Search found 112 matches

by Dak77
Jul 30 2020 4:31pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

I like it. It's giving me some ideas on future builds. I need to get a printer now. Not having to worry about tension due to using those magnets instead of spring type contacts opens up some cool possibilities concerning enclosure design. I could see a pvc tray with a 2 tiered relief for cell then a...
by Dak77
Jul 06 2020 6:57pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

Were there any signs of the plasti dip breaking down around the stress areas?
by Dak77
Jul 06 2020 5:17am
Forum: Battery Technology
Topic: 40T cycle test
Replies: 24
Views: 909

Re: 40T cycle test

nice. Not too shabby for such a high amp cell
by Dak77
Jun 25 2020 4:28pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

Let me remind LG HG2 No2 : LG HG2 No2, production date November 2017. Purchased fom nkon in September 2018. Cell stored at aprox 25 – 40 % SOC, 15° - 20°C. In December 2018 capacity 2 909 mAh at 3 A discharge, measured at ZKETECH EBC-A10H. In September 2019 : 2836 mAh at 1A, 2804 mAh at 3 A, measur...
by Dak77
Jun 22 2020 12:36am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

If there's one thing I learned in the barrage of data I've seen over the past year or so here, it's what NOT to buy. That alone has saved me a lot of time and money. Huge thank you ! to everyone involved .
by Dak77
Jun 22 2020 12:16am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

I'm sure he's going to continue testing cells in the future anyway. Very probably not, cells testing became boring. Vegetable growing is much more interesting and enjoyable. :) 1.jpg 3.jpg Comparing cells tested at different times, by different people with different equipment is impossible. Wrong, ...
by Dak77
Jun 18 2020 8:35pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

Since you're into the more obscure cell testing, another future consideration , maybe a Queen Battery qb26800 . If that thing has even decent cycle life , it would be very interesting. I saw that battery here, Thunderheart did it but something turned me off of it? probably because they wouldn't sel...
by Dak77
Jun 18 2020 1:40pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

Since you're into the more obscure cell testing, another future consideration , maybe a Queen Battery qb26800 . If that thing has even decent cycle life , it would be very interesting.
by Dak77
Jun 18 2020 1:35pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

I like the work you're doing . Would have never given magnets a serious thought until now. thanks, the 40T cycle test im doing in the other thread is using 3/8x1/8x1/8 ring magnets to see if they last. ive got a molicel p42a coming and im going to use these new magnets with the slug tape on that cy...
by Dak77
Jun 16 2020 7:34pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 107
Views: 2497

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

I like the work you're doing . Would have never given magnets a serious thought until now.
by Dak77
Apr 29 2020 5:56pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

If there's a website or forum with this type of in- depth cycle testing by equally competent observers, I haven't seen it yet. There's Mooch and Thunderheart with their load/capacity/temperature/resistance measurements, but it seems you are of the very few (possibly the only ones in the world) doing...
by Dak77
Apr 25 2020 11:01pm
Forum: Battery Technology
Topic: Queen Battery QB26800 6800mAh 20A - the big guy!
Replies: 30
Views: 3696

Re: Queen Battery QB26800 6800mAh 20A - the big guy!

Being better than something known to be grossly overpriced, of very poor quality or known to be fraudulent, is not a high bar is it. I'm not saying they may not be fantastic for people that are on a budget and don't need much power density. Whether they actually are or not, remains to be seen, when...
by Dak77
Apr 25 2020 7:26pm
Forum: Battery Technology
Topic: Queen Battery QB26800 6800mAh 20A - the big guy!
Replies: 30
Views: 3696

Re: Queen Battery QB26800 6800mAh 20A - the big guy!

john61ct wrote:
Apr 25 2020 3:12pm
Well longevity is one data point that really needs member testing.

But 1C rates likely don't inspire too many among those circles?
For the kW+ riders, probably not. For the run of the mill 500w-750w bikes , they'd make a good replacement for those stupid priced 13-15ah sh*t bricks .
by Dak77
Apr 25 2020 2:35pm
Forum: Battery Technology
Topic: Queen Battery QB26800 6800mAh 20A - the big guy!
Replies: 30
Views: 3696

Re: Queen Battery QB26800 6800mAh 20A - the big guy!

I got the data sheet on this cell, it shows different stats, its 20mohm not 10mohm. 6.8a/ 1c charge/discharge 500x is 80% capacity not 90%. at 3.4a/0.5c charge/discharge 500x is 90% capacity. still a cheap battery though http://queenbattery.com.cn/our-products/684-qb26800-li-ion-battery-cell-qb-268...
by Dak77
Apr 24 2020 2:24am
Forum: Items Wanted
Topic: Tektro Electric Brake Levers with Integrated Bell
Replies: 7
Views: 1462

Re: Tektro Electric Brake Levers with Integrated Bell

did you still need this? i ran across a couple, would need to dig them out and post pics. I recently bought a radrunner to haul my little girl around on and I am wanting to scrap these mechanical disks for some Deore hydraulics . Am I correct in assuming the yellow 3 pin connectors coming from thes...
by Dak77
Apr 22 2020 4:11pm
Forum: Battery Technology
Topic: How long is it safe to use an ebike battery?
Replies: 21
Views: 788

Re: How long is it safe to use an ebike battery?

I'm more asking than stating , but wouldn't testing internal resistance be the clear way of knowing if a battery is still safe? If it's still within a certain percentage range of original DCIR , it hasn't "decayed" to an unsafe point , correct?
by Dak77
Apr 22 2020 4:02pm
Forum: Battery Technology
Topic: Luna Charger dead after 10 uses.
Replies: 25
Views: 713

Re: Luna Charger dead after 10 uses.

That's one reason I always shake any high current / high voltage power supply or charger like a psycho before I plug them in. All it takes is one little piece of random loose conductive material to make short work of a hundred dollar bill (or 3) . Especially well ventilated units with big airy grill...
by Dak77
Apr 18 2020 4:09am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

HG2 though. Wow. I'm super stunned. That thing is a beast.
by Dak77
Apr 18 2020 3:31am
Forum: Battery Technology
Topic: Advice for homemade 13s8p pack? (low power)
Replies: 1
Views: 190

Re: Advice for homemade 13s8p pack? (low power)

I'm no expert, but I'll throw this out there based on reading the work of others . At 500watts (This is assuming your controller maxes out around 10 amps) almost any cell will do well with an 8p battery. If they're available where you live, LG cells are about the top tier 18650s in lithium ion. In o...
by Dak77
Apr 16 2020 10:27pm
Forum: Battery Technology
Topic: LiNiMnCo saturation question
Replies: 7
Views: 305

Re: LiNiMnCo saturation question

Yeh, I got the impression it was more about "plug it in and quit worrying about it" than trying to squeeze the small remaining capacity out of it. He's a very intelligent dude , but is known for shooting off the hip. The conversation started off with a discussion about using bms in mobile applicatio...
by Dak77
Apr 16 2020 2:21am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49767

Re: Li-ion cells cycle ageing

I think I remember reading a while back that 35E is very sensitive to charge current , so they may be very decent when charged at low rates around 500-700ma . Just a hunch.
by Dak77
Apr 14 2020 8:02pm
Forum: Battery Technology
Topic: LiNiMnCo saturation question
Replies: 7
Views: 305

Re: LiNiMnCo saturation question

Thank you for the clarification. I'm happy to be wrong in this case.
by Dak77
Apr 14 2020 6:10pm
Forum: Battery Technology
Topic: LiNiMnCo saturation question
Replies: 7
Views: 305

LiNiMnCo saturation question

I've had a couple of "who I consider very knowledgeable " people advise me that all lithium ion batteries can be damaged by over saturating them , even at lower voltages . For instance, setting terminal voltage to 4.05v but leaving it on charge well below 50ma before terminating . I had an electrica...
by Dak77
Apr 10 2020 11:46pm
Forum: Battery Technology
Topic: Cylindrical cell assembly concept
Replies: 25
Views: 817

Re: Cylindrical cell assembly concept

My thinking is the conductor bonding to the cell ends is completely independent of, not relying on the physical compression for the integrity of the electrical contact. That latter combined with a flexible sealant or foam, maybe potting compound, to cushion against shock / vibration. Thus the cells...