Tag Archives: Battery

DIY USB power bank from laptop battery


DIY USB power bank made from an old laptop battery @ DoItYourselfGadgets:

A situation many can relate to: an empty smartphone battery and no outlet around! That’s exactly why I recycled an old laptop battery into an USB power bank.
This article will show you the basic powerbank circuit consisting of Lithium cell charging circuit, boost converter and toggle switch as well as my improved version with self activating boost converter and LED status indicator and homemade housing.

DIY USB power bank from laptop battery – [Link]

Disconnect circuit for 12 volt lead acid and lithium batteries


KA7OEI designed a circuit that disconnects the battery when it over-discharges. He writes:

The avoidance of overcharging is usually pretty easy to avoid: Just use the appropriate charging system – but overdischarge is a bit more difficult, particularly if the battery packs in question don’t have a “protection board” with them.

Lead acid batteries (almost) never come with any sort of over-discharge protection – one must usually rely on the ability of the device being powered to turn itself off at too-low a voltage and hope that that threshold is sensible for the longevity of a 12 volt battery system.

Disconnect circuit for 12 volt lead acid and lithium batteries – [Link]

Not a battery or a supercap, but a ‘thin laminate energy device’

Murata’s UMAL is a low-profile high capacity energy device. Designed to meet the demand for a slim high capacity energy source with a maintenance-free extended life cycle in wireless sensor nodes, the UMAL has charge/discharge and life-cycle characteristics superior to conventional secondary batteries. By Graham Prophet

The UMAL has a nominal voltage of 2.3 VDC, can supply 12 mAh with a maximum discharge current of 120 mA and is able to withstand load fluctuations. It has a low internal resistance of 200 mOhm and can operate over the temperature range of – 20C to + 70C.

Not a battery or a supercap, but a ‘thin laminate energy device’ – [Link]

Build an Arduino boost converter


Lucas Reed has a tutorial on how to build a boost converter using an Arduino.

Have you ever needed to power a project that’s not near an outlet? Have you needed to test using different voltages? Are you curious about analog circuits and power? Using Autodesk Circuits and a lead-acid battery, you can create a circuit that will act as a variable power supply, outputting a range of voltages from 5V to 20V.

Build an Arduino boost converter – [Link]

Maximize the Energy from Long-Life Batteries


by digikey.com:

Battery lifetime is a key consideration for the development of the wireless sensor nodes that will populate the Industrial Internet of Things (IIoT). In many applications, the sensor nodes will need to be installed in locations that are difficult to reach let alone service. The sensor nodes need to be autonomous in terms of energy because it is too costly and difficult to run power lines to them or to have maintenance workers replace batteries regularly.

Maximize the Energy from Long-Life Batteries – [Link]

SparkFun Battery Babysitter

The SparkFun Battery Babysitter is an all-in-one single-cell Lithium Polymer (LiPo) battery manager. It’s half battery charger, half battery monitor, and all you’ll ever need to keep your battery-powered project running safely and extensively.

The Battery Babysitter features a pair of Texas Instruments LiPo-management ICs: a BQ24075 battery charger and a BQ27441-G1A fuel gauge. The charger supports adjustable charge rates of up to 1.5A, as well as USB-compliant 100mA and 500mA options. It also features power-path management, guaranteeing power to your project even if the battery has died. The self-calibrating, I2C-based BQ27441-G1A measures your battery’s voltage to estimate its charge percentage and remaining capacity. It’s also hooked up to a current-sensing resistor, which allows it to measure current and power! It’s a handy IC to have, if you ever need to keep an extra eye on your project’s power draw.

SparkFun Battery Babysitter – [Link]

Dynamic-load circuit determines a battery’s internal resistance


by @ end.com

The simplest model of a battery comprises an ideal voltage source that connects in series with a resistance whose value—often a few milliohms—depends on the battery’s electrochemical condition and construction. If you attempt to use an ordinary ac milliohmmeter containing a kilohertz-range ac excitation source to measure a battery’s internal resistance, you get erroneous results due to capacitive effects, which introduce losses. A more realistic battery model includes a resistive divider that a capacitor partially shunts (Figure 1). In addition, a battery’s no-load internal resistances may differ significantly from their values under a full load. Thus, for greatest accuracy, you must measure internal resistance under full load at or near dc.

Dynamic-load circuit determines a battery’s internal resistance – [Link]

Running NodeMCU on a battery


ESP8266 low power consumption revisited:

Using Wi-Fi is a convenient way to link your newly created IoT device into your existing IT infrastructure – including cloud services – but it also has a drawback. Wi-Fi’s demand for power usually makes battery operation impractical for any real deployment. I have been able to get around this issue for most of my projects (e.g. the train and the smart shelf described on this blog) because they are for demonstration purposes only, requiring the battery to last no longer than a few hours.

Running NodeMCU on a battery – [Link]

Battery-charging considerations for low-power applications [PDF]


By Tahar Allag:

The wearable and personal-electronics industries are booming. Devices in this market vary wildly by application and use. These multifunction devices are designed to help people in their daily activities and make their lives comfortable. They can be found in different shapes, colors, sizes, and safety measures. They may differ significantly from each other, but they all have one thing in common—the need for a battery and a battery charger. These portable devices are typically powered by batteries installed internal to the device, which must be charged efficiently and quickly on a regular basis. The user’s charging experience also needs to meet the requirement of safety, comfort, and convenience.

Battery-charging considerations for low-power applications [PDF] – [Link]

Rechargeable batteries with nanowires last forever


by Harry Baggen @ elektormagazine.com:

Researchers at the University of California (USA) have developed a nanowire-based material that allow a rechargeable battery to be charged and discharged hundreds of thousands of times without any loss of capacity. This would virtually eliminate the need to replace a battery made from this material during the lifetime of the device it powers.

Rechargeable batteries with nanowires last forever – [Link]