Douglas P. Broome / firstname.lastname@example.org
The question occasionally arises as to what modern batteries are the best equivalents to the batteries originally supplied with the Mercedes-Benz Pontons. I have concluded from the Service Manual Model 190 and the Service Manual Models 180 to 220SE supplement that the original batteries for all 12-volt gasoline Pontons  were of the same capacity at 56 amp hours (AH).  The Service Manual Models 180 to 220SE suppliment also indicates for the 12-volt 180 and 190 diesel Pontons a battery capacity of 80 AH.
Neither manual provides battery dimensions. It is therefore unclear as to any differences in original battery length, width, and height among the Pontons.
Glenn's Mercedes-Benz Repair and Tune-up Guide (Harold T. Glenn) is the only publication I found that lists (p. 90) what is today called “group” sizes. His information source was not stated. Glenn lists the following AABM  designation for all Ponton gasoline batteries except the 190SL: 28SM.  For the diesel Pontons, Glenn lists 30HR.
These designations are obsolete and not found in any current chart available at battery vendors, so I contacted the Battery Council International (BCI). They had a Battery Replacement Data Book dated 1964. It states that the dimension and capacity of the 28SM battery were:
length: 12-15/64 in.
width: 7-11/16 in.
height: 8-21/32 in. (including posts)
capacity: 56 AH
For the diesel 30HR the following information applied:
length: 13-1/2 in.
width: 6-13/16 in.
height: 9-1/4 in. (including posts)
capacity: 80 AH
Capacity of modern batteries is not an issue for Ponton owners, so any battery that fits and has correct polarity should work.  What, however, is the modern battery closest to the above dimensions? Whenever one finds listings for Pontons at battery vendors, frequently they indicate Group 24F as being the best modern group size. Occasionally charts specify Group 27F. Still other charts indicate Group 24F for the four-cylinder gasoline Pontons and 27F for the six-cylinder cars. The listings for 180 and 190 diesel Pontons, when found, are similarly varied. There is lack of consistency.
I conclude that for the original 28SM battery the closest size is modern Group 27F. That group has the following standard dimensions:
length: 12-1/16 in.
width: 6-13/16 in.
height: 8-7/8 in. (including posts)
Group 24F has the same width and height, but it is 10-1/4 in. long.
When this article was originally published (November 2001), the correct Mercedes-Benz part number for batteries for Ponton gasoline and diesel vehicles was: 000-541-33-01. Mercedes does not use aftermarket Group designations like 27F. These dimensions are according to my own measurement:
length: 10 in.
width: 6-1/2 in.
height: 8-1/2 in. (including posts)
Note: as of September 2016, the correct Mercedes-Benz part number was 002-541-87-01-26 or A002541870126. The battery had a modern looking white case, black top, with the M-B part label affixed. Measurements were not readily available. Source: Mercedes-Benz Classic Center / Irvine, California. Ed.
For the diesel Pontons modern Group 49 should fit. Its standard dimensions are:
Length: 13-1/2 in.
Width: 6-13/16 in.
Height: 8-21/32 in. (including posts)
A problem is that the original fastening bracket, fitting the top perimeter, will not accommodate the recessed posts on Group 49. It blocks the cables. Another means would have to be found to stabilize the battery in its space.  I have found no modern battery longer than Group 27F that will fill the diesel Ponton battery space and have the correct polarity. Group 30H, without recessed poles but generally hard to find, would have the correct width and length dimensions but have posts to a height of about 9-1/2 inches. Also, the posts would be towards the rear, not the front.
The foregoing is accurate to the best of my knowledge and is provided as a courtesy. No guarantees are offered. Readers should verify its accuracy before relying upon it.
 It is possible that the battery for the 190SL had reversed terminals and may need longer cables, but I have not investigated this.
 Actually, the two service manuals give slightly confusing information. At p. 00—2/39 the Service Manual Model 190 specifies 55 AH rating, while the 190 owner's manual indicates 56 AH. The Service Manual Models 180 to 220SE suppliment indicates 56 AH for all cars except the 180c, which shows 52 AH. (see pp. 00—1/2 and 00—1/8.) I have concluded that these minor discrepancies are simple printing errors.
 American Association of Battery Manufacturers. The successor organization is today called Battery Council International.
 One probable error here: Glenn includes the 180 vehicle, but that was a 6-volt system. He should have started his battery presentation with the 180a.
 Some owners use Group 35 and are quite satisfied. It is smaller in size.
 I believe all sedans have the vertical shield in front of the firewall behind which the battery sits. Whether that provides sufficient stability needs to be examined. Some coupés and cabriolets lack this shield, but others have it. Which coupés and cabriolets were and were not fitted with the shield originally is unknown to me.
Created: November 13, 2001 / Jeff Miller
Last Update: September 03, 2016