# battery

1. ### 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...
2. ### 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...
3. ### 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...
4. ### 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...
5. ### 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...
6. ### 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...
7. ### 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...
8. ### 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...
9. ### 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...
10. ### 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...
11. ### How to dim 4.5v fairy light LEDs on a USB supply?

Hi folks, plea for help. I've wired my daughter's LED fairy lights to a USB-2 supply, but now they're much brighter than the 3 AA batteries made them (and we quite preferred when the batteries were half flat), so I've been trying to find a variable resistor to put in series to reduce the...
12. ### Confirming Circuit Configuration.

Hello, I am in a research team and is designing a circuit system for powering a motor with battery and supercapacitor. The battery and supercapacitor powers the motor separately and the motor gives regeneration power back to the supercapacitor (motor driver allows for regen). Can experts in this...
13. ### 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...
14. ### battery voltage measurement

Hi, We are using a voltage divider circuit to measure the battery voltage of li-ion batteries of 3s2p configuration ( NCR18650B) The parameters are as following Vin- 12.24V r1= 604 k ohm r2 = 191 k ohm V out( expected) = 2.9V Vout (obtained) = 2.4 V. We measured voltage using multimeter at...
15. ### Running a power tool without a battery.

Hi, I have a 10.8V Bosch battery which is standard for power tools. It has 5 terminals: + - C1 C2 T I'd like to power the device without the battery using a DC power supply. When I apply just the right voltage to + and - it doesn't work. How am I supposed to mimick C1,C2 and T interfaces...
16. ### 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...
17. ### SLA Battery Charging/Maintenance

Is using a UPS i.e. APC Smart-UPS (4 battery) a recognized way to charge and maintain SLA batteries (AGM) throughout the year? Given that the batteries should be discharged about every 3 months?
18. ### Automatic transfer switch dc

hi guys, i try to make an automatic transfer switch dc for router 9VDC / 0.6A here. I want to switch automatically the power source from router adaptor to battery(power bank) that i set for power backup. and changing back when the router adaptor get an electricity again. i can't find the most...
19. ### Power to battery

New to electronics, I have a question. If I have a 12v power source that connects to a 12v battery that connects to a 12v load that is constantly on, would the battery drain of power?
20. ### problem in low battery detector circuit

I have designed a low battery detector circuit using low power comparator MCP6541 for a 4.2V Li-ion battery. This circuit checks whether the battery voltage if the battery voltage is lower than 3.5V then it will glow LED. Check the circuit below. The circuit is working properly but the...