# Questions tagged [battery-charging]

Please specify the battery type in your question. Include chemistry (e.g. lead-acid, Li-ion), voltage, capacity (in A·h or W·h), number of cells and how they are connected (series or parallel) .

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### How to Calculate the Exact Timing for CV charging mode in a lithium cell?

We charge our Battery with CC method upto 80%. We got the time for it. Capacity/Ah. Now we switch to CV method for rest of the 20%. How to calculate Time for that Dropping Current?
42 views

### Charging time in a series-parallel battery setup

So I am trying to figure out how long it would take for 24 batteries (1.5 V, 3 Ah each) to be charged from 10% to 100%. The batteries would be set up so there are 3 rows of 8 batteries in series, ...
97 views

### Charging Ni-MH batteries

I understand that the recommended charging voltage for AA/AAA NI-MH batteries is between 1.4 V to 1.6 V and c/10 charging current. If i need to choose between 2 options: Charging voltage of 1.4 V and ...
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1 vote
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### Detect when battery is missing?

I have a battery charging circuit that works fine except that I want to turn off the battery charger IC when the batteries are removed. When the charger IC is enabled and charging, it's outputting ...
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### Making a battery power supply for a portable Raspberry Pi computer

I am trying to make a portable Raspberry Pi computer, the idea is just a Pi, a screen that is powered through the Pi, a keyboard and battery power. I have been trying to figure out how one would ...
23 views

### Two 12v batteries and charge controller [closed]

I apologize if this seems stupid, but i have never done anything like this before. So I have two 12v batteries (car batteries) and one charge controller - the controller says PWM battery charging, and ...
1 vote
35 views

### BMS 3S (S-8254A) with SJT-150E charger won't fully charge

Lately, i've been trying to use a BMS 3S that is based on the S-8254A IC to charge a group of three cells that I planned on using in series. To charge the cells , I'm using a 12,6V 10A SJT-150E. This ...
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67 views

### Adding current limiting to a buck voltage converter (MT2499) with INA213 and TL431 comparator

I am designing the power supply section for a circuit that will be mounted on a sensor node up a pole. I have chosen sealed lead acid batteries for solar backup power, and the circuit will also be ...
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49 views

### MCP73871 and TPS61090 Troubleshooting

I apologize in advance if I violate any forum conventions here. If that happens I will adapt postings accordingly moving forward. Context: I have been working on a PCB design that incorporates the ...
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### Sodium batteries - How to manage batteries without a dedicated controller/monitor?

I have recently been reading and hearing plenty about sodium and sodium-ion batteries. From what I understand, they are the next big battery technology. As sodium-based batteries have a completely ...
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1 vote
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### Help review my schematic for a LiPo + USB power supply and charger

I've recently redesigned this schematic based on the feedback I've received on an earlier post. Questions: Will power source switching MOSFETs work in the configuration I'm using? Will the tri-state ...
48 views

### Microcontroller with battery backup: charging, charge monitoring, and low-battery power-off

I am working on a circuit that needs to interface with 12 V sensors and actuators. The system is normally powered from 220 V AC and it has a 12 V backup lead-acid battery, so there will be some 220 V ...
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### Please review my usb lipo charging circuit

I've followed a tutorial on YouTube on how to make a USB charging and powering circuit for some mobile device. I decided to change up some parts because they were either too expensive or had too many ...
112 views

### Why doesn't my simple 4V lead acid battery charger using an LM358 op-amp work?

I obtained the circuit copied below from: Instructables - Simple 4V Lead Acid Battery Charger I changed the Zener from 4.2 V to 4.7 V. The 7806 supplies 6 V to the circuit shown in the figure at J1-6V ...
1 vote
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### How to light an LED when a 3 cell 11.1v Li-ion battery is fully charged

I'm trying to create a charging notification module for a 3-cell 11.1 V Li-ion battery. The battery has a built-in BMS, and a 12 V DC adapter (with a 12.6 V output) is connected for charging it. What ...
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1 vote
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### Charging a BMS and providing power at different voltages

I've designed a BMS based on the HX-2S-JH20. The BMS design itself is clear to me, but as I want to use a 12 V DC plug for charging. The BMS takes 8.3..9 V, the circuit takes 5 V. I wasn't quite sure ...
83 views

### Charging circuit for Raspberry Pi Pico

Currently I am working on a kind of pager project. The main idea is that a base station communicates via LORA with my handheld, similar to a DECT phone (Fritz!fon, Gigaset, ...) The handheld should ...
126 views

### Why (4 V 1.5 Ah) sealed lead acid battery charger using LM317T doesn't work?

Link to Falstad simulation. The circuit below shows the 4 V, 1.5 Ah sealed lead acid battery charger. LM317T with heatsink is used which has 9V DC as input. The Zener diode breakdown voltage is 4.7 V. ...
91 views

### How to dimension a solar battery charger?

I am currently designing my first PCB and I am having some difficulties. It will be a solar power management board with a USB input, li-ion battery, PV module and a not yet defined 7.2 V output ...
48 views

### How to charge two 18650 cells in series with a 12 V solar panel for an ESP32 and NPK sensor project?

I'm a beginner and I'm trying to figure out how to charge two 18650 cells in series using a solar panel with a 12 V output. My goal is to power a circuit for an NPK sensor that operates at a voltage ...
76 views

### Modify USB adapter 5 V, 1 A or any 5 V mobile charger to output 4.5 V, 500 mA or 900 mA

I have a trimmer which charger is lost, and now I want to charge it with my mobile micro-USB charger. The issue I am facing is that it has two 1.5V batteries connected in series. When I try to charge ...
41 views

### Load cycler keeps stalling at same voltage

Hello I am building a load cycler using an arduino with this code: ...
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29 views

### Using a single port for either a battery or external power supply

I have a circuit that can be powered by either USB-C, a LiPo battery or an external power supply. Because of a small footprint I would like the battery and external power supply (5-18V) to share the ...
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52 views

### Battery charging slow

I have 2 batteries connected in series (each battery rating - 3.3V and 5Ah). So the combine effect after connecting in series is 7.3V 5Ah (practically getting 7.56V in the battery)[the battery has ...
35 views

### MCP73871 voltage drops on OUT with no external power supply connected

Problem I am using the MCP73871 to manage battery charging while supplying a load to a 3.3 V regulator. the downstream load is pulling on average 150 mA off of the LDO. Everything works fine when 5 V ...
21 views

### Disconnecting I2C from powered battery gauge IC to rest of the unpowered circuit

The LTC2944 is leaking current into my unpowered side of the circuit, cutting the traces between this IC and the rest of the circuit fixed it. Can I do the following to prevent this leakage? When the ...
45 views

### Theoretical equation to describe capacity fade

https://www.researchgate.net/publication/357842717_How_do_Depth_of_Discharge_C-rate_and_Calendar_Age_Affect_Capacity_Retention_Impedance_Growth_the_Electrodes_and_the_Electrolyte_in_Li-Ion_Cells I am ...
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### Is my lead acid charging circuit fine?

I would like to ask for review in my schematic circuit for charging lead acid battery with following data: 6 cells per unit (1.75 V per cell), float charging voltage between 13.7-13.9 V, maximum ...
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### Is it possible to get a dual supply from 2S Li-ion battery which has a battery protection IC connected to it

In the image below, can the node connecting cell 1 and cell 2 be used as ground and PB+ as the positive rail and PB- as the negative rail? Those positive and the negative rails will then be regulated ...
120 views

### Battery pack won't charge because it reads 4.2 V

I salvaged a battery pack from an IP camera and I want to know if it's in good shape to use for other stuff. The packaging indicates a nominal voltage of 3.8 V and a capacity of 5000 mAh. I assume it'...
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1 vote
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### Solar panel used to trickle charge four 12 V batteries

I am attempting to use a solar panel to charge four 12V AGM batteries. These are connected to batteries on quad bikes. We are hoping to allow them to trickle charge while they are in the garage. The ...
30 views

### Simple circuit to charge and balance 7.4v li-ion battery (2s) 2x 3.7v cells in series

I am looking for a simple circuit to charge and balance 7.4v li-ion battery (2s) 2x 3.7v batteries in series, and also with over-charging, discharging, current protection I have found many circuits ...
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33 views

### How can I switch between battery tracking mode and input voltage regulation mode on the BQ24210?

I'm trying to create a circuit in which a BQ24210 automatically switches between charging a battery via battery tracking mode and charging it via input voltage regulation mode. This is done by having ...
18 views

### KiCAD PWR_FLAG issue on DW01A circuit

I am building a TP4056 based battery charger circuit on KiCad. The ERC check throws the error as per the screenshot. Do I need to add the PWR_FLAG on VBAT- and VBAT+ nets as well or is there any other ...
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### LiFEpo4 issues and concern

I have a 200AH LiFEpo4 battery and I bought an inverter, my inverter has 4 output AC socket if I connected the 1st socket to airconditioneer and and the 2nd socket to the charger continue charging ...
1 vote
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Hello I am attempting to build a simple load cycler that will charge and discharge 3.7 V 18650 batteries for a certain number of cycles. I would like to program it to do something like this: I'm not ...
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119 views

### How to measure battery voltage during charging?

I have a slight confusion regarding the battery. Suppose I have to charge a battery of initially 12V to 14.2V (full charge). My charger has open circuit voltage of 15V. When I connect it what voltage ...
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### Creating a 12.6 V 3S Lithium-ion Charging Circuit from 5 V USB-C

I have some questions about what is considered standard for a charging circuit, as this is something I have not much experience in. I am constrained to the following: 3S lithium-ion battery of 2600 ...
829 views

### Impact of high-power USB-C chargers on Li-ion battery longevity

Context: I have a 24 Ah 65 W power bank. I use a USB-A 5 W charger and it takes over 12 hours to charge it. Considering buying a more expensive USB-C fast-charger + cable, as this power bank can take ...
77 views

### Protection against inrush current on battery charger

I'm designing a PCB for a battery powered robot. This battery must manage both the charge of and discharge of a 8S (29 V nominal) Li-ion battery. The voltages of the application cause big inrush peaks ...
77 views

### Charging a battery using solar panels, and IV curve of the solar panel

I am aware that a solar panel has a fixed IV curve, and the load resistance can move the operating point of the solar panel along the IV curve. If a solar panel was used to directly charge a battery ...
1k views

### Why we can not recharge alkaline batteries to their former voltage values

When a 1.5V alkaline battery drops to around 1V, it is usually insufficient for the operation of most battery-demanding technological devices. Couldn't batteries that have fallen to 1V and are now &...
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### How to design a battery charging circuit for solar panels and USB

I'm working on a low-power project using an esp32 and an e-paper display which will be used indoors. It uses a lithium ion battery. I want to harness solar power so the battery has be manually charged ...
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### How would I go about supplying the measurement circuit with multiple batteries ouputting microAmps of current

If I am doing a test for lithium-ion batteries where I am trying to measure a small current when I apply a small load (on the order of microAmps) How would I go about using this same current to power ...
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### Switching between two power sources and charging a battery pack

I am designing a circuit, which can use either the power from the normal socket (230V) to charge a battery pack and power a arduno uno R3 at the same time when a spst switch is on. When the switch is ...
75 views

### Is it safe to use a battery charger with an output voltage higher than the battery voltage? [closed]

I apologise in advance for any erroneous or obvious points or terms I may use. I have a Remington beard grooming razor, which originally contained a 1.2V 700mAh NiMH rechargeable AAA battery, which ...
1 vote
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### Would thermal vias under an Inductor be effective at dissipating heat?

I'm designing a BMS board that will be capable of charging my 1S2P battery back. I'll be using the 21700 Li-Ion cells, which will mean my batter pack will have a total capacity of 10000 mAh. The ...
1 vote
106 views

### Can I charge multipe 18650 lithium cells at fixed 4.2?

This question is edited. I am currently working on an emergency light and I want to power it with 4 18650 cells in parallel. I've tried using TP4056, but that is really slow. It takes well above 10 ...