Early HT Batteries

 Below is pictured a pair of high tension or HT batteries. They were fitted to a home brew radio and must be as rare as hens' teeth. As you can see they were made in the Hellesens Enke & V. Ludvigsen factory in Copenhagen, Denmark. Mr Hellesen was quite famous in his day because his factory produced the very first commercial léclanché cells. When were these two examples made, I wonder? Well the last date on the battery is for a medal awarded in Ghent in 1923 and later batteries included "Barcelona 1929" which means the battery was produced between 1923 and 1929.

 

 If you look carefully you'll see the words "SPECIAL FEATURE ... LONG LIFE". Well, I know that the set was last used around 1937 because in 1938 the Bowditch family bought a brand new Cossor mains radio. They must have been regular listeners because one battery was connected (lower right) and a second one (lower left) was stowed in the radio case as a spare. Alas it's now pretty flat as batteries go. The best it could produce was half a volt. That was from the one on the left between "-" and "3". Presumably because this, being the grid bias section, never supplied much current? The socket marked "12" may have been used once for the bias positive supply because its badly corroded. The cathode of any bi-metal junction, connected in a circuit, under the right conditions, for example damp atmosphere, will suck metal from the anode. The socket "47" on the right has also been connected in a circuit. Before WW2, generally, car batteries were connected with their positive terminal to the car's chassis. This was deliberately done to save the metal in the chassis from corroding due to electrolytic action. Unfortunately, for some obscure reason, the situation after WW2 was reversed and a car chassis connected to the battery negative terminal rusted in wet conditions. My guess is that part of the reason was that this resulted in more cars being sold.

 

 

 The two batteries are identical and if you study the socket labelling you'll maybe figure out that if the HT negative plug is fitted in say socket "7" then you can put the grid bias plug in the "-" socket, thus saving on a grid bias battery at a slight expense in HT voltage. Clearly the grid bias and HT plugs were red and the HT negative black.

 

 

 Now, here below, is another HT battery, an Exide Drydex H1006, not as old and probably dating to the 1940s. I haven't looked but inside there are probably around 80 cells similar to type U11.

Click the picture to see a high definition image.

 
 

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