum: EBike Technical
Topic: prismatic cell discharging test
Replies: 1
Views: 110

Re: prismatic cell discharging test

Yes, can be done. Most accurately with an electronic dummy load, or a charger designed to do this using a precisely regulated CC amps rate usually the 10-hour rate 0.1C or lower if you are trying to verify vendor claimed capacity. Cheap cells like that you might get 90%, top notch makers often deliv...
by john61ct
May 22 2021 4:28pm
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 93
Views: 2813

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

Link to the motor? Ideally the full description specs page from the manufacturer? Or has it been sighted only on Ali? Alibaba special. The bikes are called, time et electric Yes I know it's sold through Ali. As I asked, could you please just post a link to it? Google gives me no joy with that strin...
by john61ct
May 22 2021 4:23pm
Forum: EBike General Discussion
Topic: Help calculate import duties on an ebike from Singapore into USA?
Replies: 4
Views: 481

Re: Help calculate import duties on an ebike from Singapore into USA?

What, a new one, sent by the vendor?

Or one that you've bought and used while there ?

Quite possibly none in either case, obviously better odds with the latter scenario .

In practice you really won't know unless/until you get the bill.