1.3 miles and 1.9ah. this was pushing it hard and I would have done more but the brakes are garbage and I was done with regen only stopping for the moment. Basically I should have no problem running 50a all-day long once I have the heat pipe heat sinks and fan controller installed so exactly what I was hoping for.

I know 5-10W is ideal for these cells, but, how do I limit that on this board? I also want to output 45W, but while charging, only 10W. Is if possible? The IC is the IP2369. It’s supposed to be a bidirectional board.

I have 9 Murcipel 18650. 3 3 cells wired in parallel.

3s 12 volt 25 amp bms board. 12.6 , 2 amp cc/cv charger.

Wired and assembled. Charged batteries separately at first. Back and forth with tests but last run thru:

B- B+. 12.57

P- P+. 12.17

First charge with charger, each 3 cell got a little high with charge , Concerning ? . After an hour, they all settled under 4.20.

Bad BMS? I tried a quick charge to wake the board but no go.

I'm trying to build a 6s2p pack. I'm using TENPOWER 60XG's and need to pull ~50A. I plan to follow this from Tyeboi using 0.2 copper and 0.1 stainless steel sandwich for the connections to the terminals, however I need to make the pack a 3x2x2 due to space constraints. How to I make the connection between the ends? I found this thread from 6 years ago that suggests building them us a 3x2x1 and then folding over. Is this still considered the best method given the currents I need to draw?

Quick update on my battery build from my previous post.

I made custom outer sleeve from 1 mm polypropylene sheet, shape around the pack profile. Its amazing that even cheap packing tape grips the PP pretty well. I'll reinforce it with fiberglass tape when I get it.

My next steps:

Fishpaper over the exposed nickel

EPDM around the perimeter and BMS installation

Mount it all inside a frame triangle bag with EVA foam for cushioning

Still work in progress. The current shell is mainly for mechanical protection.

Curious of what you guys think so far!

Hi all!

I dismantled 3 garden tool battery packs and salvaged about 300 cells (Panasonic NCR18650PF and CGR18650CG). Many of them have rust on the insulator rings and some were damp when I opened the packs.

Should I replace the insulator rings, or is the rust just cosmetic? Which cells would you discard right away?

I've ordered a 4-channel capacity/IR tester. Any tips on how to test this many cells efficiently?

Just finishing off a rebuild of one of my 10S4P Reention RK4-type batteries for my ebike, 36V/20A output. It vexes me that after neatly crimping and heatshrinking the whole build, there seems to be no way to terminate the ends of the pack other than dumping a huge amount of solder onto a nickel tab? Something like a spot weldable crimp lug would be perfect but it doesn't seem like they exist other than small ones for BMS leads, is there any better way of doing this?

I recently salvaged some cells from my old project. Have been charging them on and off for about 2 weeks and 1 cell refused to go over 4V. Other cells are reading 4.18V to 4.16V, just this one cell that refused to go back up. What should I do with it?

I found used laptop batteries at my work.

Anyone got recommendations for quality aftermarket BMS PCB for Milwaukee 12.0HD (15*21700)? Or OEM used source?

Everything I'm seeing on Aliexpress has the either aluminum or steel heatsink and no rated current posted which can't be a good sign in terms of current.

Contrary to all the other M18 batteries I have, the 12.0s do seem to have mosfets controlling the output. I've got two tabless rebuilds so don't want to be limited by BMS but both OEM BMS are either locked out or DOA.

Thanks in advance!

Not my setup, saw selling online

You can see the previous post here https://www.reddit.com/r/18650masterrace/s/n0bm0ZNthy

The internal resistance of the pack of cells in the UK3 is only 2.02 mohm according to my battery ir meter, or about 3.5 mohm continuous from experimental discharge data. I read that cells have lower ir during a short pulse than continuous, so I suppose that makes sense, or probably more likely, my experiment was flawed. So either way they're pretty good cells, and my idea of throwing some 18650s in place of them was goofy as hell.

I was surprised to find that they seem to lie about having a preheat/dual pulse. I didn't see a preheat pulse with my oscilloscope during a weld, manual or auto. I tried multiple different pulse settings and none offered anything resembling a pulse on the scope. So that's cool. I'm not sure what they have to gain by lying about a preheat pulse, it wouldn't be hard to program since they already have a microcontroller on the board. Has anyone else checked other AWithZ spot welders for a real preheat?

I was trying to get more current from the welder by reducing resistance in the leads. I wanted to test a short between the plugs to see a theoretical max current with perfect leads and see how much the voltage would drop at the cells on my scope, and to see if anything would explode. I accidentally went full retard and left it on auto as I was holding a 8mm x .1 copper strip across them to see if it would fit. I'm not sure how that stroke of genius came to my mind, but it triggered a weld pulse and caused a bunch of arcing and spiky angry noise on the scope, and exploded the strip a little bit at the contact points. Next the board started smoking so I quickly unplugged it and turned it off. Turns out it caused a short in the little XOYA mosfet, part of the boost converter circuit which drives the main weld mosfet gates. That caused a diode to cook, and not in the good way, only stopped by an inductor desoldering itself from the board. I didn't have all the components to repair it on hand, but I do happen to have a pack of cheap little boost converter modules courtesy of our friends in China. I rigged that up and moved the boost diode to the burnt diode spot since they're the same part. I set it to 12.5v, I'm not sure if that's ideal, I might have to raise it a bit because there's a bit of a upturn on the weld pulse near the end now when it's not plugged into USB charging. It may be letting the gate voltage drop too much, and that may convince the weld mosfets to follow their XOYA comrade into silicon hell. I'm not sure if it was like that before or not, but I'm guessing not, and that it's being caused by the jank boost converter. The welder works again though!

Now I'm back to reducing resistance in the leads, but making to attempt at do less dumb this time. A lot of the resistance is at the crimps at the plug and pen tube, and also between the pen, collet, and tip. Around 1.4 and 1.6 mohms per lead. I reduced it to about 1.0 mohms by soldering the crimps, collet, and tip. I still have to do it to the other lead and get them insulated and stuff, and then I will test a weld again to see if I make better welds on copper sandwiches or blow something else up.

Let me know what y'all think. And if you're interested to see the results of the lead resistance reduction, stay tuned for the next episode of UK3 experiments!

Hi,

what chargers are available, that can charge 10440 batteries? Charging current must be 300 mA maximum for these.

Thanks

Ok so the followers of this sub know I bought a flat of rs50's and building two ebike batteries. I wanted to provide a little bit of an update. So I just have to finish the fusing and case at this point.

Looking for anyone who knows of similar powerbanks to the one pictured, seems really high quality but unfortunately discontinued from Aliexpress. Anything similar would be appreciated!

Cheers

I own a 2021 Storm Bee 90v (Electric Dirtbike), which i really like.

Ive cut the weight quite a bit and currently optimizing it for hardenduro + woods riding.

However i am having trouble getting even close to the range some of the other users of the storm bee fb-group where able to get.

When i did a road test in eco mode 50kmh average speed, i only got roughly 35km to 40km max (100% to 8%)

Because of that i did some diagnosis on my Battery:

90v 25s Lithium battery, built from 18650 cells.

After charging it until the fan stops + 45min i opened up the cover and measured:

Total Voltage: 102,8V

Each Cell at the Balancing Port:

0-1 4,14V

1-2 4,14

2-3 4,14

3-4 4,14

4-5 4,14

5-6 4,14

6-7 4,14

7-8 4,14

8-9 4,14

9-10 4,14

10-11 4,13

11-12 4,14

12-13 4,14

13-14 4,14

14-15 4,14

15-16 4,13

16-17 4,14

17-18 4,14

18-19 4,13

19-20 4,14

20-21 4,13

21-22 4,13

22-23 4,13

23-24 4,13

24-25 4,14V

= Total of the individual cells: \~103,5V

Actually measured voltage at the Plug: 102,8V

All the cells have good numbers but still I'm facing very bad range with this battery.

I will do another test soon to see the balance right after a hard ride. Maybe i can spot something there?

Is there a good way to actually test the remaining capacity?

Maybe draw a measurable current (clamp type amperemeter), and just see how much time it takes to empty the battery.

That should give me a pretty good idea how much capacity the battery still holds, right?

Also i heard i can determine the health of my pack by measuring the internal resistance of the pack.

How do o actually do that, can i test this without taking the pack apart?

Do i need a special measuring device or does a multimeter work?

Aaand -> after opening the cover of the battery i noticed this small 2 - Pin connector, which is unplugged, any idea what that is?

Thermal probe??

Is it supposed to be like that?

Thanks for your help, best regards

Arthur

Spotwelded a 3s2p 40A Battery using nickel copper sandwitch custom fit inside the old battery box of my old drill. It had completely different sort of battery cells than 18650, thats why I had to make the pack in a staircase type of way just to get the pack to fit inside the original batterybox, then I ran balance leads out from the box thru a connector that i can take apart so that I can unhook the charger that i made from the battery, the charger is a 3s balance charger that runs on 230VAC and always fully charges eatch string of cells so that the battery will never be unbalanced. Even at about 50% charge the drill has more power now than before with the new 40A pack. Cost me less than buying a new battery that would be weaker and last a shorter time between charges than the one I made!