Tektite Charge 3B

This tiny 100-gram charger can handle up to three batteries at 2 amps each, measure internal resistance, cycle, and more! Simply connect to a 100W USB-C source and you can charge batteries anywhere, without a huge mess of wires. Fits in your pocket, in your bag, and anywhere else you need it to be!

Don’t ever try to figure out which battery is the most charged out of a series of red lights or pay over $100 to haul around a charger that feels like an actual brick again. The easy-to-use interface and color LCD display tell you voltage and other interesting numbers in real time!

Have any questions? Join the Tektite Discord here and message in #charge-3b.

Design your own enclosure with the CAD here!

 To use the battery cycling functionality, purchase WITH the resistor!
You can use any 4-ohm resistor with a 2-pin JST-PH MH-FC cable, but keep in mind that if you make your own it may get uncomfortably hot.

New features from Charge 2B:
– 3.2″ color touchscreen
– Fully enclosed design
– Silicone feet that don’t come off (in normal use)
– 3 batteries, up to 100W
– Battery cycling (with external resistor)
– Reverse polarity protection
– Dynamic power limiting to support bricks down to 65W
– High efficiency

 ONLY USE WITH FIRST TECH CHALLENGE-LEGAL 12V BATTERIES!
This charger is not designed for any other types of batteries, and using it with these can cause catastrophic damage and danger.

Not included:
– 65-100W USB-C charging brick
– Batteries

Tutorial video:
– https://youtube.com/shorts/OwkvhhPU4VM

Technical specifications:
– Termination: -7mV/cell dV
– Cycle: 4 charge (1.2A), 3 discharge (0.6A)
– Mass: ~95g

What is internal resistance?
When current is drawn from the battery (e.g. while driving around), the voltage will drop. This sag is because of internal resistance, which is a number that describes how much the voltage sags depending on current draw. If Charge 3B measures the battery’s internal resistance to be 150m, that means that it drops 150 milli-volts per amp drawn, so when drawing 20A your battery voltage will drop by 3V.

For the most accurate measurement of internal resistance, measure at 12V. You can do this by using the storage feature of Charge 3B to bring the battery to 12V, but note that this can take a while. Measurements taken when the battery is fully charged will report a higher internal resistance. Here are generally accepted meanings of internal resistance values:

100-120m: Very good, typical for new batteries
100-150m: Useful for competition
150m-200m: Useful for practice and testing
200m+: Dead, try cycling the battery or replace it

What is cycling?
Voltage sag under high current draw can be caused by crystalline formations inside the battery chemistry, since those formations around the electrodes raise the internal resistance of the battery. If your batteries have been used heavily, this may be the cause of their poor internal resistance. By using the cycling feature, you can break up these crystals which can reduce the internal resistance of heavily used batteries, potentially making them useful longer.

Note that batteries can only do a finite number of cycles in their lifespan, so don’t cycle unless it’s absolutely needed!

Cycling takes around 20 hours, so make sure you do not need to move the charger or battery before beginning the cycling process.

What is storage?
When batteries are stored fully charged (14+ V) or discharged (<11 V) it causes stress to the internal chemistry of the battery, reducing their lifespan and increasing their internal resistance. For long-term storage (6mo+) use the storage feature of Charge 3B to bring the voltage to 12V.