BFL13 wrote:
If the wire is too long/thin then current will be less than it could be from start to finish,
It depends somewhat on whether we are discussing the quirks of different chargers or the preferred charge profiles. The typical charger is designed to provide constant current during bulk mode charging. It will increase its voltage until it either reaches its maximum designed voltage, or its maximum designed current limit. For a charger designed that way, the charger can't tell the difference between a long thin wire leading to a discharged battery (low SOC) and a fat thick one leading to one of higher SOC, provided that both batteries are sufficiently discharged that the sum of the voltage drop on the cables plus the battery voltage at that SOC is low enough that the charger is in the bulk mode. The charger will just increase its voltage to compensate for any voltage drop on the wires, no matter how thin or long. As long as the charger doesn't run into its voltage limit, the wire diameter/length won't have any effect.
The effect arises when the charger does run into its voltage limit. That happens sooner with the long thin high resistance cables at the end of the charge cycle.
That's for the idealized design charger.
The PD doesn't always follow that perfect charge profile. I've tested my PD9280, both before I modified it and after. Provided you give it a decent AC voltage to work with, mine is pretty close to the idealization described above. It tends to climb in current for while (about 6% up in my tests), then taper about the same % down before it leaves bulk mode.
If you do not give it sufficient AC voltage, then the PD has a tendency to taper early.
but the absolute current difference will be tiny once the "baseline" current is lower, so it is too small to matter to anybody. The difference you would notice would be in the beginning.
I don't see why you say that. The output of the charger depends on the voltage it sees at its output terminals. That's equal to the voltage drop of the cables plus the voltage of the battery. The purpose of short and fat is to decrease the voltage drop over the charge cables so that the charger stays in current limited bulk mode longer (and wastes less power in the cables).
The PD tapers anyway at the 14.4 stage, so you might not notice anything better even if you did go from #6 to say #4.
In my tests, that only happens at lower AC voltages. At higher voltages, it actually boosts for a while, then tapers.
IMO try it out as is and see if that is good enough for your needs. Then decide if it is "worth it" to change the wire to get five or ten minutes reduction in gen time to do a 50-90.
That seems like a reasonable difference, but the difference will increase if he decides he needs to go from 75 to 95. In a sense, we are in agreement. The lower the SOC, the more likely it is the charger will be current limited, not voltage limited, and when current limited, it doesn't make any difference how long/thin your wires are, except that you'll be wasting some energy heating them. Only when the charger has entered the voltage limited region do the wires matter.
Of course, none of the chargers being sold follow the perfect charge profile.