Search found 29 matches

by Taswegian
Jul 29 2019 5:00am
Forum: Battery Technology
Topic: Awesome study / information on NCA battery degradation (Panasonic NCR18650PD)
Replies: 16
Views: 725

Re: Awesome study / information on NCA battery degradation (Panasonic NCR18650PD)

From this I take the following lessons for my Ebike: I will set my charger end voltage between 4.0 or 4.1 volts and charge whenever I arrive home, less deep discharge is better and with a conservative end voltage the degradation due to storage is not so bad. Only for a big trip I charge it up to 4....
by Taswegian
Jul 25 2019 6:05am
Forum: Battery Technology
Topic: 18650 spot welding -how to- ULTIMATE REPOSITORY
Replies: 759
Views: 154554

Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

Whats the problem with the early K-weld?
I have a relatively recent one and although I've only done a few test welds so far it seems to perform exactly as advertised, ie works great!
by Taswegian
Jul 22 2019 6:41am
Forum: E-Bike Technical
Topic: 2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers
Replies: 165
Views: 17066

Re: 2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

Will there be a front wheel GMAC, or is it too crowded to fit this kind of torque arm?
by Taswegian
Jun 26 2019 1:15am
Forum: Battery Technology
Topic: Fantastic BMS And Where To Find Them (?)
Replies: 24
Views: 1247

Re: Fantastic BMS And Where To Find Them (?)

https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36 I have several of these, and ran into a number of problems including sloppy support. Biggest problem to date is complete damage of a cell group in a pack out of Nissan Leaf modules due to loss of power to the board - e-mailed them a ...
by Taswegian
Jun 25 2019 1:24am
Forum: Battery Technology
Topic: Fantastic BMS And Where To Find Them (?)
Replies: 24
Views: 1247

Re: Fantastic BMS And Where To Find Them (?)

About 4x the price of a chinese version but given you previous experience & requirements that might be a non issue for you; https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36 I haven't used one, but they appear to be well made with top spec parts. Very compact, smallest I've seen with...
by Taswegian
Jun 14 2019 4:46pm
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 1100
Views: 92673

Re: bluetooth BMS?

Could anyone please advise on their approach to soldering the B- & C- wires to these BMS. I have a couple from James at LTT power and the pads for these connections seem very small, there isn't much 'meat' around the hole to solder to. Also, on one side they don't actually even connect to the main a...
by Taswegian
May 29 2019 5:54am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1517

Re: Panny or Sanyo?

Thanks Matador for taking the time to lay it out so fully and with precise writing, well done, and this does agree with other information on the topic. There are so many variables, and of course shoddy quality, in materials purity or manufacturing QA will override these finer distinctions. So, my c...
by Taswegian
May 28 2019 4:54pm
Forum: Battery Technology
Topic: mega copper battery spotwelder
Replies: 19
Views: 965

Re: mega copper battery spotwelder

silentflight wrote:
May 28 2019 4:01pm
Just when you wonder if the Sphere is starting to go soft, somebody picks up the reins and goes wholly and appropriately overboard.

Good luck !
Yeah, stay tuned next month for a thread asking where to procure plutonium for a home made reactor powered spot welder.
by Taswegian
May 25 2019 4:50am
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 1100
Views: 92673

Re: bluetooth BMS?

are there any programmable bluetooth bms that are just 1 cell high? i need to make a flat battery and 7cm is my thickness limit. Do you mean a BMS that fits within the footprint of a single cell, ie 18 x 18 x 65 ? (Edit - or maybe you're asking for longest BMS dimension to be no more than cell leng...
by Taswegian
May 14 2019 2:56am
Forum: Battery Technology
Topic: Clarification on the 20% Rule
Replies: 14
Views: 681

Re: Clarification on the 20% Rule

ahh, so it is also much better to charge it to 50% for overnight storage? i usually charge it to 80% ready for the next morning 80% is fine. Most of the benefit comes from avoiding the top 15%. Below 80% you're into rapidly diminishing returns. 50% is ideal for longer term storage. Vacations, winte...
by Taswegian
May 08 2019 6:02am
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 1100
Views: 92673

Re: bluetooth BMS?

That's really the job of the charger rather than the BMS. There are sophisticated programmable chargers like the Grin Cycle Satiator that allow you to configure difference charging regimes and switch between them easily. Cheaper option is chargers that have two target charge levels and a physical sw...
by Taswegian
Apr 19 2019 3:50pm
Forum: Battery Technology
Topic: DIY copper/nickel buses for 18650's
Replies: 12
Views: 764

Re: DIY copper/nickel buses for 18650's

Have you researched the galvanic corrosion issue? Maybe a thin bonding coat of conductive epoxy between, rather than heat. . . Should be a non issue? Nickel & Copper are both very low and very close in anodic index, so neither becomes a preferential site of oxidation/reduction supplying the other.
by Taswegian
Apr 19 2019 7:38am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

I'd like to add a few important things that haven't got their way into the manual yet: - make sure not to apply external voltage to the electrodes - do not let them touch different voltage potentials of your battery under construction. ... - even when using an enclosure for the welder, never touch ...
by Taswegian
Apr 17 2019 10:23am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

The only thing getting warm is the silicone 8Ga. Does this welding machine have a duty cycle not to be exceeded? I dont wnat to abuse it whatsoever, and I will be patient if need be. After the weld pulse keep the the trigger switch down. The display will cycle through some info, one of these is tem...
by Taswegian
Apr 16 2019 3:52pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

My biggest problem with welding copper with kweld is that it seems so hard to make good weld at negative end of the cell. Positive is easy and as strong as 0.1mm copper can be I think. Negative maybe needs some extra joules but I am little afraid of it because I already made one hole and smelled th...
by Taswegian
Apr 16 2019 9:21am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

Good point on W/Cu blend. Tungsten is a bit over 3x resistance of copper, not quite as bad as nickel but not far off. 50/50 about halves it while still retaining most of the desirable properties.
by Taswegian
Apr 16 2019 3:19am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

I saw in another thread someone making very neat welds of copper sheet to batteries using tungsten electrodes (perhaps repurposed from TIG?) Any thoughts on offering something similar? Obviously much less conductive than copper so presumably the idea would be to clamp them in copper and only have a ...
by Taswegian
Apr 11 2019 9:18am
Forum: Battery Technology
Topic: How to dismantle a spotwelded battery?
Replies: 14
Views: 601

Re: How to dismantle a spotwelded battery?

Ordered :thumb: Damn, price history on Amazon shows they were €16 a few days ago. Not that pricey when you compare to GodHands https://www.amazon.de/Gott-hand-spn120-Ultimate-Nipper/dp/B008S51O22/ref=sr_1_1?keywords=GodHand&qid=1554990390&s=gateway&sr=8-1 :lol: you can get the wiha for 12 euro at h...
by Taswegian
Apr 11 2019 9:12am
Forum: Battery Technology
Topic: How to dismantle a spotwelded battery?
Replies: 14
Views: 601

Re: How to dismantle a spotwelded battery?

There might not be enough series connections, and that is a frequent source of voltage drop under load. The graph shows lots of little sags of a few volts that seems load related but one of the big 'box canyon' drops to 10V is with no load at all. Surely a bad connection? But not necessarily in the...
by Taswegian
Apr 11 2019 8:48am
Forum: Battery Technology
Topic: How to dismantle a spotwelded battery?
Replies: 14
Views: 601

Re: How to dismantle a spotwelded battery?

Ordered :thumb:

Damn, price history on Amazon shows they were €16 a few days ago.

Not that pricey when you compare to GodHands

https://www.amazon.de/Gott-hand-spn120- ... way&sr=8-1

:lol:
by Taswegian
Apr 11 2019 4:02am
Forum: Battery Technology
Topic: Am wanting a 10A continuous 18650-21700 cell
Replies: 21
Views: 856

Re: Am wanting a 10A continuous 18650-21700 cell

Attempt #2. Since a big battery isn't an option I'll suggest something I'm doing with some 2P short range batteries for my current bike project. Have more batteries. If it's possible have a way to dismount the battery easily & have 2 or more (I'll have 5, shared with my GF). Then it's feasible to ch...
by Taswegian
Apr 11 2019 3:39am
Forum: Battery Technology
Topic: Am wanting a 10A continuous 18650-21700 cell
Replies: 21
Views: 856

Re: Am wanting a 10A continuous 18650-21700 cell

EDIT - I replied a day after I read the thread and forgot that this battery is very space constrained on a scooter so the below doesn't apply in this case but I'll leave it anyway. Choosing a suitable cell is certainly important, but if you want good cycle life then the other very important factor i...
by Taswegian
Apr 10 2019 5:31am
Forum: Battery Technology
Topic: How to dismantle a spotwelded battery?
Replies: 14
Views: 601

Re: How to dismantle a spotwelded battery?

Wouldn't it be much less trouble to just replace the BMS and see how that goes? Is there a reason you want to change to a no-weld assembly, maybe changing pack shape?

Regarding grinding weld dags - corrosion isn't a concern but heat might be, don't be too heavy handed.
by Taswegian
Apr 08 2019 5:39am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 806
Views: 96168

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

Is there any merit in minimizing the length of the battery cables? (AWG10) I will be replacing the XT90 with XT150 anyway so its no more work to cut them shorter. Edit - I suppose going too short might risk too much heat conducting into the battery while soldering the XT150, not sure if this is an i...
by Taswegian
Apr 01 2019 9:09am
Forum: Battery Technology
Topic: mass life cycle testing
Replies: 33
Views: 2380

Re: mass life cycle testing

Thanks for sharing your test data, is there a link to an index of results so far? In various threads I've found googledocs links to individual results but couldn't figure out where to see an overview or complete list. In particular I'm making some 2P packs for short trips close to home and I'm wonde...