What is it?

Guard18650 is a board that integrate a socket for LiPo battery in 18650 package plus a battery protection based on BQ29700: a LiPo battery protection IC by Texas Instruments.

How it Works?

Guard18650 can power up all your projects that are designed to be supplied from a battery. Typical application should be to connect VBAT- to GND of the circuit you want to power up and VBAT+ to a voltage regulator in your circuit. You can directly solder VBAT+ and VBAT- to your circuit or solder the screw connector to have a more changeable system.

What inside

• x1 Guard18650 with all components soldered (except screw connector)
• x1 Screw connector
• LiPo Battery NOT included

How to Start

Insert your 18650 LiPo cell into the socket, don't worry to insert it with inverted polarity, Guard18650 provide a reverse polarity protection that ensure no damage to the Guard18650 itself and the powered circuit. If you insert the battery with wrong polarity, reinsert it into the correct position and activate the protection IC applaying a positive supply (in a range from 3V to 4V) to VBAT+ pin of Guard18650 or simply connect a charger to it and start charging battery also for an instant, this activate the IC and battery will be ready to use.

When the protection IC of Guard18650 is activate it's ready to detect any fault that can occur while using battery and between VBAT- and VBAT+ you'll measure the voltage of the cell that you have inserted.

Features

Guard18650 protect your battery and supplied circuit from five different fault states:

• Over Voltage protection (4.275V)
• Under Voltage protection (2.8V)
• Overcurrent Charge protection (about 4A)
• Overcurrent Discharge protection (about 4A)
• Short circuit

You can also set Overcurrent Charge protection and Overcurrent Discharge protection through resistors in 0805 or 1206 package.

for more details of how Guard18650 works, visit the following links:

http://ambergarage.net/2017/11/12/18650-lithium-battery-protection/ http://ambergarage.net/2017/11/22/18650-lithium-battery-protection-part-2/

Why did you make it?

Battery powered systems are getting more and more every day, also hobbysts using batteries to power up their projects like robots,remote systems and more..

Testing circuits that use light sensor,raining sensor,wind sensor need to be sometimes place outside, far away from a PC or any sort of wired power supply so a battery powered system could be the better solution.

What makes it special?

In the market you can find a lot of cells made in 18650 package all without protection, however some of these cells are sell with an integrated protection that allow them to guaranteed the same protections of Guard18650 but:

• cells without protection are easier to find
• cells without protection are cheaper

so with Guard18650 you can only change the cell and with the same Guard18650 you can try different cells without spend a lot of extra money every time you would buy a protected cell and the socket where insert it.

Guard18650 also allow you to adapt some fault threesholds to your application applying some extra resistor to the circuit and with its screw connector it can be connected with every type of circuit you want.