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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0
votes
0answers
13 views

How to make a robot charger?

I would like to equip my robot with a docking base to charge its batteries. My problem is that I do not want to turn off the Arduino in the robot during charge... I think we can't use & charge a ...
0
votes
2answers
50 views

Making a simple solar-powered lighting system, a few concerns

I'm building a fairly simple solar-powered lighting system to use at home, which charges up a battery by day and then the battery powers a few bulbs at night, switching automatically. So far, I got ...
0
votes
1answer
22 views

Lead Acid Battery Charge C/20Ah

I need to charge a lead acid battery, I will be manually developing a program to set the current. Its the "US 12V XC2" Deep Cycle battery. Here is a link to the datasheet: ...
0
votes
0answers
37 views

Adding a regulating circuit to supply 3.3v

Background I wish to power my circuit with a 18680 battery. My circuit actually has two parts: 1) a 18650 charger and power booster for USB at 5V, and 2) a Bluetooth LE module (running at 3.3v with ...
-2
votes
1answer
47 views

Show charge state of a car battery [on hold]

I'm building a mobility music box, powered by a car battery (12v, 74Ah). What can I build into this box to show the current charge state (read somehow from a display if the battery should be changed)? ...
-1
votes
0answers
80 views

Is USB charging such a hard problem? [on hold]

Is (universal) USB charging still a hard problem? I appreciate that USB negotiation is needed, but don't all devices comply with the USB protocol? I'm looking at a specific USB charger's compatible ...
-1
votes
1answer
63 views

Portable 1A battery phone charger

I want to make a little battery-powered portable phone charger with 2x AAs that outputs 1A. I have seen similar USB powered battery chargers such as the Mintyboost but it only outputs 500mA. For 1A ...
2
votes
1answer
28 views

Solar powered charger circuit for a single LiFe cell

I'm looking for a solar powered charger circuit for a single LiFePo cell. The load is a low power MCU with some sensors attached, and when sufficient solar power is available, it should be used to ...
-1
votes
2answers
60 views

how long charge li- ion battery

I have \$3.7V\$ Li-ion battery \$3800mAh\$ and Solar panel \$U=5.5V, I_{max}=290mA\$. Battery will supply arduino with sensors taking \$100mA\$ current. How long will it take to charge the battery ...
0
votes
0answers
34 views

SLA charging circuit design

I got one more question about my car-dynamo-connected-to-bike project. My dynamo needs some juice to energize the electromagnets inside, so that's why I will include a small 12V 1.2Ah SLA battery ...
-1
votes
3answers
82 views

What happens when gadget gets 100% charged

We see that when our mobile phones, laptops, i-pads, or any other electronic gadget requiring charging, gets completely charged it starts displaying that it has stopped charging like in my HTC phone ...
1
vote
0answers
54 views

piezoelectric vibration energy harvesting

Recently i'm working on a project aims to convert the vibration of sound waves into electricity to charge batteries using piezoelectric material ( MFC type ) , i was trying to use the human voice as ...
-4
votes
1answer
78 views

How many hours would a 38000 mAh powerbank will last? [closed]

i bought a 38000 mAh powerbank and to my surprise when I could only use it for a total of 6 hours and then I have to recharge it again. My battery's capacitu is 1 700 mAh. By the way I'm taking up ...
3
votes
4answers
855 views

How do I design a 2A or more power supply for my consumer USB devices?

I understand that many of my consumer devices charged by USB ports can charge at higher rates than 0.5A. However, in testing, I've found they don't consume more than this. Test Setup I have a ...
0
votes
1answer
40 views

Charging circuit for automatically 'switching' between 1A and 2.4A?

Does anyone know of a charging circuit that could automatically switch between 1A and 2.4A depending on what the device accepts? Suppose the power source is 3.6V which till be stepped up. For ...
0
votes
2answers
77 views

Is it possible to combine multiple 5V USB batteries to power a Raspberry Pi for a long period of time (months)?

I need suggestions or help thinking this problem through. I want to battery power a Raspberry Pi with multiple USB battery packs (for a remote sensing application) with no need to do anything ...
-1
votes
1answer
67 views

Can I Charge a 12V Battery While It's In Use? [closed]

I have a Time-Clock (Where employee's check-in and check-out to track working time). Currently set up like this: 12V Adapter >> Time Clock So whenever that 12V adapter loses power, the time clock ...
0
votes
2answers
68 views

Li-Ion battery charging as simple as possible

I have read articles here and there about charging Li-Ion batteries. Most of them try to solve the problem of maximizing capacity and also maximizing cycles. The most recommended method is charging ...
0
votes
1answer
32 views

When to use Battery Fuel gauge

I am designing a measuring instrument powered by a Li ion Cell, I need to display remaining battery capacity on it, so I was wondering what is good or lets say widely used method. Should I use full ...
0
votes
2answers
67 views

Fake nominal capacity of 18650 batteries? [closed]

I have bought, from different sellers, two 18650 batteries, but it seems that the capacity is much lower than the 4500 mAh or 3000 mAh label. In real life, it seems to be able to draw a constant ...
0
votes
1answer
44 views

Buck converter charge battery control output voltage

I have a buck converter charging 8 series of Li-Ion batteries ( 8 x 4.2 voltage of charging) with a source of 36 V. I am using this schematic (from here): I know that for a resistive load, the ...
0
votes
1answer
31 views

How to attain a topping charge for a lead-acid battery?

Charging a lead-acid battery involves three stages: CC, CV, and Float. I have a charge controller which charges my battery at CC to the float voltage. I would like to add a device that would charge ...
2
votes
2answers
154 views

Is over charging the phone while using headset risky [closed]

I recently came across a post in social network which was claiming to be a news about a girl getting electrocuted during her sleep with her headsets connected to the mobile and the mobile being ...
-3
votes
1answer
69 views

Homemade battery power bank safe? [closed]

My micro-usb port on my phone is no longer functioning. So instead of buying a new phone or waiting weeks for a cheap battery power bank to come in from China (stuck for cash), I was thinking of ...
0
votes
1answer
36 views

Switching High Voltage Battery from Series configuration to Parallel configuration for charging

I have a question regarding switching batteries from series to parallel to charge them. I have 36 modules of 1Sx11P Li-ion batteries connected in series. During normal operation they drive a car ...
0
votes
2answers
66 views

Can someone explain the battery management schematic for the following robot?

This seems like a good start to build my own battery management system. Can someone explain how exactly is this circuit working? See link for full size image. Link to Full Size Image Link to Robot ...
-2
votes
1answer
36 views

Rechargeable battery, power multiplexor and charging battery

I have a Raspberry Pi and a bunch of peripherials (web cam, WiFi dongle, H-bridge + DC motor, servo). Alltogether they consume ~4.5A when everything is active. And I would like to make this device ...
0
votes
2answers
78 views

Need a switching device. Should it be a relay?

I am trying to build a system where first i would charge the battery (3.7V,40A), and then discharge it through a high wattage Resistor. For this purpose i will be connecting a power supply (15V-50A) ...
1
vote
1answer
65 views

calculate Amp Hours when voltage is given

I'm trying to wrap my head around how exactly Amp Hours work. I have been trying to figure out this question for a while now, but can't seem to find the information that I need. This is the ...
0
votes
2answers
46 views

Li-Po Battery Charging and UPS [closed]

Scenario: The main device is a bank of Li-Po 18650 batteries as the main power source. Sometimes the device will be plugged into AC power when needed for longer periods of time than what the battery ...
-1
votes
0answers
41 views

Designing a DC UPS system [duplicate]

My requirements are: I need a UPS system which supplies power to a 9 volt modem. UPS should Charge 12v battery (SLA , charging curent 800ma), and it should have overcharge/discharge protection system ...
4
votes
1answer
151 views

Power from 2 USB ports for faster device charging?

Use 2x5V from USB ports to speed up device battery charging? Do we get enough current (1A) from this 2 USB ports as well as from AC charger? I assume that voltages need to be the same, but what'll ...
-1
votes
1answer
94 views

Designing 12v DC UPS

My requirements are: I need a UPS system which supplies power to a 9 volt modem. UPS should Charge 12v battery (SLA , charging curent 800ma), and it should have overcharge/discharge protection system ...
0
votes
0answers
48 views

5V USB Input and Output for Battery Charger

I am looking to create a 5V input 5V output storage device (kind of like a portable phone charger) but I am struggling to choose a battery which is suitable. The device will be used for mobile device ...
2
votes
2answers
87 views

Low battery detection

I'm using a power boost to convert a 18650 battery to 5V: How to detect low battery (i.e. battery voltage under a certain threshold), and send this information to a microcontroller? (I'm currently ...
0
votes
1answer
51 views

Need advice on my simple solar powered lighting system

I'm building a simple circuit in which a solar panel will charge a 12 V battery during the day and then switch over to battery power during at night to light up a few bulbs. I'm using an LDR which ...
-1
votes
1answer
44 views

Testing accumulator usability by measuring its short circuit current, why it doesn't work?

I've experimented a little bit with some of my old, rechargeable batteries. (They "slept" around 5 years in a cabinet. I've long forgot their previous charged status.) What I did: I've measured ...
0
votes
0answers
23 views

Li battery series charging voltage for balance board

I am looking for some boards that will charge/protect 4 li batteries in series, such as this: http://www.newegg.com/Product/Product.aspx?Item=9SIA7BF2K19148 and am not sure as to what voltage I ...
1
vote
1answer
71 views

Buck converter Mosfet gate driver

How to turn on a buck transistor via a bootstrap circuit? In my circuit, I use a AVR microcontroller to turn on and off a buck switch. What circuit should I use here? Previously, I used optocoupler ...
0
votes
1answer
34 views

Choosing a voltage regulator for a 1.3V to 1.0V drop

I am looking to power a 5V system at roughly 600mA from a 6V AGM lead acid battery (voltage varies from 6V-6.3V). My main concern is finding a regulator that is tolerant enough to deal with the ...
-1
votes
1answer
63 views

11.1 LiPo battery lead got too hot and shows 0 voltage now [closed]

I was working on my project using the LiPo battery. I mistakenly connected the battery terminals + to - and - to +, due to which the leads become too hot that it give me a heat shock. The charge in ...
0
votes
2answers
152 views

Step up converter (3.7V to 5V) that will also charge battery!

As a picture often speaks better than words, here is what I'm looking for (the yellow circuit on this picture): i.e. : a circuit that converts 3.7 V to 5 V when a 18650 battery (3.7V) is ...
0
votes
2answers
47 views

Battery simulator

I wanted to make battery simulator, used to test li ion charger, and i have the schematic of the one that i use at work. I turn the knob and adjust the voltage at P1 and i can measure sink current at ...
-1
votes
1answer
45 views

Circuit for charging 3.7 volt battery using a motor rotated mechanically

I took a 5 volt DC motor, and tried to rotate it at its maximum speed by hand. During its rotation I measured the voltage at the motors i/p wires. It comes out to be 4.5 volts. Now I want to use this ...
0
votes
0answers
55 views

2S LiPo Charger IC With Built-In Boost (allowing 5V voltage supply)

So before I get to my question, I wanted to give a bit of background info on what I am working with. Basically I have a device which is USB powered. It has an ATMega32u4, and two SN754410 H-Bridge ...
1
vote
1answer
66 views

Charging a battery with more mA than its genuine charger

I recently bought a compact digital camera and it came with a charger of 5V, 1A output. This is a wall charger and the cable is USB type as in android smartphones. I have another wall charger which ...
-2
votes
1answer
49 views

Is there a rightside up when plugging in an AC to DC power converter? [closed]

When plugging an AC to DC converter into an AC outlet, does it make any difference at all if the wall wort is "upside down" or "rightside up"? Is there anything about the electrical design that would ...
0
votes
3answers
63 views

What is the optimal battery charging speed?

I have 3.7V 4000mAh Li-ion battery. I also have 0-30V/6A power supply which can limit output current. Provided that I charge the battery with voltage limited to 4.2V, I can change the maximum current ...
2
votes
2answers
71 views

How to make USB smartphone charger? [duplicate]

I want to make a USB cell phone charger. I know USB operates in 5 volts which means i need to drop down voltage if i have battery potential greater than 5 Volts. I have 12 volts sealed lead acid ...
0
votes
0answers
24 views

Using STNS01 with an Unprotected Lithium Ion Battery

In place of using a lithium ion battery with a built in protection circuit, I was planning on using a 500mAh unprotected cell with the STNS01. The internal circuitry is basically the same as any ...