Power management

Power management forum

State Resolved
Locked Locked
Replies 41 replies
Answers 2 answers
Subscribers 65 subscribers
Views 5595 views
Users 0 members are here

Support feedback

Options

Options

Related

Recommendation for charger/ battery monitor

Sonny Zamot

Intellectual 465 points

Other Parts Discussed in Thread: MSP430FR5989, BQ24773, BQ24160, BQ24161, BQ24163, BQ24168, BQ28Z610EVM-532, EV2400, BQ28Z610, BQ24610EVM, BQ24610, BQ40Z50-R1, BQ34Z100-G1

Hey guys looking for some suggestions, I'm using a MSP430FR5989 microcontroller

This are my requirements

Charger for 1 cell LiFePo4 battery
switching regulator used for DC/DC conversion to load/ charge voltage(s). Looking in the area of ~90% efficient at near zero and large loads
be able to charge battery(max .5A) and provide power to the system (up to 1-2A continuously)
able to boost load with the battery if load need temporarily boost
not interested in fast charger
need to have a battery monitor features include, SoC, SOH, built in gauge but separately would work

thanks for all he help

over 8 years ago

0 Joel Hernandez II over 8 years ago

TI__Mastermind 25800 points

Hey Sonny,

I just want to make sure I understand your needs correctly.

Are you looking for DC/DC regulator external to the charger to charge the battery and supply the load? Or are you looking for something to provide a separate voltage rail to your system?

And when you say boost load, do you mean boost the battery voltage to a higher one? Or do you mean to supplement extra current to your system if the loading continues to increase?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

Joel,

I just want the charger to charge the battery and also to provide a steady voltage to the load,
there is a time (FEW) that I might need more current that the charger would allow, can the charge allow the battery to supply power while he is supplying power from the input?

Basically I want to have one input and tow outputs, the charging of the battery and the system load, and if the power source goes away I want the charger to allow the system to be powered by the battery

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

Joel,

on that chip it says the host should initiate charging and terminate charging, How is the host suppose to know when it need to begin/end charging? If charge is enable does that mean that the charge would automatically start/stop charging the battery?

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

In reference to your previous reply, TI offers single cell charger chips that do everything you are looking for. If you look at our single cell chargers, they include Power Path management which provides power to the system through a buck converter, AND charges the battery through that same converter and an additional controlling FET. When the system load becomes more than a programmed input current limit from let's say your adapter or USB port, the charger uses that FET to source current/discharge current from the battery in something called "Supplement Mode" to the Vsys bus. If the Vbus input is disconnected (adapter or USB port), the charger uses the battery as a source to your system, down to a certain voltage limit of operation.

Take a look at the bq2429x, bq2426x, bq2419x, bq2589x series of parts.

In reference to your second reply, which chip are you referring to?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

bq24773

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

Joel, are those charges for LiFePO4?

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

Yes those chargers are for single cell (1s) Li-ion batteries that have max voltages between 4V and 5V.

Do you have a multi-cell application (2s or more)?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

No, if anything we might put 2 in parallel I saw it said Li-ion so every chip that I see with that assume that they take LiFePO4?
this is one of the batteries we are considering,
www.batteryspace.com/lifepo4-32650-rechargeable-cell-3-2v-5000-mah-16wh---un-38-3-passed.aspx

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

So just taking a quick look at the battery your are considering, I would use from these families of chargers, preferably once with I2C to set the max battery regulation voltage to the max spec on the battery (3.65V cutoff as listed in the tech specs of the battery). It is sometimes called V_BATREG, V_REG, V_BAT, or V_BREG in our datasheet. If you do wind up putting 2 in parallel, I would look at the bq2419x family specifically. They change provide up to 4.5A of charge current.

bq2416x
bq2426x
bq2419x
bq2429x
bq2425x

Please be careful when considering these parts. Look at the 'Default' battery regulation voltage, as many of these parts default to around 4.2, which could damage your battery. Most of these parts also have charging enabled by default (through a register default setting or the /CE pin), so again these two parameters work hand in hand, and you must change one of them before attempting to charge.

You can also look at some multi-cell chargers like the bq24773 you mentioned, and others that list Li-ion and 1s-Xs capability.

Hope this helps.

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

Are they any Hardware configurable or software with flash integrated so we can set it one time?

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

I would suggest using these. They are not hardware settable, but their default charge regulation voltage is 3.6V which is fine for your battery.

bq24160
bq24161
bq24163
bq24168
bq24261M

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

Thanks for all the information with the charger we are buying some of the eval boards to see which would work.

I have a question with the gauge I bought a bq28z610EVM-532, I connected out battery found the right chemistry, and would like to see if it starts reporting accurate with SOH and SOC but I can't get the pack side to show any voltage. J1 is a 3 post terminal I connected the positive side to the pack+ (first terminal) and pack- (third terminal)

Do I have to connect P1 jumper?

thanks

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

When you say you can't get the pack side to show voltage, where are you measuring? Or are you referring to the GUI?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

I'm talking physically,
I have a load connected and doesn't see a voltage, I put a voltmeter and can't see anything,
isn't the pack where you put load/charger?

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

I can send you some of the files from the gauge and you can see if something is off?
let me know if you want that

thanks

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

How did you connect your battery to the J2 terminal?

Did you press S1 to wake up the device?

Which Communications device are you using? The EV2300 or the EV2400?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

I'm using EV2400
I did press S2 at that moment the bq studio recognize the device
2p and 1p are jumped
in 1p the positive of the battery
1n the engative of the battery

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

What voltage battery/power supply are you providing at the J2 terminal.

It seems the device is configured by default to function with a 2S battery, meaning battery voltage may play a role in powering up.

Regards,
Joe H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

What register do I need to change to make it a 1S

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

You will have to change the (via the GUI):

Data Memory >> Settings >> DA Configuration register. Bit0 (named CC0) needs to be changed to configure for 1S configuration.

Let me know if this works.

Regards,

Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

Joel, requirements change now I need the 2 S,

quick question if I want to change the I2C address how do I do it?

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

If you are using 2S configuration, you cannot use the chargers I recommended earlier in this thread. So you need a multi-cell charger recommendation?

Can you provide the new charger requirements, if any, besides the 2S configuration.

And you cannot change the I2C address of the charger or gauge.

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

I'm using the BQ24773
what should I do if I want to have more than one battery pack, I tough I could talk to them with an unique ID that way I know which battery is in what state

0 Wang5577 over 8 years ago in reply to Sonny Zamot

TI__Guru 56650 points

Do you have one bq24773 or two bq24773 in your system?

Do the two battery pack share a same I2C or SMBus?

0 Sonny Zamot over 8 years ago in reply to Wang5577

Intellectual 465 points

we have a charger model after the 24773,
that's the end game that if we need more packs we can put them in the same i2c line. we would have to give them a unique ID

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

Hello,

Haven't comment in a while. I' having trouble with my gauge bq28z610, my 0% is at 6.35V (for both cells) which that's a lot of juice in there, the nominal voltage is 3.2 of the battery, I would like to drain the battery to at least 2.8V per cell. right now when the TI chargers is shutting down (bq24610EVM) the gauge is at 62%. Any advice what can I do?

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

What did you set your Feedback resistors to on the bq24610?

Did you perform a learning cycle on your battery with the bq28z610?

When you say "TI charger is shutting down", do you mean the CHG or DSG controlled by the gauge are open? Or do you mean the current reaches termination on the charger?

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

What did you set your Feedback resistors to on the bq24610?
Are you talking about R1 and R2 in that evm?

Did you perform a learning cycle on your battery with the bq28z610?

I didn't the chemistry is there in the profiles you had, why should I still perform a learning cycle

When you say "TI charger is shutting down", do you mean the CHG or DSG controlled by the gauge are open? Or do you mean the current reaches termination on the charger?

on CHG state, I move the max capacity I saw that per cell was 2100 AH, so I move it to 3300AH

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

The bq24610EVM's feedback resistors set the battery regulation voltage to 21V.

What is the maximum voltage rating of your cells individually? Combined?

Do you have the .log or .csv file from the charge cycle of the batteries?

That could help me investigate what is going on further.

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

Joel,

Vf = 7.2V

here's the one battery I'm modeling now is from A123
ANR26650 and I'm using 2S.
I'm currently loging a full charge/ discharge and I'll send it to you when is done. I think another problem is my 0% is when my battery is around 3.1V which seems to be to soon.

thanks for the info

0 Joel Hernandez II over 8 years ago in reply to Sonny Zamot

TI__Mastermind 25800 points

Hey Sonny,

If you also post your .gg file, I can take a look at your configuration and try to figure out what is going on.

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

the forum is not letting me upload can I email you?

0 Fernando Lopez over 8 years ago in reply to Sonny Zamot

TI__Expert 8230 points

Hello Sonny,

In addition to Joel's comments, just wanted to clarify a bit the differences between chemID and a learning cycle.

The chemID includes the OCV profile and temperature coefficients for a particular cell model. Regardless of the chemID, for Impedance Track gauges, a learning cycle is required in order to update the QMAX and RA values for the cell. The algorithm uses the OCV values, the QMAX value and the RA impedance values to calculate SOC accordingly. If any of these values are incorrect, the SOC and FCC calculations will be off.

Please refer to this app note for more details on how to run a learning cycle.

Hope this helps.

0 Joel Hernandez II over 8 years ago in reply to Fernando Lopez

TI__Mastermind 25800 points

Hey Sonny,

After looking at your .gg file and looking through the bq28z610 technical manual, I believe you need to change two things:

1) Gas Gauging IT Cfg | Term Voltage | 6000 | mV

>>This probably needs to be changed to the minimum stack voltage you are looking for which is 2cells*2800mV = 5600mV.

2) Gas Gauging IT Cfg | Term Voltage Delta | 300 | mV

>>This would need to be changed according the formula from the technical reference manual (Term Voltage Delta = (3.3 - Term Voltage per cell)/Number of Cells). So for your use case, I would say (3.3V - 2.8V)/2 cells = 0.25V.

More importantly, I would also run a learning cycle as Fernando described above. It will allow the IT algorithm properly calculate SoC.

Lastly, there are a few other values in the Gauge that could be updated at your discretion in that they only set flags for discharge and recalculation purposes.

Gas Gauging | FD Set Voltage Threshold | 3000 | mV
Gas Gauging | FD Clear Voltage Threshold | 3100 | mV
Gas Gauging | TD Set Voltage Threshold | 3200 | mV
Gas Gauging | TD Clear Voltage Threshold | 3300 | mV

Hope this helps,

Regards,
Joel H

0 Sonny Zamot over 8 years ago in reply to Joel Hernandez II

Intellectual 465 points

awesome thanks

a couple of questions

any suggestion in a charger/ gauge for 4S LIFEPO4?

also how many charge and discharge for the learning cycle?

0 Fernando Lopez over 8 years ago in reply to Sonny Zamot

TI__Expert 8230 points

Hello Sonny,

Please review the bq40z50-R1 for a 4S gauge that supports LiFePO4. For a charger, the option would vary depending on your application criteria (charge current requirements, input voltage, etc.). I recommend reviewing the bq24773.

Regarding the learning cycle, we recommend the following:

Discharge to termination voltage. Let cell relax for 2 hours.
Charge to full and let the cell relax for 2 hours.
Discharge using a C/5 rate to termination voltage. Let cell relax for 5 hours.

After this cycle, you can verify if the learning cycle was successful based on the value of the "Update Status" parameter on the gauge.

0 Sonny Zamot over 8 years ago in reply to Fernando Lopez

Intellectual 465 points

thanks for the quick response can the charger and gauge be integrated in the same board or would you recommend separate them in 2 boards?

0 Fernando Lopez over 8 years ago in reply to Sonny Zamot

TI__Expert 8230 points

Hello Sonny,

It depends on your application. The bq40z50-R1 is a pack-side gauge, meaning it's expected to be on the PCB inside the battery pack along with the secondary protection ICs with the charger on the main system PCB.

If your application is designed such that the user is expected to swap battery packs frequently, a system side gauge will be more appropriate that resides on the main PCB along with the charger. The bq34z100-G1 is another 4s gauge that supports LiFePO4 and can be used both in pack/system side applications.

0 Sonny Zamot over 8 years ago in reply to Fernando Lopez

Intellectual 465 points

the application that I'm looking to design the user would provide power to charge (12V) and I want to have the charger controller, batteries and the gauge, with a battery supply for the system, with I2C line to talk to the gauge

0 Sonny Zamot over 8 years ago in reply to Sonny Zamot

Intellectual 465 points

Joel,

How do I put it in the learning cycle I want to try that route

0 Fernando Lopez over 8 years ago in reply to Sonny Zamot

TI__Expert 8230 points

Hello Sonny,

On Impedance Track gauges, you need to ensure the gauging algorithm is enabled before running the cycle described in latter posts.

On the bq28z610, you need to set Manufacturing Status[GAUGE_EN] = 1 to enable IT.