Hi, I have seen that while the board is in deep sleep mode, the GPS LED is blinking. I have deactivated the LDO2 and LDO3 channels afterwards and the LED does not turn on, but I think it is excessive consumption of 20mA on LDO1 to maintain the GPS calendar,
it’s only can maintain 4 days of battery approx.
Is this consumption even in deep sleep mode? I have to try with a multimeter better than mine
Hello,
On my side the consumption does not go below 15mA, even with ESP32 disconnected. I did not test LD01 disconnection, but I don’t think it use so much current. Did someone manage to reach µA consomption on the TTGO T-Beam Rev& ?
In this video
Consumption appears is below 0,0001A
Author uses this code
Display appears to show 0.00000A
Less than 10uA ?
Hi!
I used the same code as in the video. With the same board (except an additional screen), I have 17mA even in deep sleep. Can this be an issue with OLED?
Hi, have you tried to stop wifi and bluetooth on setup void?
WiFi.mode(WIFI_OFF);
btStop();
In a couple of days i’ll try read consumption too with new multimeter
In deep sleep mode, my multimeter shows 0.990 mA (0.00099 A)
In this video, board runs reading gps and accelerometer along 25 secs, consumption is 110-130mA (i think is a lot) and after that, goes deep sleep
Am i interpreting it well?
Hi again!, i’m back with new t-beam board. I put this boards in cows… 
This board added a red led IO4, and always is on, (very low light) but even deep sleep mode. With old boards i have 1mA of current in deep sleep, and 20mA with newer board. And in new board is needed to disconnect SCL pin of devices before uploading, if not, connect to COM port is impossible…
I put board in deep sleep as follows:
AXP20X_Class pmu;
…
pmu.setChgLEDMode(AXP20X_LED_OFF);
pmu.setPowerOutPut(AXP192_DCDC1, AXP202_OFF);
pmu.setPowerOutPut(AXP192_DCDC2, AXP202_OFF);
pmu.setPowerOutPut(AXP192_LDO2, AXP202_OFF);
pmu.setPowerOutPut(AXP192_LDO3, AXP202_OFF);
pmu.setPowerOutPut(AXP192_EXTEN, AXP202_OFF);
Anyone knows how to switch-off IO4 LED?
Thanks!
This works for me:
#define LED_PIN 04
...
pinMode(LED_PIN, OUTPUT);
digitalWrite(LED_PIN, LOW);
...Thanks it works, but with
digitalWrite(PIN_LED, HIGH);
if i set it to “LOW” it lights on harder, as a Vader’s lightsaber.
Many thanks again!
True less energy drain with HIGH.
(note to myself: don’t write code snippets from memory before caffeine kicks in)
Use a soldering iron!
So what the current now with the new board and led off?
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I have the same problem with this LED draining battery. It seems that the LED is soldered backwards (compared to the schematic) so this is the reason why it lights up when 3V3 rails is disabled. I hope that unsoldering it will solve the problem of battery drain, because there is no way a tiny LED is drawing 20mA.
Pretty much every data sheet for standard LEDs will use 20mA for typical illumination levels …
Nah, this is a tiny SMD led that was barely glowing.
After removing the LED (or rather a resistor next to it, same effect) the current consumption didn’t drop much. The LED wasn’t what caused the battery drain. I misremembered in previous post - battery drain was around 2mA in deep sleep. With LED disabled it draws maybe 0.1mA less, this could be just measurment error. Perhaps this is some SoftRF error, will check it next.
0.1mA would definitely make for a very dim LED. Quick check on my primary supplier for surface mount LEDs, out of 216 mainstream options, 191 of them are suggested at 20 to 30mA.
You may want to see what IO you can turn off / high impedance / set high, as appropriate for their connections.
Hi, I’m here again!
I’m doing several improvements to device, one of them is trying to use a lithium thionyl chloride (LiSOCl2) battery to extend lifetime. Appears that the unique voltage available to those kinds of batteries are 3.6V or 6V.
Theorically it’s fine because it’s basically the same nominal voltage as 18650 batteries, but difference is that a fully charged 18650 battery offers around 4,1-4.3V and my 19Ah LiSOCl2 batteries only output 3.71v in my multimeter.
I have connected a LiSOCl2 one to battery pins holder of TTGO T-Beam, but after pressing power button, board switchs on only for a couple of seconds, and then, switch off. Then I connected battery to 5V Vin pins of board and result is the same (but here pressing power button is not needed).
Measuring with a multimeter I think problem is that TTGO TBeam board requires a current amount higher than that such of LiSOCl2 batteries can deliver, because while board is booting voltage drops to 3.61V, and i think that when board detect votage drops below a certain value, it switchs off.
I think that is possible that voltage drops even more, but during a very short time lapse, which is unable to be measured by my multimeter (it can’t record peak values, only instant values).
I think that 19Ah value shown in battery is only a theorically mesurement of current, but in fact, those batteries can only deliver a tiny amount on mA instantly.
Using a step-up circuit to elevate voltage is not an option because that circuits have consumption even with output disconnected.
I attached a video that i think it shows clearly what i mean, replacing circuit board with a tiny dc motor.
I’ll back to 18650 again and I’ll put three of them in paralell, with 3A fuses between them and other fuse for circuit.
I’d expect much of the circuitry to actually run on 3.3V so it may well be the power management chip on this module and an LDO or Buck convertor are expecting 5v and aren’t able to cope, most typically by having to much voltage drop in processing before it gets to the actual circuit.
With a 3.6v battery I’d be mighty tempted to bypass the voltage regulation - I do that with some Pro Mini based devices, they start out on 2 x Lithium AA batteries at ~3.6V, quickly settle at ~3.4V and keep on working down to around ~2.7V.
Hi, thanks!, the TTGO T-Beam board has a 3.3V input, on DCD1 Bus and I could connect here the 3.6 V battery without problem, and board will power up pretty sure, but if I do that, I’ll not be able to deep sleep the board anymore, because AXP chip will not manage DCD1 current.