How to choose the right battery and charging technology for your work vehicle

Let’s convert that to minutes:

If an EFB (Enhanced Flooded Battery) is installed, it can only deliver about 50% of its 100 Ah without risking reduced service life. That immediately halves the runtime from 46.8 to 23.4 minutes.

Conclusion: This calculation clearly shows that electric heating in the cargo area is highly energy-intensive and not a sustainable solution for the customer. Installing more batteries to extend runtime is not practical because the vehicle’s charging system usually cannot efficiently recharge multiple batteries while driving. The recommended solution is instead to install an external 20A charger that can be connected to the grid and charge the auxiliary battery overnight.

At present, an AGM battery is the best option in Work System’s range. While it is a bit more expensive than a traditional lead-acid battery, this is offset by several advantages:

• Longer service life

• Better tolerance to deep discharge

• Higher usable capacity (more Ah can be utilized)

If price is the deciding factor, an EFB battery can be a more affordable alternative. However, it’s important to understand the limitations of EFB compared to AGM to make an informed choice. Once the value of AGM is understood, price typically becomes less decisive. A lithium battery can be an option, but for now it is significantly more expensive. It also has certain limitations in cold environments, as low temperatures can impair both charging and current delivery — which is particularly problematic if the battery is used to power an inverter.

The most traditional and still the most common vehicle battery type is AMF (AutoMotive Flooded) — a classic flooded lead-acid battery. It consists of six cells with upright lead plates submerged in liquid electrolyte (battery acid). When fully charged, it delivers approximately 12.8–12.9 volts at rest (no load).

If the voltage drops below 12.4 volts, the lead plates inside the battery begin to sulfate (degrade), which means they deteriorate and lose capacity. This occurs already when roughly 40% of the battery’s capacity has been used — for example, when 40 Ah have been drawn from a 100 Ah battery. Because of this, AMF batteries are not suitable as house/auxiliary batteries where power is drawn over longer periods; they are best suited as starting batteries, where current is drawn for short bursts.

Charging an AMF battery takes a relatively long time — often between 8 and 16 hours for a full charge. Fast-charging it with too high a current can lead to overheating and the battery “boiling.” Therefore, chargers with a maximum current of 20 amperes are recommended. A charge cycle is defined as recharging the battery after it has dropped to around 20% of its capacity. An AMF battery usually manages 200–400 such cycles before performance begins to decline and replacement is needed. Also note that AMF batteries release a small amount of explosive hydrogen gas during charging. If the battery is installed in an enclosed space — for example, in a cab or cargo area — this gas must be vented out through a hose to avoid the risk of explosion or fire.

• Affordable

• Slow charging

• Short service life (200–400 charge cycles)

• Can only utilize about 40% of its capacity before recharging is required

• Emits explosive gas during charging

EFB (Enhanced Flooded Battery) is the type of flooded lead-acid battery that we stock at Work System. It is an improved variant of the traditional AMF battery, developed to provide better performance and a longer service life. EFB is therefore a better option than AMF.

• Charges faster than a standard AMF battery

• Can deliver up to 50% of its capacity before it needs recharging

• Manages approximately 300–600 charge cycles, which is about 50% more than a comparable AMF

• Charges relatively slowly

• Can only utilize about 50% of its capacity before recharging is required

• Emits explosive gas during charging

We also stock AGM (Absorbent Glass Mat) batteries at Work System — an even more advanced type of lead-acid battery with several advantages over traditional counterparts. In an AGM battery, the electrolyte is absorbed in glass-fiber mats, which prevents acid stratification over time. This yields a more stable and efficient chemical reaction. As a result, you can use up to about 70% of the battery’s capacity before recharging, without damaging the battery.

AGM batteries can be charged almost twice as fast as traditional lead-acid batteries, without the risk of the battery starting to “boil.” The improved construction also contributes to a longer service life with up to 500–750 charge cycles. Since the electrolyte is bound in glass-fiber mats and not free-flowing, AGM batteries can be installed lying down or on their side, which is a major advantage in tight spaces. AGM batteries also do not emit gas under normal charging and therefore do not require a vent hose. For added safety, however, the battery is equipped with a pressure-relief valve that can release gas if the battery is damaged for any reason. Therefore, it’s still recommended to connect a vent hose as an extra safety measure.

• Approximately 20% higher usable capacity

• Nearly twice as fast charging compared to standard lead-acid batteries

• Can utilize about 70% of capacity before recharging

• Approximately 60% longer service life (500–750 charge cycles)

• Emits no explosive gas during charging

• Less sensitive to shock/vibration and does not have to be mounted upright

• Higher price

• Sensitive to heat — should not be installed near heat sources such as the engine or a diesel heater without proper insulation/heat shielding

Lithium batteries represent a new generation of battery technology with significantly higher performance compared to traditional lead-acid batteries. One of the biggest advantages is that they can be fast-charged in roughly one hour, provided the charger is sufficiently powerful — about the same time it takes to discharge them. Unlike lead-acid batteries, you can utilize a full 100% of a lithium battery’s capacity, providing maximum energy yield. They also have a much longer service life, typically around 2,000–2,500 charge cycles. In addition, a lithium battery weighs about 60% less than comparable lead-acid batteries and can be installed lying down if space is limited.

Despite their advantages, lithium batteries have certain limitations. They are sensitive to cold and cannot accept charge at temperatures below 0 °C (32 °F). To address this, some models are equipped with an integrated heating element that preheats the battery before charging. Another option is to place the lithium battery on an external heating pad if internal heating is not available. Another important aspect is that all cells in the battery must have exactly the same voltage during operation. This is monitored and controlled by a built-in BMS (Battery Management System), which protects against overheating or, in the worst case, fire. The advanced technology makes lithium batteries considerably more expensive than traditional lead-acid batteries.

At Work System, we currently stock Clayton’s LPS system, where the lithium battery is integrated with an inverter, charger, and other electronics in a complete solution. We are also exploring the possibility of offering standalone lithium batteries in the future.

• Approximately 30% higher usable capacity

• Can utilize about 100% of capacity before recharging

• Can be charged extremely quickly

• Approximately 300% longer service life (2,000–2,500 charge cycles)

• Emits no explosive gas during charging

• Very low weight

• High price

• Sensitive to low temperatures without auxiliary heating

We also want to highlight our battery box (item no. 928-BATLÅDA), which comes complete with box, brackets, and tie-down strap. It’s a key component for installing an auxiliary battery in the vehicle in a simple, safe, and protected way. Since batteries are supplied without mounting hardware, the battery box is a practical and necessary accessory for a proper installation.

The classic electrical system in internal-combustion vehicles (diesel/gasoline) is designed so that an alternator monitors the starter battery’s charge level and charges it when needed. When an auxiliary battery was required to power additional equipment, a battery isolator relay was traditionally connected between the starter battery and the auxiliary battery. The relay’s function was to connect the starter battery and the auxiliary battery when the alternator was charging — which always occurred when the engine was running. When the vehicle was turned off and the auxiliary battery was used to power, for example, an inverter and the voltage quickly dropped, the isolator relay sensed this and disconnected the starter battery from the auxiliary battery to prevent the starter battery from being drained, which could otherwise prevent the vehicle from starting. When the vehicle was then started again and driven for at least half an hour, the alternator could usually regenerate the energy that had been consumed.

In electric vehicles, charging of the vehicle’s 12V battery works a bit differently. The 12V starter battery is usually smaller than in internal-combustion vehicles, which makes the need for an auxiliary battery even greater. Since EVs lack a traditional alternator, charging is handled by a DC/DC converter that draws power from the vehicle’s high-voltage traction battery and converts it to 12V. This converter rarely supplies more than about 20 amperes, so it’s important to harvest as much extra power as possible. This makes it particularly important to equip EVs with a DC/DC charger.

When the Euro 6 emissions standard was introduced in 2014, it required all new internal-combustion vehicles in the EU to reduce exhaust emissions, achieved in part through increased fuel efficiency. This also affected the vehicle’s alternator, which is now software-controlled to charge the starter battery more sparingly to reduce engine load and thereby save fuel. In addition, the alternator is programmed never to fully charge the starter battery. This leaves room in the battery to store regenerated energy from engine braking, where kinetic energy is converted to 12V DC and used to charge the battery.

In short: a “smart alternator” means the vehicle does not store electrical energy the way you might expect — which is why alternative charging solutions are required to charge auxiliary batteries in modern vehicles.

Regardless of your batteries’ size or type, they need to be fully charged before the next use. Just like with a mobile phone, you can’t charge for only 10 minutes and expect the battery to last all day. Charging can occur while driving, which charges the batteries with a certain amount of current (amperes), but:

• Battery chargers are by far the best way to ensure the battery is fully charged at the start of the day

• Solar panels work well as a support/maintenance charger, but fully charging takes a long time (days).

• Battery age and health can affect runtime

• The maximum voltage allowed by the vehicle manufacturer from the alternator can affect charging and runtime

1. DC/DC charger: This is the foundation of all modern installations and ensures correct and full charging even in vehicles equipped with smart alternators (EURO 6+)

2. Shore power charger: Used when the vehicle is parked — for example, overnight — to fully charge the battery. Can also serve as a backup in high-consumption scenarios.

3. Solar panels: A perfect complement to the other systems; they keep the battery in good condition through maintenance or top-off charging.

4, Isolator relay (insufficient): Can be used in older vehicles, but provides no guarantees of a fully charged battery in modern installations.

A battery isolator relay (also called a split-charge relay) is an electrical component that automatically connects or separates two batteries — usually the starter battery and an auxiliary battery — depending on voltage levels. Note! This solution often performs poorly in modern vehicles with smart alternators and control systems and is therefore not recommended by us.

When the engine is running and the alternator is charging, the starter and auxiliary batteries are automatically connected so both charge at the same time. When the engine is turned off, the connection is broken so the auxiliary battery cannot discharge the starter battery. This process is typically controlled by battery voltage — for example, the relay closes at about 13.3 volts and opens again when the voltage drops to around 12.8 volts.

• Protects the starter battery

• Automatic operation

• Cost-effective solution

• Simple installation

Disadvantages

• Simple logic — no smart charging

• Limited function in modern vehicles

• Not suitable for high power consumption or where fast charging is required

• In simpler installations with two batteries

• For users who want basic protection against unnecessary starter-battery discharge

• When the budget is limited and a DC/DC charger is not required

A shore power charger — or a shore-power system — allows the vehicle to be connected to an external power grid. It is used to charge batteries, power electrical equipment, and supply vehicle equipment with electricity without the engine running. This is especially useful for work vehicles that stand still for extended periods or where something in the vehicle needs to operate overnight — for example, chargers for battery-powered tools.

The vehicle is connected via an inlet panel to a standard 230V outlet, and the power is then routed to an onboard battery charger that converts 230V AC to 12V DC.

• Charges batteries while the vehicle is stationary

• Powers equipment without the vehicle running

• Saves fuel and reduces emissions

• Increases safety

• Maintains heating/cooling in, for example, the cargo compartment

A DC/DC charger — also called an alternator-fed battery charger — is used to charge an auxiliary battery via the vehicle’s electrical system in a controlled and efficient way. It is compatible with both vehicles that have traditional alternators and modern vehicles equipped with intelligent charging systems, such as Euro 6 engines and start/stop technology.

A DC/DC charger is installed between the starter battery and the auxiliary battery and activates automatically when the vehicle is in operation. It optimizes charging based on factors such as battery type, temperature, and current voltage.

• Stable and efficient charging

• Compatible with modern vehicles (Euro 6 and up)

• Extends battery service life

• Safe and controlled operation

• More expensive than an isolator relay

• More complex installation

• Requires correct sizing (20A, 30A, 50A)

• In modern vehicles with smart alternators/start-stop function

• For high power consumption (tools, refrigerator, inverter, or similar)

• When using AGM, GEL, or lithium batteries

• When you want to maximize battery service life