1. L

    lithium battery with a strange behaviour

    Hello, I'd been trying to balance a couple of 12V 100Ah LifePO4 lithium batteries in order to put them in series to power a 24V inverter but I it seems that one of the batteries is not OK. The batteries had been used for different things before and had different state of charge.. one had 12.9V...
  2. eb_12345

    Hot-Swap Battery System

    I'm working on a research project at my school that includes flying a drone with an attached signal source to collect data. The signal source is powered separately from the drone and is reliant on an atomic clock that needs to be reset once it runs out of power. In order to avoid this, I am...
  3. S

    vibrating part run by battery and connects using bluetooth

    How would I make a device that can be connected to using bluetooth that does nothing but vibrate on and off that is powered by battery. This needs to be able to fit in a person's hand. I would like to see how small this can be using a chargeable battery and how small it can be using a coin...
  4. G

    Electronic Bike conversion with Lawnmower Battery? - HELP NEEDED

    Hello Everyone, I am really new to electronics and I am struggling to figure out how I would be able to use my GreenWorks 40 volt 4 amp hour battery on a 48 volt 1000 watt electric bike conversion kit. I have looked for a step up converter from 40volts to 48volts but I was only able to find one...
  5. E

    Battery life calculator software

    Hi everyone, First of all, nice to meet you all. I've always admired this field but I never thought I have the capacity to actually do anything in it. That being said I started learning stuff with the pandemic cause I had the time and yeah ... it's even more amazing now. That being said, one...
  6. M

    Load Testing a Cars Battery Using an Arduino to Monitor the Results

    I am working on a project that involves monitoring a cars battery. I can measure the voltage of it using a voltage sensor, a display and an arduino but that doesn't tell me much about the health of the battery. After researching, what seems to be the most popular way is putting a load onto the...
  7. I

    Design or Tools for Passthrought Voltage/Current Recorder for Batteries

    Okay so, currently wanting to set up a test for some rechargeable batteries, and developing a lower power mode for a system. The goal is to connect fully charged batteries to my devices to see how much current they actually drain. I have an estimate how long they should last, but its not exact...
  8. C

    Charging 440 mah lipo battery with tp4056 module is OK?

    I have a tp4056 li battery charger and I ordered a 440 mah lipo battery. Is it OK to chare battery with this or will be the current too much for battery? Do I need to modify module?
  9. S

    Battery & Power question

    Hey Guys & Gals, I have a couple questions about power for a device. I have a small handheld computer/Programmer and it has USB-C port and has a 3.7vdc lithium wired battery. The unit has the battery in the space where it could hold 4aaa batteries thou not wired for them & no contacts for them...
  10. sstech

    replace the battery cell power source (1.2v) to 5v

    I am using one machine (which has a small motor) which has battery of 1.2v which got dead and i want to change the power source to USB. The battery is of 1.2V and 400mAh. Motor connected to works perfectly fine if provide the 1.2V from bench power supply. I want to use USB power supply instead.
  11. Nikson420

    EAFC Full Automatic Battery Charger 12V Digital Display Battery Charger

    Hello Folks, as the title say I want to buy Battery Charger and found this one on aliexpress - https://aliexpress.com/e/_Ddn2rtR Price seems decent but what about qulaity? Any help is wellcome, thanks!
  12. Daniel28

    Emulate battery in charging state

    I am trying to build a circuit to emulate a lipo battery. Basically the circuit consists in a power supply to emulate the discharge behaviour and a variable load to eulate the charge behaviour. This is the circuit in a simplified way This basically generates 2 circuits...
  13. Roxx.R

    Need suggestions for this small battery and posible usage ideas.

    Hello friends, so now i have came up with this small battery and its small circuit. These are two identical circuits and i have numbered it 1 and 2 in the images attached. This circuits are from two identical vapes, it had this rechargeable battery and a type C input for charging the battery. i...
  14. Y

    Why I use MCP1640 can not get 3.3v

    When I build the circuit on the circuit breadboard. the input voltage is 1.3,but output only 2.0v without load resistance. when I input 3v with two cells batteries,the ouput only 2.8v without load. If I add load for circuit, the output voltage is lowee. So why? Is that any problem with official...
  15. bmbouter

    "closed by default" transistor design?

    I have an external switch connecting GND to RST on an 8266, it looks like this: [GND] ------ [normally open switch] -------- [8266 RST pin]. The ESP goes to sleep, and then the switch wakes it up. However while in operation I want this reset functionality disabled, but at a hardware level...
  16. EUrbanAutoTech

    If V = I x R then does it still "make sense" to refer to a battery's voltage when not connected to anything? As in I = 0..?

    I'm an automotive mechanic that specializes in electrical/drivability diagnosis. I like helping other techs get a better grasp on this aspect of our trade. Now imagine I'm with another tech and I have a battery and a multimeter in front of me. I measure the battery's voltage and get 12V. Me...
  17. F

    DW01A on pcb and integrated on lipo: double charging protection ... will it still work?

    I've designed a circuit around the tp4056 with DW01A and FS8205A included, as well as load sharing capabilities. beneath circuit is what i use (minus load sharing) now that i'm sourcing lipo batteries, i see most of them have a protection circuit already build in with the same DW01A and...
  18. T

    Electric toothbrush not working with other battery?

    I have a Braun oral-b pro 2000 toothbrush and with the original battery it now only lasts about 1 minute. I replaced the original 3757 Ni-MH battery with an AA size Ni-MH (higher capacity) battery and the red “battery low” indicator blinking. I had put it on the charger and it charged the...
  19. Svennn

    Wine bottle storage quality sensor thesis

    Good evening all, Background: I am final year Electrical & Electronic engineering student currently in the process of completing my undergraduate thesis. The thesis topic consists of making a low-cost, non-intrusive, battery powered electronic device that is small enough to fit in the punt (the...
  20. E

    3.3V battery pack / charging solution

    Hi folks! So I'm looking into the following, but having a very hard time finding any (remotely) definitive answers. For my smart home, I'm looking to integrate more and more sensors that can relay all sorts of information. Most of these sensors I create myself using ESP32's and the like...