Archive for the ‘Batteries’ Category.

KWeld spot welder

I recently bought Kweld spot welder kit for all battery welding purposes. The old, transformer welder was not good and welds were not consistent and reliable. Worst issue with transformer welder was inability to weld thicker metal strips (0,3mm Ni).

The Kweld came with everything needed to start welding except power supply source. They offer supercap bank with charger or recommend some RC batteries. I had niether. The most suitable battery pack I have was 3S1P LiFePo pack with internal resistance of 5mΩ. Unfortuantely such source is not OK for kWeld.

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Low cost single cell battery pack simulator

Modern battery operated portable devices use smart battery packs. Every new development of an electronic medical device must follow strict design flow defined by world-wide or local regulatory
directives. The development process of any such device using smart battery pack requires specific operating conditions to meet the testing criteria. When smart battery pack is one of the main power sources the host system should be tested with several battery states. The testing is necessary during development, validation and later in production testing.

Battery simulator block diagram

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Precision voltage source – voltage calibrator

_________________ Work in progress _______ Last change: 22.10.2017 ______________

 

What I missed in my workshop is nifty small programmable precision voltage source which can be used as calibration voltage source for testing and calibration purposes. I decided to make one, because instruments which have word “calibrator” have price with same digits as there is vocals in this magic word.

Let’s start with block diagram:

Voltage calibrator – Block diagram

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Battery with charger

There will be series of simple(r) circuits for my new electronic course for elementary school. For start we need power source. Batteries are fine until flattened out, therefore it’s good to have rechargeable one. I took MCP73831T-2ACI/OT, added micro USB connector and switch to select between charge/discharge mode. In the charge mode, the output is connected to +5V input supply. The power is delivered to the charger via micro USB connector, which means eny mobile phone USB supply will do the job. The charge current is limited to 2A and battery cell has integrated protection circuit. I will add 3D printed housing for the complete pack after the testing of first prototypes.

Prototype of the battery pack

Prototype of the battery pack

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LED shades

Light Emitting Dance shades – general purpose party accessory.

LED Shades v0.3

LED Shades v0.3

About this project

I believe many young adults like to party and with the rapidly growing EDM community a lot of people attend parties with electronic music. I am one of them and you can probably tell where I got the idea to make the LED shades. Projects like this one don’t just keep me occupied in my free time but are also designed to broaden my knowledge in electronics and programming. Continue reading ‘LED shades’ »

Single LiPo cell protection and charger

Single cell lithium polymer battery cell is very handsome power source for many applications. Unfortunately it is quite dangerous when such battery cell is not properly protected and charged. I prepared simple 1S LiPo battery protection and Charger on two, single sided small PCB modules. I separated Protection from the charger when only protection is needed.

final

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RGB LED Badge

This is heart shaped four RGB led badge:

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2S LiPo Battery pack

IMGP3715.jpg2S Battery pack is very useful. It can be used to supply 5V electronic circuit without DC/DC. With help of a simple boost a 2S battery can drive 3 power LED lamp with reasonable currents. Etc…

Let’s see what is required for reliable, safe lithium polymer batter pack with two serially connected cells (2S LiPo battery pack).

Obviouslly, at least two cells are needed. Unfortunately, LiPo cells are very dangerous if used over specified limits. Most dificult is maximum cell voltage during charge. If cells are aexposed to voltages above 4,2V they can burn, but not at the charging, this could happen at any time after charging.  The absolute maximum charging voltage is 4.25V per cell. To avoid burning down the house and other troubles, a battery protection circuit board (PCB) is a must with LiPo cells.

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