3.7 VOLT BATTERY POWERS 56 WATTS

[magnetman12003]

Hi all
I have one really dumb question to ask. How long does a 18650 3.7 volt battery last running these lights and what is the mA of the battery. I.E 2600?

Your question is not dumb. The 18650 3.7 volt 5800 ma battery is inside the USB charger that delivers 5 volts to the setup.  The 8 seven watt 12 volt bulbs will light up brightly for 5 minutes and all go out at one time.  Now using the same battery and charger I gave the battery a short rest where its not powering anything.  Then I can repeat the above again with same results.  I also did it a third time with same results!!!!!???  Really weird as you would think the battery would have given up on the first try.  Somehow the circuit is turning 5 volts to 12 with enough current to keep all bulbs lit.

Kind Regards
Mark

[markdansie]

Thanks for the feed back.

That makes a lot of sense given these lithiums can have a lot of bounce when exhausted.
You can also get commercial step up DC to Dc circuits and test them as a reference or control.


The amount of energy you are using in those 5 minute windows are easily achieved with a good quality Lithium battery .


Kind Regards
Mark

[magnetman12003]

Thanks for the feed back.

That makes a lot of sense given these lithiums can have a lot of bounce when exhausted.
You can also get commercial step up DC to Dc circuits and test them as a reference or control.


The amount of energy you are using in those 5 minute windows are easily achieved with a good quality Lithium battery .


Kind Regards
Mark

When I connected a 3.7 volt battery directly into the circuit input NO bulbs light up.  But put the same battery into a USB cell phone charger powering the circuit all 8 seven watt 12 volt  bulbs burn brightly then cut off after 5 minutes.  Rest the battery and can repeat many times.   Unable to exhaust the battery after numerous tries.

[TinselKoala]

I'm guessing here... but maybe the "cutoff" after five minutes is due to the USB charger's chip entering thermal shutdown mode, rather than anything happening to the battery.

You could test this by feeling the chip with your finger to see if it's excessively hot and if the charger starts up again after it cools. A q-tip with a little isopropyl alcohol (evaporates quickly from hot chips) can also be used.

[markdansie]

Hi TK
That is a pretty good guess. Some of the cheaper power banks do not use the thermal function but this makes the most sense.
Some of the nastier lithiums bounce a lot, the quality ones do not as much.
Kind Regards
Mark