How to make a galvanic isolation?

Question

Electronics

Hello. There is such a voltmeter-ammeter with aliexpress
s.aliexpress.com/NB3eMrQN?fromSns
It is good for everyone, but it requires a finished power supply. When I connect it in parallel with the measured load, the readings of this device begin to lie. This is because there is a galvanic connection between its power supply and the load. We have to separate them somehow.
But I have one power source in the circuit: an assembly of 18650 at 3.7 volts. I don’t even know how to formulate the question: how to get two unrelated ones from one power source?
What would you do in such a case?
Thanks for the advice in advance.

Answer 1

Install a boost converter (step up), which will increase 3.7 V from the battery assembly to 5 V to power the meter.
On Ali, search for "step up", "boost". You just need to pay attention to the voltage at which the module starts to work, because. if the step-up module starts working from 1V, then it can drain your batteries up to this voltage, which is undesirable for lithium ones. You need to install a protection board.
https://ru.aliexpress.com/item/DD06AJSB-DC-3-3V-3-...
https://ru.aliexpress.com/item/DC-DC-Boost-Step-UP...

Answer 2

find https://ru.aliexpress.com/item/1-B0505S-1W-5-5/328... or similar 3.3-->5v