14
votes
Accepted
Two batteries sharing ground?
Not only can you share the grounds - sharing the grounds is required for there to be any form of meaningful circuit for signals to get around the place.
To copy-and-paste a blog post I wrote some time ...
- 106k
7
votes
Accepted
Battery solution Nano 33 iOT
You can either use the 3.3V pin to supply power to the board, or use the Vin pin.
By using the VIN pin to power goes through a (step down) voltage regulator, that provides a nice stable 3.3V to the ...
- 11.3k
5
votes
Accepted
How to read high voltage (40-65v) from a Solar Battery bank
You need a voltage divider with resistors that have large values.
...but with all values I have tried one resistor almost melts as soon as you connect to battery.
This suggests that you have been ...
- 3,218
4
votes
Are any Arduino boards especially suited for low-power operation?
Technically you can use any arduino for that purpose with some modifications. I recommend to go with an arduino Pro Mini and remove the LED and the voltage regulator.
But if you don't need so much I/...
- 686
4
votes
How can I calculate remaining battery life time with arduino
you may use ADC(analogRead) to measure Li-Ion Cell voltage. unlike Ni-Cd or Ni-Mh batteries, a Li-Ion Cell Voltage is a good measure for battery status. the discharge cycle of an usual Li-Ion cell ...
4
votes
Why does using ESP8266 in deep sleep mode still drain the battery quickly?
The example shows a Sparkfun Thing, which the article notes doesn't have extra peripherals. What you show is something different, like a NodeMCU dev board, which typically has a linear regulator, ...
- 6,974
4
votes
Accepted
Powering Uno with 9v battery makes it "freak out"
Not enough current available from the battery, relays take quite a lot. As soon as the relay tries to switch the voltage drops and the Uno resets due to brownout (low voltage)
- 1,028
4
votes
power consumption of esp32
There's a number of things to consider when choosing batteries.
First is the capacity. In broad terms, the capacity is, mAh, means "This battery can supply X mA for one hour". So a battery of 1000mAh ...
- 106k
4
votes
Accepted
Measuring Battery level with ADC already in use
As @dandavis rightly says in the comments, you can't measure the battery voltage from a power bank. This is because the power bank typically includes a step-up converter to turn the batter voltage (3....
- 106k
4
votes
How to connect a LiFePO4 battery directly to an esp32?
I know this question is two years old but it still pops up on research. I just wanted to add something from my experience with this:
If you take an Enerpower HTCFR18650 for example datasheet you see ...
- 41
4
votes
Accepted
Can I use LiFe PO4 batteries in a 18650 battery shield?
In my opinion it is NOT SAFE, if your 18650 Battery Shield also charges the battery.
Anyhow some pages state that it is possible to charge LiFePo4 batteries with 4.2V instead of the recommended 3.65V. ...
- 1,533
4
votes
Accepted
Slow WiFi reconnection after deep sleep (6 to 10 seconds)
When a device trying to connect to a WiFi network, it scan the entire WiFi spectrum to find all the SSID and the BSSID(i.e. Mac Address) associated with each SSID. It is in general take around 6s for ...
- 1,978
3
votes
How to use a DC buck converter to regulate Uno R3 input voltage?
The barrel jack needs 9-12 V, the internal voltage regulator of the Arduino will reduce this to 5 V.
Since you only supply 5 V, there is a loss in the internal voltage regulator why you probably get ...
- 13k
3
votes
Accepted
cheap long lasting options for battery?
9V batteries are not meant for high-current discharge, as you would find when powering a motor. Not only that, they are low capacity. If you need to power motors, you should use batteries such as C or ...
- 6,974
3
votes
Arduino (or clone) powered with one or two AA batteries or one CR2032, but still able to give +3.3V or +5V
The modern low voltage versions of a bare ATmega chip can run from either 2xAA or a lithium coin cell - you wouldn't want to use a voltage regulator, as that is not only unnecessary but introduces ...
- 5,411
3
votes
Accepted
LiPo + charge/boost circuit vs pre-built "power bank" - contrasting portable power sources
The thing to remember with power banks bought on places like eBay and Amazon is:
THEY LIE ABOUT THE CAPACITY
A typical power bank you would expect to get around 3600mAh from, even though it may say ...
- 106k
3
votes
Accepted
Read both battery voltage and analog sensor value with NodeMCU ESP8266
to read VCC voltage, ADC pin must be kept unconnected. Additionally, the following line has to be added to the sketch:
ADC_MODE(ADC_VCC);
The setting of a purpose of the analog pin of esp8266 is at ...
- 18.3k
3
votes
How to calculate battery usage of my arduino project?
I suggest using a second Arduino to make yourself an "Energy Meter".
Get a very small power resistor (0.1 Ohm) and power your project through it.
Second Arduino will measure voltage drop on it and ...
- 1,312
3
votes
NodeMCU ESP32s can't get Vin to work?
Assuming you are using a 9V block battery: They don't deliver the current you need for the esp32 to run/create an access point/act as a client. What you can do is connect 6 AA batteries in a row (6*1....
- 164
3
votes
How to read high voltage (40-65v) from a Solar Battery bank
It sounds as if you have tried using far too small a value resistors. For example, if you used resistors totaling , say, 1,000 ohms across a 50V supply then they would dissipate V^2/R watts = 2.5W. ...
- 149
3
votes
Accepted
Powering an esp32cam by a battery
The official ESP32-CAM has a AMS1117 voltage regulator that creates the 3.3V for the ESP.
The AMS1117 has an Absolute Maximum Input Voltage of 15V. It has a Dropout Voltage of 1.1-1.3V.
So you should ...
- 11.3k
3
votes
Accepted
9 volt battery unable to power 2 plastic yellow motors
9v batteries are incapable of supplying enough current for a motor; their best application is tiny-current, standby devices like smoke detectors. You need a power supply that can deliver much more ...
- 15.4k
3
votes
Is there a 3.3V and 12V 18650 circuit?
I would suggest using a 12V controller, and then adding a 3.3V switching regulator using the 12V supply. That would be 2 off-the shelf components and you're done.
- 5,752
3
votes
Accepted
Chips & High voltage: Connected in Series?
If you put three resistors of the same value in series, then you would get equal voltage division between them.
But chips are not like resistors. Their current usage is not constant and typically ...
- 1,593
3
votes
Battery for WS2812 Strip? (Something's not right)
There are a few things that may contribute to your lower than expected battery lifetime.
Effective capacity: you should aim to never use more than 50% of the capacity of a lead acid battery or you ...
- 1,681
3
votes
Accepted
Battery voltage measurement with voltage divider
The problem comes because you are powering your load through the voltage divider you use for reading your battery voltage.
You cannot do high-side current reading like that with a voltage higher than ...
- 106k
3
votes
Accepted
Could I put an arduino in series with a battery charger?
Just for clarity: your diagram shows the Arduino, the batteries, and the charger connected in parallel - which is correct for what you want to do. However, a 12v power supply (batteries, charger, or ...
- 15.4k
3
votes
Accepted
ESP32 Wifi not working when powered by battery
I agree with chrisl, the battery does not have a low enough impedance to operate your project. What you are not taking into account is the transmitter current when it is transmitting to the wifi. I ...
- 1,863
3
votes
Accepted
AA alkaline batteries on firebeetle?
The following is based purely on the small amount of information in your question. You haven't described your code or your setup, which would allow this answer to be more specific.
According to the ...
- 1,681
2
votes
Accepted
I have built a battery level indicator and have tested with a 12V battery Would it harm my arduino board if I connect a 48V battery?
You have a voltage divider there, which would give (if the pre-set pot was set to the maximum):
Vout = (Vin * R2) / (R1 + R2)
Vout = (12 * 10000) / (100000 + 10000)
Vout = 1.09
Thus a 12V battery ...
- 38.9k
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