one cell group wont fully charge

[m3vuv]

glad you sorted it as i spent well over an hour+ inputting data for 120+ cells only to see half of it missing when i saved it,it pissed me off big time,handy site tho but i am not sure how the battery configurator on the site works!

 

[mickyd]

glad you sorted it as i spent well over an hour+ inputting data for 120+ cells only to see half of it missing when i saved it,it pissed me off big time,handy site tho but i am not sure how the battery configurator on the site works!

I don't see a battery configurator on the https://www.repackr.com/ site. Do you??

I am aware of this one....... https://e4bike.ru/page/battery-shape-configurator?lang=en .

 

[mickyd]

its this.i spelt it wrong.https://www.repackr.com/

I appreciate you sharing that site. I'm going to practice my first battery build using old cells and it will really help me make the best parallel combo with my used varying cells.

If someone has done this already, apologies from the newbie since I haven't read every post in the forum yet. :lol: Plus I probably wouldn't even remember if I did.

If anyone wants to try out that 'rePackr' website https://www.repackr.com/ that m3vuv mentioned, you can use the string of data below. The site is used to determine the optimal arrangement of measured cell mAH capacities to put into each parallel group so that they are close to each other. Use this string of 41 pretend cell mAH values just to see how the site works. Cut and paste them into the field found after you select the 'Packer' icon on the left side of the page.

2501, 2562, 2514, 2562, 2514, 2631, 2842, 2356, 2485, 2545, 2565, 2566, 2455, 2112, 2585, 2574, 2595, 2578, 2985, 2678, 2578, 2356, 2543, 2566, 2333, 2111, 2456, 2589, 2546, 2865, 2568, 2456, 2564, 2666, 2333, 2314, 2111, 2100, 2564, 2658, 2653

On step 2 of the process, indicate 13 series and 3 parallel in the respective fields. You can then proceed and figure things out. You notice that the program will automatically exclude the 2 lowest cells since there are 41 values but only 39 are needed for the 13S3P configuration.

I thought this site was VERY helpful.

 

[eMark]

If anyone wants to try out that 'rePackr' website https://www.repackr.com/ that m3vuv mentioned, you can use the string of data below. The site is used to determine the optimal arrangement of measured cell mAH capacities to put into each parallel group so that they are close to each other. Use this string of 41 pretend cell mAH values just to see how the site works. Cut and paste them into the field found after you select the 'Packer' icon on the left side of the page.

2501, 2562, 2514, 2562, 2514, 2631, 2842, 2356, 2485, 2545, 2565, 2566, 2455, 2112, 2585, 2574, 2595, 2578, 2985, 2678, 2578, 2356, 2543, 2566, 2333, 2111, 2456, 2589, 2546, 2865, 2568, 2456, 2564, 2666, 2333, 2314, 2111, 2100, 2564, 2658, 2653

On step 2 of the process, indicate 13 series and 3 parallel in the respective fields. You can then proceed and figure things out. You notice that the program will automatically exclude the 2 lowest cells since there are 41 values but only 39 are needed for the 13S3P configuration.

I thought this site was VERY helpful.

Thanks for posting. There are 4 low cells (2112, 2111, 2111 and 2110) with two highest cells at 2985 and 2865 (e.g. 2985 - 2112 = 773mAh variance and 2865 - 2111 = 754mAh variance) ??

Could you post how that program would matchup the above thirteen 3 parallel groups ? Would be of some interest to see if 2985 & 2111 are in the same 3p group and 2865 & 2112 in the same 3p group.

2985 + 2111 = 5096 ÷ 2 = 2548 ... 2865 + 2112 = 4977 ÷ 2 = 2489. Would be interesting to see what the minimum mAh variance is among the thirteen 3p groups using that repackr program. Do you have a link to the actual program where one can plug in the mAh rating of above cells for a 13s3p battery and a 10s4p for comparison using these same cells.

Wasn't able to find link that will direct to actual program for best arrangement of used cells having varying capacity.

 

[mickyd]

Thanks for posting. There are 4 low cells (2112, 2111, 2111 and 2110) with two highest cells at 2985 and 2865 (e.g. 2985 - 2112 = 773mAh variance and 2865 - 2111 = 754mAh variance) ??

Could you post how that program would matchup the above thirteen 3 parallel groups ? Would be of some interest to see if 2985 & 2111 are in the same 3p group and 2865 & 2112 in the same 3p group.

2985 + 2111 = 5096 ÷ 2 = 2548 ... 2865 + 2112 = 4977 ÷ 2 = 2489. Would be interesting to see what the minimum mAh variance is among the thirteen 3p groups using that repackr program. Do you have a link to the actual program where one can plug in the mAh rating of above cells for a 13s3p battery and a 10s4p for comparison using these same cells.

Wasn't able to find link that will direct to actual program for best arrangement of used cells having varying capacity.

Just to make sure you know.....my data was made up...not actual test values.

You mentioned you couldn't find the actual program for best arrangement. It's found at https://www.repackr.com/

I attached two screengrab analysis from that site for the 13 groups. You'll notice on the bottom there are UNUSED cells, which were automatically excluded since they were lowest.

Enjoy the review!!

 

[eMark]

That link ... https://www.repackr.com/... only lists several replies from 2020. There is no further link to open up the actual builder for entering cell capacities and pack size(s).

Found this link ... https://cellsaviors.com/pack-builder ... that basically does same. It would be interesting if able to open Repackr Builder to compare with Cellsaviors Builder using same cell capacities and two different pack sizes (e.g. 13s3p and 10s4p).

Also youtiubes ... https://www.google.com/search?rlz=1C1GCEJ_enUS1024&q=How+do+I+use+Repackr+com%3F&sa=X&ved=2ahUKEwjcxNKfnan6AhV9FzQIHTAWAX4Qzmd6BAgSEAU&biw=1920&bih=969&dpr=1 ... offer additional suggestions

 

[mickyd]

That link ... https://www.repackr.com/... only lists several replies from 2020. There is no further link to open up the actual builder for entering cell capacities and pack size(s).

Found this link ... https://cellsaviors.com/pack-builder ... that basically does same. It would be interesting if able to open Repackr Builder to compare with Cellsaviors Builder using same cell capacities and two different pack sizes (e.g. 13s3p and 10s4p).

Also youtiubes ... https://www.google.com/search?rlz=1C1GCEJ_enUS1024&q=How+do+I+use+Repackr+com%3F&sa=X&ved=2ahUKEwjcxNKfnan6AhV9FzQIHTAWAX4Qzmd6BAgSEAU&biw=1920&bih=969&dpr=1 ... offer additional suggestions

To use the site, you need to click the 'Packer' left menu item shown below. You were stuck on the 'Home' page.

I'll check out your other links in a few. Thanks.

 

[mickyd]

Found this link ... https://cellsaviors.com/pack-builder ... that basically does same as https://www.repackr.com/. It would be interesting if able to open Repackr Builder to compare with Cellsaviors Builder using same cell capacities and two different pack sizes (e.g. 13s3p and 10s4p).

Using the SAME CELL CAPACITY DATA from my previous post (https://endless-sphere.com/forums/viewtopic.php?f=14&t=117655&p=1733451#p1733284), I found differences between the 2 sites in their recommended cell groupings to go in each parallel group. What's odd is in a perfect world, there should be only 1 mathematically best combination and NEITHER of them are giving it.

I need to better understand before posting my results. Instead of piggy backing on this thread, I'll created a new one. If having consistent parallel group mAh ratings is important, the info I came across needs to be shared.

As a teaser, Repackr's individual group capacities were closer to the average capacity of the entire pack. That's the goal, right???

 

[eMark]

As a teaser, Repackr's individual group capacities were closer to the average capacity of the entire pack. That's the goal, right???

Right; especially with an ebike performance pack versus a powerbank with lower amp drain. The more p-groups the better (at least 5p).

Personally i wouldn't use 7 those 41 make-believe cells (2985, 2865, 2842, 2012, 2011, 2011, 2011), even if just for powerbank application. If ebike use for casual riding i might also eliminate 2333. 2333, 2314. Better to have noticeable variance on high side (e.g. 2678, 2666, 2664) than low side (e.g. 2333. 2333, 2314). IMO, there's too much capacity variance on high side with these three ... 2985, 2865, 2842.

There should be some rule of thumb for allowable variance when building a pack with old unused cells or used cells of questionable quality. IR variance is another factor that needs to be considered.

 

[mickyd]

imwaiting on delivery of a litkala lii500 then will test the cells,i am going to leave my bike on charge overnight and check pack voltage on the throttle display and with the bt app,,need to take the guts out of the battery to fit a uart interface anyway so will tear it apart then.

Glad I read this thread a couple days ago. I was going to buy an Opus BT-C3100p for $50 but instead, got this LitKala Lii-500 Intelligent Charge for $28 with same features + the one button charge / discharge Nor function for capacity testing. . Doing my first practice 13S3P build from a $100 blue shrink tube pack where a couple cells went bad. Thanks for mentioning.

 

[eMark]

Iteresting when comparing these two: https://cellsaviors.com/pack-builder ... and ... https://www.repackr.com/ using same identical 41 mAh capacities for that 13s3p (what-if) salvaged 18650 DIY build.

Using the SAME CELL CAPACITY DATA from my previous post (https://endless-sphere.com/forums/viewtopic.php?f=14&t=117655&p=1733451#p1733284), I found differences between the 2 sites in their recommended cell groupings to go in each parallel group. What's odd is in a perfect world, there should be only 1 mathematically best combination and NEITHER of them are giving it.

Repackr will calculate different groupings each time you go back and click on "Start Again". I did this ten times using the same identical cell capacity sequence and came up with different groupings each time i clicked on "Start Again". Apparently there are numerous combination possibilities. I stopped at ten with the realization i could go on forever?

2501, 2562, 2514, 2562, 2514, 2631, 2842, 2356, 2485, 2545, 2565, 2566, 2455, 2112, 2585, 2574, 2595, 2578, 2985, 2678, 2578, 2356, 2543, 2566, 2333, 2111, 2456, 2589, 2546, 2865, 2568, 2456, 2564, 2666, 2333, 2314, 2111, 2100, 2564, 2658, 2653

Then I tried doing the same with Cellsaviors Builder using the same 41 cells, but entered them two different ways ...

2501, 2562, 2514, 2562, 2514, 2631, 2842, 2356, 2485, 2545, 2565, 2566, 2455, 2112, 2585, 2574, 2595, 2578, 2985, 2678, 2578, 2356, 2543, 2566, 2333, 2111, 2456, 2589, 2546, 2865, 2568, 2456, 2564, 2666, 2333, 2314, 2111, 2100, 2564, 2658, 2653

and again usng same identical 41 cell capacities, but rearranged in this order from lowest mAh capacity to highest ...

2100, 2111, 2111, 2112, 2314, 2333, 2333, 2356, 2356, 2455, 2456, 2456, 2485, 2501, 2514, 2514, 2543, 2545, 2546, 2562, 2562, 2564, 2564, 2565, 2566, 2566, 2568, 2574, 2578, 2578, 2585, 2589, 2595, 2631, 2653, 2658, 2666, 2678, 2842, 2865, 2985

Either way resulted in same thirteen with the same identical three cells in each 3p group using Cellsaviors Builder.

Confusing when Cellsaviors Builder only has one solution; whereas Repackr Builder has at least ten different 13s3p capacity arrangements when clicking on "Start Again" ten times. Logic would suggest that there's not a perfect arrangement with thirteen 3p groups. This is where IR becomes another factor to consider for a mathematical combination. Having two sites for comparison is helpful. Wonder how many times you'd have to "Start Again" with Repackr Builder before arriving at the same identical grouping as with Cellsaviors Builder (could take forever :wink: ).

BUT, But, but is Cellsaviors Builder the best possible mathematical arrangemed marriage for those 41 unique cells :wink:

 

[mickyd]

Iteresting when comparing these two: https://cellsaviors.com/pack-builder ... and ... https://www.repackr.com/ using same identical 41 mAh capacities for that 13s3p what-if salvaged 18650 DIY build.

Confusing when Cellsaviors Builder only has one solution; whereas Repackr Builder has at least ten different 13s3p capacity arrangements when clicking on "Start Again" ten times. Logic would suggest that there's not a perfect arrangement with thirteen 3p groups. This is where IR becomes another factor to consider for a mathematical combination. Having two sites for comparison is helpful. Wonder how many times you'd have to "Start Again" with Repackr Builder before arriving at the same identical grouping as with Cellsaviors Builder (too long for me to try).

A 13S3P pack has 39 unique cells so there are 9,139 possible combinations of 3 cells in parallel. The 'perfect' arrangement (least capacity difference between all parallel groups) is only known when trying all 9,139 combinations, then comparing each group average to the average capacity of all cells combined. Neither CELLSAVIORS or rePackr go to this extent, yet they COULD if programmers wanted their result 'the best'.

I guess it really comes down to how close is close enough....aka the 'tolerance' of group capacity differences, which I have NO idea what it should be. Maybe both sites stop calculating when they are within x% ???

In the attachment below, you'll notice the DIFFERANCE between high and low group capacity between the 2 programs:

rePackr = +32 to -33 mAh. *****rePackr give you different results each time you run it****
cell savior = +91 to -90 mAh. *****CELLSAVIORS give the same result each time you run it****

Based on that 1 run, rePacker had the least variation.

 

[eMark]

here it is now,looks ok to me?

That's a very 'smart' BMS that can balance the 13 p-groups within 0.005V of each other (2 of the p-groups at 4.200V and the other 11 at 4.195V). Approximately how many hours did you leave the Charger plugged in after GREEN light came on to balance all 13 p-groups within 5mV of each other ?
https://www.ebay.co.uk/itm/313332095639?hash=item48f40c5a97:g:Xu4AAOSweR9fzJ41&amdata=enc%3AAQAHAAAA4Mo7%2FLy%2BN2kDq9IqPpGAe1Dv%2BlcIZ1SkxXtGZaX18N%2BsXDyXFLvxtv8sgHB1Mp29EzNauR%2BBdUYlbFURZVzjRZRUk9hD%2FJdxusX2Tr%2FTWjpSIXhoF479YEwZkES9SAo64ibUaQkeIPM7CeNN0tmQDve0i6ssyGB%2BbdApcXYel%2FJ5mDEUG9GYcvQOjcQGC2f4i6IAFHwmKzLnDcgV7BLzIr04tu9k%2Fv4ZfnIOPDPVcRgqg%2F%2F7D7zCzp3E%2F39WNRpdih%2BO69FV5VGp3f7AgS8T7U5wn4OrxtKZFlcjE1lpSbCL%7Ctkp%3ABFBMvIDx0eNg ... $50-$55

According to the above example readout the balance deviation between the 13 p-groups is 0.029V. We've always assumed the best a generic inexpensive BMS could balance the p-groups was within 25-30mV of each other. A tolerance which we all accepted as 'reasonable' (good enuf). Can current 'smart' BMS technology equalize p-groups within 5mV ?

The above 12S example readout is hard to figure why only 7 of the p-groups are being balanced. One has to assume the balancing is constantly changing between the 12 p-groups and just happened to be on these 7 when captured by a digi-image. Is this 12S BMS also capable of "actively equalizing" the 12 p-groups within 0.005mV of each other(?) as with your 13s 40A BMS.

Just a matter of how many hours is required after GREEN light comes on before equalizing all p-group voltages within 5mV. NOTE: The above readout supposedly represents the same 13S & 14S 'smart' BMS technology even though only a 12S 'smart' BMS shown in readout ... https://www.ebay.co.uk/itm/313332095639?hash=item48f40c5a97:g:Xu4AAOSweR9fzJ41&amdata=enc%3AAQAHAAAA4Mo7%2FLy%2BN2kDq9IqPpGAe1Dv%2BlcIZ1SkxXtGZaX18N%2BsXDyXFLvxtv8sgHB1Mp29EzNauR%2BBdUYlbFURZVzjRZRUk9hD%2FJdxusX2Tr%2FTWjpSIXhoF479YEwZkES9SAo64ibUaQkeIPM7CeNN0tmQDve0i6ssyGB%2BbdApcXYel%2FJ5mDEUG9GYcvQOjcQGC2f4i6IAFHwmKzLnDcgV7BLzIr04tu9k%2Fv4ZfnIOPDPVcRgqg%2F%2F7D7zCzp3E%2F39WNRpdih%2BO69FV5VGp3f7AgS8T7U5wn4OrxtKZFlcjE1lpSbCL%7Ctkp%3ABFBMvIDx0eNg

So your 13S 'smart' BMS (if it could also speak) with respect to your thread title begs the question: What is your current assessment of your DIY pack of salvaged cells ("one cell group wont fully charge") being your 'smart' BMS balanced your 13 p-groups within 5mV of each other ? Two p-groups fully charged to 4.200V with the other eleven p-groups charged to 4.195V.

 

[m3vuv]

this is it rtoday after being on charge all day,now its max v+ is 51v,seems cell groupe 1 reaches 4.3v cutting off the charger before any other groups charge,see blured pic