TP4056 - Voltage and Wire Gauge Questions :)

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New member
Dec 5, 2016
Hi all :)
I am currently building an 18650 testing station:


The heat-sinks (Aluminium) works extremely well with Self-amalgamating tape (great thermal performance) as electric isolator. The high temp of the TP4056 is practically gone. I'm proud of that addition!

I have had a few issues with the TP4056's. From what I understand they should all charge to 4.2v.

ISSUE A - I put a cell in backwards, hehe, that's why no.3 is, I only did this once and learnt my lesson!
ISSUE B - 2 x TP4056's only charge to 4.15v with multiple tests of batteries.
ISSUE C - The other TP4056 appears to charge above 4.4v! (This is the first in line from the PSU) before I pulled the battery, and is inconsistent with testing with multi-meter. eg. testing from TP4056 PCB reads 4.4v where cell directly on Multi-meter read 4.1v, but another battery charges to 4.5v when testing from the PCB, and 4.1v from the Multi-meter. I know the multi-meter is accurate, it's the TP4056.

Voltages into all TP4056's is 5.18v

I have read that using the right gauge wire is very important - too thin, obviously more resistance. Too can that affect it, (Could the fact that I am using a 3mm 10amp [Twin Core - Does that mean 5amp each?] cable affect the TP4056) I could see it being a benefit by reducing resistance it could reduce the error margin with mAH across charger and dischargers, is that right? And how? What wire/cable gauge should I use on the 5v rail through the TP4056's? Should I use multiple 5v wires together through the TP4056? I have read this can cause inconsistent voltages and using one is better? OR is it just faulty PCB's? Can I put more questions in this paragraph??

So I guess my questions are numerous, but best summed up...
How can a thicker wire affect the TP4056? Would a thicker wire reduce resistance thus make for more accurate mAH readings across the board?
What gauge of wire is best for 4 x TP4056 dischargers?
Why are the TP4056's not charging to 4.2v?
Is this even worth it, or should I wait for Project JEHU?