With what, how much
dollars in time?
Two inputs, both at once: any USB PD charger to USB-C1 (up to 240 W) or your laptop's own adapter to the KX-D end (up to 330 W). Trio charges to 80% in 36 minutes with two sources.
Charging
With what, how much
dollars in time?
There are two ways: any USB-C PD charger (up to 240 W, PD 3.1 EPR) to the USB-C1 port or your laptop's own adapter (up to 330 W) with the KX-D tip. Both can be used simultaneously. Fast charging is only done when the cell is between 15–35 °C and up to 80%; the rest slows down.
| charging source | Solo 5%→80% | Solo full | Duo 5%→80% | Duo full | Trio 5%→80% | Trio full |
|---|
Since the Solo is a single module, it is stuck at the 1.5C limit per cell; so chargers above 140W will not charge the Solo faster. EPR (28–48 V) requires a 5 A USB-C cable with e-marker.
from inside the charger
Power and
temperature
Average input power and hottest cell throughout the charge in the simulation. The Solo doesn't draw much power from the large charger, as it's stuck at the 1.5C fast charging limit per cell; Trio cools 330 W because it divides the same current into three modules.
| Source | Solo avg. login | Solo hottest cell | Trio avg. login | Trio hottest cell |
|---|
BQ25756
The 70 V bi-directional buck-boost charge controller converts USB-C voltage (5–48 V) to the battery bus. Charging voltage accuracy ±0.5%: cells do not exceed 4.15 V.
LM5177 in reverse direction
The two-phase output stage, which delivers 330 W to the laptop, works in reverse and transfers the power of the adapter to the battery bus. No need for a separate charging circuit, up to 330 W.
sharing
The firmware divides the power of the two sources according to the cell temperature and the number of modules; the total never exceeds 1.5C per cell.
Charging rules
Boundaries that protect the cell
- Fast charging only when the cell is between 15–35 °C and up to 80%; then it slows down.
- Above 45 °C charging stops (the cell manufacturer allows 60 °C), below 0 °C it does not start at all.
- Cell upper limit 4.15 V instead of 4.20 V: cycle life is extended by approximately 30%.
- The device, which remains charged for 72 hours without using the output, goes into desk mode and keeps the cells at 3.90 V.
cable
5 A cable for EPR
The 28 V and 48 V (EPR) contract is only made with a USB-C cable whose e-marker chip supports 5 A and 50 V. Most 240W class GaN chargers come with this cable. With ordinary 3 A cable, FRAGWATT steps down to 20 V / 3 A (60 W); It charges but slowly.
USB-C1 is also the output: a phone, tablet or laptop with USB-C is powered by up to 140W. USB-C2 outputs 65W.