Camping without limits: How to find the perfect battery for your motorhome
Content
The leisure battery (onboard battery) powers lights, the water pump, the heating fan, the refrigerator electronics, and chargers in your motorhome – independently of the vehicle's starter battery. Which battery is right for you depends on how often you'll be without shore power. Here you'll learn the differences between AGM, gel, and lithium (LiFePO4) batteries, how to calculate the required capacity, and what to consider when charging and using electricity at campsites in Italy.
Short answer
- AGM/Gel (Lead): inexpensive, but only about half the capacity is practically usable and significantly heavier
- LiFePO4 (Lithium): More expensive, but approximately 90–100% usable, about half the weight and with thousands of charging cycles.
- For lots of free camping Lithium plus solar is worthwhile; AGM batteries are often sufficient at campsites with mains electricity.
- Retrofitting lithium only with a suitable charger/electrical control unit and, if necessary, a charging booster
- Italy: The blue CEE plug is standard; smaller campsites sometimes only have household sockets – bring an adapter.
Battery types compared: AGM, Gel or LiFePO4?
Three main types of batteries are currently installed in motorhomes: AGM and gel batteries (both maintenance-free lead-acid batteries) and lithium iron phosphate batteries (LiFePO4). Traditional wet-cell lead-acid batteries are now rarely used as leisure batteries.
| AGM | Gel and | LiFePO4 | |
|---|---|---|---|
| Usable capacity | about 50% | about 50% | approx. 90–100% |
| Cycles (guideline value) | Approximately 500–600 at 50% discharge | Similar to AGM, but tolerates deep discharge somewhat better. | Approximately 3.000 at 90% discharge |
| Weight | hoch | hoch | about half as heavy |
| charging | tolerates high charging currents | does not like high charging currents | tolerates high charging currents, do not charge below 0 °C |
| purchase | favorable | medium | Significantly more expensive, possibly requiring a new charger. |
AGM and Gel
Lead-acid batteries should only be discharged to about half their capacity; otherwise, their lifespan is significantly reduced. Realistically, you can expect around 100 Ah from a 50 Ah AGM battery when discharged. In a practical test conducted by promobil, a 120 Ah AGM battery delivered 72 Ah, while a 110 Ah LiFePO4 battery delivered the full 110 Ah. Gel batteries tolerate deep discharges somewhat better than AGM batteries but must not be charged with high currents. For use with shore power at campsites and short periods of inactivity, lead-acid batteries are a cost-effective solution.
LiFePO4 (lithium iron phosphate)
LiFePO4 batteries consist of four cells, each with 3,2 V, giving them a nominal voltage of 12,8 V. They can be almost completely discharged, are lighter, and can withstand many more charge cycles. A built-in battery management system (BMS) protects against deep discharge and overcharging. Disadvantages include the higher price and sensitivity to cold temperatures – most LiFePO4 batteries cannot be charged below 0 °C; the BMS then blocks the charging process. Models with integrated heating are available for winter camping.
What capacity do you need?
A battery's capacity is measured in ampere-hours (Ah), while its energy content is measured in watt-hours (Wh): Wh = Ah × voltage . A 100 Ah LiFePO4 battery therefore stores approximately 1.280 Wh. Here's how to determine your needs:
- Listen Sie alle 12-V-Verbraucher mit ihrer Leistung in Watt auf (Typenschild oder Datenblatt).
- List all 12V appliances with their power consumption in watts (nameplate or datasheet).
- Divide the sum by 12 V – this gives the requirement in Ah per day.
- Multiply by the number of days without recharging.
- For lead, double the value (only about 50% usable), for LiFePO4, add about a 10% reserve.
Example calculation with assumed values: 360 Wh daily requirement ÷ 12 V = 30 Ah per day. For two days without recharging, that's 60 Ah – with an AGM battery you would need around 120 Ah nominal capacity, with a LiFePO4 battery about 70 Ah. Those who frequently camp off-grid should also consider solar power or a charging booster instead of just increasing the battery size.
Charging: Shore power, alternator and solar
charger and power supply unit
In motorhomes, the leisure battery is usually charged via shore power using a charger integrated into the electrical control unit. The correct charging profile is crucial: those upgrading from AGM or Gel to LiFePO4 batteries must check whether the charger and electrical control unit offer a lithium charging profile, or how the battery should be set according to the manufacturer – otherwise, the battery will not charge properly, or the charger will need to be replaced.
Charging while driving: Charging boosters for Euro 6 vehicles
Many Euro 6 base vehicles have a "smart" alternator that only charges when needed and deliberately doesn't fully charge the starter battery. This means the auxiliary battery is only charged insufficiently while driving. A charging booster (DC/DC converter) can remedy this by charging the auxiliary battery with its own charging curve. Some manufacturers install it as standard equipment; otherwise, it can be retrofitted. It's best to check with your dealer or a specialist workshop to see if your base vehicle is affected.
Solar
A solar panel on the roof with a charge controller keeps the battery charged in sunlight and significantly extends the operating time without shore power. The yield depends on the panel's power output, the season, its orientation, and shading – it's high in the height of summer in Tuscany, but considerably lower in winter and under trees. An MPPT charge controller utilizes the panel's power output more efficiently than a simple PWM controller.
Electricity at campsites in Italy
Most campsites in Italy use the blue, three-pin CEE plug (230 V, max. 16 A). However, smaller sites and some pitches may only have standard household sockets. Therefore, pack an adapter from CEE to Schuko or to the Italian socket – we explain the different plug types used in Italy under " Sockets in Italy".
- Electric wire: Rubber hose cable H07RN-F, minimum 2,5 mm² cross-section, maximum 25 m length. Always unroll the cable reel completely, otherwise it can overheat.
- Fuse: The fuse rating of the electrical pedestal varies depending on the location and is often less than 16 A – ask at reception. A rule of thumb: power = 230 V × amperes, so at 6 A it's approximately 1.380 W. Using a kettle, hairdryer, and air conditioner simultaneously will quickly blow the fuse.
- camper pitches They often offer no electricity or only chargeable electricity – here a large auxiliary battery with solar power pays off.
You can find suitable pitches in our overviews of motorhome pitches in Tuscany and the most beautiful campsites right by the sea . You will also need gas for your refrigerator, heating, and stove while traveling – German gas bottles are not exchanged in Italy; you can find more information under Camping Gas in Italy.
Power station as an addition
Eine mobile Powerstation ist ein Akku mit eingebautem Wechselrichter, 230-V-Steckdosen, 12-V- und USB-Anschlüssen. Sie ersetzt keine fest eingebaute Aufbaubatterie, ist aber praktisch für Zelt, Kastenwagen ohne Bordbatterie oder als Zusatzspeicher, etwa für Laptop, Kaffeemaschine oder Akkus von E-Bikes. Achten Sie auf Kapazität in Wh, Dauerleistung des Wechselrichters in W, Ladezeit und die Möglichkeit, per Solarmodul nachzuladen. Kleine Powerbanks genügen dagegen nur für Smartphone, Kamera oder Stirnlampe.
care and storage
- Do not deeply discharge lead-acid batteries and fully recharge them after every trip; recharge them regularly in winter or leave them on a charger with trickle charge.
- Store LiFePO4 batteries with at least 50% charge and check them approximately every six months.
- Disconnect the battery from the vehicle's electrical system via the main switch if the vehicle is going to be stationary for an extended period – otherwise, quiescent currents will drain even fully charged batteries.
- Keep battery terminals clean and secure; always disconnect shore power and consumers before working on the battery.
All camping-related topics – from campsites by the sea to pitches and rules – can be found in our guide Camping Holidays in Tuscany.
Frequently asked questions about motorhome batteries
Which battery is best for a motorhome?
For frequent off-grid camping, a LiFePO4 battery is the best choice: it offers approximately 90–100% usable capacity, is lighter, and lasts for thousands of charge cycles. Those who mostly stay at campsites with shore power can get by with a less expensive AGM battery.
How much capacity should an auxiliary battery have?
Calculate the daily power consumption of your devices in watt-hours, divide by 12 V, and multiply by the number of days without recharging. For lead-acid batteries, double the value, as only about half of the capacity is usable.
Can I simply switch from AGM to lithium?
Only if the charger or power supply unit, solar charge controller, and any charge booster are suitable or adjustable for LiFePO4 batteries. Otherwise, the battery will not charge correctly. If in doubt, have the conversion checked by a specialist workshop.
Why isn't my auxiliary battery fully charging while driving?
In many Euro 6 vehicles, the alternator only works when needed and deliberately does not fully charge the batteries. A charging booster solves this problem because it charges the auxiliary battery with its own charging curve.
What type of electrical connection do campsites in Italy have?
The standard plug is the blue CEE plug with 230 V. Smaller campsites sometimes only have household sockets, so you should bring an adapter. The circuit protection is often less than 16 A.
Is it safe to charge a LiFePO4 battery in freezing temperatures?
Most LiFePO4 batteries cannot be charged below 0 °C; the BMS interrupts the charging process. Batteries with built-in heating are available for winter camping.
