Arduino nano powering through 9V battery - issues

Using a Nano to power my gimbal project.

the GY-521 and servos are powered through the 5V port, and the 9v battery is connected to the VIN port and the black lead to the GND port.

the code has been uploaded and works perfectly when the nano is powered through the USB cable, however when I connect the 9V battery, only the POW light comes on on the nano, and the GY521’s led isn’t lit.

Thanks in advance,

If you mean the tiny batteries used for smoke alarms they are too puny to power servos and the like. You need a decent 5V power supply connected to the 5V pin or the USB port. Old cell phone chargers are good.

yep, those are the ones.

im using mini 9 gram servos though, and I need the gimbal to be isolated, can’t use a wall charger of any kind.

secondly, the issue isn’t with the servos or anything, just that the nano powers on but not the gy521.

anything else you can recommend?

Use AA cells , you can get plastic holders for these too.
You need to power the servos separately from these , not from the nano.
Try this


update - the gy521 wasn’t powering up because of a continuity issue, sorted out and now its powering up perfectly, however the servos have no power.

regarding using aa cells and the holders, is there a more space-efficient way to go about it? as I said its a gimbal and space inside is a bit of a constraint.

powering them separately is a bit odd, considering that I did make a sanitiser dispenser using a servo and powered it from the board itself, however that was an UNO not a nano.

any other suggestions about powering it externally are welcome, its something I am willing to consider.

thanks in advance,

Even the smallest servos need a power budget of 1A each or so for reliable operation. Servos contain motors, motors are a length of copper wire connected between supply
and ground in a magnetic field, copper wire has a low resistance… Most newcomers
drastically underestimate the power requirements of motors and servos, and in
particular are not familiar with stall current ratings.

what do you suggest to power the servos through then? externally or through the nano itself?

and if externally / through the nano, how can I do it keeping space in mind?

Externally - never share power between motors and logic chips (you’ll have less nasty
surprizes and avoid random resets and such nonsense) If you have to run from the
same source of power, use a buck-converter or voltage regulator to isolate the logic supply
from the spikes and dips…

Servos are designed for “receiver packs” in the RC world - 6V or 7.2V NiMH packs capable of reasonably large currents (many amps).

Same Old Story!

The clear blunder is not comprehending what the “Vin” or “RAW” terminal is. The regulator on the Arduino UNO/ Nano/ Pro Mini/ Mega2560/ Leonardo/ Pro Micro has very little heatsink, so will not pass very much current (depending on the input voltage and thus, how much voltage it has to drop) before it overheats and (hopefully reversibly) shuts down. It is essentially little more than a novelty provided in the very beginning of the Arduino project when “9V” power packs were common and this was a practical way to power a lone Arduino board for initial demonstration purposes. And even then it was limited because an unloaded 9 V transformer-rectifier-capacitor supply would generally provide over 12 V which the regulator could barely handle.

Nowadays, 5 V regulated switchmode packs are arguably the most readily available in the form of “Phone chargers” and switchmode “buck” regulators to regulate down from 12 V or other available voltages are cheap on eBay so these can be fed into the USB connector or (more appropriately) 5 V pin to provide adequate power for most applications. Unfortunately, many tutorials or “instructables” are seriously outdated or misleading and have not been updated to reflect the contemporary situation.

If powering directly from batteries, as long as the battery pack cannot exceed 5.5 V, this must be connected to the 5 V pin.

yup, am very avid in the RC world. I use lipo packs in all my models

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