Video on compelling benefits of 48V Systems

In modern engines with smart alternators, the ECU changes the way the alternator charges. This is done to meet engine emmissions control regulations and optimize fuel consumption. The result is whats called a “Smart Alternator”. In fact the alternator is no really the smart piece. Its the vehicle ECU:

  • The ECU waits for the starter battery to be charged to drop to around 70-80% before enabling the alternator.
  • When the engine is “braking” and there is no acceleration, the ECU directs a high charging voltage to the alternator which maximizes charging power.
  • When the battery quickly reaches 100% capacity, the ECU turns off the alternator charging.
  • When back under acceleration, the ECU will direct a lower charge voltage to put less load on the engine from the alternator saving fuel and reducing carbon emmissions.
  • The ECU will also direct a voltage change if the vehicle has auto start-stop.

Now imagine trying to charge a second battery with all this going on!

Scotty AI has this nailed! The AI out-smarts the “smart alternator” and extracts maximum power.  There is no modification to the alternator nor the vehicle wiring. As such, Scotty does not impact the compliance of the engine.

A regular DC to DC alternator controller, particularly the Victron unit, can be switched between “power supply” and “battery charging” mode. In power supply mode, the unit applies power regardless of the battery condition and is commonly used to put power into a flat battery.

In battery charging mode, the DC to DC applies a load to the alternator. Whilst the level of load can be pre-set in some models, it is generally on or off. Victron DC to DC have an engine detection system based on a voltage range that automatically turns the unit on and a separate range for isolating the starter battery, that is called “lock out”.

Fixed power DC to DC units are generally kept at a low level of less than 600W (50A nominal). This is because if on when the engine is idling, the load may cause the alternator to overheat as there is less air flow. Fixed power DC to DC units range in efficicency of 55-80%. The generate significant heat.

Placing 4 units in parallel as suggested in the brochure of an Australian manufacturer, would produce around 30% of 3000W in heat which is 900W. That amount of heat is difficult to manage.

Scotty What does it do for you?

Compliance to Emmision’s Control

Back to where this article started, emmissions control, particularly with European engines has a strict requirement on the ability of the vehicle to reduce alternator load at times. Adding charging of a second battery with a regular DC to DC will immediately change the fuel consumption level. In Australia, this is presently allowed. However, it may be restricted in the future. Safiery has (Patent Pending) technology that will operates the “Scotty” when the vehicle is in regenerative braking and then puts no load on the alternator when it is not. This makes this technology absolutle leading edge and future proof. This is idle setting “Soft”.

Using an External Regulator like Wakespeed or Balmar (Trademarks apply to each)

For automotive vehicle neither of these products will meet vehicle compliance.

For Marine, RV, and 4WD applications here are the problems using external reulators:

  • They only charge in one direction at the same voltage. 
  • For 48V systems, there are no avalanche diodes in 48V alternators. Should there be a sudden stop charge, then there can be a load dump. tears follow.
  • Once tuned manually, the controller would need manual tuning again for different load conditions.
  • For 24V and 48V systems there is no DC DC conversion to 12V
  • These controllers need to read engine RPM for variable power tuning.

There is still an application for these products but the depth of application is reducing significantly because of demand for multiple voltages to achieve maximum efficiency.

Scotty AI is a variable power bi-directional DC DC with up to a 10:1 power turn down ratio. 

Safiery’s pending patent describes how this is done. The load performance curve is calculated as a mathematical equation during the 2 minute “Auto-tuning” process. The equation is then extrapolated to the maximum output value of the alternator. The clever part is knowing at any point in time, is the engine RPM increasing or decreasing without actually measuring it. There are multiple control equations for Scotty load control when the engine RPM is increasing and a different set when decreasing. The result is:

  • Auto-tuning of the alternator.
  • Auto change of load variables when other loads are applied to the engine.
  • An independent high side > low side trigger value for bi-directional power.
  • An independent Smart Battery Protect on the HS Lithium battery to LS power. 

Its generally once in a lifetime that we see a revolutionary product that changes the game. Scotty is such a product. o the product.

Technical Detail

Safiery Scotty Wiring Install and Operation Manual


There is 5 years warranty on Scotty. This is a manufacturer’s express warranty and is listed on our website.

Examples of alternator control

“Simplicity is at the very heart of this system”

Use your 4WD as a power station for your caravan or camper trailer “plug in and run 240V”.