[JohnnieB]

The "20L4" on the label is a UL listing rather than a model number.

How the charger is described in the cart manual is more or less irrelevant since the charger with the cart now isn't likely to be the one that came with it 30 years ago.

I suspect you have one of the two types of changers pictured below. Both came in a variety of case colors and label colors, so disregard the colors and look closely at the timer in the upper left.

If the first number clockwise from OFF is a "1", like pictured in the first attachment, you have a manual charger with timer. That type charger stays on for however long the timer is set for.

If the first number clockwise from OFF is a "11", like pictured in the second attachment, you have an automatic charger with a mechanical backup timer. That type charger shuts off when the battery pack's On-Charge voltage climbs into the 44V to 46V range, or when the 12hr timer ties out if the On-Charge voltage doesn't reach the predetermined shutoff voltage.

Which type do you have?