1. Tapish

    Charging individual 3.7V Li-Ion batteries that are connected in series to from 7.4v supply

    Hope you all are staying safe and healthy. The Pandemic lockdown has forced us to work with the only components we have at home. I am working on a battery-operated esp32 pico board having other sensors hooked up to it that need 5v of supply. So I connected two rechargeable 3.7v Li-Ion batteries...
  2. G

    12v DC 7A UPS from Li-ion Batteries

    Hi All, Complete beginner here so please bear with me! Trying to work out a solution for changing the main battery on my portable video switching system. The project is powered off a single 12V DC 8A V-Mount battery which powers the system perfectly. That said, I can't find a UPS with the...
  3. A

    Li-Ion battery current limitation??

    Hello all, I am using TPS61253 Boost IC to boost 3.8V from 375mAH Li-Ion battery to operate a load of 2A and also charge the backup Li-Ion battery of 115mAH using BQ25895 chip. Looks like battery is not able to deliver the necessary current and the load circuit does not boot up correctly. Is...
  4. D

    Question about charging two 18650 batteries

    Hello! First time ever posting to a forum of any kind. I have a charger made for charging a single 3.7 volt Li-Ion battery or more than one cell could be charged but at a slower charge rate. My question is there anyway to charge the two cells ran in series as the picture I attached shows with...
  5. ParamedicDad

    Wind-up generators and Li-ion batteries

    Tl;dr: Are putting Li-ion batteries in a Wind-up flashlight a thing? If not, what options are there for a more reliable, renewable light source? Hello, I'm a Paramedic, husband and father of a small family of 3. We don't make much money and live in an area where we are often heavily impacted...
  6. D

    Connecting 2P2S battery pack to BMS

    Hi All, I have four identical 18650 Li-ion batteries 3.7v \ 2500mAh and a BMS 2S. My goal is to get 5v (with step down) and more current capacity. so I though of connecting the batteries as 2P2S as battery university suggested. 2P because the Li-ion will balance themselves and for more...
  7. Cyirxrc6vec

    Charging Li-ion circuit

    Hi, I made a circuit that charge Li-ion battery. When I simulated it, I found something strange; the time for charging was too short. I made it with 'LTspiceXVII' and here's my circuit's diagram and the graph, also I uploaded the 'Li-ion bat file'. So, would you like to help me if you don't...
  8. G

    Li-ion cell charging module resistor selection?

    Greetings. A vendor selling TP4056-based 5 V charging modules for Li-ion cells specified the following resistance values and resulting current for selecting the current-programming resistor: R (kΩ) I (mA) 30 50 20 70 10 130 5 250 4...
  9. P

    Li-ion battery charging termination current

    Hi all, I have a question about Li-ion rechargable batteries. I have almost no experience with it. Documentation to battery is very poor, but there is an info about charging profile: Stage 1: Constant Current 0.82 Ampere (0.2C) until Voltage reach 4.2V Stage 2: Constant Voltage (4.2V) with...
  10. eliasklk_04


    Good night. I bought this flashlight for my bike: https://www.ebay.es/itm/Luces-Bicicleta-Luz-10000LM-Impermeable-3XT6-LED/292872854958?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 But the light that comes out seems very little to me. I think it has more potential. Could I modify...
  11. Tamás Fegyvári

    Non inverting DC-DC converter that makes fix 4V from a decreasing voltage from 4,2V to 2,8V?

    Hi! Is it possible to make a a non inverting DC-DC converter that makes a fix 4V from a Li-ion battery's voltage. I need about 1,5A. The input voltage starts from 4,2V and decreasing to 2,8V as the battery discharging.
  12. Carlosonline

    Li-Ion Battery Managment IC Issue

    Hi, I would appreciate if someone would be able to comment/advice on the following matter. I have been looking around for an IC that would charge and balance Li-Ion cells 2-3 of them in series. It seems that the balance feature is absent in most cases. MCP73841 appears to provide most of the...
  13. N

    Battery protection board needs to have voltage applied to output before turning on.

    Hello I have a Lithium ion battery pack that uses a small protection board that protects the battery pack from short circuits and under voltage. I am using 2 lithium ion cells in series for a nominal 7.4 volt output. The wierd thing is the protection board has to be first initialized by...