Charging problem
Parasitic Drain Support
When you have a known parasitic drain, a maintainer can keep the battery topped up until the drain is fixed.
Using a maintainer when drain can’t be fixed yet
If you have identified a parasitic drain but cannot fix it immediately (e.g. waiting for a part or a garage slot), a battery maintainer can prevent the battery from going flat. Connect it when the vehicle is parked and leave it on; it will supply the current that would otherwise be drawn from the battery and keep the voltage in a safe range.
This is a temporary measure. Long term, the drain should be repaired—constant discharge and recharge cycles can still shorten battery life. In the UK, common culprits are glovebox or boot lights, aftermarket accessories, and faulty alternator diodes (which can drain the battery when the engine is off).
Recommended tool
Use our charger tools to confirm the right charger or check compatibility for your battery.
Open charger matcherRelated charging guides
Related charger types
Related charging problems
Recommended chargers
Smart chargers and maintainers that work with car, van, motorcycle and leisure batteries. Check AGM/EFB compatibility for Start/Stop vehicles.
CTEK
CTEK MXS 5.0 Smart Charger
Advanced 8-step charging with automatic reconditioning for dead batteries. The gold standard for battery maintenance.
Best for:
- •Vehicles parked for weeks at a time
- •Maintaining battery during winter
- •Recovering deeply discharged batteries
Prices and availability vary by supplier. Always check compatibility with your battery type.
CTEK
CTEK CS ONE Battery Charger
Compact APTO adaptive charging for cars, motorcycles, leisure and marine. One-button operation, AGM/EFB compatible.
Best for:
- •Start/Stop and AGM batteries
- •Motorcycles and leisure batteries
- •Simple one-button charging
Check compatibility with your battery type (AGM/EFB/lead-acid).
NOCO
NOCO Genius 5 UK Smart Charger
6V/12V 5A smart charger with Force Mode for dead batteries and desulfation. Works with AGM, lithium and leisure.
Best for:
- •Recovering very flat or dead batteries
- •AGM, EFB and lithium batteries
- •Cars, bikes and caravans
Ensure correct voltage (6V/12V) and battery type setting.
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Next steps
Match your battery type and use case with our charger sizing guide. For product options see our best car battery chargers UK. If the battery is beyond charging, use our Battery Fitment Finder. Not sure what’s wrong? Run battery diagnostics, or browse our battery guides.