Battery charger FAQ - Charging & maintaining correctly
Whether motorcycle, car or motorhome – with a high-quality battery charger from electronicx you can extend the service life of your 12V or 24V battery by up to 200%. In these 30 FAQs we explain everything about correct charging, maintaining and selecting.
Basics
What is a battery charger and what do I need it for?
A battery charger converts 230V mains voltage into 6V, 12V or 24V direct voltage in order to safely charge discharged vehicle batteries. High-quality devices achieve over 1000 charge cycles. Automatic switch-off prevents overcharging, which can extend the service life of a 60Ah AGM battery from 5 to 8 years.
Which battery types can I charge with a modern charger?
Modern chargers charge lead-acid, AGM, gel, EFB and lithium batteries (LiFePO4) with 12V or 24V. Our devices detect the battery type automatically and select the appropriate end-of-charge voltage, e.g. 14.4V for AGM or 14.8V for flooded lead-acid. The charging characteristic is controlled in 7 stages in order to fully charge even 100Ah batteries in 8 to 10 hours. A car charger with lithium mode works at a constant 14.2V for 4 cells.
How does automatic battery voltage detection work?
When connected, the charger measures the battery's rest voltage with ±0.05V accuracy. If it is between 11.5V and 13V, the 12V programme is selected automatically. At 22V to 26V the device detects a 24V battery. A 6V mode is activated at 5.5V to 6.5V. The measurement takes 5 seconds and prevents incorrect settings, which cause 80% of all battery damage. A buzzer warns of defective cells at voltages below 2.5V.
What does trickle charging mean and when is it useful?
Trickle charging supplies the battery with a low voltage of 13.5V to 13.8V in order to compensate for self-discharge of 3% per month. A 12V charger with trickle function can remain connected for months without damage – ideal for seasonal vehicles. The quiescent current consumption is below 1W, the number of charge cycles rises to over 2000 in continuous operation. This keeps your 60Ah battery ready to start even after 6 months of standing and prevents sulphation.
How long does a high-quality charger last?
A quality charger with temperature-controlled fan and IP65 achieves 15 to 20 years of service life. The internal electronics are designed for 100,000 operating hours. Cables made of H07RN-F rubber withstand 50,000 bending cycles. The charging clamps are designed with 1.5mm² copper cross-section for 30A peak current.
Can a charger rescue a deeply discharged battery?
Yes, deep discharge below 10.5V leads to sulphation. Our reactivation programmes send pulses of 16.2V and 2A for 15 minutes, which break up sulphate crystals from 0.1mm in size. From 6.5V the normal charging process starts. For a 44Ah battery with 4.5V residual voltage, recovery is successful in 70% of cases. After 3 charge cycles the capacity rises by up to 85% of the original value. Prerequisite: the battery is mechanically intact.
Difference between constant current and constant voltage?
Constant current (I phase) charges at a fixed 4A, 6A or 10A until the battery reaches 14.7V. In the constant voltage phase (U phase) the device maintains 14.7V and reduces the current to 0.1A. This IUoU characteristic is gentle on the plates: the gassing voltage of 14.4V is only briefly exceeded. With 12V batteries the I phase lasts 6 hours for 60Ah, the U phase 2 hours. This prevents water loss and extends service life by 30%.
How often should a vehicle battery be charged?
In winter at temperatures below 0°C, charge every 4 weeks with at least 6A. Self-discharge rises from 3% to 8% per month. A 74Ah starter battery falls below 12.2V after 6 weeks of standing – that corresponds to 50% discharge. With a 6A charger, recharging takes 5 hours. With daily use, a maintenance charge every 3 months is sufficient. Our battery tester displays the state of charge in 0.1V steps.
Why is the end-of-charge voltage so important?
Too high a voltage from 15V boils the battery dry: for every 0.1V, water loss rises by 20%. Too low below 13.8V leads to sulphation. Our devices regulate to 14.7V (±0.1V) for lead-acid and 14.4V for AGM. A correct end-of-charge voltage increases cycle endurance from 400 to 600 at 50% depth of discharge. The voltage is re-measured every 20 seconds and adjusted by 0.03V per 1°C temperature change.
Technology & specifications
What does the ampere rating (A) on the charger mean?
A 4A charger charges an empty 44Ah battery to 80% capacity in 11 hours. The rule of thumb: capacity (Ah) divided by charging current (A) = charging time to 80%. A 10A model does the same battery in 4.4 hours. For 100Ah we recommend at least 6A so as not to exceed the 0.1C charge rate. Our 6A devices fully charge a 60Ah starter battery in 10 hours with 14.7V end voltage.
Which voltages (6V, 12V, 24V) do the devices support?
6V is used for classic car and motorcycle batteries up to 45Ah, end-of-charge 7.3V. 12V covers 98% of all cars with 44Ah to 110Ah, end-of-charge 14.7V. 24V is intended for lorries and working machines with 150Ah to 230Ah, end-of-charge 29.4V. The 24V programme delivers 5A continuous current, which fully charges a 180Ah battery in 36 hours.
What is an IUoU charging characteristic?
The IUoU characteristic combines three phases: main charging with constant current (I) from 10A to 14.7V, follow-up charging with 14.7V constant voltage (Uo) for 2 hours and maintenance with 13.8V (U). This 7-stage characteristic analyses the internal resistance every 20 seconds. With a 70Ah gel battery, the charging current falls from 6A to 0.5A during the Uo phase. This prevents gassing, which would otherwise cost 5% capacity.
How does the microprocessor control work?
The microprocessor control with 16-bit chip analyses the battery condition every 20 seconds and adjusts the charging voltage in 0.1V steps. With 12V batteries, main charging is carried out at 14.7V, follow-up charging at 13.8V. The chip detects sulphation from an internal resistance of 30 milliohms and starts a 15-minute desulphation pulse at 16V. This increases capacity by up to 95%.
What role does temperature compensation play?
At an outside temperature of 0°C, temperature compensation automatically increases the charging voltage by 0.3V to 14.9V. At 30°C it reduces it to 14.3V, because hot batteries need less voltage. Our sensor on the terminal head measures the temperature to an accuracy of ±1°C. This adjustment prevents overcharging in summer and undercharging in winter, which increases the cycle endurance of AGM batteries from 400 to 600 cycles at 50% DOD.
What is the difference between pulse charging and continuous charging?
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Pulse charging sends 40Hz pulses at 17V for 50 microseconds, which break up sulphate crystals without heating the battery. Continuous charging at 14.7V is gentler from 80% state of charge. This saves 25% charging time compared with pure continuous chargers and reaches 98% full charge.
What does IP65 protection class mean?
IP65 means complete dust protection and protection against water jets from any angle (12.5 litres/min for 15 minutes). The plug connections are sealed with silicone gaskets 0.5mm thick. An IP65 device withstands 30 minutes of heavy rain at 100mm/h. This can extend the service life, as corrosion on the 2mm² copper contacts is avoided.
How does reactivation work for sulphation?
The reactivation programme measures the internal resistance: above 50 milliohms indicates heavy sulphation. It sends 16.2V pulses at 2A for 15 minutes, followed by 5 minutes of rest. After 3 cycles we measure the voltage drop. If it falls from 0.5V to 0.1V in 10 seconds, reactivation was 90% successful. A 60Ah battery with an original residual voltage of 3V shows 12.2V after 2 hours and has regained 70% capacity.
Which maximum charging current is suitable for 100Ah batteries?
For 100Ah batteries, we recommend a charging current of 10A (0.1C rate) to keep the plate temperature below 40°C. Maximum short-term 15A for 30 minutes. At 15A the charging time would drop to 7 hours, but cycle life would decrease by 20%.
Can the chargers also be used as a power supply in diagnostic mode?
Yes, our professional units have a diagnostic mode with 13.5V/5A stabilised voltage (±0.1V) to test control units without a battery. The residual ripple is below 50mV, which is necessary for sensitive ECU modules. The unit delivers 60W continuous power for up to 8 hours. A buzzer signals overload at current draw above 6A. This allows you to check headlights or a radio without discharging the battery.
Purchase & delivery
How do I find the right charger for my battery?
The decisive factors are the charging current in amperes (A) and the battery voltage (6V, 12V, 24V). Divide the battery capacity in Ah by 10: for 60Ah you need 6A, for 100Ah 10A. The battery type (AGM, gel, lithium) must match the charging mode – our 7-stage automatic system recognises 98% of all types correctly.
Which payment methods are available?
We offer purchase on invoice with 14 days payment term, direct debit, credit card (Visa, Mastercard) and PayPal. With PayPal, buyer protection is 180 days. Purchase on invoice is enabled from the second order.
How quickly will my order be delivered?
The tracking information will be sent to you by email 30 minutes after dispatch.
What is included in the scope of delivery?
Each charger comes with a 1.8m rubber cable H07RN-F (2x1.5mm²), fully insulated pole clamps for 12V and a 230V mains cable with Euro plug (1.4m). You also receive a quick guide in German and a hook-and-loop cable tie. The professional models include a temperature sensor (40cm cable) and a battery tester.
Can I also use the charger for lithium batteries?
The charging process ends exactly at 14.2V without trickle charging, as required by cell manufacturers. Balancing of individual cells is handled by the battery management system (BMS). A 60Ah lithium battery is fully charged to 100% in 6 hours. Lithium-ion batteries with 14.6V nominal voltage require our special Li-ion mode.
How do I reach technical support?
You can reach our support team Monday to Friday from 7:00 to 15:30 on tel +49 7135 7194106. On site in Cleebronn (Hindenburgstr. 37A, 74389) you can test and collect devices in person by prior arrangement. We answer 95% of all emails to [email protected] within 2 hours. The average waiting time on the phone is 40 seconds.
How do I assess the long-term quality of the chargers?
The circuit boards are 1.6mm thick with 35µm copper coating. The capacitors are rated for 105°C, which corresponds to 10,000 operating hours. The modular design with 8 plug contacts makes repairs easier. Defective units are analysed and repaired within 48 hours.
Do you also offer adapters for cigarette lighters?
It is designed for charging currents up to 6A and has a 3m coiled cable with 1.5mm² cross-section. The voltage loss at 6A is only 0.3V over 3m. The adapter is protected by an integrated 10A fuse and fits all standardised DIN-ISO-4165 sockets. For charging via the cigarette lighter, the vehicle must be in ACC/ON, otherwise the control system can draw 0.5A quiescent current.
What ambient temperature can the units withstand?
All electronicx chargers operate reliably from -25°C to +45°C. At temperatures below -10°C, the electronics reduce the charging current by 20% to prevent condensation ice formation. Above 40°C, the fan switches to level 2 (3000 rpm) and the charging power is reduced by 15%. Deep-frozen storage down to -40°C is possible, but the unit must then warm up to +10°C for 2 hours before use. Operation at 95% humidity is permanently permitted thanks to IP65.