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Campervan Battery Charge Time Calculator
Solar, B2B & Mains Hook-Up

Solar PV, B2B Alternator, or 230V Mains Hook-Up?
Accurately calculate exact charging times for your leisure battery bank (Lithium LiFePO4, AGM, or Gel).

🔋 Your Leisure Battery Setup

Ah
Empty (0%) Full (100%)

⚡ Charging Sources & Equipment

Watts (Wp)
Amps (A)

Recharge Time

✅

Healthy State

Requires 0 Ah to reach full charge.

🚐
Driving (B2B Charger)
0h 00m +0% / h
Continuous driving time required.
☀️
Solar Panels
0h 00m +0% / h
Continuous daylight exposure.
🔌
230V Mains Hook-Up
0h 00m +0% / h
Connected to campsite pitch or grid.

Time Comparison (Hours)

Why Calculate Your Campervan Battery Recharge Time?

Managing campervan electrics isn't just about estimating your daily power draw (your Electrical Power Audit). It is equally critical to understand how quickly your off-grid system can replenish that stored energy.

If your 12V fridge and LED lighting consume 50 Amp-hours (Ah) per day, but your solar array only returns 20 Ah, your leisure battery faces a steady, inevitable discharge. Using our campervan battery charge time calculator allows you to plan driving routes (to leverage alternator B2B charging) or schedule campsite stops (to connect to a 230V mains hook-up).

Solar, B2B, or Mains Hook-Up: Which Charges Fastest?

In a modern campervan conversion, you typically rely on three independent charging sources:

  1. DC-to-DC (B2B) Battery Charger: Usually the fastest and most dependable charging method. While driving, your van's alternator produces significant current. A 30A B2B charger injects 30 Amps into your leisure battery bank for every hour on the road, regardless of weather conditions.
  2. Solar Panels (MPPT Controller): Essential free energy for off-grid camping. However, output varies greatly by season and latitude. A 200W solar array can supply around 10A per hour during peak UK summer daylight, but drops significantly under overcast winter skies.
  3. 230V Mains Charger (Hook-Up): When connected to a campsite hook-up pitch or home mains supply via a CEE inlet, an onboard AC charger provides smooth, steady current. Perfect for reaching 100% State of Charge (SoC) before a road trip or during winter storage.

The Impact of Battery Chemistry on Charging Speed

Our calculator incorporates internal resistance and charging efficiency curves for different battery types. Lithium (LiFePO4) leisure batteries feature near 95% charge efficiency and accept high charge currents right up to full capacity. In contrast, Lead-Acid batteries (AGM, Gel, Flooded) have higher internal resistance and suffer up to 15-20% energy loss as heat during charging. Consequently, topping up an AGM battery takes considerably longer than a Lithium battery bank of equivalent capacity.

⚡ Maximise Your Off-Grid Power Autonomy

B2B charger, MPPT solar controller, or 230V mains hook-up... Learn how to combine your charging sources smartly in our complete campervan electrical guide.

Read the Electrical & Power Guide →

FAQ: Charging Your Campervan Leisure Battery Bank

How long does it take to recharge a 100Ah leisure battery?

Recharge times depend directly on your power source. Using a 30A B2B (battery-to-battery) charger, it takes just over 3 hours of driving to recharge a completely flat 100Ah Lithium battery. With a 150W solar panel in UK summer daylight, it requires approximately 10 hours of direct sun exposure.

Can I discharge my AGM or Gel leisure battery to 0%?

Absolutely not! Traditional lead-acid batteries (AGM, Gel, Flooded) should never be discharged below 50% of their total capacity without risking severe permanent damage and sulfation. If you install a 100Ah AGM battery, consider that you only have 50Ah of usable capacity.

Why do Lithium (LiFePO4) batteries charge so much faster?

Lithium leisure batteries feature extremely low internal resistance. They accept maximum charging currents right up to 100% State of Charge (SoC). In contrast, AGM batteries drastically reduce their absorption rate once they reach ~80% capacity, slowing down the final 20% of the charge cycle significantly.

What is a DC-DC / B2B Battery Charger?

A B2B (Battery-to-Battery) charger (such as a Victron Orion-Tr Smart) is installed between your vehicle's starter battery (engine) and your leisure battery bank. It steps up or regulates voltage from smart Euro 5/6 alternators, supplying the precise charging profile required by your leisure battery while you drive.

How many Amps does a 100W solar panel produce?

Dividing peak wattage (100W) by average charging voltage (~13.5V) yields a theoretical maximum output of around 7.4 Amps. However, in real-world UK conditions (flat roof mounting, cloud cover, atmospheric haze), a 100W solar panel typically delivers between 4 and 6 Amps in peak summer daylight.

How can I charge my leisure battery if I'm not driving and it's raining?

If you have no solar yield and aren't moving the vehicle, your only option is connecting to a 230V mains hook-up point (at a campsite, pitch, or home) using your exterior CEE hook-up socket and onboard AC smart charger.

Should I disconnect my solar panels during winter storage?

No, leave them connected to your MPPT charge controller. Even though UK winter solar yields drop significantly due to low sun angles and short daylight hours, this small "trickle charge" (float mode) helps keep your leisure battery healthy and prevents self-discharge over winter.

What is an MPPT solar charge controller?

An MPPT (Maximum Power Point Tracking) controller links your solar array to your leisure battery. It is a smart DC converter that transforms high solar panel voltage (e.g. 20V+) into optimal charging voltage (e.g. 14.4V), harvesting up to 30% more energy compared to older PWM controllers.

Why won't my Lithium battery charge when temperatures drop below freezing?

This is an active protective feature managed by the battery's BMS (Battery Management System). Charging Lithium cells below 0°C causes permanent lithium plating and cell damage. For winter vanlife in cold climates, place your leisure battery inside the heated living quarters or select a battery model with built-in internal heating pads.

Can I charge my leisure battery using solar and the B2B charger simultaneously?

Yes, absolutely. When driving during sunny daylight, both your engine's B2B charger and MPPT solar controller will feed current into your battery bank. Modern multi-stage smart chargers automatically adjust their output to safely charge your battery bank without overloading.

The Electrical Workshop