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Help me design the Circuit, Answered

hello everyone;

I want to make power backup for my internet router which runs on, 9v and 0.6Ah or 600mAh, I bought the 9v battery but it could not provide enough current to the router to work properly, so now i have two 6v batteries which provides 4Ah current each and i want to use them for power backup, now i,m stuck at the point that how i'm going to make this voltage lower i.e 12V to 9V, however, I figured out how I can limit the current to 0.6Ah or 600mAh, i,m using 12v charger to charge these batteries while connected in series and will use it with router as well, can any one help me out the how can i decrease the voltage to 9V and use it power my router.i'll be grateful


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1 year ago

Look for a "step down converter".
Or "DC DC converter".
Some come with a fixed output voltage but most are adjustable, just check before buying.
These things turn a wide range of input voltage into a fixed output voltage.
No need to limit the current coming from the batteries as the router will only take what it needs.
You might want to add a larger size electrolytic capacitor to the output of the converter to minimise interferences.
2200µF or bigger should do.