Useful Tips

How to charge camper camper batteries


People should live in houses, cars should be located and serviced in garages. This is ideally true. Even a comprehensive option is possible - private home ownership.

There is enough space for the home, and for the workshop, and for the garage. But what about residents of apartment buildings in which the car is stored in a parking lot in the yard, or in a common parking lot?

We will not consider safety and security issues, this is a topic for another article. Serious maintenance and repair, in this case, is done at the service station.

But what about elementary maintenance and prevention? Add fluid to the washer reservoir, or even bring the oil level to normal, you can in the yard. And if you need to charge a car battery?

Why do I need to charge the battery, how is the battery arranged and working

During operation, the internal combustion engine independently provides itself and the rest of the electrical equipment with energy. That is a generator. However, when the crankshaft stops, electricity ceases to be generated.

How to start the engine again? Previously, a “curve starter" was used for this - a special handle for manually starting the engine. Modern cars use a starter and a battery for this purpose.

Under normal conditions, the system operates in a closed cycle: with the help of the battery, the engine is started, after which the voltage that generates the generator, the battery restores the lost electricity.

However, there are no ideal operating conditions, and any car owner may encounter this situation: in the evening I arrived in the yard with a working car, and in the morning the engine will not start. For what reasons can a battery suddenly run out?

  1. The most likely reason is active self-discharge. If the car stood idle for a long time (accordingly, the battery did not recharge), the connected electrical appliances gradually ran out of battery power. You should not think that if you turned off the headlights and closed the doors tightly (the interior lighting does not light), the battery does not discharge. Immobilizer, comfort unit, multimedia system, on-board computer: all these modules consume a lot of energy even in standby mode.
  2. Passive self-discharge. A dirty and wet battery case, low air temperature, can lead to lower battery levels than critical.
  3. Expired service life, insufficient electrolyte in battery banks.
  4. Incorrect operation. If you made short trips with constant jamming and starting the engine for several days, the battery simply did not have time to recharge.

So, the battery is low, you are standing at your door. It requires recharging the car’s battery, but how to do it at home? Firstly, the battery must be removed from the vehicle.

If it is discharged to such an extent that the alarm does not work, open the door with the key. The hood also opens mechanically, this is a general rule for all cars.

First, disconnect the “mass” (negative terminal), then the positive. This is a universal requirement for any vehicle circuit. Then, carefully, without tilting, we remove the battery from the niche.

Connect manually

So do on boats. The four-position switch alternately connects the starting and service batteries for charging.

However, if you charge two batteries of different types, for example, a gel battery and a liquid electrolyte, the gel battery will be constantly recharged and the liquid-acid battery will be undercharged.

A system with a manual switch is not immune to errors. If the batteries are disconnected during engine operation, one of them will not charge. If the engine is turned off and the batteries are left connected, the starter will be discharged, and the next time you will not start.

or use a battery isolator

Battery diode insulators transmit current in only one direction. Current flows from the generator to both batteries, but not between them, so the starter battery does not discharge during operation of the additional battery.

The disadvantage of battery insulators is a large voltage drop. Since the difference between a charged and a discharged 12-volt battery is 1 volt, due to a voltage drop of 0.6-1 volts on the diodes, the additional batteries will never be fully charged

And if you install an isolation relay

The relay closes the contacts and connects the batteries in parallel if the voltage on one of them rises to 13.3 volts. This happens after starting the engine or connecting the charger. As soon as the charge source is disconnected, the voltage on the battery drops, the relay opens and isolates the batteries from each other.

Relays are still in use. On cars manufactured in the early 2000s, for connecting low-cost small-capacity batteries and where the requirements for charging quality are not high.

For many modern cars, the generator voltage ranges from 12.2-16 volts. It is not possible to charge an additional battery on such vehicles using the isolation relay

Neither the switch, nor the insulator, nor the relay will allow the generator to quickly and 100% charge an additional battery

Deep discharge batteries have thick plates. During the discharge, current is drawn first from their surface and then from the inner regions. Thanks to the massive plates, the batteries can withstand the load for many hours or even days.

But in order to 100% charge such a battery, it is necessary to carry out chemical reactions throughout the thickness of a dense lead plate. It takes several hours at a voltage of 14.4 - 14.8 volts. If using a mains charger, this is not a problem.

The deep discharge battery must be charged like this

However, the voltage of a standard automobile generator is 14.0 -14.2 volts, and the charging current decreases after a few minutes of engine operation. This means that the generator will never fully charge the extra battery, and you will not be able to use its capacity to 100%.

When parked, the battery will run out quickly and you will have to start the engine frequently. Instead of silence and comfort, you will get additional fuel consumption.

Due to regular undercharging, the battery capacity will gradually decrease and will have to be replaced ahead of time

DC Charger

What it is?
This is a device with a built-in microprocessor, which is installed between the starting and additional batteries. The charger makes the generator work at full strength and uses its excess power to charge deep-discharge batteries.

It is safe for the generator and for the starting battery. Intervention in the electrical system does not occur, and warranties are not violated.

What gives such a charger?

  • The DC-DC charger charges 5-10 times faster than the generator. For the same period of time, a deep-discharge battery receives several times more energy, which means it keeps charging longer

So charges the DC device

  • Charging two different rechargeable batteries from one generator results in poor charging of both. If a DC-DC charger is installed, the starter and traction batteries can be of any type. The device can be configured for AGM, GEL, LiFePO4 and liquid-acid batteries. As a result, the batteries will be charged according to the manufacturers recommended algorithms, which means they will last longer
  • The large distance between the additional batteries and the generator leads to voltage losses and increases charging time. The charger works even if the voltage at its input drops to 10 volts. The output voltage is always stable, so the batteries charge quickly and in the correct mode.

So the voltage at the output of the generator of a modern car changes

The isolation relay is useless in that case. Red line voltage output from the charger

Is it really so?
Let's do an experiment. Compare the quality of charging batteries located in a camper trailer directly from a Range Rover car generator and through a Sterling Power BB1260 charger

This is how the Range Rover, connected to the camper with a standard connector, charges. Current 4.1 A, voltage - 12.88 Volts.

The results of measuring the current and voltage on the camper battery while charging it directly from the generator, through the standard connector. Battery voltage 12.88 Volts, charging current 4.1 Amps

The Sterling Power BB1260 charges differently. The battery voltage is 14.2 volts, the charging current is about 40 A. The charger is connected to the generator of the same Range Rover as in the first experiment

The engine runs and the Sterling Power BB1260 charges the camper's battery. The battery voltage is 14.2 volts, the charging current is about 40 A.

After 1 hour of charging, the batteries receive

From the charger: 37.9 A × 14.2 V × 1 h = 534.4 Wh

From the generator: 4.1 A × 12.9 V × 1 h = 52.9 Wh

The Sterling Power charger solves the problems of autonomous power supply of a motor home or camper and allows you not to get attached to parking lots with stationary power supply. You can now restore the charge of additional batteries within two to three hours of movement along the highway

Sterling Power BB1230Sterling Power BB1260
Suitable for:Additional battery 100-150 Ah. GEL, AGM, LiFePO4, liquid electrolyteOptional battery 200 Ah or more. GEL, AGM, LiFePO4, liquid electrolyte
Maximum current, A3060
Input voltage, V1212
Output voltage, V1212
Weight, kg1,21,4
Sizes, mm190 x 160 x 50190 x 160 x 70

Charging an additional battery is 5-10 times faster and 50% more complete than directly from the generator. The battery is 100% charged, lasts a long time, and you are sure that it will not fail.

Resuscitation and storage of the car battery at home

If your car is located under the windows of the apartment, you can extend the extension cord into the window, and restore the battery directly to the car. However, this is the exception rather than the rule.

First of all, it is necessary to determine the room for charging. To the question: “Is it harmful to charge the battery at home?” - the answer is unequivocal: Harmful! Inside the battery is an electrolyte, in which lead plates coated with sulfates “bathe”.

Even natural fumes saturate the air with harmful impurities. And during the charging process, the electrolyte heats up, the vapors become more intense. Ordinary living rooms or kitchens are not considered at all.

If you have ventilation in the hallway, you can install the battery there. Charging a car battery is a long process. Therefore, every 30-60 minutes it makes sense to open the doors to the stairwell for ventilation.

Bathroom, suitable room, subject to intensive ventilation. True, the bathroom does not always have a power outlet, but this is a technical issue. The hood should work continuously, as well as within an hour after charging. This is especially important in small enclosed spaces.

Why is it dangerous to charge the battery at home? When capacity is restored, the electrolyte releases hydrogen. If its concentration exceeds the permissible norms (and this is possible in a small room without ventilation), an explosive mixture may form.

Therefore, the ideal place where at home you can charge the car’s battery - a balcony or a loggia. Of course, windows should be open on the loggia, and no smoking! There is a problem of low temperature in the winter. Batteries are designed for similar operating conditions, just charging will take longer.

This video shows how to properly charge a car battery. Remember! The room should be well ventilated!

Some car owners prefer not to operate the car in harsh winters. In this case, it makes sense to remove the battery for a long time.

Can I store the battery at home? The restrictions are not as strict as when charging. Store it in any room, just make sure the plugs are tight and the case is intact.

Of course, before this it makes sense to charge it to its maximum value. For winter, a balcony or a loggia is undesirable; an entrance hall or a storage room is quite suitable. You can pack the battery in polyethylene.

Consider how to restore a car battery at home

First, we measure the residual voltage of the battery. If your battery is serviced (that is, it has plugs), you can measure the density of the electrolyte. For this, a hydrometer is used. Density of a charged electrolyte: 1.25-1.27 g / cm3 at a temperature of + 25 ° C.

However, this occupation is definitely not for the apartment. Therefore - a multimeter to help you. A simple voltage measurement will not work: you just recognize the EMF of the battery. The true voltage value is measured with the load typical of this battery. Enough 35-50 watts.

Take a halogen lamp for the headlight, and connect during voltage measurement. Even better - first connect the terminals of the device, and then give the load. Then you will see the "subsidence" of voltage in the dynamics.

If the NRC on the terminals is lower than 12.1 volts, this is a critical point. A voltage of 11.6 volts indicates the beginning of sulfation of the plates. It is possible to restore the battery, but this will require a special charger, with a desulfation function.

Tips from the masters to restore dead batteries.

Such a charger first brings the battery voltage to an acceptable 12.5 volts using low currents. Then the typical mode starts: the current strength is 10% of the nominal capacity of the battery.

If you know how to properly charge a sulfated car battery, you can set the charge parameters manually. If not, you must purchase a fully automatic charger.

How do I know if the battery is charged?

If you set the parameters manually, then you can calculate the charging time according to the table:

For example, your battery capacity is 60 Ah. The NRC is 12.2 volts, meaning the battery is 50% charged. Need to give 30 Ah. With a charge current of 6 A (10% of the nominal capacity), a charge of up to 100% will take 5 hours. After this time, a voltage measurement should be checked.

Therefore, charging the battery must not be left to chance. Of course, this applies only to chargers with manual setting of the charge current. Automatic devices are automatically turned off at the end of the process.

What else needs to be checked before charging a car battery with a charger at home?

  • If the battery is maintenance free, check the cleanliness of the pressure relief valves and the integrity of the housing.
  • If the battery has plugs, carefully open them and check the electrolyte level. If necessary, add (carefully!) Distilled water.

Restoring the capacity of a discharged battery at home is not such a difficult task. The main thing is to observe safety measures, and protect the process from pets and young children. Well, the fulfillment of the general requirements of electrical safety: high-quality connections and protection against short circuit (nothing should fall on the terminals).