It's also worth putting a voltmeter on the battery to make sure you're not overcharging which will cause the battery to boil.
I've always mixed my baking soda in water and poured it over the battery to clean off any acid. Is that a bad idea? Is it better to sprinkle dry soda on it?

Ooops, looks like Barry and I were breathing the same ether at the same time at different ends of the continent.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13