# Optimum Battery (and Wire) to Power 10x Mini 1.5V Bulbs in Parallel?

• Jingoo
In summary, when powering 10 mini 1.5V bulbs in parallel, it is important to use an optimum battery and wire combination. The battery should have a high enough voltage to power all 10 bulbs simultaneously, while also being able to supply enough current to prevent voltage drops. The wire should have a low resistance to avoid energy loss and overheating. Additionally, it is crucial to properly connect the bulbs in parallel to ensure that they all receive equal voltage and do not burn out.
Jingoo
TL;DR Summary: We purchased a 9v battery box and planned to wire it—in parallel—to 10 mini bulbs, assuming 10 bulbs drawing from the 9v would be more than enough voltage drop to not go up in smoke.

We purchased a 9v battery box and planned to wire it—in a parallel circuit—to 10 mini bulbs, assuming 10 bulbs drawing from the 9v would be more than enough voltage drop to not go up in smoke.

I then started to question our wire choice, also…30ga…because it could handle the amperage of the 9v battery and cheap. But we also purchased some 20-24ga, thinking the thicker wire might be better for heat/more resistance to prevent that up in smoke error.

I assume there are some calculations one could make to figure out the best/most efficient solution (I think we can choose between AA, AAA, 1.5V (!?!), or 9V (but no more than 9v)).

And we probably shouldn't be deciding on wire thickness/gauge based on our desire to add more resistance (can't use resistors in the circuit btw), so not sure how to decide on the best inputs (battery + wire) to get the best output (i.e., equal brightness and as bright as possible before we hit that up-in-smoke scenario).

The mini-bulbs are: 1.5 volts at 0.3 amps bulbs x10

If the bulbs are in series with one another then they could take up to 15 volts before exceeding their rated voltage (1.5V x 10 bulbs). The current through the circuit would be 0.3 amps. This website recommends at least 26 gauge or larger for that kind of current, though they do say their table of values is very conservative.

Jingoo said:
I assume there are some calculations one could make to figure out the best/most efficient solution (I think we can choose between AA, AAA, 1.5V (!?!), or 9V (but no more than 9v)).
If you're looking to get the best performance out of your bulbs then I recommend some combination that's close to 15 volts. AA , AAA, C, and D are all 1.5V, the only difference being capacity, so they would be relatively easy to connect in series to get 15 volts. If you're stuck with 9V batteries then I'd try to get 2 more bulbs to raise the voltage drop of the bulbs to 18 volts and then use two 9V batteries in series.

I don't recommend mixing and matching battery types to get to 15V, as the capacities are different and you run the risk of damaging the batteries (same reason you don't want to put new and partially used batteries together in a flashlight or other device).

Thanks!

We can't use more than 9v AND the circuit must be wired in parallel. :)

After doing a little more digging, I believe we had it backwards—no voltage drop in parallel, right, because each bulb would be receiving the full 9v from the battery? ...so adding a bunch more bulbs (falsely factoring in voltage drop) wouldn't allow a 1.5v bulbs to work (for long!) with a 9v battery, it seems?

Jingoo said:
We can't use more than 9v AND the circuit must be wired in parallel. :)
So is this a project for school? If so I can move your thread to the schoowork forums for you. Can you post the exact project statement for us? Thanks.

Yes, for school....was more of a generic question on determining the proper battery + wire size, given the bulbs/sockets.

(i.e., we figured out 9v in parallel would be no bueno for our 1.5v 0.3a lights), but then wondering how one would determine if a AA/C/D battery (all being 1.5v, I believe) would be best, then 26ga vs 30ga wire type of analyses, etc). :)

I am sure we can buy any of the wire and make something that works, but really wondering how one would approach to do it right...one battery choice better than the other...one wire thickness, given the resistance, better than the other, etc. I hope this makes some sense. :)

Jingoo said:
We can't use more than 9v AND the circuit must be wired in parallel. :)
Ah, I see. I thought you meant that the batteries were in parallel, not the bulbs.

Jingoo said:
After doing a little more digging, I believe we had it backwards—no voltage drop in parallel, right, because each bulb would be receiving the full 9v from the battery? ...so adding a bunch more bulbs (falsely factoring in voltage drop) wouldn't allow a 1.5v bulbs to work (for long!) with a 9v battery, it seems?
If the bulbs are in parallel with each other and the battery then they would all receive the same 9 volts. Not good for a bulb rated for 1.5 volts. A single alkaline battery (AA, AAA, C, or D) should be fine, but you can always add in another battery in parallel if you need more capacity.

Jingoo said:
I am sure we can buy any of the wire and make something that works, but really wondering how one would approach to do it right...one battery choice better than the other...one wire thickness, given the resistance, better than the other, etc. I hope this makes some sense. :)
I'd just follow the guidelines from the website I linked in my first post. The resistance of the wire is typically so low that it just doesn't matter for a project like the one you're doing as long as you've got a reasonably sized wire.

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