Balmar Alternator 621-100-SV Single Foot 100 Amp 12 Volt

Balmar 621-100-SV Alternator

Alternator 621-100-SV - 621 Series 100A, 12V, Spindle Mount (Single Foot), 1-2in, Single Deep Vee Pulley, Isolated Ground

The Balmar 621-100-SV is a 100-amp, 12-volt small-case marine alternator from Balmar's 6-Series line. It has a single-foot (spindle) mount for 1-inch or 2-inch engine brackets, a single deep-vee pulley and an isolated ground. It suits boat owners upgrading a stock alternator for faster battery charging, either on its own internal regulator or with a Balmar external regulator.

1″ Motorola-Style Mounting; Typical for Westerbeke, Lehman, Hino & Pathfinder Engines

2″ Delco-Style Mounting; Typical for Volvo Penta (Gas & Diesel), John Deere, Perkins, Mercruiser, Pleasurecraft, Crusader, Indmar, Marine Power & other GM-based Engines

Specifications (Balmar 6-Series product data sheet)

• Output: 100 A at 12 V; power take-off 4.0 HP
• Style: small case, positive field excitation (P-type)
• Regulation: internal Smart Ready fixed-voltage regulator (14.1 V for 12 V systems), or external P-type regulator (ARS-5 or MC-614)
• Cooling: dual internal fans
• Grounding: dedicated terminal (case isolated)
• Positive output: M8 x 1.25 threaded stud
• Low-RPM cut-in: 1,320 rpm
• Case diameter: 5.35 in (136 mm); overall length with SV pulley 6.63 in (168 mm)
• Mounting foot bore: 1/2 in (1-inch foot), 3/8 in (2-inch foot)
• Ignition protection: USCG Title 33, ISO J1187, CE, SAE 8846
• Altmount pulley kit: not required (single vee)

Balmar 6-Series product data sheet (PDF)

Questions & Answers

Will it fit my Volvo Penta or Westerbeke engine?

Balmar lists the 2-inch Delco-style foot as typical for Volvo Penta, John Deere, Perkins and GM-based engines, and the 1-inch Motorola-style foot as typical for Westerbeke, Lehman, Hino and Pathfinder. The 621 Series covers both foot widths; measure your bracket to confirm.

Do I need an external regulator?

Not always. Balmar says the internal Smart Ready regulator may be enough for small battery loads with frequent engine running. For larger deep-cycle banks or less frequent running (most sailboats), Balmar recommends its ARS-5 or MC-614 Max Charge regulator. The 621-VUP-MC-100-SV kit pairs this alternator with an MC-614.

Do I need a new pulley or belt kit?

Balmar's 6-Series table lists no Altmount pulley kit as required for the 100 A, 1-2 in spindle model.