A resting voltage flatters a cell; a load test does not
A multimeter reads a battery's open-circuit voltage, which a nearly flat alkaline cell can still pass. A battery tester applies a small load while it reads, and that is the difference: it reports what the cell does under demand rather than at rest. The practical specification is which sizes and chemistries fit the cradle — button cells and 9 V blocks are where cheap testers stop. We compare cell sizes and chemistries accepted, whether a load is applied, analog needle or digital display, and whether the tester needs its own battery.
AA / AAA / C / D / 9 V / button cells · alkaline, NiMH, lithium, zinc-carbon
A tester covering every household cell size and four chemistries, showing the measured voltage and state of charge on an LCD, from a battery maker.
Best for: The drawer full of cells nobody can identify as good or flat.
AA / AAA / C / D / 9 V / CR123A / CR2 / button cells · three-state LCD
A tester covering the widest cell list here — including CR123A and CR2 photographic lithium cells — reporting GOOD, WEAK or LOW on an LCD.
Best for: Anyone with camera, torch or sensor lithium cells that no other tester in this hub accepts.
AAA / AA / C / D · button cells · 1.2, 1.5, 3.0 and 9 V · voltage in volts
A tester covering almost every household cell at 1.2, 1.5, 3.0 and 9 V, displaying the remaining voltage in volts alongside a color-scaled charge state.
Best for: Sorting a mixed drawer, where the numeric voltage is the useful output.
AAA / AA / C / D / 9 V blocks · LCD charge state · no setup
A universal tester for primary and rechargeable cells with an LCD charge indication and no configuration — insert the cell and read.
Best for: A household tester where the only question is whether to bin the cell.
6 V and 12 V lead-acid · 100–2000 CCA · battery, starter and charging tests
A different instrument from the rest of this hub: a vehicle battery tester using conductance measurement to check a 6 V or 12 V lead-acid battery, its starter draw and its charging system.
Best for: Diagnosing a car that will not start, where the question is the battery, the starter or the alternator.
≈ $68
A tester that only accepts one size leaves half the batteries unverifiable. Versatility is what makes the instrument useful.
A simple tester separates spent batteries from those still good, which stops usable ones being thrown away.
A spent cell still shows a decent voltage as long as nothing is asked of it. A stated load test is the only measurement that separates a good cell from a dead one.
It measures the open-circuit voltage, which stays correct on an exhausted battery. A tester applies a load, which is the only meaningful test.
Its internal resistance has risen: it holds up with nothing connected and collapses as soon as an appliance draws current. Exactly what the load test reveals.
Yes, allowing for their lower nominal voltage. A tester that does not make the distinction declares them spent wrongly.
In a dedicated slot that makes contact on both faces. With probe tips the contact is unstable and the reading erratic.
The test applies a brief load and consumes a negligible amount. Repeated dozens of times, the effect stays marginal.
A battery stored a long time discharges on its own. Testing before fitting it avoids a false diagnosis on the appliance.
In the collection points provided, never with household waste. An obligation, not a recommendation.
A rechargeable cell shows a lower nominal voltage than a primary cell of the same size, and a scale made for primaries wrongly calls it dead. Instruments that tell the two apart say so.
An exhausted battery shows a correct open-circuit voltage: only a test under load is meaningful, which a multimeter does not do. Test button cells in a dedicated slot, and a battery stored a long time discharges on its own — test before blaming the appliance.
A column is raised only if four instruments in five publish the value. Below that, it would be measuring the silence of the manuals.
| Model | Price | Power |
|---|---|---|
| TOPDON BT100 | $68 | — |
| kraftmax SB-122 | — | AAA / AA / C / D / 9 V blocks · LCD charge state |
| VARTA 893101111 | — | AA / AAA / C / D / 9 V / button cells · alkaline, NiMH, lithium, zinc-carbon |
| DLYFULL B2 | — | AA / AAA / C / D / 9 V / CR123A / CR2 / button cells |
| TFA Dostmann 98.1126 | — | AAA / AA / C / D · button cells |
Specifications: manufacturer sheets for measuring instruments and the matching Amazon product pages. Prices and availability: Keepa. Every figure in this table names its source.
Most recent revision in this category: August 31, 2026.
Prices quoted in these summaries are dated readings. The live price is shown next to each product.
