Technical: Battery and Fittings
Roger Meinke, Jerry Raino, Jack Raino, Paul Rako, Dave Hennessey

6 Volt Era - 1952 through 1964

The 6-volt H-3 battery was used on all the K models and Sportsters through 1964. It was also used on the littlest Harleys, the Model 125 (1948-1952) and Model 165 (1953-1959). Production of these batteries probably stopped in the late-1970s, since the last bike to use them was the 1964 Sportster. The aftermarket company WISCO also produced a H-3 lookalike, but they too probably stopped production around the same time. Unfortunately, it is highly unlikely you will find one today in usable condition, but we'll show you what they looked like.

On the bottom of the 1948 to 1965 batteries is a small recess with a code, like IR 57 or MR 57. We believe the “57” indicates the year of production, but more research is needed.

The years shown are the approximate years of production

Compare the accessory catalog illustration (left) with the parts book illustration (right). The parts book illustration shows an extra line of text and a different right side than the accessory catalog. Most examples found look like the accessory book battery, but we have recently uncovered several examples that look like the parts book battery. More research is needed.

KH Engine - Trap Door and Tall Cylinders

In 1955 (or more probably, late-1954), a “trap door” was added to allow easy removal of the transmission for service. This was a wonderful idea, and was continued on Sportsters through 2003. The left engine case was modified for the trap door, and this shows up externally as a ridge and recess where the primary case meets the main body of the engine case. Click on the photos below to see details. A side-effect was that the ridge interfered with the battery carrier where the left tie-rod hooked on. The battery carrier was modified with a built-in “vertical leg” that provided the necessary clearance.

The battery in the 1952-1953 K models sat fairly close to the rear cylinder. The taller cylinders of the KH exacerbated this problem. The solution was to modify the battery carrier so that the battery would sit a little farther rearwards, away from the cylinder. However, the position of the tie-rod mounts did not change, necessitating an undocumented change in the battery cover.

Battery Carriers

There were four different 66224 battery carriers, including the poorly documented -52A.

The -52 and -52A carriers had the battery in the forward position, and the -52B and -52C shifted the battery rearwards. Thus, it appears that in the illustration in the 1956, 1957, and 1959 Parts Catalogs, the carrier is labelled -52B, but the drawing is really a -52A.

Battery Covers
The -52 and 52-A battery carriers use the early battery cover with round holes.  The -52B and -52C carriers used the later battery cover with slots. The slots allow the battery to move about 3/8"  The flanges on the 52-B and -52C battery carriers moved the battery location rearward, but the tie-rods stayed in the same location. The slotted cover was needed to allow the battery to shift rearward.
6 + 6 = 12 Volt Era - 1965 and 1966

The 1964 Servi-Car (not the 1965 Electra-Glide) ushered in a new era of (gasp!) electric starting. The size and weight of a 6-volt battery and cables to power a starter was prohibitive, and since most automobiles had gone to 12-volt systems a decade before, it made sense to finally take the 12-volt plunge. A huge, heavy battery was fitted to the Big Twin, but for the kick-start Sportster, a strange compromise was used. The Aermacchi-Harley Sprint-series used a small 6-volt battery that was longer, but thinner than the old H-3. Harley simply fabricated the 66235-65 battery carrier to hold two of 66001-61A batteries, and wired them in series. This strange setup was used only on the 1965 and 1966 XLH. Both XLH and XLCH switched to 12-volt generators, regulators, and light bulbs.

12 Volt Era - 1967 through 1969

Electric starting proved popular, and the 1967 XLH began another new era, along with a behemoth battery, the 66006-65A. This required a completely new mounting system. The XLCH remained kickstart-only, with a magneto and no battery, through 1969.

Another era began in 1970, when the XLCH gained a battery and circuit breaker. We'll leave that era for someone else to document.