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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1answer
19 views

Charging lithium polymer

I bought a mcp73812 charging ic from digikey and I found a circuit online. I don't know much about electronics but I feel like there are issues with the circuit: First of all it says the green led ...
0
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1answer
51 views

Charge battery when power up, use battery when power down

I have a tiny little esp8266 that runs happily on 3.3V and draws about 250mA and I can make it sleep and use very little battery power at all. What I want to do is use supplied power when possible ...
0
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2answers
68 views

PID Control implementation for charging battery really necessary?

If one is to make a battery charger, lets say a Li-Ion battery charger (using a micro-controller with buck converter), is it necessary to do some kind of control implementation inside the ...
2
votes
1answer
37 views

How to monitor voltage and charge status in USB battery pack

What's the easiest, least intrusive way to monitor voltage, charging status, and remaining charge of a USB battery pack? Battery packs and charging circuits for mobile projects can be complicated and ...
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2answers
39 views

external battery claimed iPhone 6 charges versus my calculated charges mAh vs Wh and voltage step down confusion

I did a charge on this page and could not find the answer I was looking for. Perhaps it was over my head, or perhaps I was using the wrong search terms, so here goes nothing: I am trying to ...
0
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1answer
30 views

LiFePO4 Batteries Discharge Fast After Recharge

On my application I have four 200 mAh LiFePo4 cells, configures as sereies of two parallels, thus achieveing a 6.4V battery. I understand this cells in series need balancing, I would like to leave ...
0
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1answer
101 views

How to increase watts ? out of 12 volt?

I am making a project, a DIY so please co-operate I don't know much about electronics the overall project needs some electric combinations... I have a rechargeable fan with built-in battery but I am ...
0
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2answers
51 views

Simple way to charge 5 x AA via USB - any off-the-shelf component for that?

I need to power a gadget I am building with 5 x AA batteries (6V), but I also want to be able to recharge it via USB (5V) while the gadget is on (that is, I want to be able to plug and unplug the USB ...
0
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1answer
68 views

Makeshift way to drain a battery?

I have a 3.8V mobile-phone battery that I need to discharge. However I don't have any electrical components (say led) with me. What is a crude way to do this using household items?
0
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0answers
25 views

Solar battery charger using MPPT?

I am designing a solar-powered battery charger, but I am currently having a problem with it. Here's the battery specs: 1.2V, NiMH, 2300mAh I'v read online that the safest way to charge a NiMh battery ...
3
votes
1answer
88 views

How to make 5V 650 mA on a summer camp?

On our summer scouts camp, I need to power a tablet (it simulates the computer from The Lost, and the children must activate it every 108 minutes). It requires 4.3 - 5.3 V and about 650 mA. I need to ...
1
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2answers
87 views

If Li-Ion battery is deeply discharged, is it harmful for it to remain in this state unused?

It is well known that Li-Ion batteries should not be deep discharged. But sometimes they do discharge deeply. Is it OK for the device to remain in such state for a long time (and recharge again only ...
0
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0answers
39 views

Battery charging via Buck or LDO?

I am supposed to charge a Li-Ion battery (12V 50Ah) and then discharge it over a period of time for testing purpose to measure its efficiency. And this charging and discharging is to be done using ...
1
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0answers
74 views

Creating a battery backup unit

I live in a area with frequent power failures lasting up to 5 hours. During this time I would like to power my router so that I can still use the internet with my phone/PC. I've looked at UPS ...
0
votes
1answer
32 views

USB powered Switch Mode Li-ion Charger

I want to design a Switch Mode Li-ion charger which uses 5V as input and charges a single cell Li-ion cell. I am referring this AppNote On page 4 they have given the equation to find inductor value ...
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votes
1answer
83 views

Is there any IC which can generate -12V using a +12V input?

generating -12V using +12V. Is a simple inverter circuit is enough to generate a -12v using +12V voltage supply?
1
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1answer
55 views

Significance of Vf terminal in Li-Ion Battery

i was going through some propriety schematics that i can't post the battery used in the schematic is a li-ion battery of 3.8V/2.1Ah/ from samsung, which gives out three pins ...
2
votes
1answer
45 views

Li-Ion battery over discharge protection

I'm designing a Li-Ion battery charger circuit with a bq24702 chip. I will use it with two Li-Ion batteries connected in series. In order to protect the batteries from over discharging, I have to ...
0
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1answer
77 views

Battery Recharge Circuit Help

Can you help me understand how this circuit works? I really don't understand the resistor connected to the 0V rail. How does the BJT ever turn on?
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0answers
73 views

Simplest way to switch between power sources?

As I mentioned in another question, I have a battery charging setup where currently AC power feeds a AC-to-DC power supply which outputs 48VDC to a battery charger. The limis for the charger are: ...
3
votes
1answer
388 views

Will it hurt a non-powered power supply to see 12/24V on the output?

For an RC (mostly LiPo) battery charging setup I've got a 48V Meanwell AC->DC PSU supplying power to the charger. I'm considering simple ways to power the charger either by this PSU or directly by a ...
1
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2answers
56 views

Charging a bank of lead-acid batteries in paralel

I have a lead-acid battery similar to the one in the picture (mine is 15Ah) and I also have a spare car battery (50Ah). Is it safe, or a good idea to put them both in paralel to achieve a bigger ...
0
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1answer
31 views

Safe discharge cut off point for 12v SLI calcium lead acid battery

I want to make a circuit that cuts off a mains power inverter connected to a vehicle's battery. I have found, however, SLI batteries come with very sparse specifications. For example, the Varta E43 ...
1
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1answer
56 views

Why do laptop batteries and chargers differ in voltage output?

As an example, my laptop's charger gives out 19,5V and 3.42Ah while it's battery gives out 11,1V and 2.2Ah, what's going on exactly?
1
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1answer
81 views

Questions about circuit diagram, Lipo charger

Circuit diagram from here I've asked couple of questions about PS and Chargers, I keep facing new issues using the diagram above "an automatic lipo charger, sort of",why would the zener diode ...
0
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1answer
25 views

Capacitor Battery Charge Circuitry

Just a forewarning I am a complete rookie when it comes to capacitors I am looking to supply a 0.5mV charge into a capacitor, then have the capacitor discharge to a battery once the accumulated ...
2
votes
3answers
86 views

How to gauge safety of cheap Lipo batteries?

I see a ton of cheap 12V lipo batteries for sale on Ebay, but other than the mAh rating, I can't find any info or datasheets on how to safely operate them. I'm looking for a good battery to power a ...
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0answers
16 views

Shifting of battery in BMS

I was working over the topic Battery management system where now I have encountered a problem due to lack of proper knowledge in this field. My Problem statement is to achieve an uninterrupted power ...
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2answers
32 views

charging an auto battery for a gate opener?

Commercial gate opening systems use solar recharging systems frequently. My location is inappropriate for solar but is right next to a small stream. What properties of a mini hydro generation would be ...
0
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0answers
42 views

Switch based on battery voltages

I have two batteries. I would like a circuit which looks at their voltage, and puts them in parallel if they are the same. If they are not the same, the one with the higher voltage should be taken out ...
0
votes
1answer
29 views

Charging small capacity battery

I have a questions regardin charging batteries. I have a Li-ion, 3.6V, 150 mAh battery and I am looking for a suitable charger. Unfortunately I was not able to find a compatible charger. The ones I ...
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0answers
32 views

Determine lead acid battery safe float charge level for a range of state-of-charge

My question: I want to know how to determine the highest safe voltage for a given SoC (state-of-charge). Or for a given float charge voltage, determine the lowest safe SoC. Helpful hints to the ...
0
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1answer
32 views

Selection of charge controller to charge Lithium Ion battery

I have a DC generator with an output voltage of 27.5 Volts and current of 102 Amps. I need to use this charge my 24V 100Ah Lithium ion battery. So, I need to put a charge controller in between to ...
0
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1answer
29 views

Charging questions, current limitation and voltage

I'm having few issues with chargers, current delivered to a device etc... just need to connect the dots I guess. When I connect a phone to a charger for example IPhone which is rated at (5v,1A max), ...
1
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1answer
98 views

What do I need to trickle charge rechargable batteries with a solar panel

Hi I have a chicken coop door opener that is battery operated. The batteries tend to run down every other month even though the thing is basically just a digital alarm clock with a stepper motor ...
1
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0answers
66 views

What's wrong with this LiPo battery?

I have an 11.1v LiPo battery that has be working just fine and it recently dropped to 8.3 volts as it normally does during use. However this time when I plugged it into the charger the charger started ...
4
votes
2answers
72 views

Heating a li-ion battery for use in sub-zero temperatures

I have a design that I'm working on that is to be outdoors year round, with a 1 watt solar panel trickle charging a 6 Ah li-ion battery during the day. I expect there to be about 3 to 4 months of ...
0
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1answer
31 views

Solar: Reason For Joining Batteries/Solar Panels in Series

I understand the concept of what happens when you do, but I do not understand the reason behind why some set-up require to double the voltage on the batteries, since the point is to store as much AH ...
1
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2answers
31 views

Understanding Battery Controller

I'm thinking of doing a small-scale Solar off-grid setup 1-2 80 Watt panels with a 12v 40Ah Deep Cycle battery. I have questions for those parts in another thread, but for now, my question is about ...
0
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1answer
36 views

Reviving an overdischarged NiCd 12v battery

Some time ago I recovered a 12v 1700mAH Ni-CD battery from an ancient Commodore Amiga black and white display laptop. The laptop works perfectly when powered by a 1.5a 12v adapter, but unfortunately ...
0
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1answer
51 views

USB charger with power bank charged from solar panel and peltiers

I would like to charge some batteries (maybe 1 lipo?) from either a 12V solar panel (about 300mA) or 2 peltiers (also about 200-300mA) in series (about 4V, but it’s really unstable and voltage changes ...
0
votes
1answer
79 views

TA/USB battery charging

Apologize if the question seems silly, searched for the answers on google but couldn't get an answer, so please manage to help. I am studying detailed charging process of a smartphone ...
0
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0answers
24 views

How to rewire a 6-port usb charging hub

For a project in school I am building a product which displays and charges any device which can run from a usb port. The problem is that I have the holes for the usb ports cut out of custom positions ...
0
votes
1answer
37 views

Lead Acid Battery [closed]

Hi so I was taking apart this old machine and found a 6v lead acid battery. I don't know lead acid batteries and I measured the voltage to be at 200mV. Now I'm pretty sure that this is bad and I don't ...
1
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1answer
41 views

Charging Lead Acid Battery from dynamo

I want to build a Lead acid battery charger. for that I want to use a small IC engine coupled to a dynamo and the dynamo I got is rated at 12V, 35A and I want to charge 12V 7.5 Ah Lead Acid battery. ...
0
votes
1answer
47 views

Operation of a micro USB phone charger outside its limits

Many micro USB phone chargers give 5V DC and 1500 mA output at input 100-240 V AC at 50-60 Hz (these values are from a Sony EP 880 charger). What happens to the output when voltage rises above 240 and ...
1
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1answer
67 views

How to design a Lithium-Ion battery pack?

I have a project that I am working on that requires the use of a rechargeable battery pack. The major issue I have is that the battery pack needs to be as slim as possible. So far all I could find are ...
0
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1answer
44 views

how to calculate solar panel size needed to run circuit

Iam doing a project and want to calculate what size solar panel to use to run my circuit. the only thing is that I have some size constraints involved cant be bigger and \$5\times5\$ in. I have a ...
0
votes
1answer
121 views

Any good microcontroller with highly accurate ADC for voltage and current measurement? [closed]

I have to build up a battery cell(single) monitoring system which can calculate the cell's (single) efficiency which should be atleast 0.1% - 0.5% accurate. The cell would be charged over a couple of ...
0
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1answer
48 views

LiPo battery charging pcb [closed]

I am looking for a 3.7V LiPo battery circuit that will handle over-voltage protection along with charging and 3.7V to 5V boost. I've found this popular pcb on ebay: ...