This is one of the best Poundland purchases I've made in a while, purely because of the Google trek for knowledge that it sent me on. Most of Poundland's power banks in this style come completely discharged due to the higher than usual quiescent current of the circuitry. I wanted to know if that was a serious issue or not.
Here's the best documented test I found.
https://www.nature.com/articles/srep30248
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
Here's the best documented test I found.
https://www.nature.com/articles/srep30248
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
I have an old cell samsung 2000mAh phone battery that was left totally discharged and when I found it the cells open circuit voltage was only 1.65v! barely more than an AA battery!
I put it on a super slow trickle charge with a 500 ohm resistor and a 5v source and it slowly rose in voltage up until about 3.3v then suddenly dropped down to about 2.9v
However what actually happened was the protection circuit was not kicking in and only allowing a tiny quantity of energy to flow into the battery. causing an elevated voltage reading while charging at the low current. until the protection circuit came to life and the real open circuit voltage was about 2.9v
I kept charging it with the resistor and source until about 3.4v
I then slowly charged it with a 100mA charge rate until it was about 3.7v resting voltage. then raised the charging current to 400mA
It kept climbing right up to 4.2v and fully charged up.
I then discharged it at the C/5 ratie down to 3v and I got JUST OVER 2000mAh of capacity out of it! About 2112mAh! Like brand new! From 1.65v to brand new capacity!
Did a storage test for several months at 40% state of charge about 3.75v and it did not budge from that. did not even drop a single millivolt after months of sitting!
I had some wire leads soldered to the gold plated pads so I can reuse it for various projects. it works fantastic.
if its slowly discharging, then can we use this for faster discharge application. Ex: Cordless drill.
Hi, I have a question: I built a circuit without any microprocessors which discharges a single 18650 at a constant current of 1A until the terminal voltage is 2V9 which ( as I understand it ) is the lowest voltage acceptable. If I remove the cell and place it in a dedicated charger it tells me that the cell has 25% of its capacity left.
How do I interpret this? It seems to show that only 75% of the nominal cell capacity is actually available for use.
If I fully discharge a battery and I let it just sit somewhere forever in a fully discharged state. Is this dangerous? Or is it, the RECHARGE activity after full discharge that is dangerous? I can only pick up hints from this video and other sources online that it is actually the activity of recharging which is the dangerous part, yet y'all keep saying "deep discharging is dangerous". Is this just sloppiness on your end or is it really the act of depleting all energy from a battery that is dangerous (in my uneducated, yet logical brain, this doesn't make much sense lol)?
How common are battery disasters? My friend used old drill batteries in his e cigarettes. He pulled off the contact strips, not so bright. Whilst in Wickes his trouser leg burst into flames leaving him with a third degree burn roughly 12 inches by 6 due to the battery. A second battery two months later did something similar – cause unknown. One wonders about Darwin Awards! Whilst at the burns unit the nurse said that exploding batteries especially on e.cigs was very common, the latest being a girl drawing on the cigarette when it exploded destroying the skin on the end of her nose requiring skin grafting. The question is, how common is it? Data from a burns unit or two would be interesting.
I've found that from zero volts is no issue I've done thousands now been buying used laptop battery's by the 25kg lot and it mainly comes down to 2 things …the original condition or charge level ..and how it was drained ..if it drained via years and bms then no issue but likely one is dead or sad or unhappy typically the anode or tail end in rows of series ..
0.2a of load or less u can drain to zero …I drain my bad batteries with led rings …then there safe for recycling ..I've done laptop batteries .phone.mac.drones and vapes ..100% lipo is best
Can you give details of your USB test light seen at 0-38. Thanks
Also, the low voltage storage affects the IR and capacity of the cell.
Does the circuit doesn't have BMS??
Which device should I purchase to test the real capacity of 18650 battery any cheap device
Recycling dicarded non-medical inhaler Li-ion cells that have been subject to overdischarge. Using the built-in chargers from the rechargeable versions of these inhalers, the minimal circuitry checks for the cell's ability to carry a certain amount of charging current, continuing to charge if the criteria are met, or switching off if charging levels are too low. Under normal use the built-in LED 's forward voltage limits the voltage down to which the cell can be discharged. However discarded device cells can even be found with zero or even negative volts (how can this happen? ), especially when the discarded item exposed to the elements, where condensed water can result in continued discharge below designed cut-off voltage. Overdischarged cells can be charged in parallel with cell discharged to acceptable voltages like 3.2v, since the max charge voltage is set to something like 4.13v on the charger circuit, and the fully discharged cell can be forced to accept a charge at this voltage over time and the charger can then kick back in. Just take suitable pie-dish precautions when charging potentially dodgy cells and don't use them for mission critical situations like attack UAVs
Excellent video. Really enjoyed the theory behind these cells. Will watch again to soak up more info.
Good day sir. I didn't know about these batteries until I learned about them in your videos. I like them, you showed a small charging board and I got a bunch they were cheap. You mentioned in a video that if you connect the batteries in parallel that even a difference of .01V can create an overheat of the leads on the battery. So while I'm playing with them I discovered I can charge them all to within .002V and I connected 2 in parallel and held the leads and never felt a temperature difference so I think I did it safely. I remember though you had said to discharge the batteries to the same voltage before connecting them together. May I ask why I should have discharged rather than charge the batteries? Pardon my ignorance, I am learning tho. If I'm in the wrong video and this comment doesn't make sense please accept my apology
I was just watching another video about trying to revive these cells and I thought "I wonder what Big Clive thinks of this" and then this video popped up in my suggestions.
… If you're going to start popping up when I think I need your advice, disturbing images of you as my fairy godmother are going to form in my head.