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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1
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2answers
16 views

Current limiter for NiMH battery charger

I am trying to learn about electronics by making my own MCU controlled battery charger for standard AA 1.2V NiMH and NiCd batteries. The supply voltage is 5V from a USB battery pack. I did a lot of ...
0
votes
1answer
55 views

Battery chargers that can recharge disposable batteries. How do they work and are they safe?

A few years ago a product called SecondWind appeared, which claimed that it could recharge disposable batteries. To a layman like me that sounded like a great idea, but does such a product really ...
1
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2answers
74 views

Designing effective usage time from 12v car battery

Need a little power design help: I have a project I'm working on where I have measured that I will use approximately 14.4Ah over 24 hours. This is quite the load for a small timelapse setup where I ...
-1
votes
2answers
67 views

Documentation on Apple's USB Chargers? [closed]

I'm worried if someone charges my single-cell lipo with an Apple USB power supply that it'll get damaged. Is there documentation on Apple's USB chargers? I'm imagining I want to be able to support ...
2
votes
0answers
46 views

How to charge via USB from any power supply?

I'm trying to ensure my device can charge via USB from any standard 5V AC adapter and computer port. I always hear of engineers getting burnt by Apple's power supply in particular, and want to ...
0
votes
1answer
32 views

Calculating minimum trickle charge power requirements

I'm looking to buy a solar panel to trickle charge my phone + other devices while out and about. Obviously I don't want a panel that is excessively large/heavy but also I want something that won't ...
0
votes
1answer
35 views

How to put a battery and battery charger parallel in a circuit

I am making a speaker that runs at 3-5.5 RMS and I need a battery to supply power to it and so I got a house phone battery pack with a diode now I need a way to charge this so when it is charging that ...
0
votes
1answer
34 views

Measuring smartphone's battery State-of-Charge during charging

I'm designing a mobile device that uses a Li-Ion battery. It is required to indicate to the user the State-of-Charge of the battery, similar to how it's done in smartphones. At first I considered ...
1
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3answers
69 views

Prevent voltage to drop under threshold in solar panel

This is a solar charger for my smartphone built with two panels wich I want to keep attached all day long with the phone turned on. When the sun is going away, voltage output starts to go under 5V and ...
0
votes
1answer
60 views

How to charge double cell lipo battery with single cell charger?

My setup is simple: I have this bluetooth module with a built in single-cell Lithium ion/polymer battery charger. I have this double cell LiPo battery and I also have an arduino nano that I will have ...
0
votes
1answer
46 views

LiPo Battery: series to parallel charging switching circuit

simulate this circuit – Schematic created using CircuitLab So, I have two 2000 mAh LiPo batteries that are going to be powering a GSM modem (on an arduino shield) a GPS and a motor. I ...
0
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3answers
141 views

How to drive optocoupler with BJT properly [schematics]

Recently I asked a question about optocoupler: Shematics: optocoupler controls a transistor and doesn't work as expected I have one more question related to the topic. PWM input comes from the ...
0
votes
1answer
48 views

Charging 2 Li-Ion Batteries via a single charger

I'm currently building a portable USB charger. It uses 2 Li-ion batteries in series connected to a USB port via a 5V regulated buck converter. While a single Li-ion battery would suffice for most ...
0
votes
1answer
42 views

Solar Charge Battery Low Voltage Disconnecting

I have a 4.2V 120mA max solar panel and 3.7V 1200mAh battery. I'm trying to make a solar power system for my arduino. I search through battery management IC's and generally understand the charge ...
0
votes
1answer
78 views

Can batteries be charged and discharged at the same time? And do they wear down faster when doing so? [duplicate]

Imagine batteries connected to a charge controller and a load at the same time. When the load asks for power, and the charge controller delivers power, there are three possible situations: P_in > ...
3
votes
1answer
66 views

Li-po Charging circuit question (switching between battery and power supply)

I'm building a circuit containing a Li-Po battery and a battery charging chip. I do understand the working of the chip, but don't really get how to switch the system load to a normal power supply ...
0
votes
1answer
78 views

Li-ion battery choose question

I am new to this forum and I hope you can help me with this. I want to build a small circuit that will have: an ATXMEGA ucontroler that uses all of its 5 USART and one bluetooth module. This circuit ...
0
votes
1answer
90 views

24 Hr A Day Powered Aquatic Pump

I am looking to install a DC 12V 6W submersible aquatic pool pump for use in a small scale hydroponic setup. The location of the beds will be too far away from mains electrical, and I would like to ...
1
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0answers
77 views

L7805C/L7812C Voltage Regulator with 22V Solar Panel Not Outputting a Constant Voltage

First, here is my solar panel: http://www.amazon.com/Instapark%C2%AE-Black-Mono-crystalline-Charge-Controller/dp/B005LR9IOG And the regulator: ...
0
votes
1answer
54 views

POWER SUPPLY / CHARGER [duplicate]

I have a 14.4v NI CD power drill with a charger that outputs 18v 400mA (original charger for drill) but the charger supply lead no longer works. Looking to get a replacement but finding it difficult ...
1
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1answer
55 views

Buck boost converter for lipo 6s charge info request

I need to dimension a Buck boost converter to charge two LiPo battery packs 6s 20ah starting from a variable input voltage. Both packs have their own PCB BMS board. This one: ...
0
votes
0answers
41 views

Designing battery circuit for a custom tablet

I am designing a tablet with SOC computer. I am trying to figure out how the battery will interface with this. I know that I will need to use some Charging IC that can supply constant current and ...
0
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0answers
36 views

NI-MH battery charger using MAX712

I don't belong to electrical engineering but I am trying to develop a intelligent Ni-Mh battery charger for one of my project. I am using MAX712 battery charging management IC. Reason behind that is ...
0
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2answers
68 views

Charging lead acid (car) batteries with a common ground

I have three identical lead acid batteries. All three batteries are on a common ground since they power different components on a same circuit. I have three independent "intelligent" chargers whose ...
4
votes
2answers
438 views

Is charging an empty Li-Ion cell to 50% more or less efficient than charging it from 50% to 100%?

Many devices that are powered by a Li-Ion battery can be recharged over 5V DC supplied by a USB connection. Is the 5V voltage internally converted by the charging logic to something lower, and is ...
0
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1answer
69 views

Charging of Cell Phone Batteries and Electricity! [closed]

Does charging an already charged battery of cell phones/laptops consume electricity? Whenever my cell phone becomes fully charged while charging, it asks me to remove the charger from the socket to ...
2
votes
3answers
435 views

What to plug in first to usb charger when charging: wall outlet or cell phone and why? [closed]

I asked this question on Physics StackExchange but was advised to ask it here. When I charge me cell phone or notebook or whatever device what should I plug in first? Should I at first plug in usb ...
0
votes
1answer
71 views

Charge at 24v and discharge at 12v for battery system

Is my thinking correct. Below is a simple diagram of the concept I want to check. Is this: 1: Possible 2: Feasible? I.E are there any concerns or foreseen issues with this design? Edit:
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2answers
121 views

Single inductor buck-boost idea for MPPT (maximum power point tracking)

Basically my inspiration is this guy's work. A buck converter that provides MPPT as long as the solar voltage is higher than the battery voltage. But I want to extract power to the battery even at low ...
1
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2answers
87 views

Possible to charge one phone off another?

What's stopping the ability of charging a cell phone from another cell phone? If I were to create a crossover/patch USB cable and connect it between two phones or tablets, would there by any way to ...
1
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1answer
88 views

What is the difference between Pack- and Bat- on a LiPo Battery

I am trying to figure out how to use the TI bq34z100 to measure the charge in a 29.6v 8s1p 5.4Ah pack. Out of this pack I have A charge connector with + and - and a discharge connector with + and - ...
0
votes
1answer
84 views

Input voltage of LM317 drops when lead acid battery is connected on output

I have built a voltage regular circuit with LM317. Its input is connected to my solar panel. As in many circuit examples, there is a voltage divider to bias the adjust pin. Also, I have connected a ...
1
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2answers
65 views

Can I use LIPO battery voltage checker for 12V lead acid battery? [closed]

Can I use the LIPO battery voltage checker to monitor voltage of my 12V 7Ah lead acid sealed battery? Currently I use a multimeter to check the battery voltage frequently as I am experimenting with ...
0
votes
1answer
42 views

Charging batteries at different rates and the associated side-effects?

I am quite new to batteries and charging them. I have a Polymer Lithium Ion battery (7.4V) and am about to attempt to charge it with a battery charger. The charger has a myriad of options from battery ...
1
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1answer
31 views

External cellphone battery - to keep on, or only use when phone battery low? [closed]

I found the charge in my smartphone (Samsung Galaxy s2, if that matters) was insufficient to carry me through a day of constant usage, so I bought myself an external battery case (Lithium polymer, ...
0
votes
3answers
64 views

Converting variable voltage to constant voltage / variable current

I'm using solar panels + a micro wind turbine to charge a decent sized LiPo battery using this circuit - http://www.adafruit.com/products/390. The problem is that the solar/wind stuff will produce a ...
0
votes
2answers
131 views

NiMH battery charging by MAX712 IC

I am using MAX712CPE(DIP) version for charging 1.2 volts × 8 batteries. Using the datasheet and available information on the Internet, we made the circuit schematic and are about to implement ...
0
votes
2answers
76 views

laptop battery cells measurement [closed]

I have two dell laptop Li-on batteries (J1KDN, 11.1 V Capacity 48Wh, Min 4.2a). One battery seems to loose its charge very fast and the second one just turns turns off around 70% (with no warning). ...
0
votes
1answer
93 views

Can I connect a Qi wireless charging receiver directly to a battery? In parallel with battery?

My phone does not seem to have any devoted extra contacts to accept an aftermarket wireless charging receiver. (I've seen that some other phones do. My phone is the Samsung S Duos GT-S7562.) Is it ...
0
votes
1answer
74 views

How can I disconnect a Battery Charger from the Battery while not Charging

I have a LiIon Battery Charger IC which will draw around 50µA when not needed, see circuit 1. This is a lot of current for no work in my opinion. Now I search for a solution how I can disconnect the ...
1
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0answers
81 views

USB battery charger noise in an audio amplifier

As the title says, I'm having some issues with battery charger noise and an audio amplifier. The PCB with the charger and amplifier is connected to a GSM device, and that's where the audio signal for ...
1
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0answers
50 views

Why does the QI charger I recently bought only charge for a couple of times? [closed]

I recently bought a QI compatible charger for my Nexus 5. On the box it states, that the wireless charges up to 500 times. I don't understand why the charger is only able to charge my phone 500 times. ...
1
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2answers
70 views

How to efficiently heat a lithium-ion battery so that it can be charged in sub-zero environment?

A common knowledge and practice on lithium-ion batteries is that they significantly loose the capacity and cannot be charged when their temperature drops below 0 deg of Celsius due to increased ...
3
votes
2answers
55 views

What voltage do you measure while implementing the charge algorithm?

So the charge algorithm for recharging a battery is (I will be using a lithium-polymer): Pre-charge Constant current charge Constant Voltage charge But I have learned that the open circuit voltage ...
0
votes
1answer
46 views

Home Built Hybrid EV Battery Charge current limiting

I have a hybrid EV that I'm working on which uses 2 48V DC motors with a maximum load of 300 Amps each, for a total maximum load of 600A. I have 2 alternators running off a gas engine generating 125 ...
2
votes
1answer
134 views

Solar and battery for small usb camera

As the title suggests, I'd like to power a Dropcam without laying new wire in our community garden (code enforcement makes wiring a headache). When I wired my Raspberry Pi to work off solar power it ...
1
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3answers
248 views

Step up DC-DC converter for powering Raspberry Pi from batteries

I will power a Raspberry PI with 4 NIMH batteries, but they quickly lose charge, and end up at 3V instead of the 5V needed. I was wondering about a DC-DC step up converter. I want a converter that ...
3
votes
1answer
109 views

Circuit for charging RC car battery with solar

For my high school engineering course I have to make a project that involves solar panels. I have chosen to convert an RC car to recharge the battery while driving with solar panels, because I realize ...
3
votes
1answer
65 views

What affect does charger wattage have on lifetime of LiIon batteries?

This questiuon is generic to LiIon and LiPo batteries but a Mac is used as an example. A Mac 'laptop' is provided with a 85 Watt charger. It is possible to charge it with 45 Watt charger that was ...
0
votes
1answer
132 views

Why fully charge Lithium battery powered devices before first use?

I recently bought a Bluetooth headset and it turned out to be faulty. On getting the replacement, when I asked the customer care guy to test it after little charging, he refused to do it citing ...