# Wire mod on springs

About that mod, does that work better on in parallel or in series batteries? For example, 4x18650.

I have a light that run on 16+V which is 4x18650. I figured that those spring lengths would add up in series. Also a spring for the top of the battery caddy.

It does not matter if parallel or in series the power loss is always the same if same power per battery is used

Ok, are we talking voltage or amperage?

Resistance effects both.
Each spring would have a v-drop that would reduce current. The lower the resistance the less v-drop keeping the voltage higher increasing current.

My bats are 4.14V each so for 4 I have 16.56 volts. My meter shows 16.54 volts on the caddy. So I lost .02 volt because of the springs?

Not significant enough to do the mods?

It does not function like that. Imagine: you are capable of running 10mph. And you are capable of lifting 200pound. But not at the same time. The voltage drop you measure is at an amperage of almost zero. It’s a static voltage, that drops when the Amps rise. The relative voltage drop will be higher if there is much current flowing through those springs.

You are running a closed circuit of: batteries, springs, leads, a driver and one or more led’s. So you have to imagine how much resistance is added/removed from that circuit if you bypass the springs, compared to the total resistance of the circuit.
Four batteries means five springs. Most springs are good in absorbing physical motion and poor in conducting electricity. Or the opposite, but almost never good in doing both at the same time.
To cut a long story short: five springs? That screams: bypass!!

As the current increases the losses become greater under a load. Under a load you have to consider in battery voltage sag also.
P = V x I
An example of what can be gained with a Q8 by a spring Bypass and other losses. DBcustoms is a expert at reducing voltage losses.

Less resistive springs help eliminate the need for a bypass. BlueSwordM offered several batches of these type springs.

It would really depend on what the spring resistance you have now and batteries used as to what gain you would see.

Ahh, I didn't realize that. Maybe I'll try it.

Bypass always has positive effect, just make sure to take ultra flexible leads so they don’t break too fast from mechanical stress

As I wrote before it does not matter if in 4S or 4P if you draw for example 80W from the batteries and the voltage sags per spring 0.2V each cell has to deliver at 4.2-0.2V=4V
Each cell has to deliver 5A, so parallel 4V*20A in series 16V*5A

It’s pretty easy to do. Personally I like to put it in the inside of the spring using 22 gauge silicone wire.