Tag Archives: battery

DIY 18650 Powerwall with onboard BMS

A DIY 18650 Powerwall with onboard BMS @ openhardware.co.za While I cannot afford a Tesla PowerWall, I’ve spent some time drawing up a PCB to house 7x 18650 cells in series. Each board has onboard Battery Management: *Overvoltage Protection (per cell) *Undervoltage Protection (per cell) *Balance Charging *Overcurrent Protection *Main pack Fuse The design files […]

Automatically re-connecting low-voltage cut-outs for 12 and 24 volt battery systems

KA7OEI writes: In a previous post I described a simple circuit that provided a low-voltage cut-out that could be used in a battery-operated system – see the article “A latching low-voltage disconnect for 12 volt lead-acid and lithium batteries”. That circuit – intended mostly for lithium-based batteries – required manual intervention to “reset” the device, […]

How to design and build your own Lithium battery pack

Adam Bender posted detailed instructions of how to design and build a custom DIY lithium battery pack with 18650 cells: Designing a custom lithium battery pack is a fun way to learn about electricity and engineering. Lithium batteries can be used for countless applications including electric bikes, scooters, vehicles, backup power suppliers, off the grid […]

PortL2 – Portable electric vehicle charger

Here’s a project log covering the build of a portable level 2 electric vehicle charger by Andrew Rossignol: This is a battery-powered EV charger that allows destination charging where L2 charging is not ordinarily available. This can be used as a range extender for electric vehicles with smaller batteries. This system has a ~7kWh battery […]

Tool battery teardowns: Craftsman 19.2V and Ridgid 12V

Russell Graves did teardown of a Craftsman 19.2V DieHard battery and a Ridgid 12V battery: It’s time for more tool battery teardowns!  This week, I’ve got a Craftsman 19.2V DieHard battery, and a cute little Ridgid 12V battery.  They’re both lithium, and I’m going to dig into both of them, because that’s what I do with […]

Low cost single cell battery pack simulator

Mare writes: There are many battery cell simulators available which could simulate battery cell(s). Unfortunately, none is emulating any of the digital protocols used by fuel gauge devices. Optimal solution to efficiently emulate given smart battery pack is to use custom solution based on battery cell simulator and fuel gauge protocol emulator. Both parts could […]

An A/B battery replacement for the Zenith TransOceanic H-500 radio with filament regulation

KA7OEI built a battery pack to replace the obsolete “A/B” battery for Zenith TransOceanic (ZTO) H-500 and wrote a post on his blog detailing its assembly: There are several things that I decided that this voltage converter should do: Automatically power up and shut down when the radio is turned on and then off Cause […]

App note: Using Cymbet™ EnerChip™ batteries instead of coin cells and super capacitors

High charge/discharge cycle and solid state reliability EnerChip from Cymbet make this a good replacement for super caps and coin cell backup batteries. Link here (PDF) Primary and secondary (i.e., rechargeable) coin cell batteries, as well as super capacitors, have been in use for years as auxiliary power sources for applications including SRAM, real-time clocks, […]

A low-voltage disconnect for 12 volt lead acid and lithium batteries

KA7OEI 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 […]

Automatic 18650 Analyzer

Gregor wrote an instructable detailing the build of his Automatic 18650 Analyzer project: The idea behind this project was to create a cost effective device that could automatically charge and discharge multiple 18650 cells while determining the effective capacity of each individual cell. Individual cells can be binned by capacity, so multiple parallel packs with […]

App note: Fast charging control with NTC temperature sensing

Vishay’s application note on fast charging control using NTC and TI’s BQ2005. Link here (PDF) The need for increased autonomy for new models of laptops and cellular phones has resulted in high-energy density power packs – Ni MH and Li-ion batteries. These batteries can be charged quickly, on the condition that the fast charging complies […]

App note: Building a battery operated auto ranging DVM with the ICL7106

Intersil’s application note (PDF!) on building a battery operated auto ranging DVM with the ICL7106: This application note describes a technique for auto-ranging a battery operated DVM suitable for panel meter applications. Also, circuit ideas will be presented for conductance and resistance measurement, 9V battery and 5V supply operations, and current measurement.

Battery fuel gauge with zero parts and zero pins on AVR

Josh Levine writes: It can be nice to know how much battery power you have. It becomes critically important with LiPo batteries since you can permanently damage them by running the voltage down too low. Typically battery voltage detection requires adding a circuit with extra parts and their associated power requirements. Wouldn’t it be great […]

BT-C3100 intelligent battery charger teardown

Alan Parekh of Hacked Gadgets writes: Thanks to GearBest for sending in this Opus BT-C3100 V2.0 Intelligent Battery Charger for review. at a quick glance this charger might look like any other charger that you see at the grocery store.  Your generic store bought brand probably also has 4 charging bays for AA and AAA batteries, it probably has 2 […]