Username1 said:
So is the CC charger PROVIDING a set amount of amps at all times?
You will not be using a "CC charger".
Just call it a charger. All the ones we use are CC/CV, by definition.
A good way to look at it is, the charge source "makes available" a certain current.
The load (here, a battery) may pull less.
If it tries to pull more, that is why chargers usually are "current limiting".
Sucky ones are just "current protected", latch off like a circuit breaker.
A little better is "hiccup mode", keeps trying after temp falls.
The worst just burn.
But 99% of devices sold as chargers are properly current **limiting** , so a big LI pack won't release the magic smoke.
> but then some of the power gets turned to heat by resistance (by varying amounts depending on state of charge), so the charger increases the voltage so the battery is actually RECEIVING the same amount of overall power?
No, and never mind about power here.
Power is watts, just derived from the V&A
And no significant heating need be involved in the process I described above.
The battery voltage is usually too low at first for the CV / Absorb setpoint to be reached
also the C-rate is too low (Ah capacity too high relative to the current) and the chemistry has a certain CAR charge acceptance rate, aka based on internal resistance, lead is way higher than any LI.
This is the "Bulk" or CC **stage** of the usual CC/CV charge cycle.
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Think of the charger **striving** to get the combined circuit voltage up to the setpoint. In effect that's all it "knows",
V < setpoint, keep pushing until the **combined circuit** get there then hold that setpoint as max V.
And then after the CC-CV transition, usually keep going a bit
as current **naturally falls** (trailing amps, taper down)
until the algorithm says Stop charging - that may mean shut off Off, or
maybe drop to Float for a 3-stage "smart" charger designed for lead, RVs, boat House banks etc)
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At a low Bulk stage C-rate, SoC is much higher at the CC-CV transition, Absorb Hold Time for the CV **stage** afterward, is much shorter, may get to 100% Full in just a few minutes. Careful, overcharging can be dangerous!
At a high Bulk C-rate, the CV setpoint is reached more quickly, but SoC is much farther below Full, longer AHT needed to get to 100%.
But remember, staying away from Full is a Good Thing so long as your use case does not require every mAh of capacity be used for maximum range, stopping sooner will increase cell / pack longevity.