[RESOLVED] Changing battery voltage

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leonana69
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[RESOLVED] Changing battery voltage

Post by leonana69 » Fri Jan 24, 2020 9:14 pm

Recently I want to power the crazyflie with a 11v battery but I found the BQ24075 doesn't support that. So I decide to find another way to realize it. My design is connect the 11v input to vusb since I never use usb port for communication and BQ24075 can support up to 18v input. That works.

But the next step I want to remove the original 3.7V battery. Here comes the problem. I can't flash the firmware, the command line said "fail to warmboot". So I want to know why the battery is essential and is there any solution to flash the firmware using just usb power supply.

Thanks.



kimberly
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Re: Changing battery voltage

Post by kimberly » Mon Jan 27, 2020 11:24 am

Hi !

This is unfortunately due to this issue right here:

https://github.com/bitcraze/crazyflie2- ... /issues/35

This is I think valid for both warm and cold boot (warm = computer says that it should go into bootmode and cold = is where we do the long press with the button) and only for the crazyflie 2.x, not for 2.0

This seems to be an bug, so in order to put it in bootmode, there need to be a battery connected to the battery connector...

tobias
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Re: Changing battery voltage

Post by tobias » Mon Jan 27, 2020 1:57 pm

But the next step I want to remove the original 3.7V battery. Here comes the problem. I can't flash the firmware, the command line said "fail to warmboot". So I want to know why the battery is essential and is there any solution to flash the firmware using just usb power supply.
I don't really know but I have my suspicion. When you boot up something must have changed with the inrush current that hits the USB current limit which causes a voltage dip. This dip causes the STM to constantly reboot. The battery does not have this current limit.

tobias
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Re: Changing battery voltage

Post by tobias » Mon Jan 27, 2020 2:50 pm

BQ24075 can support up to 18v input
Maybe you can explain a bit more what you want to do. Even though the BQ24075 support high import voltage I don't think it supports much current before things will get hot.

After some digging I also found the problem with the booltoader mode when running from USB power only. It is a bug in the bootloader that does not enable 500mA USB current limit. So if you have a debug adapter kit and a stlink you can fix this by building and flashing the nrf-booloader firmware with

Code: Select all

make clean all USES_RFX2411N=1 USES_TI_CHARGER=1 flash
If you don't have that there is unfortunately no fix right now as the bootloader can't update itself wirelessly.

leonana69
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Re: Changing battery voltage

Post by leonana69 » Mon Jan 27, 2020 4:33 pm

tobias wrote:
Mon Jan 27, 2020 2:50 pm
BQ24075 can support up to 18v input
Maybe you can explain a bit more what you want to do. Even though the BQ24075 support high import voltage I don't think it supports much current before things will get hot.

After some digging I also found the problem with the booltoader mode when running from USB power only. It is a bug in the bootloader that does not enable 500mA USB current limit. So if you have a debug adapter kit and a stlink you can fix this by building and flashing the nrf-booloader firmware with

Code: Select all

make clean all USES_RFX2411N=1 USES_TI_CHARGER=1 flash
If you don't have that there is unfortunately no fix right now as the bootloader can't update itself wirelessly.
And I found an interesting thing, when you remove the R24(which is connected to NRF51822 in the crazyflie 2.1 schematic), then connect the pin5 of NRF51822 to the VUSB, it works normal w/o battery.

leonana69
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Re: Changing battery voltage

Post by leonana69 » Mon Jan 27, 2020 4:35 pm

What I want to do now is make the drone powered by 11v battery.

tobias
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Re: Changing battery voltage

Post by tobias » Wed Jan 29, 2020 3:35 pm

And I found an interesting thing, when you remove the R24(which is connected to NRF51822 in the crazyflie 2.1 schematic), then connect the pin5 of NRF51822 to the VUSB, it works normal w/o battery.
To me this sounds like a bad idea. You will put 11v on pin5? Or did you maybe remove R25?
What I want to do now is make the drone powered by 11v battery.
Does this include flying? The motors could/would burn up because of excessive power. If you anyway would like to try, even though I would advise against it, these are the things I think needs to be done.

1. Cut track going from +BATT to pin 2 & 3 on BQ24075 so you don't power chip out of spec
2. Change resistor R24 from 200k to 400k to scale for 11v
3. Change resistor R18 from 100k to 200k to scale for 11v
4. Connect +BATT to VUSB
5. Check that BQ24075 doesn't get to hot

To fix the bootloader you could "hardcode" the chip by connecting pin6 PM_EN1 to VCOM and pin5 PM_EN2 to GND to always enable 500mA USB current mode. Cut these wires to the NRF51822 as well.

leonana69
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Re: Changing battery voltage

Post by leonana69 » Thu Jan 30, 2020 10:01 pm

tobias wrote:
Wed Jan 29, 2020 3:35 pm
And I found an interesting thing, when you remove the R24(which is connected to NRF51822 in the crazyflie 2.1 schematic), then connect the pin5 of NRF51822 to the VUSB, it works normal w/o battery.
To me this sounds like a bad idea. You will put 11v on pin5? Or did you maybe remove R25?
What I want to do now is make the drone powered by 11v battery.
Does this include flying? The motors could/would burn up because of excessive power. If you anyway would like to try, even though I would advise against it, these are the things I think needs to be done.

1. Cut track going from +BATT to pin 2 & 3 on BQ24075 so you don't power chip out of spec
2. Change resistor R24 from 200k to 400k to scale for 11v
3. Change resistor R18 from 100k to 200k to scale for 11v
4. Connect +BATT to VUSB
5. Check that BQ24075 doesn't get to hot

To fix the bootloader you could "hardcode" the chip by connecting pin6 PM_EN1 to VCOM and pin5 PM_EN2 to GND to always enable 500mA USB current mode. Cut these wires to the NRF51822 as well.
I won't drive the motor by 11v. I only need to power the board to make all functions, expect motors, work normally.

I remove R24 and R18 for safety. Then when I tried to increase the VUSB from 5v to 7V (no battery), the output of BQ24075 (voltage on R17) dropped from 5v to 1v. I'm confused about it since the reference manual says it can accept up to 28v of input.

tobias
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Re: Changing battery voltage

Post by tobias » Fri Jan 31, 2020 8:36 am

After checking the datasheet a bit more the operating voltage range is 4.35V to 6.4V, thus it will not regulate the voltage above ~6.4V so It looks like it can not be powered by more then that.
bq24075-vop-range.png

leonana69
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Re: Changing battery voltage

Post by leonana69 » Fri Jan 31, 2020 3:28 pm

tobias wrote:
Fri Jan 31, 2020 8:36 am
After checking the datasheet a bit more the operating voltage range is 4.35V to 6.4V, thus it will not regulate the voltage above ~6.4V so It looks like it can not be powered by more then that.
bq24075-vop-range.png
OK, I'd rather using a external 5V LDO instead.

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