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Not really suitable due to the amount of current needed and the voltage being wrong to replace lead acid, look into LiFePo4 cells instead.
A 4S LiFePo4 pack with BMS would basically be a drop in replacement for lead acid.
Instead of utilizing the common Li-Ion 18650 chemistry, find some LiFePO4 cells instead, as they are better suited for a UPS (and are actually frequently used as lead-acid replacements).
As an example, this 12v battery is in the same form-factor as a standard UPS battery, but utilized the LiFePO4 chemistry cells.
The reason why LiFePO4 is a better lead-acid replacement is because of their high discharge current, high charge/discharge cycle count, and because of their "minimum discharge voltage = 2.5 V, working voltage = 3.0 ~ 3.2 V, and maximum charge voltage = 3.65 V" (source). This means that a 4s configuration of LiFePO4 cells would have a minimum voltage of 10V, and a max voltage of 14.6v, which is very close to the specifications of lead-acid cells.
Wife bought this on amazon to keep our kid a little more comfortable in the stroller on hot days. I thought hey neat it can be used as a power bank. I was bringing it into the house one day and noticed the hatch on the bottom. I was surprised to see these batteries in there.
https://www.amazon.com/dp/B07B8JDNSK/ref=cm_sw_r_cp_apip_sOnHvmxCbdEou
This Tenergy battery specifically cannot be used with the C3100. It has a charge voltage of 3.6v unlike other li-ons.
There's a charger for these if you want to continue using them.
https://smile.amazon.com/Tenergy-Charger-RCR123A-Rechargeable-Batteries/dp/B001BFH7H2
I was looking for the same and found these https://www.banggood.com/LantianRC-18650-Battery-Holder-Case-Box-for-6S-Battery-p-1602943.html - I've ordered some and can let you know if they work ok when they arrive from China
to answer your question: probably not.
for lithium any cc-cv supply will do. cost depends on amperage and voltage needs. here's one I'm using currently
for 1-6s packs nimh/lithium, and traditional lead acid, there are a ton of low priced "hobby chargers"
Important it does .01 seconds not .1 game changer. Trigger it with your pedal or switch, power it with 5v USB, done! $13
Timer Relay, DROK Time Delay Relay DC 5V 12V 24V Delay Contr... https://www.amazon.com/dp/B07DFT2WDS/ref=cm_sw_r_sms_awdb_btf_t1_Ov2oFbR29XRH5
Lifepo4s aren't that bad. Amazon has a 20am 12v lifepo4 for around $50.
https://www.amazon.com/ECO-WORTHY-Rechargeable-Phosphate-Protection-Trolling/dp/B09NB97XGL
That being said you could do a s4p13 assuming you have 2ah cells. Would give you a 14.4v (Assuming the scooter can handle the slightly higher voltage), 26ah battery. It's a lot of work and 52 cells with a bms.
I use this… it takes a while to get capacity
LiitoKala Lii-500 Battery charger for 18650 26650 AA AAA battery LCD display test the battery capacity https://www.amazon.com/dp/B073R7VCMZ/ref=cm_sw_r_cp_api_glt_fabc_KMG7S9CTRR1TT0YD8B31
yes for discord/slack/spotify/homeassistant/workflowy/looking something up on chrome
the smallest i could find quickly (didnt see any on alie either, but didnt look that hard). i was hoping to find something that i could fit in the tube, but, alas. it's slapped on the back of the copper pipe you can see the edges of it :/
i thought a lot of bulbs dont use 5/12v but rather have a large string of leds in series and use higher v- but that would be great if what you suggest is doable. it's a philips wiz bulbs from home depot. last i looked there wasnt a teardown, and i didnt want to break it pulling out the board. but i have a ton of them from a pricing error order.
I have one of these. It will max charge and then discharge and then charge and give you max maH.
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The way the NiMh pack is designed is like a nunchuk style. 4 stack and a 3 stack wired together. I figured I could fit a 18650 where the 3 stack goes and the other 18650 and BMS where the 4 stack goes.
Battery pack looks like this one: https://www.amazon.com/Mighty-Max-Battery-Butterfly-Replaces/dp/B00LHRH756
Just don't buy the ones designed for audio. They're pretty but that doesn't serve any purpose. These ones would be more than enough for your application. They can handle huge currents, that's why RC modellers use them.
Timer Relay, DROK Time Delay Relay DC 5V 12V 24V Delay Controller Board Delay-off Cycle Timer 0.01s-9999mins Trigger Delay Switching Relay Module with LCD Display Support Micro USB 5V Power Supply https://www.amazon.com/dp/B07DFT2WDS/ref=cm_sw_r_cp_api_i_-5IMFbR1ARY7B?_encoding=UTF8&psc=1 heres the timer relay I got
A variable voltage power supply is ideal since the energy stored in the cap is a function of voltage. You might get lucky using a fixed supply. You could also find a highish volt (say 15-20) and then build a circuit to consistently charge the cap to a variable level.
If you're into electronics, or even batteries, I strongly recommend a bench power supply. Beyond just powering stuff, you can use them to very gently recharge over discharged cells. Ebay has tons of used units for sub $75 shipped that have multiple voltage rails or sub $50 shipped with a single rail. The unit in the pictures is available via Amazon. I prefer my huge linear supply over this one (2x 0-32 volt at 0-6.4 amp rails, which you can run in series, parallel, or independently + a fixed 5 volt rail), but it weighs close to 50 pounds and has a pretty big footprint.
You're in luck!
These do in fact exist, and for cheap!
They're controller boards for DIY USB power banks. (good thing you want 5v)
You can find tons of them on Amazon or other sites.
For example here's some I've used in the past:
https://www.amazon.com/gp/product/B07D6M2LCS/
I'm just using this thing I got on Amazon for ~$5.
So right now, when I test a cell at:
.5 Amps ----- my cell measures at ~2.6Ah
~2 Amps ------- ~2.3Ah
So why would 2.6A bring me to 2.6Ah? It should be even less than at 2 Amps.
I think I understand now. If I test at 1C, or 2.6A, my mAh would probably drop even further. Which means that these USED batteries only have a capacity of ~2100mAh or so.
I really like this necklace fan, which uses a single user replaceable 18650.
I ordered 8 pack of these batteries arrive tomorrow.
I bought a couple of these WORX tool battery packs. 5s2p sold as 6.0AH might be 5.
2475mah cells https://www.amazon.com/dp/B0943TBC8Z?psc=1&ref=ppx_yo2ov_dt_b_product_details
18350 3.7V 900mAh Rechargeable Li-ion Battery with Flat top Battery 2 Pack
Flat top probably give the length dimension you are looking. Button top are longer.
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📌 40% OFF Baseus Power Bank, 65W 20000mAh Laptop Portable Charger, Fast Charging https://www.amazon.com/gp/product/B08THCNNCS?th=1&linkCode=ll1&tag=4gtri-20&linkId=578d1aabb37731299922df1346780dfe&language=en_US&ref_=as_li_ss_tl
13.5k members in this Reddit so I had hoped to get some replies by now.
Been reading this group for a few days and got some ideas.
Thinking about a power bank from a more reliable company instead of unknown brands from eBay or Aliexpress. Do not want to burn the house or damage the cells by a poorly designed charging process.
So far I found XTAR PB2S but it is only for 2x 18650. I planned x6 or x8 cell one. I like the design and portability though. https://www.amazon.co.uk/XTAR-Batteries-Charger-Unprected-included-Black/dp/B07WG6RK9M
As for a charger. I keep hearing that many of you have and use XTAR VC8. I like it, especially because it measures resistance. I also do not need an additional power supply and it fits the bill perfectly.
The others I found popular are: 1. LiitoKala Lii-500 2. LiitoKala Lii-500S 3. Xtar VC4S
What would you suggest? Opinions and recommendations are welcome. I am sure we have some owners in this Reddit.
Thanks.
Here's another: https://smile.amazon.com/DaMohony-Portable-Charging-Wireless-Compatible/dp/B08T259GM5/ref=psdc_2407761011_t4_B09BDXK4RH
the similar items section on these pages shows similar items :)
Something like this?
Nope, unfortunately.
This vc4 plus charger could meet your requirements: https://www.amazon.com/XTAR-VC4-Battery-Charger-Rechargeable/dp/B09FSB8V83
If you can't spend $40 for a proper charger I don't think you should be messing around with LiPo cells: https://www.amazon.com/EMEPOVGY-Battery-Balance-Balancer-Discharger/dp/B09X2YP64P/ref=sr_1_51?crid=3W235S59TK6VN&keywords=3s+lipo+battery+charger&qid=1665414392&qu=eyJxc2MiOiI0Ljg2IiwicXNhIjoiNC42NSIsInFzcCI6IjQuNDIifQ%3D%3D&sprefix=3s+%2Caps%2C332&sr=8-51
Using an improper device to charge them can cause them to catch fire.
Yoooooo! This is just a stupid good deal. Pretty sure Jehu also posted a video of him expanding the battery capacity by using a 36V scooter battery through the solar input. Let me see if it would work with this model
Not the cheapest but none of the el cheapo ones are this big. This kinda blends into the audiophile world and that stuff is silly expensive so don't buy the 100 pack for $4.99 because they are 2 or 3mm tall at best. All my chargers now sit on these
Not sure if by "devices" you are specifically referring to flashlights or not...
https://www.amazon.com/DEWALT-DCF680N2-Gyroscopic-Screwdriver-Battery/dp/B00DL7QDS2
This Dewalt gyro driver (I'm a big fan) uses 2S 14500s.
Yes, these are much cheaper but you're limited from then on.
Avoid these. Output amperage is very weak. Often 1amp or less. You need every bit of 1.25A you can get when you use it as a PD port. These would plug into the USB A port. Can you use both USB and USB C to get more juice out? Probably not. A lot of these boards are very limited in output.
​
If you need a solid basic charger, take a look at this FC2: https://www.amazon.com/Charger-XTAR-Battery-Rechargeable-Batteries/dp/B07H8CB588?th=1
Yay for heat dissipation. I don't want my chargers to die early. I put one of these to push air under or over every charger I have depending on vent locations. $2 a piece, simple USB or cut the USB connector and wire up to 5V. 12 of them running quite a bit and havent had one fail in 6 months.
https://www.amazon.com/dp/B0899H1GZF?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details
If you're charging from 5V it's pretty easy to just use 1s and step up. It saves a lot of complexity for balancing and charging. Something like this will step up and it's not too expensive. Probably can handle 1A just fine.
Also came across this, what do we think of it?
Nickel strips can be found on Amazon, eBay aliexpress etc.
Here’s a link for Amazon:
Something like that should work.
Also, what model number of cells are you planning on using? Need to be sure they can handle 4.5 amps.
https://www.amazon.com/gp/product/B09QS7Y89G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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$49.00 with a 5% coupon on top!
Works amazing and you wont kill yourself.
yea. if wrapping is damaged. fix it before it evolves into a bomb. they are silly cheap and well worth it. https://www.amazon.com/OCR-Shrink-Tubing-Battery-29-5mm12/dp/B072LQQMDQ/ref=sr_1_5?crid=3R0BWF0O8UCPO&keywords=battery+shrink+wrap&qid=1658246809&sprefix=battery+shrink+wrap%2Caps%2C91&sr=8-5
besides. makes reclaimed cells look new again! :D
would one like this be sufficient?
I googled “18650 powerbank Qi wireless charging” and didn’t get any good looking results.
The only half way decent looking option was https://www.amazon.com/Battery-Charger-Wireless-Function-Support/dp/B08DLG9FDL#
But I can’t vouch for it
Flush cutters or side cutters. I used to buy the knipex, but these things are basically a consumable, so now I buy the 5 pack Chinese ones on Amazon: https://www.amazon.com/gp/product/B07J19N2RS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Hmm. 10kohms is pretty high. You could put like 10 of them in parallel and it would still take a loooong time. Like, weeks. I would suggest to buy a 10 ohm power resistor.
Like this:
Should be a slower yet decently quick drain.
That isn't a good reason. It won't be a $100 pack because you are forgetting about all the other parts:
- "Testing voltages" isn't enough. You need to test capacity. At minimum that uses a $20-$40 analyzing charger. Though with 4 bays and an 8 hour test cycle you are looking at 2-3 weeks of testing and you might want to get several.
- Assembly. Specifically spot welding. The cheapest spot welders are $100 on their own.
- BMS. You said you want to power AC units and heaters? Those are big loads! So you will probably want an 85A-100A BMS. That is another $45.
- Case and packaging. You want to haul it around and have it be waterproof? Another $70 for that.
> complaining saying the discharge rating is lower on them
That will affect you. You will be discharging the battery pack at close to 1C.
Looks nearly identical to my unit except mine has no foot switch and cheaper looking welding pens.
2022 Upgraded Mini Spot Welder,... https://www.amazon.com/dp/B09NM9B1RK?ref=ppx_pop_mob_ap_share
I paid $75 after tax when it was on sale which it usually is…then got a large chunk of that refunded so I paid…$25 😅
Hate to say it man but the Sunko ones just don’t make sense. Mine has pouch batteries inside so I’m guessing LiPo that are 100C or something pretty intense. Battery life is so long I don’t recommend paying extra for my model. Just check the specs to see what the max amperage is. The Amazon sleazeball sellers don’t make this easy and might be lying but it looks like a short burst from a high C lipo battery has the traditional transformer design beat
How do you plan on powering the 220V input? I’m pretty new to this stuff so maybe the mod would crank yours up to welding .20mm on 2P 50 and .25mm (pure nickel) on 2P 99. Some big e-bike or high performance scooter battery builds have to go the route of custom brass plates for series connections while doubling up .15 or .20 pure nickel strips on the parallel. If you can crank out .25 or better you’ve created a monster that would work for nearly any build short of full size electric vehicles. DO IT!!! (Or don’t and return it and grab a power bank style. I’ll link what looks good in a bit.)
7s400p, that's an impressive project! It makes sense that the magnet version would have more resistance then the welded version. 2 pieces of metal touching can never be quite as conductive as 1 piece of metal. Do you remember how much of a difference there was in conductivity between the magnet and welded versions? Also, did you use anything to help facilitate the connection? I'm thinking that adding a tiny amount of some conductive grease between the cells and the metal could fill the microscopic gaps between them and improve conductivity.
It looks like what you are looking for is something called a Battery Management System, or BMS. You use a BMS to charge a multi cell battery, like the 4S battery you show. The BMS will make sure they all get charged equally, make sure they discharge equally, and should also cut off the power output if the get discharged too low to protect the cells.
Something like this: https://amazon.com/dp/B07ZJ96FTJ/ref=cm_sw_r_apan_i_N7DGE4T0T4MJVJ6B2Z4Q
I have had mixed results with BMS's on Amazon, but they are convenient and widely accessible. Some of the BMS's have worked great, others have essentially had one dead cell due to the circuit not working correctly.
That's what I did for my large 4S battery. It can be annoying not to get full capacity out of the battery, but I figure this way it will last longer since batteries don't "like" being charged to full capacity anyway. It can be difficult finding inverters that even go up to 16 V for the cutoff voltage though. I've had decent luck with lower wattache Giandel products. Currently using the 600 / 1200 watt version from the link below. I had the 300 / 600 watt version, but it kept cutting off at 15.8 volts.
This one? 5S 21V 100A BMS Li-ion Lithium Battery Protection Board Circuit Li-Polymer Balance Charging Module for 3.7V LCO Battery Packs (5S 21V) https://www.amazon.com/dp/B08NJJQ6D9/ref=cm_sw_r_apan_i_NK7VTKBHTJEN2YKSVWYE
MTM shot shell cases each case holds 25. You can probably get 6 cases in an ammo box. Now you can put those ammo boxes in a crate. The perfect system if you have 1000 cells. Or just get the box I linked. Very high quality stuff. You should be able to find them in your outdoor recreation stores. Cabelas, bass pro, Turners if you’re on the west coast.
Some stores, are selling an updated version of the VC4H, calling it "2022 NEW", e.g. Amazon: https://www.amazon.co.uk/gp/product/B08R3DRFLB.
The VC4H was was released in 2021. Can you please explain what the changes are in this "2022 NEW" version?
The VC4 Plus doesn't seem to have a new 2022 version. Is the VC4H "2022" more reliable than the original VC4 Plus?
I ordered this [smaller quantity version](rockdig 360 pcs 18650 battery sleeves flat pvc wrap heat shrink tubing tube(and 360 pcs self-adhesive insulator ring cyan) https://www.amazon.com/dp/B099MV6MZL/ref=cm_sw_r_apan_i_EZ373EPKNEMZ6367DAJJ?_encoding=UTF8&psc=1) a week ago and they work and fit perfectly too.
https://amazon.com/530Pcs-Insulator-29-5mm10-Battery-Batteries/dp/B08RZDWCM1/
Here is a kit. You can use a heat gun or if you're in a pinch, a lighter held as far away as you can to get the heat shrink to shrink
XTAR VC2L could charge 21700 protected, the longer 21700s
https://www.amazon.com/gp/product/B09KX9S5NP?th=1
2 slot--VC2L $17.99
4 slot--VC4H $19.99
Even more of a reason to put a BMS. A 2S BMS cost a couple bucks, even cheaper if you order directly.
Here’s one of the more expensive examples, still worth it: ACEIRMC 2S 7.4V 8.4V 8A 18650 Charger PCB BMS Protection Board for Li-ion Lithium Battery Cell (8pcs) https://www.amazon.com/dp/B08HLQQCQJ/ref=cm_sw_r_cp_api_glt_i_PFJ182WGFXHXQSZGCAAF
This may help get them closer it helped me..
14S 1.2A Li-ion Lipo Lifepo4 LFP Battery Active Equalizer BMS Balancer Inductive Balance Lithium Battery Energy Transfer Board (14S) https://www.amazon.com/dp/B09C3J6F5J/ref=cm_sw_r_cp_api_glt_i_7328F3THSC9P75ZKXG8D
I'd do 4x cells. Voltage just isn't that picky on, well, anything really. They were 9.6v because it was difficult to reach higher voltages (more batteries, more cost, more space). Hell, if it's just the motor (and not the controls), you can probably feed it 48v for short periods.
Do 4 cells in series and just don't go ham on the drill for too long. You'll have the extra power when you need it.
Is this the best drill to convert? Isn't that keyed chuck going to drive you mad? I'd take a quick chuck any day. People be throwing out nicad drills when the batteries don't work, can probably get them for free.
Amazon and Ebay and the usual china sources will have tons and tons of BMSs.
All you need is a balance function. No need for it to have the low voltage cutoff or to handle the full output current.
If you're smart enough to convert a drill, you're smart enough to not run the drill right to fuckin' zero volts and hold it there and then leave it there without recharging. Go with the cheapest possible BMS with no interrupt, just balancing.
Random first link I found that's probably fine: https://www.amazon.com/Current-Lithium-Battery-Protection-Overcharge/dp/B07V85XTFN/ref=sr_1_2?keywords=4s+bms&qid=1645074859&sr=8-2
$2.66
Literally the first thing I randomly found, not an endorsement.
You might get responses if you asked questions.
> have last for some time.
What is "some time?" I get about 3.5 hours, running a RPi 4 (with a flash drive & Logitech receiver) from a tiny, 4060mAh power bank.
I'd look at UPS boards.
I used the below for a RC car 18650 conversion project. On the cell side it pulls almost 5amps peak. I have not measured the output side. It's being stepped up to 9.6V from 4 parallel 18650s.
Onyehn 2pcs LTC1871 DC-DC Boost Step-up Voltage Converter Module 100W High Power Adjustable Output 3.5-35V Power Regulator Board with LED Voltage Meter https://www.amazon.com/dp/B08BZM1NSZ/ref=cm_sw_r_apan_glt_i_741ZCYGRKZ3BBSZ2PQYR?_encoding=UTF8&psc=1
Not exactly what you're asking for and I'm assuming you don't want to modify your existing enclosure: you can get one of these battery adapters: https://www.amazon.com/Lenink-Adapter-Battery-Replacement-Decorations/dp/B095NZZD9D/
Which lets you hook, via a barrel jack, to a wall wart.
And since it looks like your 3 AA batteries are connected in series, it has a nominal operating voltage of 3.6v to 4.5v, which happens to be about the same as a single 18650 cell. So you could then just wire up a protected 18650 cell to a barrel jack and use that instead of the wall wart.
So far, this looks like my best bet. $9 for 2 single 18650 cell holders that look to be able to stand up to some higher currents:
https://www.amazon.com/dp/B0721Y3NDQ/ref=sspa_dk_detail_6?psc=1&pd_rd_i=B0721Y3NDQ&pd_rd_w=vL9iE&pf_rd_p=887084a2-5c34-4113-a4f8-b7947847c308&pd_rd_wg=frusH&pf_rd_r=GMW615R36S6BHBQVR58X&pd_rd_r=aaef1071-37c2-4451-b844-3a087b5e294f&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyWEZSRVU1VTA4OEFVJmVuY3J5cHRlZElkPUEwMDY0MzUzM01YNFZDNUpNTDJZTyZlbmNyeXB0ZWRBZElkPUEwNDE0MjM5MzhEVEg5QVBJM0VFRyZ3aWRnZXROYW1lPXNwX2RldGFpbCZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
After some more googling and lots more poking around I think I found something that would work for 18650s, which is my main use case.
$10 for a set of single, double, triple, and quad 18650 cell holders with leads already soldered. That solves for the charging use case as well as an easy power supply for small projects!
Personally i would go with something like this, it steps down the 12v from the battery to the 5v usb uses.. I would also hook up something like this, it beeps and blinks when the battery is under 10.4v to protect the battery. Make yourself a box with the wiring done, and two crocodile clips or something poking out for the battery, and i think you have a pretty good system.
this is what i plan on getting. I'm not sure if that's what you meant but it sounds similar. I've actually never used one but im going to be doing traveling work for several months and trying to prepare so i can not have to eat out and buy drinks etc at the gas stations all day. It gets too expensive. I was also going to get a food warmer (car style with low watts). I'll also have to get a cheap inverter to charge the battery. That way while i drive it charges but when i stop to work a job it won't kill my truck
Depends on the cooler. I have one that's essentially a glorified ice chest with a peltier and a couple fans. It might use 50-60 watts. Something like this might work if that's all you have. You might experiment to see if outputting 14V rather than 12V will lower the current consumption.
You'll want to get a step down converter. Something like this: https://www.amazon.com/Converter-DROK-Adjustable-Regulator-Transformer/dp/B08LPVWX74/ref=sr_1_3
But be mindful of the max power draw. Your electric cooler might require a beefier converter.
Those boxes are $5, hold 25 batteries and have convenient flip-top lids, but I get your point, I 3D-print accessories and fitted organizer boxes all the time, if not as smooth as yours.
Does she really need the 60W ring light? Honestly, it may be cheaper to just buy like a 10W ring light (ie USB powered). I got mine for like $30 something bucks. https://www.amazon.com/gp/product/B08TMHS53W (this particular model not sold anymore, but you could probably find similar). The reason I say it's cheaper this way is because unless you have the tools to create a charging port and the inverter, etc... it may end up being more costly that way. Then you can just use a USB 5V to charge it (basically any powerbank).
If you still want to go about it this way, I'd look up 12V chargers. Those are going to be the safest way to charge.
You can in theory probably wire a USB-C input and use something to set the voltage to 12V and have your output going to your battery. Someone probably has already premade that PCB, but I've haven't encountered it yet. I know the voltage switch exists, but I'm forgetting what the board is called. You would also need to control the amperage. Probably would be important to buy an inverter that's efficient and small, otherwise it'll drain a lot of power just to run it. I think the cheap one I got has a 0.5 amperage draw at baseline just to power the fan.
Alternatively, you could also just buy one of those power banks that go up to 60W or 100W. I have a couple of those. They use proprietary boards, which I haven't found on the DIY side yet. Both Anker and Ravpower have made reliable ones.
Another crazy idea I had to charge the board with this cutoff - was to use the circuitry from this board and hook it up to each series per bay. It would be a slow charge, but I assume a healthy way to do so? (And allow me to just leave it plugged in over night)
I see. That was the original thought I was thinking about.
Although, I'd like to get something that would shut the charger off when it reaches max capacity. (Also, I thought there was a 'healthy' way to charge the batteries with a variable voltage / amp?)
Another crazy idea I had to charge the board with this cutoff - was to use the circuitry from this board and hook it up to each series per bay. It would be a slow charge, but I assume a healthy way to do so? (And allow me to just leave it plugged in over night)
Okay that makes alot of sense! I'm still lost on where to pull power from? So do I pull power from the Negative and positive terminals of the entire pack? Or are there pads on the BMS to pull power from? I feel like I can only pull power from the battery packs positive and negative connectors as pulling 150W+ through a single BMS would probable set it on fire. Also this (and all the other ones I can find on Amazon) BMS only has power in, no power out pads
Ah okay yeah that can easilly be done. Any chance you know where I can find a 6s BMS board? I've seen some on Amazon but I don't know how reputable they are. The one I've found that looks the least sketchy is this one
I just ordered this unit from Amazon: https://www.amazon.com/gp/product/B07RHZMXPD/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Do you think this handles the proper charging profile?
FYI - I'm running a low-draw 5s-10P pack
No. They are fully assembled and come with a BMS. For example. You would need to add a charger but many of them are designed to work with generic SLA chargers.
Something like this would probably work: https://www.amazon.com/gp/product/B08K341JBP/ref=ppx_yo_dt_b_search_asin_title
If you look at the pictures, there's one that shows that you can select the number of Li ion cells in your pack from 3 cells to 16 cells
https://www.amazon.com/Upgraded-Enhanced-Rechargeable-Portable-Adjustable/dp/B08B4RJ58B/
Some tips: don't push down when spot welding. It works by resistance. The greater the resistance, the better of weld is made
Since it is portable, it might not weld thicker nickel strips but you can stack and weld them together to get the thickness you're aiming for.
I got one of the portable ones for $50. It worked very well for a e bike battery build when kept on the charger and the highest “gear” probably better options but it worked good enough Spot Welder, Kerpu Mini Spot Welder, Portable Spot Welder Machine, Spot Welding Equipment Energy Storage 5000mAh for DIY 18650 Battery, Portable Battery Welder with Type-C port 2A Input https://www.amazon.com/dp/B092DB5R3S/ref=cm_sw_r_cp_api_glt_fabc_A8Y7HV2E79JMBADWYJ1R
I'm looking to create this setup for this project, can you let me know if this looks reasonable?
This is the BMS I'd like to use:
Yes!
Xiaomi makes one. It's a bit expensive, but theoretically feature packed. DX stocks them. The problem? I think the interface on them isn't very English friendly and I also get the impression that they might be ham band only.
I bought this one. Haven't used it much yet, just made sure it was in working order when I recieved it.
That won't be cheaper than buying a couple of capacitors though, if that's what stopping you from DIYing one.
Thanks for your kind reply! So sorry that it needs some time to transship the stock from China to US warehouse. If you are interested in new four bay charger, the VC4 Plus has stock now: https://www.amazon.com/XTAR-Battery-Charger-Rechargeable-Protected/dp/B09FSB8V83/ref=sr_1_3?keywords=XTAR+VC4+PLUS&qid=1637720851&sr=8-3
ISDT C4 Evo is my choice. As for internal resistance, you'll need to do some maths.
For battery 🔋 blocks with high capacity, I use this thing which will discharge and count.
That'll give you an idea for sure, but it wouldn't be considered a constant load because the resistance appears to remain static. That means as the voltage of the battery drops during discharge the current also changes.
I use this tester on amazon with great success. It varies the resistance as the cells drop so that you're pulling the same amperage the whole time, which would be more accurate. It would also help in your particular situation where you could test against a very small or specific load.
To do this, I'd hook up a workbench power supply to your project and get a sense of how many amps it draws during normal use (if it's variable, you'll have to estimate the average in some way). When you know that you can plug that current into the tester and drain the battery at that rate and boom, you'll have a good time estimate of how long that battery would last for your specific application. ✨
No this wont work, as you cant charge a 4S with that charging board, because the board only provides 4.2V and the battery needs 16.8V to charge to 100%. With 4.2V you cannot charge the battery at all. What you need is a CC charger with CC and CV mode you can get a buck converter which has a CC CV mode like this and then use a DC Barrel jack connector and a laptop power supply, but make sure to set up the Buck converter to 16.7V (for margin of error) and a maximum amperage of 1A
There is the purchase link: https://www.amazon.com/XTAR-VC8-Display-Rechargeable-Battery/dp/B09KN4RJ3F. The stock will arrive at US warehouse around next week.
Looks super nice!
I would leave space for this meter so whenever I want I can upgrade the pack with more features.
What about DC circuit breakers? maybe they are out of scope of the purpose of the pack. Depends on what's your target.
Btw, I've got several of the voltmeters shown in the render, they are ok for voltage but i could never make the ammetter work. They don't look special anyway.
I'd be very curious about this too. I recently bought this one from Amazon and while it definitely is on the cheap side I haven't had any issues with it yet.
Oooh, I love this question! So measuring voltage (specifically voltage under a load) will give you an indication of state of charge, but not capacity. To get the capacity, ideally you would use a constant load test.
This means you put the battery under a constant amp draw (typically Lithium cells are rated for 1/5th their capacity in amp draw). Since these claim to be 2000 mAh cells, then you'd want to draw 1/5th of that, so 400 mAh.
To do this, you need a constant current device. I've been using this one from amazon with great success. It's definitely on the cheaper side, but I have yet to have any issues with it and it gives me at least a pretty good clue as to weather a battery can hold what it says it does. To test your batteries with it, you'd just hook it up to the positive and negative terminals (I like to use magnets to hold the leads in place) and then spin the lower dial (lower dial is fine adjustment, top dial is course adjustment) until the tester starts drawing 400 mAh or 0.4 amps. You then just let it run!
There is a setting on the device where you can tell it to cut out at a particular voltage, so you'd set that to 2.5 volts which ends the test when the battery dips below this value. Then you wait (typically 5 hours since you're theoretically only pulling 1/5th the capacity) and it'll tell you your mAh, Watt hours, and how much time the test took to complete (it'll also show amps and watts while the test is in progress).
Also, if you have any more questions I'd be happy to help! I've recently gotten into rechargables and I've been learning a ton and having a looot of fun along the way.
I was looking at this ultrafire WF - 502B with 18650 batteries and charger for a half decent el cheapo torch to use every so often. Whats wrong with proprietary batteries?
If you're looking for the absolute cheapest thing, I found this. No idea if it's any good, but it's got decent reviews if that helps.
If you're willing to spend a bit more, then I'd recommend this. It's what I use and I find it to be pretty reliable and haven't had any issues with it.
Can you tell me about the Kweld? I've only been using this spot welder from amazon (honestly it has been super helpful, no complaints), but I'm curious about other models since I literally bought the cheapest option.
Got me six good condition HohmLife 3077 mAh cells and two unbranded cells, along with two Eastshine S4 chargers. Going to have to get my buddy a drink, this is an awesome little surprise.
At the moment I'm conflicted about the BMS. I bought this one from Amazon to test out, but I'm not sure it'll be a permanent installation for this project. Problem is the batteries only cost $25 after shipping, which would make the BMS about 45% of the total cost. Plus these are all new cells that all arrived in the same box, so odds are they'll keep balanced for quite a while. ¯\_(ツ)_/¯ Guess that'll be one of the things I test every now and then.
As for the boards, not sure what you mean. Though I can say it'll be for the BE550G model of APC.
It sounds like you've already done some extensive testing, which is really good! It looks like you may have already done a capacity test, but if not I found this item on amazon works really well for that. It puts them under a constant load by constantly monitoring and adjusting the resistance, and then measures how much amp hours and watt hours of energy it was able to extract from the cell.
If you're looking to test each cell to see if it actually has what it's supposed to then this is the way to go. Then you can just go off the datasheets and put them in your project to see if it works!
I have some ISDT lipo chargers, and have been eyeing this one:
Oh dope, that really helps! So for that kind of power draw, basically any 2S BMS should work fine. I found this set of 5 chips on Amazon for about $14.
As for the charger, what kind of breakout board are you using?
And as for the wear on lithium ion's being fully charged, I don't know how much you can do to mitigate that. If it's a battery backup, you kinda want it charged all the time for cases where you want to leave with it. I can do a little more research about this, but not sure what you could do to avoid it besides keeping the cells at their storage voltage (which wouldn't be anywhere near fully charged).
If you are powering an ebike get a greenworks 40v battery. (10s so it is practically 36v). There are 3d printed adapters on ebay.
https://www.amazon.com/dp/B07VGPK4KQ/ref=cm_sw_r_awdo_navT_g_SYY87P31776YPPRM93SF