Should a 3m cable charge speed be significantly different than a 1m cable?

Solution 1:

The 3m (meter) 3rd party cable is the problem here. There are two possibilities:

• it's for an older iDevice that didn't have or support quick charging (iPods, iPhones, etc.)

• it's a cheap knockoff where the manufacturer didn't supply the correct chip to request higher power delivery

When selecting a 3rd party (non-genuine) Apple accessory, it's always good to go with known brands - I myself prefer Anker or even Amazon basics.

Understanding power adapters and cables

There's a lot of misunderstanding in the question about the role cables play in the charging process. Let's clear some of that up...

• The cable itself, doesn't dictate how much power drawn. Two cables of similar AWG (gauge or diameter of the wire) isn't going to draw vastly different amounts of power. For the inherent resistance of the cable to become a factor in dropping power, we start looking at distances in the kilometer range (a thousand times longer than what you're working with).

• A typical 20 AWG copper cable can support from 4A (multi-core like braided wire) and up to 6A (solid core) of current. At 2A, you are well within the tolerances and "getting warm to the touch" is perfectly normal.

• There are many differences for the amount of current draw on a device:

  • Load - an idle computer draws less power than one crunching away displaying video
  • Charging state - a fully charged battery draws less power to charge than a depleted one. Also intelligent chargers go from "rapid charge" to "trickle charge" once a threshold has been reached.
  • Power Negotiation - intelligent devices like quality Apple cables or USB 3.1 chargers negotiate the amount of power delivered.

The issue specific to your situation is the last point - power negotiation. In Apple cables - both Apple branded and high quality 3rd party - there is a chip that negotiates with the power brick how much power to deliver

^{Photo courtesy Chipworks}

If the chip in the cable only requests 1A of power, the power brick will only deliver 1A of power.