Acid Accumulator, Transparent

Quick Answer: The transparent acid accumulator is a lead-acid storage cell built in a clear case, so the lead plates and the sulphuric acid electrolyte can be seen while the cell is charged and discharged in electricity and electrochemistry lessons.

A Secondary Cell You Can See Into

An acid accumulator is a secondary cell: unlike a dry cell, it can be recharged by passing current through it in the reverse direction. In the lead-acid type, one set of plates carries lead dioxide and the other spongy lead, both standing in dilute sulphuric acid. During discharge both plates change towards lead sulphate and the acid becomes weaker; charging reverses the reaction. Each lead-acid cell has a nominal voltage of about 2 volts, which is why a car battery is built from several cells in series.

A clear case turns this into a teaching piece. Students can see the plates, the separators between them and the electrolyte level, and can connect what they see with what a voltmeter and a hydrometer show. Towards the end of a charge, gas bubbles rise from the plates, which links the cell to the electrolysis of water shown with the Hofmann electrolysis apparatus.

Commercial batteries hide all of this inside opaque boxes, so a transparent acid accumulator is mainly a demonstration and practical item for physics and chemistry classes rather than a power source for heavy loads. The number of cells, the plate arrangement and whether it is supplied filled or dry are details to settle when ordering.

Specifications

Practicals and Demonstrations

• Showing the difference between primary (dry) cells and secondary (rechargeable) cells.
• Charge and discharge practicals, recording terminal voltage against time.
• Measuring electrolyte density with a hydrometer at different states of charge.
• Observing gassing at the plates near the end of charging, and discussing why accumulators are charged in ventilated rooms.

Care & Handling

• Wear eye protection and gloves when checking or topping up; the electrolyte is corrosive, and a splash in the eyes needs immediate rinsing at an eye wash.
• Charge with a suitable DC supply at a modest current, in a ventilated place away from flames and sparks, because charging releases hydrogen and oxygen.
• Top up with distilled water when the level falls towards the top of the plates, not with more acid, unless acid has actually been spilled.
• Never short the terminals: a lead-acid cell can deliver a large current that heats connecting wires quickly.
• Store the cell charged, since a lead-acid cell left flat for long periods sulphates and loses capacity.

Why Choose LabEquip

Physics and chemistry teachers in secondary schools and colleges buy a transparent acid accumulator to make electrochemistry visible in a single lesson, often alongside electrolysis carbon rods for simple cell and electrolysis work. LabEquip lists it in General Lab Products, and teachers can discuss the cell arrangement they need through the contact page.

Frequently Asked Questions

What is the difference between an acid accumulator and a dry cell?

A dry cell is a primary cell: once its chemicals are used up it is discarded. An acid accumulator is a secondary cell, so passing current through it in reverse restores the plates and the acid, and it can be charged and discharged many times.

Why is the case transparent?

So that students can see inside while the cell works. The plates, separators and electrolyte level are visible, and gas bubbles can be watched near the end of charging, which makes the chemistry easier to connect with meter readings.

What voltage does a lead-acid cell give?

A single lead-acid cell has a nominal voltage of about 2 volts. The exact reading depends on the state of charge and on whether current is flowing, which makes the cell a useful subject for voltage measurements during charge and discharge.

Is the accumulator safe to use in a school lab?

Yes, with supervision and basic precautions. The electrolyte is corrosive, so eye protection and gloves are needed when handling it, and charging must be done in a ventilated area away from flames because hydrogen is released.

How is the accumulator charged?

Connect a DC supply positive to positive and negative to negative, set a modest current and charge until the cell voltage stops rising and gassing begins. Overcharging drives water out of the electrolyte and produces more gas, so charging should be supervised.

How can the state of charge be checked?

Measure the open-circuit voltage with a voltmeter, or the electrolyte density with a hydrometer. Both rise as the cell charges, so recording them at intervals during a practical shows the charge and discharge cycle clearly.

Last Updated: September 2026