A smart multi-stage car battery charger steps through a full charge sequence — desulphation, bulk, absorption and float – rather than applying one fixed voltage. That’s what recovers a flat battery properly and then holds it without cooking it.
It’s not the same as a trickle charger. A genuine trickle charger pushes low current continuously regardless of what the battery is doing, and left connected for months it will gas off electrolyte and damage the battery. Every charger we stock monitors the battery and switches to a maintenance stage when it’s full.
Match the car battery charger to the battery capacity. For lead-acid, the rule of thumb is a charger rated at roughly 10–20% of the battery’s amp-hour figure. Under-size it and a flat battery takes days; over-size it and you risk heat and gassing. Lithium accepts considerably more.
| Model | Output | Stages | Suits | Warranty | Price |
|---|---|---|---|---|---|
| Projecta IC10 | 10A / 6A / 4A / 2A | 7-stage | ~50–100Ah | 5 years | $289.48 |
| Projecta IC15 | 15A / 8A / 4A / 2A | 7-stage | ~75–150Ah | 3 years | $338.75 |
Set the chemistry before you charge. Multi-chemistry chargers have a selector for a reason. AGM, gel, flooded and lithium want different absorption voltages, and lithium wants no conventional float stage. Charging on the wrong profile is the quietest way to shorten a battery’s life.
Don’t charge lithium below freezing. LiFePO4 must not be charged below about 0°C — it causes permanent cell damage. Discharging in the cold is fine. This matters more in a Canterbury or Central Otago winter than most overseas advice suggests.
What size battery charger do I need?
For lead-acid, roughly 10–20% of the battery’s amp-hour capacity. A 100Ah battery suits a 10–20A charger. Lithium accepts much higher currents.
What does 7-stage charging mean?
The charger works through a sequence including desulphation, bulk, absorption and float, rather than applying one fixed voltage. It recovers a deeply discharged battery gently and then maintains it without overcharging.
Can I leave a charger connected permanently?
Yes, if it’s a true multi-stage charger that switches to a maintenance stage. Both Projecta units do. A dumb trickle charger left on for months will damage the battery.
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The perfect car battery charger, especially for large batteries such as those found in boats, camper trailers and caravans, the IC15 is ideal for permanent fixture offering a fast and comprehensive charge when off the beaten track. Comes with a 3 year warranty. Features 7 Stage Automatic. 240W Input Power. 12V Output Voltage. Input (Nominal):…
Compact in size but full of features, this small yet powerful car battery charger can be set to suit a range of battery chemistry types and sizes, ideal for charging deep cycle batteries used by travellers and work vehicles. Comes with a 5 year warranty. Features 7 Stage Automatic. 160W Input Power. 12V Output Voltage….
The new REDARC Manager30 S3 is a 30A state-of-the-art battery management system designed to charge and maintain auxiliary batteries by incorporating AC, DC and solar inputs, ideal for recreational vehicles, caravans, and camper trailers with multiple battery banks. BMS1230S3 Instruction manual