18650 battery output to 5v. How?

[Asheekay]

So. I'm back after a long hiatus.

After getting the 5v WiFi relay, I'm hooked to it completely. It's love. It's beauty. It's ease.

Now the problem is that this thing works at 5v, 1 amp. 1 amp is far too much to supply for a 9v or 23A sized 12v battery, even after stepping the potential down to 5v.

So I ordered two HG2 model 18650 batteries which supply 3.7 volts and 20 amps.

How do I step up the 3.7v from these batteries to 5v required by the relay? Any DC to DC step up module will be highly appreciated since I don't want a whole gigantic setup just to run the relay.

Thanks.

 

[Nigel Goodwin]

18650 batteries are 4.2V anyway, 3.7V is when they are flat - and usually should be fine feeding such a device - for a start try it and see. But 18650 to 5V converters are common place, and available in a wide variety of types, both with and without USB sockets on them.

This looks like the one I've been using recently:

10pcs 1A DC-DC 3V to 5V Converter Step Up Boost Mobile Power Supply Module

Only US$12.99, buy best 10pcs 1A DC-DC 3V to 5V Converter Step Up Boost Mobile Power Supply Module sale online store at wholesale price.

uk.banggood.com

 

[sekemiat ke]

they give out approximately 4.7 v when they are seriously at work

 

[Pommie]

All the recent post are from you. And, so far, not seen anything remotely useful you've posted.

Mike.

 

[crutschow]

Is this for backup power if the mains goes down?
If so, how will you switch from mains to backup?

 

[Asheekay]

Is this for backup power if the mains goes down?
If so, how will you switch from mains to backup?

It's just to power up a small 5v, 1amp WiFi relay module, bro.

 

[crutschow]

It's just to power up a small 5v, 1amp WiFi relay module, bro.

Okay, "bro".
And how long do you expect to power it from the battery?

 

[ChrisP58]

Assuming that this is the battery you're using, there may be some issues with what you're planning to do.

https://www.batteryspace.com/prod-specs/9989.specs.pdf Numbers in ( ) below refer to sections of this datasheet.

The capacity in AmpHours is 3000mA Hours (2.1)

While the Fast discharge current is 20 Amps (2.6.2), the Standard discharge is only 600 mA (2.6.1).

What this means. You can only expect the full 3 Amp Hour rating if you're at or below 600 mA. Higher currents will reduce the AmpHour capacity.

Also, even if your conversion efficiency were 100%, to make 1 Amp at 5 Volts will take 1.38 amps at 3.6 Volts. And even more current as the battery voltage falls.