E-Bike Fast-Charge Case (48/52V) — GamerzCrave

EBIKE 48/52V CC/CV

E-Bike Fast-Charge Case (48/52V)

Trailhead top-ups without drama: a portable CC/CV charger case with DC meter, anti-spark/contactor safety, and swappable output leads.

Safety First

Match charger to battery chemistry & series count. Common full-charge voltages:
13S Li-ion “48V” → 54.6V 14S Li-ion “52V” → 58.8V 16S LiFePO₄ “48V” → 58.4V Use the exact value from your battery maker/manual.
Only charge packs with a BMS. Don’t bypass protection. Keep charging supervised and in a ventilated area.
No cold charging. Don’t charge Li-ion below 0 °C (32 °F). Warm to room temp first.
Connector discipline. Use anti-spark or precharge to avoid inrush arcs. Verify polarity before plugging into any e-bike.

What You’re Building

Output: 48–59 V DC Current: 2–8 A (adjustable) Mode: Constant-Current / Constant-Voltage Meter: V/A/W/Wh Safety: XT90-S anti-spark + contactor & precharge Swappable leads: XLR / XT60 / SB50 / RoPD

Two proven cores: (A) a certified multi-profile charger (e.g., Satiator-class) for AC-in convenience, or (B) an adjustable CC/CV charger module (AC-DC or DC-DC boost) with hard stops for voltage & current.

Parts (Core)

Charger core, pick one
- AC-in universal charger, 12–63V / up to 8A (multi-profile, certified), or
- AC-DC or DC-DC adjustable CC/CV module rated ≥400 W (heatsinked)
Safety & switching
- XT90-S anti-spark inline connector (battery/charger side)
- DC contactor (≥60 VDC, ≥20–40 A) + precharge resistor (e.g., 100–220 Ω, 5–10 W) & momentary precharge switch
- DC fuse (ANL/ATO) on input & output as appropriate
Metering
- Inline DC meter with shunt (0–60 V, ≥20–50 A), Wh/Ah accumulation
Outputs
- Lead set #1: 3-pin XLR (check polarity!), or OEM connector
- Lead set #2: XT60/XT90, Anderson SB50, or Rosenberger RoPD if used by your bike
Case & cooling
- Compact hard case, panel mount DC jack / gland
- 80–120 mm 12 V fans + grills, 24→12 V buck for fans if needed

Specs & Profiles

Pack	Cells	Full Volts	Typical Fast A
“48V” Li-ion	13S	54.6V	3–8A (≤0.5–0.8C)
“52V” Li-ion	14S	58.8V	3–8A (≤0.5–0.8C)
“48V” LiFePO₄	16S	58.4V	3–8A (≤0.5C typical)

Set CC (amps) to what your battery/BMS allows. Lower amps = cooler cells and better longevity.

Wiring Snapshot

[ AC In or 12–24V DC In ] --> [ CC/CV Charger Core ] --> [ Contactor ] --> [ Output Leads ]
                                       |                         |
                               [ DC Meter + Shunt ]        [ Precharge Switch ]
                                       |
                                 [ XT90-S inline ]
                                       |
                                   [ DC Fuse ]
Outputs (one at a time):
  - XLR-3 (verify pinout!), or
  - XT60/XT90 pigtail, or
  - Anderson SB50, or
  - Rosenberger RoPD (if your bike uses it)

Always verify the bike’s charge port polarity and voltage before first connection. XLR pinouts vary by brand. Use a DMM.

Step-by-Step Build

Layout & airflow — Dry-fit charger module, meter, fuse, XT90-S, contactor, and precharge switch. Keep airflow front-to-back. Drill for fans, output gland, and panel mounts.
Input side — For AC-in, add an IEC or power inlet to the case with strain relief. For DC-in (from vehicle or power station), add an XT90-S or SB50 input and a suitable input fuse.
Precharge & contactor — Wire a small resistor across the contactor and a momentary button. Sequence: Precharge → then close contactor. This avoids inrush arcs into big capacitors.
Meter — Place the shunt on the charger output so Wh/Ah count what you deliver to the pack. Bring the display to the panel.
Output harness — Terminate to a universal jack inside (XT90 or SB50), then make adapter leads: XLR-3, XT60, OEM magnetic, etc. Label each lead with Voltage and Polarity.
Cooling & buck — Power the 12 V fans from a small buck (if your core is 48–60 V). Fit grills and dust mesh.
Settings & test — With no battery connected, set the charger Voltage (CV) to your pack’s full volts and Current (CC) to a safe value. Verify with a multimeter at the output.
First connection — Connect output lead to the bike’s charge port; press and hold Precharge 1–2 s; close the contactor; begin charge. Confirm CC then CV behavior and taper.

Charger Settings (Profiles)

13S Li-ion (48V): CV 54.6V, CC per spec (e.g., 3–5 A travel, 7–8 A fast).
14S Li-ion (52V): CV 58.8V, same CC logic.
16S LiFePO₄ (48V): CV 58.4V; many makers prefer lower float or no float.

Certified multi-profile chargers include presets for these packs; pick or create the right profile and lock it.

Charge-Time Estimator

Quick math for a top-up. Assumes CV taper adds ~10–20% time.

Battery Capacity (Ah) Start SOC (%) Target SOC (%) Charge Current (A) Overhead (taper) %

—

Tip: For longevity, stay ≤0.5–0.8C and avoid holding packs at 100% when hot.

Connectors & Polarity

XLR-3: common on e-bikes, but pinouts vary; many use Pin 1=+, Pin 2=−. Always meter first.
XT90-S: anti-spark; great inline to reduce arcing on connect.
Anderson SB50: rugged, keyed colors, up to ~100 A class (with proper contacts & wire).
Rosenberger RoPD: magnetic, up to 60 V / 40 A on LEVs; use OEM cables when possible.

Troubleshooting

Sparks on plug-in: Use XT90-S or precharge; verify contactor sequence.
Charger won’t start: Wrong profile/voltage, reversed polarity, BMS lockout, or contactor open.
Stops early: Hitting CC current limit due to low temps/high resistance; warm the pack; check leads.
Runs hot: Lower amps; improve airflow; don’t charge in a hot car.

Do Not

Charge below 0 °C (32 °F). Lithium plating risk.
Exceed the pack’s specified max voltage or charge current.
Guess polarity. Measure every adapter lead you make.
Leave charging unattended or near combustibles.

Sources & References

CC/CV charging basics & Li-ion voltages: Battery University — How Chargers Work (CCCV), Charging Li-ion.
Preset charge profiles & 48/52V full volts: Grin Cycle Satiator Manual — table shows 48V Li-ion 54.5 V, 52V Li-ion 58.8 V, 48V LiFePO₄ 57.6 V; multi-profile setup and safety notes. PDF.
Temperature limits: Battery University — Charging at High/Low Temps.
Anti-spark/precharge: Sensata Whitepaper — How to Design Precharge Circuits; XT90-S anti-spark datasheet — RS PRO XT90-S.
Connectors: Anderson SB50 — product page; Rosenberger RoPD (LEV) — overview.
XLR pinouts warning: Common convention Pin 1=+, Pin 2=− exists, but verify; examples: connector info.

Always follow your battery’s specsheet and BMS limits over any generic guide.