# battery

1. ### Homemade Power Supply How to?

I'm posting today hoping for some guidance on a project i would like to attempt. I recently came into a lot of 64 12v 7AH Sealed Lead Acid batteries from a backup UPS. The batteries are still good and take a charge and load like normal for the most part. Since i only have the batteries and...
2. ### Protective elements for powering dc motors

Hi everyone! I am building a robot that carries a drill to make holes in the ground. I have not been able to find similar size/power references regarding how to power the motors. I would like to know how to protect the battery and motor drivers, my specific questions are: - Where to place...
3. ### how to properly make a charging circuit -- 2s 7.4V to 5V 2A

I have 2 18650 li-ion cells, each at 3.7v (in case you don't see the pictures, they are available here : https://raspberrypi.stackexchange.com/posts/121847 ) and this bay with this white connector I saw on youtube that depending on the length of the cell, we can know whether they have...
4. ### ESP8266 battery power supply

Hello all, First of all I'm a complete newbie about circuits and electronics. I recently bought a 3D printer and I saw this project on thingiverse. Quick sum up : LEDs (WS2812) lamp controlled by an ESP8266. The main issue is that the firmware of the ESP8266 provided to control the LEDs do...
5. ### Battery impedance measurement

For the past few days I have been trying to buy a proper battery impedance measurement device that is good and also falls under my budget of 1000 dollars. I will be mostly using it to test 3.7V Lithium ion batteries. Could anyone suggest a good measurement device for that
6. ### Can i use a 13s bms for a 7s project? And how?

I have a 13s bms laying around and I want to use it as a 7s bms, is there a way to do that?any suggestions would be greatly helpful.
7. ### Lithium battery (Operating temperatur range)

Hi; Is it possible for a lithium battery, whether Li-ion or Lipo, to resiste a temperature of 90 up to 100 ° C in a period that does not exceed 3 minutes? knowing that its working temperature range indicated in its datasheet is 60 ° C. thank you for any information given
8. ### No-load voltage of lithium ion battery (10th order polynomials)

Hello everybody I'm going to simulate a Lithium ion battery whose no load voltage depends on its DoD (DoD=1-SoC). I used the book of Soylu in which he obtained a 10th order polynomials for no-load voltage of the battery...

Hi guys, I have been using a pair of Sennheiser headphones for quite some time now (HDR 118). They offer good sound and sit comfortably, however they do work based on RF signals (863 - 865 MHz) and have been catching a lot of interference as of late. Instead of just getting a new pair of...
10. ### Wiring Headlight and turn signals for a simpleton

Greetings, My current project is trying to wire a headlight and two turn signals to a motorbike using a 12v rechargeable battery. There are no existing electrical parts of any kind for lighting aside from what I’m doing currently. Complete custom job. I need advice: What I have is: A switch...
11. ### Battery for ESP8266 ESP-12S A9G GSM (IoT Node v1.0 module)

Ive bought this board: link to shop (Elecrow ESP8266 ESP-12S A9G GSM GPRS+GPS IOT Node V1.0 Module) Here Ive read about it: wiki page I would like to use that board with 1inch screen and send data with GSM. I would like to buy LiPoly rechargeable battery for it. I have quite basic electronic...
12. ### Current control for a battery charge

How can I control the current that is supplied to a battery? I need to balance current consumption to avoid some parts of the system run out of power. My system is described in the attached file. I have a 12V input which goes into a Boost regulator to get 48V. Those 48V are used to feed a...
13. ### Ideas for using a 24V 40Ah LiFePO4 battery with damaged cell to power a 12V 500W inverter?

I acquired the battery in subject from one of the local recycle groups. It consists of nominally sixteen 3.2V 20Ah LiFePO4 pouch cells arranged in 8s2p configuration (pouches in pairs soldered to a PCB that puts them in series). One of the pairs developed a fault and was desoldered and removed...
14. ### Very new to this. If I were to make a DC Motor shaft with cogs and gears circuit, how would I know the required ampage of my power unit?

Very new to this so bare with. If I were to make a DC Motor shaft with cogs and gears circuit, how would I know the required ampage of my power unit (im thinking, battery AA holder). And are there any pre cautions I should take to prevent damage or potential fire hazard? I roughly know about...
15. ### Battery Consumption

Hi guys, I am new here and still not an engineer and have not much knowledge in Battery / electricity but have a major project I am working on and would be very happy to get some answers.. I am trying to build a machine that is using a spin motor that work periodically in set times (650 spins...
16. ### replace a Li-on polymery battery

Hi everyone, I own a Creative Zen Touch mp3 player which seems only working when the power supply is connected. Even though I tried to charge several times and after that turn on the device, seems don't work. I guess could be the battery. I opened today and I found that has a 3.7V polymer...
17. ### Solar charger & timer

Hi I need help building the electronics for a home project. Essentially I am trying to: 1. Charge a battery with a solar panel 2. Activate a 12solenoid valve controlling pressurized water with a push button 3. Have the solenoid close after an adjustable time delay I was able to find solar...
18. ### Making a lamp portable with 18650

Hey! I have a lamp which is powered by a 5V power supply and I want to upgrade it by powering it with a battery pack. The issue is I want to use the lamp while charging its batteries but as I know charging and draining at one time is impossible so I searched for simple switching circuit but I...
19. ### What Battery/batteries to Use for EDF Project

Hello everyone! I’m glad to have found this forum as I am an engineering student at University of South Florida. I had a question about batteries and motors, specifically what rechargeable batteries to buy for my specific need here. I am building a skateboard powered by 2 electric ducted...
20. ### Electric discharge from electric motor controller after unplugging battery.

Hello! I was being a bit careless after unplugging a 48v electric bike battery and I dropped the power cord leading motor's controller, it hit the rim and shorted the remaining current from the motor's controller. (I assume the steel rim completed the connection between the prongs and shorted...