The yellow wire from a battery plus velcro

I am well into a project with a feather huzzah and it is powered by the battery as shown in the picture.
So, what is the yellow wire from the battery good for ? It reads about 3.5 volts which just happens to be a supply that I can use. Can I go ahead, wire it up, and use it ?
My other options are to use the DC-DC voltage regulator which is what I was planning to do. I have 1 for 3.5 volts and 1 for 6.0.
My 2nd question is about the use of the velcro to attach the voltage regulators to the chassis. Is it ok to use it like I did ?

Battery.JPG

hextejas:
I am well into a project with a feather huzzah and it is powered by the battery as shown in the picture.
So, what is the yellow wire from the battery good for ? It reads about 3.5 volts which just happens to be a supply that I can use. Can I go ahead, wire it up, and use it ?
My other options are to use the DC-DC voltage regulator which is what I was planning to do. I have 1 for 3.5 volts and 1 for 6.0.
My 2nd question is about the use of the velcro to attach the voltage regulators to the chassis. Is it ok to use it like I did ?

trying to figure out how to do inline images.

Battery.JPG

thank you aarp, I am still trying to figure out how to do that.

Battery.JPG

Posting images:

I think the yellow wire has to do with temperature but not sure.

G O O G L E

I don't see any yellow wire in the photo but I'm guessing, as the battery is a 2 cell Lipo, you are looking at the battery balance lead.

This has connection to ground( normally black), then a wire for cell number 1 ( probably your yellow wire), then another wire for cell number 2.( maybe red)

The main high current leads are normally much heavier cables and are normally red and black.

Should be ok to tap the balance lead if low current requirement but it will discharge just the one cell and the battery will end up out of balance.

This out of balance condition would normally be corrected with a typical "balance charger" which requires not only the heavy red and black lead for charging but also the balance lead to be plugged into an appropriate balance port on the charger.

Unless your velcro is ESD rated, it will produce GREAT static voltages when pulled apart.

Paul