Dc step converter / mah

Projects General Guidance
1

Hi guys I want to use a 3.7v lipo battery with 1000mah and use a dc to dc step up to get it to 5v.
What I want to know is what happens to the 1000mah does it stay the same?

Many thanks
M.....

2

Yes, but how that relates to your final output is another matter. If the step up is 100% efficient (practically impossible), then the Amp Hours you get at 5 volts will be 3.7/5ths of that at 3.7v. In reality it'll be somewhat less, probably about 90% of that.

3

Thinking of it another way:

1,000 mAh at 3.7 V is 3,700 mWh

With 90% efficient DC-to-DC converter you will get 3,330 mWh out.

At 5 V your 3,330 mWh becomes 666 mAh.

4

Thanks for the reply's guys then the battery will work for me because I only need 400mah.

Thanks again.

5

Undermentioned:
Thanks for the reply's guys then the battery will work for me because I only need 400mah.

Just as well. Batteries rarely live up to their published Ah rating. If you tried to draw an Amp for a solid hour from a battery rated at 1000mAh It's exceedingly unlikely you'll get it.