Just want to say great job to Sparkfun for breaking out all the capabilities of these ICs. I know most of the use cases won't need a thermistor, but it is infuriating when you have a board with a capable part but it isn't in an accessible area since the designer didn't think it would get used.

Great job guys.

I was wondering if I can use this module to power a raspberry pi 3, since it seems that it cannot deliver a steady 5V (depending the battery state)?

Maybe I must combine it with a boost converter?

What if I wanted to combine this with a boost converter so I could get the output to 5V at 1A? (i.e. TPS61200) Is that possible and if so how would it be wired?

I know the Raspberry Pi likes a 2A supply, but would this work as a long term (continuously running on grid power) battery backup option for a Raspberry Pi? I've been running one in a stable config on a 1.5A adapter for a while, now. Any thoughts or other suggestions are welcome.

!WARNING! It appears there is no over-discharge protection, or at least it is faulty on my boards, and I can't find any such documentation that it exists. The power LED on the BB shuts off when the battery goes below 2.4 V or so, but it was still draining at low current to the attached load when checked with a multimeter. I spotted this after the voltage had dropped to 1.8V on my 3.7 V LiPo! This can be quite dangerous! The simple TP4056 modules even have this feature (tested at 0.000 mA when I swapped it for the BB). I think this is very dangerous to advertise this the way it is, i.e. "handles everything related to battery charging". Maybe I misinterpreted this, but I think a lot of people are going to ruin their cells, if not worse with this lacking key battery management feature.

I see that the minimum input voltage is 4.35V. If you used something like a solar panel (or array) that may drop below that voltage would it be bad for the chip or would it just cutoff? I'm interested in coming up with a LiPo solar charging solution that allows for unattended operation (assuming sun during the days).

Is there a good chip already designed for this that anyone's familiar with?

Thanks.

Hi,

My LI-PO battery have a third yellow wire, mainly used for temperature measurements to my understanding. Is there is a recommendation on how to connect this type o batteries?

What is the output voltage of this if it's running with a 3.7V LiPo?

Hi, cool project! But can you elaborate why the BQ24075's TS pin is connected to BQ27441's BIN pin? According to the datasheet it should (for removable batteries) be connected to VSS, right?

I bought this along with some LiFePO4 batteries, only to discover upon closer reading of the datasheet that this device can only work with batteries whose chemistry lets them go up to 4.2V. Unfortunately my project requires LiFePO4 which has a max voltage of 3.6V! There is no way to modify the output of this device to intercept the 4.2V and drop it down to 3.6V without making all the other features of the device basically pointless. Glad I read that before plugging it in to those batteries.

For anyone who's curious about the differences in chemistry, you should use a LiFePO4 chemistry for use-cases where the device will mostly get power from elsewhere (like the wall) and the batteries will be sitting at full charge for long periods of time without being exercised. LiFePO4 doesn't mind sitting at full charge for long times, unlike other lithium chemistries which will degrade faster if they're not exercised and if they're kept at full charge. (Don't keep your phone or laptop at 100%! Cycle it every day and let it "die" every once in a while).

--> Sparkfun: Please note in the product description that this device is ONLY for use with batteries that have a max voltage of 4.2V. Other lithium battery chemistries with lower voltage maximums will not work and will experience an over-voltage event if they're used with this.

Hi, everybody. Can anyone help me? Do you know if and how it's possible to add an external on/off switch to the SF Battery Babysitter? Maybe using the SYSOFF pin? I'm developping a timing system for sport; the shield is placed inside a 3D printed case and the switch on the board is not accessible. I wpuld like to completely deactivate the power output VOUT, to be sure to not drain any energy from the battery, when I'm not using the timewatch, using a swith, placed on a panel of the case.

Thank you for your help! Fabrizio

Does this board support a remote power switch, perhaps using the SYSOFF pad?

Hi All, Make sure you your battery bank capacity no exceed 8000mAh as BQ27441-G1 max is 8000mAh. Having more wont harm the chip but it will mess-up the readings like SOC Capacity etc. Did anyone upgraded this board with a high capacity chip from Ti? Any suggestions?

Maximum of how much current can this deliver? Anyone had done a test on it?

I'm a little confused about the 4 parameters recommended to be set in the data sheet for the BQ27441 on power on. I understand the Design Capacity (in my case 400mah) and Design Energy (400mah * 3.7). Terminate Voltage I'm a little less clear on what a good value is for a SparkFun 400mah battery, maybe 3.8v? Higher? Taper Rate, I'm not really sure I understand how to compute. In the data sheet, they talk about using the Taper Current to compute the Taper Rate, but I'm not sure how to figure out the Taper Current for a SparkFun 400mah battery. Thanks for any help!

Is it posible to drive the CE pin using the PGOOD output? I intend to use the bq2407 IC with a power source with unsteady voltage, and the PGOOD output seems to detects when the voltage source is good enough for charging a battery.

Can this charge 3 of these: https://www.sparkfun.com/products/13855 if parallel to get 6000mah?

I'm using this board with a Photon and the libraries are working happily. One thing I've noticed is that when the battery is fully charged and still on external power, the voltage and state of charge are both reported as 65535. I understand this is the maximum value for an integer variable, so I could just read it as "full", but I was wondering why the exact values are no longer given in this condition.

Excellent board by the way.

Hello! The BQ27441 Fuel Gauge is a flash-based part, which means it has its own firmware that can be updated if you want to better suit your particular battery or application. My former employer has allowed me to open-source a project I made that allows you to use an Arduino or Energia compatible processor to program flash-based gauges. Here it is.

If you want to do this, or want more information about this chip and why you'd want to program it, see the Technical Reference Manual, which should probably be added to the product description.

One word of warning: flash-based gauges can be permanently bricked if you program them with bad firmware. TI recommends that if you try to program a flash-based gauge, you should have several on hand in case one is rendered inoperable. I probably destroyed at least 10 gauges when I was debugging the sketch.

Is it ok to have the battery always in here? As in, while charging, under load, on standby.

Is it possible to talk to more than one BQ27441-G1A on the same I2C bus , I looked through the data sheet but don't seem to see if its possible .

I purchased this an a TeensyLC for a project I'm working on. I was wondering if it is reasonable to split an incoming USB connection to feed the data lines directly to the Teensy, the power lines to the Babysitter, and have the Babysitter provide power to the Teensy, regardless of the USB connection?

I am curious why my battery is not being detected? Has anyone else had any issues with this? If I could get it to be detected (BIE status pin = 1 in the Control () Flags register) then I could take measurements on my device!

I NEED HELP!

Sincerely, Michael

Is anyone else having an issue with the I2C interface where sometimes the Pi will read the board after using i2cdetect -y 1, and sometimes the 0x55 register will not show on the grid?

There

Trying to use a Raspberry PI to talk I2C to this board to get the device_type. I would expect the value to be 0x0421 per the datasheet, but, I am receiving 0x7400 and wondering what I am doing wrong on reading a simple address:

Here is my simple code:

#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <wiringPi.h>
#include <wiringPiI2C.h>

#define I2C_ADDRESS 0x55


int main()
{
    int fd=0;

        if ((fd=wiringPiI2CSetup(I2C_ADDRESS)) < 0)
        {
         fprintf (stderr, "Unable to open I2C device: %s\n", strerror (errno)) ;
             return 0;
        }
        delay(100);

        int x4 = wiringPiI2CReadReg16(fd,0x0001);

        printf("read from I2C: 0x%04x\n",x4);

return 0;
}

Output: read from I2C: 0x7400

Wonder if someone could give me assistances. I want to make sure I understand the I2C communications before trying to incorporate the library.

Does the GPOUT Pin always go to the SDA Pin of the I2C section of the RPi or Arduino (Specifically RPi)?

It seems that if we want to measure anything this pin has to be setup as such. Yet in his video it doesn't look like he's using the GPOUT pin. Just curious!

The main battery charger supports an input up to 28V, how come did you limit it to 5V (or 4.6 to 6.4 as stated on the board?)? Can it be powered using a 12V input?

I have a 2W solar panel with an open-circuit voltage of ~6V, when I connect it to VIN of the BQ24075, it drops to about 4.5V and the CHG LED indicates it is charging. However, there is no change in mA,mV,mW of the charge circuit (BQ27441). After about 30 minutes of charging (no load), there is no change in the State of Charge (soc %). I am using a 3.7V 2Ah LiPo battery. Is my battery charging?

I have tried all three modes on EN1, EN2... the full 1.5A does not seem to work as it loads the solar cell below the VDDO threshold of 4.35, but both 500mA and 100mA hold a steady voltage at the solar panel. The datasheet of the 24075 indicates it likes to regulate the voltage at VOUT at 5.5V, whereas the 24072 tracks VBAT + 225mV. I had assumed this chip would still be able to charge the battery as long as the VIN was above VDDO (4.35). Can anyone help me understand what is going on?

Double post, sorry.

I'd like to use this for one of my Teensy projects, supplying power when the USB cable is disconnected to the Teensy. When the USB cable is plugged in, I would like the USB port to power the Teensy instead of the battery. Would this let that happen?

I think I found a bug in the code - line 343 in SparkFunBQ27441.cpp:

while ((timeout--) && (!(status() & BQ27441_FLAG_CFGUPMODE)))

The CFGUPMODE bit is not in the status register, but rather the flags register. This causes this bit of code to fail. The correct line of code would be:

while ((timeout--) && (!(flags() & BQ27441_FLAG_CFGUPMODE)))

This works as expected. You state in the hookup guide after mentioning the setCapacity function:

Expect a short delay – 1-to-2 seconds – before your Arduino completes the execution of this function.

I suspect this delay is because setCapacity calls this function and it times out on this line because it is checking the wrong register! :)

The hookup guide shows the following charge currents incorrectly, in relation to the datasheet and your schematic:

EN1 EN2 Charge Rate

0 0 Suspend Mode (no charging)

1 0 Fast Charge (1500 mA default)

0 1 500 mA

1 1 100 mA

Should be:

EN1 EN2 Charge Rate

0 0 100 mA

1 0 500 mA

0 1 Fast Charge (1500 mA default)

1 1 Suspend Mode (no charging)

I need something like this that then automatically rotates through around 8 single cells. Round-robining a top off/state check on each battery. ideally a channel expansion board, maybe 4 each, so you could just add as many ports as you needed. I2C controlled or such.

Hello, I've some questions:

• What happen if I select 1.5A charging but the power supply only can give 500mA?

• What is the max output that can handle at 3.3v? I need power enough to power a GSM/GPRS that need 2A sometimes.

• Can I use this circuit for ultra low power applications? What power consumption it have?

Best regards

I see that the maximum input current rating for the chip is 1.5 A, which I am assuming is based on the charging current rating also being 1.5 A. However, the maximum output current rating is 5A, which is from Battery to Output. My question then is this: What is the maximum current rating from "Input" to "Output"? Is the Path managment IC only capable of directing 1.5A from the input to the output? Phrased as a scenerio: Given a 6A input, a 3A load on the output and a battery (battery specs irrelevent for this case), is this "Battery Babysitter" capable of directing the full 3A required by the load from the input - or will it only direct 1.5A from the input and the remaining 1.5A it will pull from the battery?

Can this be used with this Polymer Lithium Ion Battery - 6Ah ?

Also, how would you wire this if you needed this Polymer Lithium Ion Battery - 6Ah in series for 7.2v ?