Questions tagged [battery-charging]

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

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How should I select a battery solution for my project? (24 V/150 mAh with recharging)

I'm designing my first ever electrical project and have questions about selecting an appropriate battery solution. I'll put the requirements up front. Max power draw - 24 V @ 150 mA Average power ...
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0 votes
2 answers
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Why does an 18 volt cordless drill charger output 21 volts?

The charger says on the back that it outputs 21 volts and 400mAh. 21 volts seem too high for an 18 volt battery. Wouldn't that damage the battery?
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BMS with lead-acid battery pack

I assembled a lead-acid battery pack with six batteries. Is it possible to add a BMS for a lead-acid battery?
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55 views

Why is my lead acid battery suddenly dead?

I have a 12v 12ah sealed lead acid battery that was used 3 years in a battery friendly environment. Now I wanted to use it to power a security camera. I use a cv cc buck converter as a charger. I ...
1 vote
0 answers
53 views

Is there a simple way to slightly lower the output voltage of a e-bike charger?

For my e-bike (it's actually a scooter) I bought a 71.4V/10A "smart" charger. The original charger is a 70.4V/4A charger (it says it's a 60V charger, but I measured 70.4V and that's about ...
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Circuit design options for 58V lithium battery charger

I have an Echo 58 volt chainsaw and the battery charger has malfunctioned so that it no longer charges the battery pack. I have been charging it by using a 2A current limited lab power supply set to ...
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2 votes
0 answers
46 views

What's the minimum float voltage to maintain a small lead-acid battery?

I wish to 'float' a Yuasa Y7-12 7 Ah, 12V sealed lead acid battery. On Battery University it says that a voltage of 2.25-2.3 V per cell (so 13.5 - 13.8 V) will allow a lead-acid battery to regulate ...
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1 vote
1 answer
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Does a "normal" lithium battery BMS limit the current going into the battery when charging?

If I hook up a 42 V voltage source with an absurd peak amperage to a 42 V battery through a BMS, will it protect the battery from too much current?
-1 votes
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60V, 19S battery not charging because the 13S cell group is showing 0.0V

I have a 60V, 19S battery pack but the 13S cell group reads 0.0V. This makes the battery fail to charge unless I use a small wire to link the 12S to the 14S. Does that mean that the cells in the 13S ...
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Uninterrupted single cell li-ion power supply design for always on IOT device

I am desigining an IoT vehicle tracker for industrial use. We have 2 stages of buck-LDO to get 48V to 3.3V. My aim is to build a UPS circuit so that a single cell Lipo can power the whole board when ...
2 votes
1 answer
46 views

Charging series connected Li-pos one-by-one

I wish to charge a 4s li-po battery cell by cell, with a charger for 1s li-ion/li-poly charger (TP4056). I know this isn't a problem electrically, since only one electrode of the adjacent battery will ...
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0 answers
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Battery charger IC max. discharge current

I want to incorporate a battery charger IC to my design which has around 8 A maximum battery discharge current. I want the charger IC to boost my 5 V USB input to charge 2S Li-ion batteries (8.4 V) ...
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3 answers
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Can a battery's open circuit voltage be measured without actually disconnecting the load?

Is there: a specific tool for it or a method for its calculation which includes the terminal voltage I'm actually in need of a method which would not require disrupting the circuit by removing the ...
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4 votes
2 answers
891 views

How do I lower current usage on a 12 VDC fan hooked to a battery without a rheostat?

I have a 12 V fan hooked to a battery. I also have a solar charger to charge the battery. The issue I have is that the fan runs very fast when the battery is fully charged and runs the battery down ...
1 vote
1 answer
50 views

NiMH or Li-Ion for a 5v <1A powered device for a kid?

I'm building a small device based on ESP32 and powered by a 5V power supply (looks like <1A even when speakers are playing). I want to power it on batteries and it seems that everyone does Li-Ion ...
0 votes
3 answers
102 views

How to make a copper/zinc penny battery rechargeable?

I just saw the copper+zinc+vinegar battery also known as "penny battery" and I thought it would be perfect to make at home since I don't know anything about chemistry. On the Wikipedia page ...
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6 answers
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How to find the root cause of this relay failure

The following is the schematic for the relay section of the board: VBAT: 45-56 V. RY_REAR_MOT: Power to the front motor controller RY_REAR_MOT_EN: 3.3 V enable signal from the MCU. On power up, this ...
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2 votes
1 answer
50 views

Circuit to limit a variable-voltage DC supply to 30V

I want to charge a powerbank which supports 11-30V input with a solar panel with an open-circuit max voltage of 48V (41V under load). I live in a cloudy area, so I don't expect the solar panel to ...
2 votes
3 answers
84 views

How do I distribute an energy load over a battery and generator?

In a motor efficiency test, I use a motor, a generator, and a battery (Not an over-unity or perpetual machine attempt). I connect the motor's shaft with the generator and use the battery to initially ...
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0 votes
1 answer
44 views

Can I bypass battery protector for battery level indicator?

I have 2 series Li-ion batteries which are connected to a 2s battery protector. I want to indicate battery level only when a button is pressed. The problem starts when I measure battery level while ...
4 votes
3 answers
284 views

What is the lower limit of NiCd cell voltage?

I have some old NiCd cells, and I have a bench power supply. From what I read about NiCd batteries, I understood that a psu alone can’t charge them fully because it can’t measure the delta V. I saw ...
1 vote
0 answers
43 views

Charging a single cell battery from two inputs

I'm trying to charge a single cell battery from two inputs, solar and USB. Currently, I have the battery charging only from solar using a BQ24210 charger. I have a USB connector on the PCB and I want ...
4 votes
1 answer
84 views

Convert AAA battery device to LiPo

I have lots of small (500mAh) LiPo cells taken from Vaping devices (eCigarettes). I want to reuse them in some consumer electronics devices that run off 2 AAA batteries. There is generally space ...
7 votes
4 answers
2k views

For how long should I charge my dead car battery without damaging it?

I drained by accident my car's battery. When I connect it now to a multimeter it shows 3V. I connected the battery already to a trickle charger and I would like to know for how long I should charge it,...
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1 vote
2 answers
60 views

Different readings when measuring the resistance of rechargeable 1.2V battery

I have 2 rechargeable AA batteries. One is fully charged and one is almost used up. I directly connect the red probe of the multimeter to the positive pole of the battery, and black probe to the ...
2 votes
1 answer
63 views

Help to ID this SOT-89 component

I need your help to try to repair a battery charger of a Black & Decker drill. The charger is composed of two devices; one is a simple power supply, and the second one is the BMS. Unfortunately my ...
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1 vote
0 answers
51 views

Ringing seen when charger is presented to DUT

The following is my setup: Charger is set to 56V and 15A. When charger is turned on there is significant ringing measured by the probe directly at the charger terminals. However this ringing is ...
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1 vote
1 answer
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Rechargable battery problem in thermocouple simulator

I use a MicroCal 1 TC thermocouple simulator in my project. The specifications for this simulator say to use 4 x "AA" alkaline 1.5 V batteries, but I used rechargable batteries. I find that ...
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1 vote
0 answers
38 views

Charging a large array of LiFePO4 prismatic cells: How many is too many?

48 large (150Ah) LiFePO4 prismatic cells were wired in parallel (48P) for days to bring them all into balance; each cell metered 2.800 volts. Perfect! It would seem possible to initially charge the ...
7 votes
6 answers
3k views

How come modern electronic devices support charging with various voltages through USB-C?

According to this blog post which tested charging a Samsung laptop through the USB-C port with multiple types of USB-C adapters and external batteries, it seems that that laptop can be charged with 5V,...
0 votes
1 answer
69 views

What is the "Smart Battery Connector" for 9V rechargeable batteries?

I'm looking for a battery charger for 9V rechargeable batteries (must be switch-mode, not linear). I came across the "Smart Battery Standard Connector" structure in a controller IC datasheet ...
0 votes
5 answers
108 views

Why does current decrease in CC mode before reaching 4.2V in CCCV method for 18650 Li-ion charging?

I'm trying to charge 18650 cells from LG which have a capacity of 3200 mAh. I read the datasheet of the cells and it said 4.2 V and 0.5C of nominal charging. I'm not an expert so I did some research ...
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Trying to replace battery pack with dedicated power supply

I have a touch sensitive sink faucet that runs on 6 AA batteries. I'd like to replace the AAs with rechargeable 18650 batteries and also connect a power supply to power the faucet, but also keep the ...
0 votes
0 answers
21 views

AC MCB or DC MCB

I'm using MCBs on one of my projects involving a battery pack. Is it safe to connect using an AC MCB (Brand Legrand India) for switching between the states (on/off)? Vbat < 100 V, expected current &...
0 votes
0 answers
49 views

Is it possible to limit current by some amount of amperes?

I have an accumulator that has a maximum charging current of 3A. The battery connected to solar panel for charging and invertor for discharging. Solar panel can give for i.e. 10A, so, I want to send ...
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2 votes
2 answers
174 views

Very simple solar lithium charger (18650)

I need a very simple charger for 18650 LiPos (2.6Ah.) Since the solarcell (6V/150mA) will not be over the CC of the battery, I think only a precise 4.2V CV limiter will be sufficient. Has anybody ...
0 votes
0 answers
33 views

BQ2057WSN battery charger test

I am building a circuit to charge a Lithium-polymer battery using a BQ2057WSN. Now, I am thinking how can I test this circuit. I am planning to use a multimeter to check the charging current and ...
0 votes
0 answers
33 views

What IC to use for single Li ion charging / load sharing for a 250mA load that can be left plugged in to USB?

You wouldn't think it would be so complicated, but I'm self-taught in EE and the rabbit holes just keep getting deeper the more I investigate. Simply put, I'm trying to build a LED lamp that is both ...
0 votes
0 answers
60 views

Charging and discharging Li-ion cell dynamically

I intend to use an EBL 6F22 5400 mWh, 9 V Li-ion block as buffer for an USB-level solar charging station. It comes with a micro-USB charging slot and necessary voltage regulation. Not much can be ...
0 votes
1 answer
74 views

Will this design charge my batteries or burn them?

I have designed the following circuit to charge my Li-Po batteries while in circuit. Note that VIN is expected to pull a current as high as 2A when the board is running. Here's an explanation of what ...
0 votes
1 answer
53 views

Solar - charge batteries at 24 VDC, use 12 VDC loads

I have solar panels to charge controller to batteries to DC loads. The charge controllers can handle twice the power at 24 VDC as they can at 12 VDC. The loads are 12 VDC (mainly LED lights). Can I ...
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2 answers
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Battery management system usage [duplicate]

Does the BMS of a Li-ion battery protect it from overcharging in the long run? Also is it by itself sufficient to to protect it and maintain safe health of the battery or are some other components ...
0 votes
0 answers
60 views

Lithium ion battery life

We are developing a device for automobile cabin use. It has 2 modes of operation, the first mode is where our device will be powered by the automobile battery through the USB port of the vehicle. The ...
0 votes
0 answers
60 views

Help understanding datasheet of battery charger IC

I intend to use the TI BQ25798 battery charger IC for powering a hobby project. The specs look nice and I could power my project either from external power supply or battery or even solar panel. ...
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1 vote
1 answer
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Is it dangerous to charge gadgets at less than 5 V?

I'm using a solar panel, which gives me unstable current (from 0 to 9 V approximately), then I use a step-up converter to increase te voltage a little (my goal is to keep it between 7 and 12 V in ...
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2 votes
3 answers
107 views

Li-ion battery charging circuit issue

I have added a Li-ion battery charging circuit to my project for powering up the whole circuit by taking reference from this site. The issue I am facing here is maybe related to static charges. When I ...
1 vote
2 answers
136 views

Do these TP4056 charging boards have built-in load sharing?

I'm trying to design a simple rechargeable circuit that when plugged in, safely charges an 1S 18650 li-ion while also powering a load. I've been researching for awhile and can't seem to find ...
0 votes
1 answer
50 views

My UPS inverter is making treble noise

My home UPS is making noise mainly 19.5 kHz as shown in image while charging. It’s 7 years old now. Model is Sukam Falcon 800 Q. How to solve this issue?
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1 answer
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Is charging a 48V 100 Ah series of batteries with a 48V 140-270 Ah charger ok?

I bought a used electric utility vehicle that normally uses eight lead acid 6 V 260 Ah batteries wired in series. The utility vehicle instead came with four 12 V 105 Ah batteries wired in series. The ...
0 votes
2 answers
31 views

Solar inverter/charger to battery connection protection

I have a solar off grid inverter/MPPT charger and I want to install protection on the link between the unit and the battery. I thought of using a Circuit Breaker like this. But the problem is that DC ...

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