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1.1.2 Alternator

Premier Power Welder HO-C28 Alternator

Type: High-Output Welding Alternator

Model: Premier Power Welder HO-C28

Manufacturer: Premier Power Welder

Product Page: Cummins R2.8 270A Alternator

Rating: 270 amps

Application: Cummins R2.8 Turbo Diesel

Price: $899.95

Specifications

  • Output: 270A continuous
  • Voltage: 12V (standard automotive)
  • Application: Cummins R2.8 engines
  • Type: High-output welding alternator
  • SKU: HO-C28

System Configuration

Primary Function: Charges START battery and powers vehicle electrical systems

Output Capacity: 270A continuous (exceeds system maximum draw of ~326A with margin)

Mounting: Direct bolt-on replacement for Cummins R2.8

Wiring

Connection Destination Notes
Positive Output START battery+ (driver rear wheel well) See START Battery Distribution for wire specs
Ground Engine block Bonded via alternator mounting bolts

Ground Path: Alternator case → Engine block → Engine bay ground bus → START battery- (driver rear wheel well)

See START Battery Distribution for complete wire specifications (gauge, distance, voltage drop calculations).

Load Analysis

Alternator Capacity: 270A continuous

Worst Realistic Load: 201A (offroad scenario) = 69A margin (26% headroom)

The alternator supplies START battery loads plus BCDC charging. AUX battery loads (SwitchPros, ARB compressor, winch) do NOT draw from alternator.

See START Battery Load Analysis for complete scenario details.

Outstanding Items

High (3)

  • JL Audio amp feed: 100A CB exceeds 4 AWG ampacity (95A @ 20°C) (#149) — The amp's battery feed is 4 AWG (95A continuous @ 20°C per the project reference table) protected by a 100A CB. The amp's internal 80A fuse is downstream and does not protect the battery-to-amp run against a chafe/short. This violates the project's "CB protects the wire" rule and is NOT covered by STANDARDS-EXCEPTIONS (which only sanctions the SwitchPros/SafetyHub 150A-on-2-AWG case).
  • START+ auxiliary distribution busbar + breakers for relocated fan / iBooster / TCU (#135) — Relocating the radiator fan, iBooster, and TCU from the PMU to START-battery-direct adds three breaker-protected feeds. All three loads are forward (engine bay / transmission) while the START battery is rear, so the chosen architecture mirrors the AUX forward-feed pattern: a single master-protected feed forward to an engine-bay busbar rather than three long runs or ~9 stacked lugs on the battery post.
  • Dakota Digital Panel Mounting (#39) — HDPE sheet dimensions and location for the Dakota Digital panel.

📋 Medium (10)

📝 Low (1)

🔍 Verify (2)

Build Tasks

  • Determine alternator positive output terminal size (for 1/0 AWG lug selection) — see Vendor Inquiry below
  • Verify alternator voltage regulator set point (14.2–14.4V is the correct AGM target;1 confirm the HO-C28 actually regulates there) — see Vendor Inquiry below

Vendor Inquiry — Premier Power Welder (draft)

Both open items above are answered by one email to Premier Power Welder:

Subject: HO-C28 (Cummins R2.8 270A) — output stud size & regulator set point

Hi Premier Power Welder,

I'm wiring the HO-C28 270A alternator (Cummins R2.8) into a dual-battery
truck and need two specs to finish the install:

1. Output terminal: what is the thread/stud size of the positive output
   post? I'm sizing a ring lug for 1/0 AWG cable and want the correct
   stud diameter (e.g. 1/4"-20, 5/16"-18, M8, etc.).

2. Voltage regulation: what is the regulator set point, and is it
   suitable for AGM batteries (target ~14.2-14.4V at the battery)? Is the
   regulator internal and fixed, or adjustable? My START battery is AGM.

Application: HO-C28 on a Cummins R2.8 Repower, charging an AGM start
battery (~850 CCA).

Thanks,
[name]

  1. AGM batteries take an absorption/charge voltage of ~14.2–14.7V at the terminals (mfr range 14.0–14.7V), so the 14.2–14.4V target is correct; many stock regulators sit lower (13.8–14.0V) and undercharge AGM. The target is validated — what remains is confirming the HO-C28's actual set point (vendor or field measurement). General AGM charging references (Victron / battery-mfr guidance), accessed 2026-06-03. ↩