Bosch Classic Battery, © Robert Bosch GmbH, should have fit my Ponton perfectly. But it doesn't. Not their fault though...
Battery brackets and fixing frame
I thought this would be pretty straight forward. Clean the battery frame and fix new battery floor brackets as replacements for the old, rusty one. Of course it wasn't…
While fixing frame and brackets, I double checked the measurements to find out what battery would fit. A nice-looking Bosch old style battery was the goal. To my surprise it wouldn't fit. My data card shows that the car came with a normal Varta battery. The measurements of it I haven't been able to verify. With the help of Bosch Automotive Tradition (who spent a lot, lot of time on this matter together with me! Thanks a lot!!) I got hold of their old data sheets for the 219 (specifically for model year 56 – 59). According to that their standard battery was named BA/12/56/2 (also known as 0 180 055 611) and has the following dimensions:
- Length: 311 mm (incl 5mm spare between rim and battery housing to the left and the right)
- Width (=depth): 182 mm (according to Bosch no spare between rim and housing)
- Height: 220 mm
With my depth measure this would be a problem. From the front end of the bracket to the dividing wall (the wall between the engine bay and the coupe) I have 174mm and from that you have to remove another +2mm for cardboard of the sound dampening. Note photo above of the sound dampening board where there actually is no sound dampening material right behind the battery (see also article "Instrument panel" and the section "Sound dampening"). I miss at least 10mm for being able to buy the "correct" Bosch battery!
My father has done nothing in this area. Me however, have had some of the lower parts of the dividing wall replaced. Moisture (and/or battery acid?) in the sound dampening had caused severe rust. One could of course suspect that when the welder redid these parts, something went wrong. On the other hand, my old bracket fits perfectly, the wall is completely straight and everything else fits and seems to be ok. You can see the last picture in the first group above that the wall is perfectly straight along the steel ruler. Remember, only parts of it was replaced so I can check that. From a Mercedes-Benz 220S -59 owner I got measurements that perfectly fits this Bosch battery. His battery shelf was not only deeper but also looked slightly different around the right bracket.
Very tight fit on the battery floor, behind the dividing wall (not yet with its sound insulation)
What I know is that my car, an early (February) 1957, seems to differ in a number of detail designs, compared to other, especially later, cars. As usual, neither Mercedes-Benz in Sweden nor MB Classic Centre in Germany have been able to help me out. According to them there is only one design of the battery shelf for the Pontons...
Well, I bought an old style battery from Oldtimer Batterie Service from Germany that fits. But it is a bit annoying and strange. I ordered their 12V 60AH battery with the dimensions L250 x B165 x H225 and the plus pole to the right. My plus pole actually sits to the left when mounted in the car but you define left/right, at least at Oldtimer Batterien, by having the poles facing rearwards.
I had new brackets made. The right one I "designed" so that it would allow for (minor) adjustment to different battery lengths. Unfortunately, the finish of the job was not the best but I take another short cut here since it only concerns the screw holes (!) and they won't be visible.
And then we have the before and after pictures of the battery fixing frame.