Meilan 5s Duel Redmi 4x: What 100 Yuan of Quick Charge Actually Buys

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  How the Meilan 5s duel Redmi 4x charging path differs
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  Battery capacity, heat and the real ceiling
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  When the 100 yuan premium pays back
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  What buyers should check before paying
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  Meilan 5s duel Redmi 4x: charging and power comparison

The Meilan 5s uses MediaTek's mCharge protocol. The charger negotiates a higher voltage and current pairing than a standard 5 V / 2 A brick, so the phone can pull more power during the constant-current phase. The Redmi 4x uses Qualcomm's Quick Charge path, which talks to the PMIC over a different handshake. Both approaches raise the charge rate, but they do it at different points in the circuit.

The practical difference shows up in the first 30 minutes. A mCharge-capable brick pushes the Meilan 5s closer to its current limit early, while the Redmi 4x relies on a slightly more conservative ramp. Neither phone charges at a constant rate. Both taper hard once the cell passes roughly 70 to 80 percent state of charge, because the charger switches to constant-voltage mode to avoid lithium plating.

That taper matters to the 100 yuan question. If you buy the quick-charge bundle, you are paying mostly for the early phase of the curve. The last 20 percent takes almost as long on both phones whether you paid the premium or not. This is normal lithium-ion behavior, not a firmware trick.

Protocol mismatch is the most common failure. A Meilan 5s will not negotiate mCharge with a Quick Charge-only charger, and a Redmi 4x will not negotiate Quick Charge with an mCharge-only brick. In that case both phones fall back to 5 V / 2 A and the 100 yuan premium does nothing measurable.

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  mChargeHigher voltage negotiation, MediaTek platform.
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  Quick ChargePMIC handshake, Qualcomm platform.
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  Fallback5 V / 2 A when protocol does not match.

The Meilan 5s carries a 3100 mAh cell; the Redmi 4x carries 4100 mAh. That 1000 mAh gap is larger than the quick-charge upgrade itself. A bigger cell at the same charge current takes longer to fill, but it also spreads heat over more electrode area. The Redmi 4x can therefore hold a moderate charge rate for longer without the surface temperature climbing as fast.

Heat is the binding constraint. Charge current heats the cell internally through its internal resistance, and the phone's thermal management cuts the current when the cell or the board gets too warm. In a 25 °C room the difference between the two phones is small. In a 35 °C car or a pocket on a summer day, the Meilan 5s throttles sooner because it has less mass to absorb the heat.

This is where the 100 yuan premium has a second effect. A capable charger holds a steady output instead of sagging under load, so the phone does not hunt for a stable operating point. Cheap chargers often drop voltage when they heat up, and the phone responds by reducing current. The result looks like slow charging even though the protocol negotiated correctly at the start.

Cell age changes the picture too. After a few hundred cycles the internal resistance rises, the charge curve shifts, and the early-phase advantage shrinks. Quick charging is most visible on a healthy cell. On a worn cell, both phones converge toward the same slow taper.

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  3100 mAh cellMeilan 5s, less thermal mass.
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  4100 mAh cellRedmi 4x, spreads heat better.
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  Ambient above 30 °CBoth throttle earlier.

The premium pays back when you charge in short windows. A 20-minute top-up before a commute, a quick charge at a desk between meetings, or a partial fill before a flight all sit in the early, fast part of the curve. That is exactly the region the quick-charge bundle improves. If most of your charging happens overnight, the taper dominates and the premium buys very little.

It also pays back when you keep a compatible charger with you. The phone only negotiates the fast path with a brick that speaks the same protocol. Leaving the bundled brick at home and plugging into a random USB port returns you to 5 V / 2 A. The upgrade is attached to the charger, not to the phone alone.

For the Redmi 4x specifically, the larger cell already covers a longer day. The user who ends the day at 40 percent has less reason to pay for speed. The Meilan 5s user who ends the day near 10 percent feels the difference more, because the 3100 mAh cell needs the top-up more often.

There is no scenario where quick charging damages a healthy cell in normal use. The charger and phone negotiate within the cell's rated window. The risk sits with uncertified chargers that ignore the handshake and push current the cell was not specified for. Buy the certified bundle or skip the upgrade; the middle ground is where problems live.

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  Short top-upsPremium pays back.
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  Overnight chargingPremium buys little.
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  Uncertified chargersReal risk, not the protocol.

If you are sourcing phones or chargers in volume, the 100 yuan is a line item you can audit. Ask for the charger's rated output and the protocol it implements. A charger rated at 5 V / 2 A cannot deliver a quick-charge result no matter what the box says. Match the protocol to the phone model rather than to the brand.

Check the cable too. Thin cables have higher resistance, and the voltage drop across them reduces the power that reaches the phone. A short, thicker cable keeps the negotiated voltage closer to the phone's input. This is a measurable effect, not a marketing claim.

For repair and refurbishment work, the same logic applies to replacement batteries. A cell with a lower discharge rating or higher internal resistance will not accept the same charge current. Fit a cell that matches the original specification, or the quick-charge path will throttle early and the user will blame the charger.

None of this is exotic. It is basic power budgeting: source, cable, connector, cell. Each stage has a limit, and the slowest stage sets the result. The 100 yuan premium improves one stage. It cannot lift the others.

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  Rated outputMatch the charger to the phone protocol.
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  Cable resistanceShort and thick beats long and thin.
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  Replacement cellsMatch original current rating.