New model, allows full and fast charging of the service batteries via the engine alternator. Get a charge up to 5 times faster than using the standard alternator. Essential to charge Lithium batteries (LiFePO4) without ruining them. This product is also suitable for Euro 5 and Euro 6 vehicles and campers. New 70 Amperes model.

Charging the service batteries with the engine alternator has always been an operation not without obstacles.

In fact, the standard alternator is equipped with a cheap and unsophisticated voltage regulator, which simply regulates the alternator voltage to about 14.4 volts and does nothing else.

If we also consider the voltage drop along the cables that carry the current from the alternator to the utility batteries, and that caused by a diode charge divider that may be installed downstream of the alternator, Here comes a voltage just over 13 Volts to the batteries and therefore completely insufficient to guarantee a complete and fast recharge of the service batteries. In these conditions the charging times are considerably longer, since the current delivered by the alternator drops to very low values (often no more than 10-15 Amps even using an alternator of 80 Amp or more).

Sterling Power's Battery To Battery Charger is basically a sophisticated charger like the dock ones, only instead of being powered by 220 Volt alternating current, it is powered directly from the alternator via the engine's starter battery.

It will no longer be necessary to have a charge divider that divides the current produced by the alternator between the two batteries (starter and services).

The alternator will in fact be connected directly to the starter battery, and this will be connected to the entrance of the Battery to Battery Charger, while the output of this will be connected to the positive of the batteries of the services.

Here's the typical (entirely legitimate) question: But doing so does not drain the engine battery?

No, because the Battery to Battery charger Starts and starts charging the service batteries only when he understands that the starter battery is charging , That is, when the alternator is producing current, it will in fact take the current not from the motor battery, but from the alternator itself.

As soon as the engine is switched off, the alternator ceases to produce And therefore within a few seconds the voltage of the engine battery drops below 13 volts. At this point, the Battery to Battery charger automatically shuts down.

The installation as you have understood is very simple, but by purchasing the Battery to Battery charger from LITIO.STORE you will have our technical support available, which we will eventually guide you and give you advice when installing the product on board your camper or your boat.

• To radically decrease charging times from the service batteries alternator (up to 1/5. Yes, you got it right: 1 hour instead of 5 hours, in the most favorable cases!)
• To avoid voltage drops along the cable from the alternator to the batteries. Electrical systems are often not made to perfection and have cables that are too thin. Or you have to charge batteries very far from the alternator (for example the battery of a bow thruster). The Battery To Battery charger compensates for the voltage drop and therefore at the poles of the batteries there will always be the correct voltage necessary to guarantee an optimal charge
• To charge batteries AGM or Gel services: the standard alternator cannot be set for these types of batteries, so in the long run they would be damaged due to wrong voltages
• To charge Lithium batteries. This is very important and even indispensable. Read the paragraph on LiFePO4 Lithium batteries at the bottom of this page
• To charge 24 Volt service batteries, having a 12 Volt alternator (serves a 24 Volt 12 Volt Battery to Battery charger, available on request. Ask us for information)
• To charge 12 Volt batteries having a 24 Volt alternator (serves a Battery to Battery charger from 24 Volt to 12 Volt, available on request. Ask us for information)

• Full and very fast charge of the service batteries
• Possibility of compensating for the voltage drop produced by the cables ranging from the alternator to the battery
• It avoids the overcharging of the batteries of the services during long motor journeys, as when the batteries are 100% charged they are put in "Float", that is, in the process of holding the charge, with a lower voltage and configurable depending on the type of batteries.
• Fully configurable for any type of battery: Many preset programs, plus one definable by the user, with the possibility of selecting voltage and duration of the period of "absorption", voltage of the phase of Float (maintenance)
• Much longer life of the batteries (Lead batteries-including AGM or Gel - in fact they are damaged if they are not often fully charged, or if they are kept at high voltages for motorcycle time, even after reaching full charge

What's the difference between Battery to Battery and Alternator to Battery Charger?

• The Alternative to Battery Charger, also developed by the British company Sterling Power, is a product very similar to the Battery to Battery charger. The main differences are two: The alternator to Battery charger is directly connected to the output of the alternator and works as an "intelligent" charge divider, so it has two outputs that are connected to the starter battery and those of the services, respectively.
• The Battery to battery charger, on the other hand, has only one entrance and one exit. The alternator is connected to the starter battery, while the Battery to battery charger is connected between the starter battery and the service battery (see connection diagram above)

• The Alternator to Battery charger does not have a current limiter and thus takes as much current as the alternator can deliver. This can be an advantage if the alternator is of excellent quality and therefore can work at high power for long periods. Many series alternators on marine or motor engines are not designed to work under heavy conditions, so with high currents they burn out, as well as give problems to the belts (they wear out very quickly and tend to slip due to high friction). The Battery to Battery charger is instead limited in design to a certain current value (30 or 60 Amperes), so if correctly sized in relation to the alternator will never give him problems.

Charge Lithium Ferrophosphate (LiFePO4) batteries

The Battery to Battery charger is Practically essential to charge lithium or lithium-ferrophosphate (LiFePO4) batteries .. These batteries, in fact, have special needs to be respected during the charging phase. If the voltages and currents are not properly applied, their life will greatly reduce.

A Lithium battery was born to last 15-20 years, But without the appropriate precautions it is easy that his life will be reduced to a few years .. And with what it costs is a shame!

Lithium batteries, moreover, due to their very low internal resistance (which is one of their biggest advantages compared to traditional Lead batteries) Absorb a very high amount of current from the alternator, very close to the limit that this can deliver ..

So the alternator, which is often not a product designed to work for a long time under these maximum yield conditions, literally overheats and burns. This is especially true in the case of banks of lithium batteries of high capacity (200 Ah or more), connected directly to an automotive-derived alternator.

The Battery To Battery Charger has a current limiter inside it , Unlike other similar products, called DC-DC Converter.

This means that a 70 Ampere Battery to Battery charger can deliver no more than 70 Amperes, so it will go very well with a 130/140 Ampere alternator that in this way will always work at half power and therefore It won't come to burn itself ..