1. Car Starting Batteries
- How they work: They are designed exclusively to deliver a large amount of current in a split second to start the engine, and then they are immediately recharged by the alternator.
- Best suited for: Starting the van's engine.
- Major Disadvantage: They are not suitable for powering appliances (fridge, lights, laptop). If they are discharged even a few times below 80-90%, they are permanently ruined.
2. AGM Batteries (Absorbed Glass Mat) – Deep Cycle
- How they work: They belong to the lead-acid family but are sealed (spill-proof, with no free liquid). They are designed to deliver a stable current over many hours.
- Usable Capacity: You can safely discharge them down to 50% of their capacity (if a battery is 100Ah, you have 50Ah available).
- Advantages: They are budget-friendly to buy, vibration-resistant, and completely maintenance-free.
- Disadvantages: They are quite heavy and charge relatively slowly.
3. Lithium Batteries (LiFePO4) – The Modern Solution
- How they work: The top-tier technology for vanlife today. They offer massive energy storage with minimal weight.
- Usable Capacity: You can discharge them almost entirely, up to 80% to 100%, without causing any damage.
- Advantages: They weigh 1/3 of an AGM, charge extremely fast, and last up to 10 times more years (charge cycles).
- Disadvantages: They have a high upfront purchase cost and must not be charged in sub-zero temperatures (unless they feature a built-in heater).
Consclusion For starting the van, you stick with the car battery. For your "house" electronics, if you are on a tight budget, you choose AGM, whereas if you want autonomy for years, fast charging, and low weight, the Lithium is the best investment.