If you’ve been shopping for a deep cycle battery, you’ve probably noticed ratings like 100Ah, 120Ah, or 200Ah.
But what do amp hours (Ah) actually mean?
More importantly, how many amp hours do you really need?
Choosing the wrong battery capacity can leave you with a flat battery halfway through your camping trip—or see you paying for more battery than you’ll ever use. Understanding amp hours helps you choose the right battery for your vehicle, caravan, boat, or off-grid power system.
If you’re looking for quality deep cycle batteries, Battery Warehouse stocks a wide range of options to suit camping, marine, caravan and solar applications.
What Are Amp Hours?
An amp hour (Ah) is a measurement of how much energy a battery can store and deliver over time.
Think of it like the size of a fuel tank.
A larger fuel tank doesn’t make your vehicle more powerful—it simply lets you travel further before needing to refuel. Likewise, a battery with a higher amp hour rating doesn’t produce more power; it simply stores more energy, allowing it to run your equipment for longer between charges.
For example:
- A 100Ah battery can theoretically supply 5 amps for around 20 hours.
- A 120Ah battery can run the same equipment for longer.
- A 200Ah battery stores roughly twice as much energy as a 100Ah battery.
Actual runtime will vary depending on battery chemistry, temperature, charging conditions and how heavily the battery is being discharged.
Amp Hours vs CCA – What’s the Difference?
One of the biggest misconceptions is that a battery with a higher Cold Cranking Amp (CCA) rating is automatically better.
It isn’t.
Amp hours (Ah) and Cold Cranking Amps (CCA) measure two completely different things.
| Amp Hours (Ah) | Cold Cranking Amps (CCA) |
|---|---|
| Measures battery capacity | Measures starting power |
| Indicates how long a battery can power equipment | Indicates how well it can start an engine |
| Important for camping, caravans, marine and solar | Important for cars, utes and trucks |
| Designed for sustained power delivery | Designed for short bursts of high current |
If you’re running camping fridges, lights, fish finders, CPAP machines, pumps or inverters, amp hours are far more important than CCA.
Are Higher CCAs Better?
Not necessarily.
For a starting battery, you should always choose a battery that meets or slightly exceeds the manufacturer’s recommended CCA.
Once you’ve reached the required specification, buying significantly higher CCA won’t normally improve how well your vehicle starts.
For deep cycle batteries, CCA is often irrelevant because these batteries are designed to supply steady power over long periods rather than deliver a huge burst of current to start an engine.
When Do You Need More Amp Hours?
The amount of battery capacity you need depends entirely on how much equipment you’ll be running and how long you’ll be away from charging.
Small Capacity (20–60Ah)
Ideal for:
- Fish finders
- Small trolling motors
- Portable power packs
- Emergency backup systems
Medium Capacity (100–120Ah)
This is the sweet spot for most campers.
Perfect for:
- Camping fridges
- LED lighting
- Charging phones and tablets
- Portable CPAP machines
- Water pumps
- Weekend camping trips
One of our most popular choices is the Synergy 120Ah AGM Deep Cycle Battery, offering an excellent balance between capacity, reliability and value for money.
Large Capacity (200Ah+)
Larger capacity batteries are best suited to:
- Large caravans
- Motorhomes
- Solar storage systems
- Extended off-grid camping
- High-powered inverter systems
While bigger batteries offer longer run times, bigger isn’t always better.
Very large AGM batteries become extremely heavy, are more difficult to handle, and heat management becomes increasingly important as battery size increases.
For many larger installations, Battery Warehouse often recommends using multiple medium-capacity batteries or 6V 230Ah batteries wired in series rather than a single oversized AGM battery. This approach often provides better weight distribution, easier installation and greater flexibility if a battery ever needs replacing.
Our Recommended High Amp Hour Batteries
If your setup genuinely requires a large-capacity battery, these are the batteries we’d recommend.
Remco RM12-200LFP (200Ah Lithium)
Our preferred high-capacity lithium battery.
Ideal for:
- Serious off-grid camping
- Caravans
- Motorhomes
- Solar power systems
Lithium batteries offer significantly more usable capacity, lower weight and a much longer cycle life than traditional AGM batteries.
If you’re considering upgrading, have a look through our range of Lithium Batteries.
Predator ED122200 (200Ah AGM)
An excellent AGM option where lithium isn’t suitable.
Ideal for:
- Marine use
- Caravan power
- Backup systems
Predator ED122600 (260Ah AGM)
Designed for larger permanent installations requiring substantial energy storage.
Because of its size and weight, this battery is generally better suited to fixed installations than portable camping setups.
Is One Big Battery Better Than Two Smaller Batteries?
Not always.
Two quality 120Ah batteries can often provide advantages over one very large battery, including:
- Easier handling
- Better installation flexibility
- Simpler replacement if one battery eventually fails
- Improved weight distribution
For larger battery banks, many installers also choose 6V 230Ah deep cycle batteries wired in series.
How Many Amp Hours Do You Need?
Start by asking yourself one simple question:
How many hours do I need to run my equipment before I can recharge?
Then estimate the current draw of everything you’ll be using.
| Equipment | Typical Current Draw |
|---|---|
| Camping fridge | 2–4A average |
| LED lighting | Around 1A |
| CPAP machine | 2–5A |
| Phone charging | Less than 1A |
| Water pump | 3–8A (intermittent) |
The more equipment you use—and the longer you’re off-grid—the more amp hours you’ll need.
Where Can You Buy High Amp Hour Deep Cycle Batteries in New Zealand?
Battery Warehouse stocks one of New Zealand’s largest ranges of deep cycle batteries for camping, caravans, boats and off-grid power systems.
Whether you’re looking for a dependable 120Ah AGM, a high-performance 200Ah lithium battery, or simply want advice on choosing the right battery capacity, our experienced team is here to help.
Browse our full range of Deep Cycle Batteries, explore our Lithium Batteries, or contact the Battery Warehouse team for expert advice on the best battery for your application.
Frequently Asked Questions
Is a higher Ah battery always better?
Not necessarily. A higher Ah battery will provide longer run time, but it will also cost more, weigh more and take longer to recharge. The best battery is the one that matches your power requirements.
Can I replace a 100Ah battery with a 120Ah battery?
In most cases, yes, provided it physically fits your battery compartment and your charging system is suitable.
Does a higher Ah battery last longer?
Generally, yes. A higher capacity battery stores more energy, allowing it to power your equipment for longer between charges.
Can you compare CCA with Ah?
No. CCA measures starting performance, while Ah measures battery capacity. They are completely different measurements and shouldn’t be directly compared.
Final Thoughts
Amp hours don’t tell you how powerful a battery is—they tell you how long it can continue supplying power.
For most campers, boaties and caravan owners, a quality 120Ah AGM battery offers the ideal balance of capacity, size and value.
If your power demands are higher, a 200Ah lithium battery may be the better option. However, bigger isn’t always better, and in many cases multiple medium-capacity batteries provide a more practical solution than one oversized battery.
If you’re unsure which battery is right for your setup, the Battery Warehouse team is always happy to help you choose the right solution for your needs.
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