Service · Charging system
Mobile Alternator Testing & Diagnosis
Battery keeps going flat? It might be the alternator. Mobile charging-system diagnosis across the West Midlands.
A car that keeps eating batteries usually doesn't need another battery — it needs the alternator checked. We test alternator output voltage, ripple current and field voltage on the driveway.
If the alternator is faulty we'll tell you plainly and recommend a workshop for the replacement (that's not a driveway job). But if the alternator is fine we'll find the actual culprit — parasitic draw, wiring, ECU output — and save you buying yet another battery.
Who calls us for this
Owners on their third battery in as many years, garage customers with a repeating 'battery light on' complaint, and cautious used-car buyers.
What we actually see on these jobs
- Failing diodes are a common cause of overnight drain — a battery test alone won't spot it.
- Alternator field voltage tells us if the regulator is at fault (occasionally fixable) vs the whole unit.
- We refer to trusted local garages if you don't have your own — no kickback, just recommendations.
Key facts — Mobile alternator testing
- Tests performed
- Charging voltage under load, ripple current (diode health), field voltage
- Output
- Written diagnosis with numbers
- Duration
- 20–30 minutes
- Replacement
- Workshop job — not on the driveway
Mobile alternator testing — specific questions
Q.Can you diagnose an alternator on my driveway?
Yes — full charging-system diagnosis is a driveway job. Replacing the alternator itself isn't, but we can refer you.
Q.How do I know it's not just the battery again?
That's exactly what this service tells you. We test both systems and give you the numbers.
Q.Can you fit a new alternator?
No — that's workshop work. But we'll diagnose accurately and get you to the right garage.
From call to key-turn
- 1
Call
Talk to a real engineer, not a call centre. Fixed price on the phone.
- 2
Route
We tell you our ETA and route via the fastest corridor — no vague windows.
- 3
Test & fit
On your driveway, in a car park, at the roadside — same process, honest result.
- 4
Recycle & warranty
Old battery taken away, warranty registered, all in one visit.
Related guides
General questions
Q.Are you insured?
Yes — fully insured with public liability and goods-in-transit on every callout and every battery we fit.
Q.Can you invoice on account for businesses?
Yes — 30-day account terms available for fleets, lettings, dealers and repeat trade customers. Single monthly PDF invoice.
Q.What if it's not the battery?
We'll tell you honestly — sometimes it's the alternator, the starter or a parasitic drain. Better to know than to buy the wrong part.
In short
If batteries keep dying, stop buying batteries and get the alternator tested. That's what this service exists for.
Third battery in 3 years? Might not be the battery.
Full charging-system diagnosis with numbers — driveway callout.
Stranded with a flat battery?
Call now or send a WhatsApp — we'll confirm your quote and dispatch the nearest engineer.