I built a power bank which had Seven 18650, savage some from laptop batteries and others from an old power bank… I recently just noticed that the power bank circuit won't charge the batteries though the output process is good to go… It came to my knowledge that charging the batteries directly from the charger would severely damaged the batteries.. So I dropped the voltage using two diodes connected in series, it gave me 4.0V, I don't need an ammeter to know that the diodes also took down the current, because it took an hour and half to charge a 18650 from 2.8V to 3.2V meanwhile I'm using a 5V 1A charger… So any help on how to increase the current or any alternative to charge a 3.7V 18650 using a 5V 1A charger. Thank you in advance for your anticipation on getting me a solution..
Forgive my English, its crappy.
Electronic – Charging a 18650 battery using a 5V charger
battery-charging
Related Solutions
Did you read my answer to your question that you posted 3 days ago?
What you need is a battery manager, or BMS. This is the current standard way to handle your problem. There may be other jankeyer solutions, such as charging your pack 6s at a time using an RC balance charger, but I wouldn't recommend them if you don't know exactly what you're doing.
Here's some examples of battery managers that I found with a quick google search.
https://vruzend.com/product/48v-13s-battery-management-system-bms/
https://bmsbattery.com/bmspcm/713-10s-13s-30a-50a-lipo-battery-bms-system-bms-pcm.html
Picture in case the links die:
A battery manager is powered from the pack and will actively balance the cells. All you have to worry about is charging the pack to the correct voltage.
Just make sure 18650 battery cells mechanically fit, properly elecrically connected to tablet or protection circuit from original battery (if present) and recommended to have end discharging voltage of at least 2,7V ( must be written in datasheet ). Tablet will charge the batteries to voltage it can accept anyway and upgrading charger to more powerfull one is not neccesary, it will only use more time to charge a bigger battery.
Best Answer
ATTENTION! If you overcharge a lithium-ion cell it can explode and cause some serious damage. Also if you get the cell into undervoltage condition and try to charge it again it will explode too.
This is why lithium cells should never be used without a battery management system which supervises every cell condition.
Lithium cell should be charged with a CC-CV algorithm. Every cell is different about the end of charge voltage, under voltage border, maximum currents and so on. Without out knowing anything about the cell I would not risk burning down my house while experimenting with lithium-ion cells.
Mixing different cell types can also be dangerous because there can be compensations currents which are not intended.
(Source: I work at a company which develops battery management systems and builds battery packs. Even with a high experience we have burning cells from time to time for example when we get packs back from a customer and do not know what he has done with it.)