Half the batteries we are asked to replace do not need replacing, and a fair share of the ones people nurse along should have been changed a month ago. Testing settles it in minutes and costs far less than guessing wrong in either direction.
A proper test is not a voltmeter across the terminals. Resting voltage tells you what the battery has at that moment, not what it can deliver under a several hundred amp cranking load, and it says nothing at all about whether the alternator is putting anything back. We measure state of health, cranking performance, charging output and, where it is warranted, what the car draws while it is locked and asleep.
What we measure and what each figure tells you
Each part of the test rules something in or out, which is why we do all of it rather than picking one number and forming an opinion.
- State of charge: how full the battery is right now
- State of health: how much of its original capacity is left
- Cranking voltage: how far it collapses while the starter turns
- Charging output at idle and at raised revs, with loads on and off
- Ripple, which exposes a failing diode pack inside the alternator
- Parasitic draw once the vehicle has gone to sleep, where a drain is suspected
The three faults this separates
A car that will not start is one symptom with three common causes, and they are treated completely differently. A weak battery replaces cheaply. A charging fault will flatten any battery you fit, new or otherwise. A parasitic drain leaves both looking innocent while quietly emptying the car overnight. Testing tells you which conversation you are having.
Worth testing before winter, and before a long trip
Cold weather cuts the current a battery can deliver at exactly the moment the engine needs more of it, so batteries that coped all summer fail in the first hard frost. A test in the autumn, or before a fleet goes into a busy season, turns an emergency into a planned job.
- Before the first cold snap, particularly on batteries past four years old
- After any vehicle has stood unused for several weeks
- When stop start has quietly stopped working
- After a jump start, to find out whether the battery is recoverable
- Across a van fleet, so replacements are planned rather than reactive
What the test results mean for you
Typical outcomes and the honest recommendation that follows each.
| Result | What it means | Recommendation |
|---|---|---|
| Good state of health, low state of charge | Battery is sound but was discharged by something | Charge properly and find what flattened it |
| Low state of health, charging normal | Battery capacity has gone | Replace, and we can fit on the spot |
| Battery fine, charging output low | Alternator, belt or wiring fault | Do not buy a battery. The charging fault comes first |
| Everything passes but it goes flat overnight | Parasitic drain while the car is asleep | Current draw test with the vehicle asleep to find the circuit |
Questions
Q.Can you test the battery without taking it out of the car?
Yes. Testing is done in situ at the terminals, which is also the only way to check charging output and cranking behaviour properly, because both need the battery in the vehicle.
Q.How long does a battery and charging test take?
The battery and charging checks take a matter of minutes. A parasitic drain test takes longer, because the vehicle has to be left to go to sleep before the reading means anything.
Q.My battery reads 12.6 volts, does that mean it is fine?
Not necessarily. That is a healthy resting voltage, but a battery with failed plates can show it and still collapse the moment the starter draws current. Only a load or conductance test shows capacity.
Q.Can you test a fleet of vans in one visit?
Yes, and it is a sensible way to do it. Testing a yard of vehicles in one visit lets you plan replacements rather than lose a van on a delivery morning.
Towns and districts we cover
Birmingham, the Black Country and the surrounding Midlands towns. Pick your area for local detail.
- Birmingham
- Coventry
- Wolverhampton
- Solihull
- Sutton Coldfield
- Dudley
- Walsall
- West Bromwich
- Oldbury
- Halesowen
- Stourbridge
- Smethwick
- Tipton
- Wednesbury
- Bilston
- Kingswinford
- Rowley Regis
- Cradley Heath
- Brierley Hill
- Sedgley
- Willenhall
- Aldridge
- Brownhills
- Cannock
- Rugeley
- Nuneaton
- Bedworth
- Rugby
- Redditch
- Bromsgrove
- Edgbaston
- Moseley
- Kings Heath
- Harborne
- Selly Oak
Find out before you spend anything
A test on your driveway tells you whether it is the battery, the charging system or something draining it, and we can fit a replacement the same visit if it needs one.
Testing carried out on your driveway or in the works car park, 24 hours.