Are you “theHac” there? 
Same problem described…
30Qs should work, especially if you can snag some with the tabs already attached.
Nope, link? what did they buy? I figured the Q would work, but rather have the higher capacity if there is no need for higher discharge
Are these battery terminals reusable? or do i have to buy those strips of metal and solder them on?
Probably spot-welded on, so they ain’t coming off in one clean piece.
I hated soldering to NiCd cells way back when, and I wouldn’t try it on Li cells.
’Though ax Barkuti about low-temp solder, as he might be able to walk you through it.
Definitely. I always hit it with a thermal sledgehammer. Temperature cranked up as high as it can go, big chisel-tip, blob of already-molten solder on the tip for better thermal contact and no need to waste time melting solder paste or anything, and bam!, get in there, melt what you have to, and get out just as fast.
But low-temp solder (eutectic vs 60/40, or different composition lower-MP solder) means it doesn’t have to get as hot to do its job.
There are now cheap spot welders that can be powered off a car battery or other 12V source.
They seem to get good reviews.
https://www.aliexpress.com/item/4000436631776.html?spm=a2g0s.9042311.0.0.3da24c4df9PzwQ
Thanks for advice. Would using these battery holders be a better solution?
https://www.amazon.com/gp/product/B07Q13T3RH/ref=ox_sc_saved_title_3?smid=A2ZY5CARD1LVTF&th=1
Any way to adapt it to use power tool batteries? That’s what I did with my dyson. 18v power tools are usually 5 cell. I had to get 6 cell for the dyson but 5 cell are more common anyway.
I bought a 3d printed adapter on amazon, pulled the cells and circuit board out of the original battery and ran the wires through the battery shell.
Pip. That’s very cool and a great idea. Thanks
I did surgery on my Dibea F6 (great old model vacuum you can’t find any more) this afternoon. I used that stick cordless for three years- about 3 times a week. It originally ran over 25 minutes when new but slowly came down to about a 3-4 minute run-time lately.
So I grabbed some Samsung 25S batteries from 18650battery.com last month and finally rolled up my sleeves and disassembled the old pack. Not sure what was in it (soft, blue wrap marked “2200 mAh” among other things- looks like a “knocky-offy” of some kind). But it seemed to run well for years, so I’m testing these old 18650s now. And thankfully, the new pack tested good about 3 hours ago- and is on the charger now. I am hoping to find one bad battery from the old pack and then reuse the rest in smaller lights going forward.
As these cordless vacs run hard and drain deep (at least when I use them 
), I am happy with the three years of service I did get out of them. But no battery packs for this vac were available (… ever, I looked for years) so I knew it was going to come a time when these guys would be giving up the ghost and so it was time to hit the bench with a few beers today and gittt’er done.
And, as BMS systems typically are fixed capacity… I figured these new high current 25S’s with 2500mAhs would go years longer than the originals as they will never get to 4.2V and are undoubtedly better batteries too. The idea was to get a good HIGH current rated battery with JUST over the old mAh rating of the old batteries. And, as I guessed (got lucky) the old ones were indeed 2200mAhs. So guessing these will never charge over 4.1V or so and give me at least another three years of “stick” vacuum service if not more.
I enjoy these projects when the wife is binging on Netflix (always chick-flicks, uhg!). And when the weather sux, and I have a Sunday otherwise uninterrupted- the three hours went without any hiccups. I agree soldering these batteries is a careful process I would NOT attempt without the right tools and experience. But given everything is carefully handled (not too many beers!), I feel with good tools and a fast spot solder- one is fairly safe doing this kind of work.
I removed (and straightened back out) the original conductive spot welded straps (*razor’ed off by tapping an exacto knife with a small hammer- placing the blade behind/between the spot welds). I use a better solder station with eye protection, correct tip, and hold the old spot weld tabs in place at 800 degrees for 12 seconds, then drop the solder while holding the old tabs in place with a dental pick after lifting the solder tip. This makes a super tight solder joint.
I’ll update with run-time and the old battery test results. 
Update on the OLD vacuum batteries (above) 
:+1:
I tested three of the six old pulls (marked 2200mAhs) overnight in my ZanFlare 4 bay tester.
#1- 2500 mAhs
#2- 2440 mAhs
#3- 2000 mAhs
I wasn’t expecting ANY of them to hit their marked 2200mAhs, but I did expect a dog or two from the lot of six. The other three are testing now and I’ll update later when they are done.
But not too bad for what will be some higher drain batteries I can use in my “pocket-rocket” 18650 lights (#1 and 2 above).
Welp…
Given the first three tested also hit about 50ir, and came from a vacuum pack (which HAS to have high drain to start with), I think the cells that test good will deliver plenty of current to crank-up about 1/2 my lights and deliver around 8-10 amps fine. So I think my IF25a, SP32 V2, C8G, etc. can use these ok as they won’t be pulling a lot of current even when on turbo.
Like I said, if anything they’ll make good yard light or back-up cells with the lower capacity too. But time will tell after I A/B test them with some Q30s.
Hey, I LIKE that power bank you have there- might have to look into that as an option too
Your point is well taken. And thanks for the tips on the powerbank too)
But I would question the one bad battery scenario which as we know can shut down a pack that’s almost new. I’d like to know more about late life current capacity drop in general too. I KNOW it goes down, but by how much over time? I’m sure “cycle” hours won’t hold the same effect as over-all age (too). I’m sure they BOTH factor into that equation.
I have pulled a few tool/laptop packs apart the last few years and most (good) batteries I’ve gotten out have worked fine for about anything but long run-time. It helps most of my lights also have turbo throttling after a minute or two anyway 
The 17 year old Sony I tested last night hit 2100mAhs and went back into the wife’s SD-02 which stays parked by her bed and gets used once a week. I charge it about every 4 months or so and it usually has over 4Vs. And it’s been in the light the last three years and for the job- it works fine.
Last three tested:
- 2470
- 2465
- 2535
I’ll have to compare to newer high drain batteries now. But #3 battery was bringing the pack down compared to the other five batteries which tested great… well over their labeled “2200mAh”.
I would watch for a cell that may exhibit high self discharge. I once had a Lenovo 9 cell pack fail due to one cell having this issue. In that case, it drained all cells in parallel, too. Charge them all up at a low cutrent and let’m sit for a week before comparing voltage and optionally capacity.
Did you measure OCV of each cell upon removal? Another scenario was that the capacity imbalance over time resulted in that one Tell never fully charging and being constantly over discharged.
On the original topic…
The NEW Samsung 25S batteries ran over 15 minutes at first use yesterday. But I didn’t run it to it’s cut-off like I used to. I didn’t need it for more time and I NOW won’t be using it on carpet any more (where I used to run it till it stopped). It never really worked well on carpet anyway, but it is super on our hard floors (2/3rds the house) and a “one hand” machine that gets in lots of places without having to move much around. I am HAPPY to have the “transplant” go so well after-all!
The stick vac is starting up faster and running at a slightly higher RPM than it was before the change-out. Although a Q30 probably would have given me more run time, I didn’t want to take a chance on not having ample current and these Samsungs are some of the top tested 18650s for current here… and so they are my confirmed suggestion!
On the old battery side-project:
Well yah, who knows what the BMS was up to for a few years there? But I’m guessing it stopped at some low voltage setting so perhaps the pack wasn’t charging to full, but who knows at this point.
But… five of the six batteries charged up WELL past their stamped 2200mAh rating (with one only hitting 2000mAhs).
I haven’t tested them next to a Q30 yet, but this morning I put the charged batteries back in the charger to test their resting voltage overnight.
4 had 4.16V
1 had 4.17V
1 (the bad battery charging just to 2kmAhs) was at 4.14V
I have two identical SC31 Pros lights I will load up: one with a topped off 30Q and the other with one of these old batteries. I’ll then go out tonight and hit turbo on both simultaneously and compare.
I’ll run them a while too and check for battery heat while I’m at it. This will be the tail-tell whether these will hold some current or have massive voltage drop. I expect they will be somewhere in the middle but I’ll see and report back.
I’m about to perform the same battery swap on the Pivot version of that vacuum. I have one outside in the garage and one in the house. The house one has been used almost daily for years. Now, it only runs for about 3-4 minutes.
The stock cells were LGDAHB71865, which I believe are only 1500mah. I’m sure that any current, decent higher-ish drain cells will do fine in any of these vacuums. I didn’t check the amp draw before dismantling mine, because I figured the cells weren’t able to deliver what the vacuum wanted anyway, so I may test it out further upon reassembly.
UPDATE: I stumbled across some datasheet info online, and it looks like these LGs were 15A constant/25A peak cells. There are plenty of LG, Sanyo, and other high drain cells out there that will do just fine in this application. In all honesty, if I need to use a hand vacuum for more than 10-15 minutes, I probably ought to just be grabbing the regular corded one.
You can roughly estimate the average amperage based on the runtime the device achieved when new. For example, if it lasted 15 minutes continuous from full charge to shut off, then roughly that’s 4C or approx 6A with 1.5Ah cells. Since this is an inversely proportional relationship, the largest source of error is runtime. If it were 10 minutes for example, the current would be approx 9A.
For cost and safety overhead reasons, oems always seem to use cells with more amperage and less capacity than needed or is possible.
I would say a 30q could do the job current wise, but would get pretty hot most likely. A 25s seems like the sweet spot IMO. But on a cost levelized field, 25r likely takes the podium
With the six 25s batteries I put in, I have run the rebuilt vacuum over 20 minutes a couple of times now. I used to run my old (original) batteries down completely in about that time, but I don’t plan to do that as often with this set now that I understand these thing better. 
The 25s set of six (on sale) was about $8 more for the set of 25r’s (from 18650battery) which I agree… the 25r’s would have probably done fine. But I like having the extra capacity with the 25s pack rebuild— and knowing they probably will run a bit cooler (and hopefully longer given a newer design to boot). Of course that ALSO assumes I can keep the rest of this 3 yr old vacuum from breaking down too
Time will tell, but having installed a new 900 ft sq. hard floor last week (why I rebuilt it last minute), I used the heck out of this thing since and so far it’s running great!
I’ll take my luck so far
PS. on the old pack “pulls” I had one bad battery with the rest testing over their labeled capacity (around 2500mAhs). I have been using them in my SP32a v2’s I snagged from Sofirn on last month’s deal page at $13 each- GREAT lights with ramping and decent 5k output. Glad I saw them when I did- grabbed four of them for me and some buddies I’ll be gifting to here next month at hunting camp.
[quote=jp9mm]
I rebuilt easily this battery, but doing a power MOD.
I took 10 of lgdbmh11865, and I built a 5s2p battery. Now it lasts forever! And 2p solution gives enough current it needs with almost no changing of temperature.
You have to:
- Disassemble the whole battery, and cleaning inside the shell removing every plastic part and support;
- Desolder BMS circuit from battery and reuse it in the new configuration;
- build a new battery back, five side by side, negative and positive poles alternated, so that each one is in parallel with the same in the other row. Every couple is in series with the next one.
- I slightly desoldered LED, to put it horizontal and in front of the transparent plastic lens;
- solder wires in the same sequence at the new battery;
- fix everything with hot glue (not a ton);
7)Clean everything with happiness!
it;s a lot of trouble
what if the motor quits before the new batteries.?
i;d just wait
what is your actual problem that you hope to improve, and what is the goal?