Search found 121 matches

by BYqSXt8Z
Nov 06 2019 10:06am
Forum: Battery Technology
Topic: Gear for logging C-rate vs Temperature, also capacity
Replies: 13
Views: 1789

Re: Gear for logging C-rate vs Temperature, also capacity

Doesn't hit all the points, but for 10$ of parts I log charge / discharge cycles at up to 20A discharge, 5A charge, and accuracy is pretty good, reliability is excellent. I'm not quite done yet, but the latest version is far more robust and quick to assemble. I still need to figure out how to better...
by BYqSXt8Z
Sep 27 2019 3:20pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1242
Views: 188382

Re: JP spot welder

Depends what polarity, of 12V logic supply no, it has protection diode (if it doesn't work, just reverse the polarity), but don't mix the polarity from the welding battery. Welder goes to the negative pole. If you have any doubts please ask before trying, thanks! :) And once I've screwed that up, w...
by BYqSXt8Z
Sep 08 2019 4:03pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1242
Views: 188382

Re: JP spot welder

Yup, I bought the last 2 diy kits and I'll upgrade those heatsinks... I'll get amazing duty cycle :D Sent from my CLT-L04 using Tapatalk Which heatsinks will you use? I'll be putting in copper bars where the aluminum bars currently are. Maybe with some slots in there too. Sent from my CLT-L04 using...
by BYqSXt8Z
Sep 08 2019 3:49pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1242
Views: 188382

Re: JP spot welder

tomjasz wrote:
BYqSXt8Z wrote:
Sep 08 2019 12:20pm
Yup, I bought the last 2 diy kits and I'll upgrade those heatsinks... I'll get amazing duty cycle :D

Sent from my CLT-L04 using Tapatalk
Which heatsinks will you use?
I'll be putting in copper bars where the aluminum bars currently are.

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Sep 08 2019 2:54pm
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

If you're going to use it, the SSD1306ASCII library is amazingly small and efficient.

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Sep 08 2019 12:20pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1242
Views: 188382

Re: JP spot welder

Yup, I bought the last 2 diy kits and I'll upgrade those heatsinks... I'll get amazing duty cycle :D

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Sep 06 2019 4:10pm
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

Oled 0.91" display

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Sep 06 2019 1:00pm
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

Battery cycler prototype built! Now custom pcb coming to clean it all up. Ps since there was a comment about the resistor board, it's super simple but here I the design anyways. I use jumpers to make any combination from 1 - 15 p resistors to get a bunch of different values. It's based on putting 5w...
by BYqSXt8Z
Sep 06 2019 6:48am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

I just confirmed, the a123 data sheet specifies ac testing at 1khz... I'll have to compare usefulness!

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Sep 03 2019 10:02am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

Impedance measured at 1kHz won't tell you the same thing as IR measured at DC, but it's easier to make the tester. DCIR measurements can be done by watching the voltage sag and recovery from a high load placed on the cell for a few seconds. There are some testers out there that do this. Ummmm I wen...
by BYqSXt8Z
Sep 03 2019 8:08am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

Thanks :) I'm not super happy with the reliability of those b6 but no surprise there. They are still very helpful for bulk processing to ready everything for the precision tests or for regular use though. V1 of the arduino prototype will be tested today when I get my high current 22650 holder in :) ...
by BYqSXt8Z
Sep 02 2019 10:29am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

So to get the correlations down I'll be doing some endurance testing on some sacrificial cells (1000 cycles). The issue I'll have is it takes around a month to run a single cell. That means I need to test with many cheap testing rigs, so I've designed one from jellybean components and modules, contr...
by BYqSXt8Z
Aug 31 2019 10:57am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

By measuring cell IR and voltage you can get a pretty good idea if a cell is bad or not, but the only way I know of to check capacity is to do a full charge/discharge test. You might try doing the fast tests on a sample of cells and see how it correlates to the actual capacity. If the cells were no...
by BYqSXt8Z
Aug 31 2019 8:07am
Forum: Alternative Energy
Topic: Testing large amounts of cells quickly
Replies: 16
Views: 2062

Re: Testing large amounts of cells quickly

Hi guys, Battery University came up with a quick way to analyze lithium cells using pulse frequencies... If someone could reproduice this electronic device to adapt to many individual channels (multiplexing circuit) then many cells could be checked in a very short time. https://batteryuniversity.co...
by BYqSXt8Z
Aug 29 2019 1:02pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1242
Views: 188382

Re: JP spot welder

riba2233 wrote:Cmon guys, still available! :)
Pmed you

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Aug 23 2019 4:27pm
Forum: Items for Sale - New
Topic: Lifepo4 BMS, shrink tubing, and watt Meters
Replies: 0
Views: 560

Lifepo4 BMS, shrink tubing, and watt Meters

I have various Lifepo4 bms for sale. All located in, and shipping from Canada. Prices in USD. 1s 2A with tabs 1$ 4s 30A balancing with temp shutoff 10$ 12s 30A balancing with temp shutoff 12$ 24s 30A balancing with temp shutoff 20$ I also sell some shrink tubing 1/4" - 0.3$ per meter (clear) 1/2" - ...
by BYqSXt8Z
Aug 08 2019 4:55pm
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

Other useful threads https://endless-sphere.com/forums/viewtopic.php?t=98407 https://www.rcgroups.com/forums/showthread.php?2406395-An-effective-variable-load-automatic-LiPo-discharger/page32#post40969831 https://www.rcgroups.com/forums/showthread.php?1107072-How-to-build-a-constant-current-dischar...
by BYqSXt8Z
Aug 08 2019 10:53am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

john61ct wrote:Here's a start, but of course googling the right keywords will yield a lot more

http://www.skoolie.net/forums/showthread.php?p=342306
Huge thanks, and noted for the CC! You've been great help... Time for more troubleshooting!

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Aug 08 2019 10:28am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

First off, the same constant-current controller device (electronic dummy load) should be used for both rates for accurate comparability. Make sure the same precise 100% charge point is reached before every test, holding the exact same Absorb termination / voltage until a precisely (accurately) meas...
by BYqSXt8Z
Aug 08 2019 6:46am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

john61ct wrote:Are you saying you are relying on mAh totalizers, counting coulombs?

As opposed to using an CC electronic load tester and precise timing to determine discharging capacity?
Oh wait you mean constant current or coulomb counter?

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Aug 08 2019 6:33am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

Are you saying you are relying on mAh totalizers, counting coulombs? As opposed to using an CC electronic load tester and precise timing to determine discharging capacity? I'm using a load tester for the higher discharge, it's the lower discharge rate (0.025c) that I did with the b6ac in a charge (...
by BYqSXt8Z
Aug 08 2019 1:04am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Re: Lower capacity at lower discharge current

Two different ways, the first is with a dedicated dc watt meter, the other is with my b6 charger.

Sent from my CLT-L04 using Tapatalk

by BYqSXt8Z
Aug 08 2019 12:46am
Forum: Battery Technology
Topic: Lower capacity at lower discharge current
Replies: 14
Views: 640

Lower capacity at lower discharge current

So I'm trying to test some lifepo4 batteries and I've come across a very strange behaviour. I'm hoping someone here may have an explanation for the phenomenon in question. When I discharge batteries at 0.5c, I get near nominal capacity, and the measured charge Wh is generally pretty close to the dis...
by BYqSXt8Z
Aug 07 2019 8:58am
Forum: Battery Technology
Topic: MiniSpotA spot welder
Replies: 56
Views: 7847

Re: MiniSpotA spot welder

It's amazing, and even more so that he left the plans up / AFAIK it's open sources hardware ! I had lots of fun trying to make mine. I just need foil and a bigger battery to test it with [emoji14] I decided to make myself a challenge and shrink it down to 1cmx10cm with smd so I can machine a pen sha...
by BYqSXt8Z
Jul 21 2019 4:58pm
Forum: Items for Sale - Used
Topic: Ebike etc garage sale: motors, controllers, mechanical bits
Replies: 4
Views: 1045

Re: Ebike etc garage sale: motors, controllers, mechanical bits

Payment sent for LYEN controller and CA

Sent from my CLT-L04 using Tapatalk