Today of course [and thank God] we take electricity for granted: it is always there - well nearly always. In the early days of radio, the mains supply [DC] was readily available and all kinds of machines throughout the ship turned the DC into AC or generated AC from batteries running alternators and rotaries. The power requirements of the earliest of W/T receivers was minimal for the receivers had relatively few components and things like coherers drew minute amount of amps from whatever the supply source was.  On the other hand, the more the W/T transmission side evolved with ever ambitious plans to go one step further,  the more power was required.  Transmitters were always inefficient machines and a naval transmitters could take thousands of Watts from the switchboard just to put say, 1kW on the aerial. It was ever thus, and at the end of our story, ICS2, its associated wideband amplifier the WBC was still "behaving badly" or inefficiently!

When the break-through of the thermionic valve came, when every "modern" receiver boasted the device within its circuitry, things changed on the power front. Having a modern receiver meant having the ability to supply power to these valves, at the right places and with the requisite power stated by the manufacturers, and this was not possible at that time from mains, DC or AC.  Instead it had to be supplied by batteries and this in itself became a major logistics exercise to supply the Fleet with enough of them, and an onerous task for the W/T operators to keep them all charged ready for use.

Just putting aside the story for a moment, I couldn't help smiling when, whilst researching, I came across the way the electrolyte should be mixed before offering it up to a battery. The sulphuric acid was lightly glossed over and the kind of water to use got the headlines. If at all possible the mix of roughly four parts water to one part acid should be distilled water - that we know and still use to this very day.  However, if distilled water was not available tap water was to be considered the last choice.  The preferred alternative to distilled water was filtered melted artificial ice and after it, filtered rain water. We all know that sailors of yore drank copious amounts of beer, wine and rum, mainly because it was nice and did nice things to them, but because the water was rotten and could cause ill health if not death if they drank it to quench their thirst.  It made me wonder whether the drinking/washing water had improved over that 100 years which brought us to the early 20th century,  because if it was too impure for a battery what would it do to ones body?

The valves and their constituent parts, the anode, filaments etc, each had different power supply requirement and therefore each had to have its own battery. Other types [sizes and power rating] were also required for other W/T uses [not necessarily for receivers] and as previously mentioned, to supply the DC for the generator making AC.  Remember people like the "fresh water tanky", well the W/T department had a "battery tanky" and his job kept him busy at all times, day and night?

Batteries were used for these purposes for a long time until, just post WW2, all voltages were taken from the incoming power AC and either transformed down to required AC voltages or rectified and used as DC voltages.

As an example only here is a file showing you some of the battery requirements of those days batteries for receiver valves c 1924.pdf.  Note the cost column !