Understanding the 1.5V, Lithium Battery

I’ve known some people who had the preconceived idea, that in general, batteries would generate – or produce – a voltage of 1.5V, and whose main distinction was either between battery formats, or brand-names. This idea would imply that those people had no exposure to The series of electrode potentials which all elements and most compounds have, relative to hydrogen. Different electrode potentials lead to different battery potentials, as long as the latter are taken separately, for the positive and the negative electrode.

But additionally, Engineers had an early goal, of supplying 1.5V batteries, which could act as direct drop-in replacements, for Carbon-Zinc batteries, where the carbon or manganese-oxide powder actually act as a hydrogen electrode, but which would provide much higher amounts of charge, before becoming passive. And so somewhere along the way, they also designed 1.5V lithium-based batteries, that could not be recharged. Considering that lithium itself has an electrode potential of about -3V, the only way in which this could be realized, was in a composition being chosen for the positive electrode, which offset some of those 3V, against the efficient generation of electricity.

In other words, these batteries wasted some of the energy which lithium offers as a fuel, just to arrive at less than 3V battery voltage. And closer examination of that subject should reveal, that some choice of metal was likely, as a positive electrode. But this is easily doable, as many metals will absorb the element lithium, yet have some electrode potential of their own, near -1.5V . Either Zinc or Manganese in their metallic form should work.

Dirk

 

Distinguishing between Different Battery-Types

One of the things I recently did, was to pair my Linux-laptop, which I name ‘Klystron’, with an external Bluetooth-Mouse, because even though this advanced, HP laptop has as its hardware, an advanced Synaptics touchpad, that emulates a mouse quite well, we can grow tired of always using the built-in touchpad. I documented here, what I needed to do, to accomplish this pairing.

Well one of the features which the KDE Desktop Manager gives us under Linux, is to indicate the battery-charge-levels, not only of the laptop’s built-in battery, but also those of attached BT-mice, or of anything else which is connected, that has a battery, and the hardware of which is able to report as telemetry, the battery-level.

What was surprising me about this arrangement, was that the indicated battery-level of the mouse seemed to track accurately over the days, that the mouse was connected. This surprised me, because as I was remembering events, I had placed Nickel-Metal-Hydride batteries into the mouse some time ago, and most devices which are physically designed to accept batteries in the AA-format, or in the AAA-battery-format, would be calibrated for Alkaline, Zinc-Manganese-Oxide batteries. When such accessories try to gauge the battery-level, if they have the chip to do so, the voltage-curve of a Ni-MH battery tends to remain lower than that of an Alkaline. A fully-charged Ni-MH only generates about 1.2V per cell, while an Alkaline generates 1.5V. And so when a Ni-MH battery is inserted, this chip will usually indicate a partially-discharged battery, even immediately after it has been charged, and then, when this battery-type finally goes dead, its voltage will collapse almost instantly.

Before the indicated charge-level dropped below ‘70%’, I decided to take the AA-format batteries out, and to put them into a charger I have, that’s designed for Ni-MH batteries, and what I found was, that the LEDs in the charger refused to light up, for the inserted batteries. They did not indicate partially-charged or anything, they just stayed ‘off’.

And so next, my thinking was, ‘Darned! I now have either batteries which have failed on me, or worse – a charger which has failed on me 100%…’

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