MAN 6x6 with 8kW generator driven from PTO

High Energy Capacity Unlocks Power

Lithium batteries have revolutionised energy storage. This article is about stored lithium energy to run air-conditioners, cooking appliances, high power communication systems and other power hungry devices. Whilst large lithium systems are still not cheap, they are compact enough for mobile applications.

The difficulty, until now, is replenishing the lithium battery energy. Solar and the vehicle's alternator are "self contained" options. However, a 2 kW Solar panel array on a mobile installation is massive in area. It also only replenishes for limited hours, has variable power, and is only effective on a good solar day. Yet limited 2kW solar power is not enough to replenish demanding power devices. When you are moving, the power produced from the vehicle's alternator is small and inefficient. So you either have to pull out a portable generator, fill with petrol, and suffer the noise; or use limited power for a limited period of time.

The enabling game changer is rooted in a simple invention. Simplicity that came from a complex problem and ten million dollars plus in research and development. It is not renewable energy but very close. It "steals" in-efficient power from the engine to generate DC power while the engine is running. It can produce a massive 8kW of power. This power transfers directly and efficiently to large lithium battery sets. Within 3 hours of driving or even idling, you can store 24kWh of energy in Lithium batteries. 24kwh will run a typical 240V air conditioner for a large room for 24-30 hours. With this replenishment technology, large lithium battery sets are now practical to use. Whilst this technology needs the vehicle engine to run, it doesn't have to run for long.

An 8kW portable genset may weigh 160kgs+ and measure 800 x 800x 700mm. It will need an additional battery charger to transfer energy to stored lithium batteries. The 8kW DC generator weighs 15kgs, measures 245 x 220 x 220mm, runs at 48VDC and transfers power directly to the lithium batteries. Game Changer!

The clever bit: this invention is close to renewable energy. The software in the controller carefully maps the efficiency of the vehicles engine so that it loads and unloads the engine to get best efficiency. Although this is rocket science stuff, it requires no user intervention. It is completely automatic. It means the DC generator attached to the engine takes very, very little additional fuel to run. Power and lithium storage systems will be totally redesigned in RV's, special vehicles and the marine market.

48VDC becomes the baseline for stored energy. This is the same baseline used in home energy storage systems. It provides an efficient energy system and is less than the voltage level requiring a step up in electrical safety. This keeps it affordable. The 48V DC generator combined with lithium batteries is not only a true hybrid power system, but an incredibly efficient one. It will become the norm in off-road applications.

Game Changer

It's not the ability to have an 8kW generator attached to the engine that is the game changer; it is this generator's ability to "steal" power from the engine that is. It "steals" power by loading the engine when it is inefficient in such a way to increase it's efficiency. It also does this from a very low rpm. These 2 factors are the "game changer".

We all want renewable energy as a replenishment source for power. However, if that is not available then pushing fossil fuel to be more efficient is the best way to go.

This generator is $10m of reasearch and many years in the making. This totally changes the game: when the vehicle is idling the generator puts out an incredible 2-3kw and at full load 8kw.

Charge Acceptance Rate and Efficiency

Previously, lead acid chemistry whether AGM or Gel dominated the Special Vehicle market. This battery chemistry is inferior at the charge acceptance rate and the charge efficiency, two important factors in efficient energy storage every day.

Lithium technology has now unlocked the easy ability to accept and store large amounts of electrical energy.

Examples of End User Benefits

One of the big power loads that requires AC power is airconditioning. A 6-8m Special vehicle may require 3-5kW (thermal load) of airconditioned cooling. Apart from the high starting current, these airconditioners will use 7-10,000wh in a 24hour period, depending on the environment.

With the DC generator, that is 1.5 to 3 hours of operation to replenish. Add some solar for other loads and you have a very capable off-grid solution.

There are other high power loads like pumps, communications power, and heating applications.

A typical design sees 10,000 to 30,000 Whrs of stored Lithium energy. This is quite compact and the weight is now acceptable. As a guide, 10,000Wh weights about 110kgs and is less than 900 x 450 x 210mm. It can be rated at IP65 and good up to 60-65 deg C.

Energy Architecture

The design of these systems is completely different to tradition. The benefit is:

  • wiring costs are far less
  • appliances are lower cost
  • energy losses are less
  • energy storage is more compact
Power In DC generator Solar AC Site Power
Max capacity for 8m Special vehicle 8,000W 1,400W 3,500W
Time to replenish:
20,000 Wh Lithium Batteries 2-3 Hours 40% in a day  6 hours
Big Power Consumers:
4kW Thermal load Airconditioner Consumes 7-10,000wh a day
Efficiency 100%+* 15-20% after controller 90%

Redundancy is built into the design


The preferred design has good redundancy built in. The probability of a total power failure because of a single point of failure is very low, if not nil.

Redundancy is built into the design

Our expertise is in doing the design

We dont publish our designs but we can give you a quick evaluation and budget. Then if acceptable we do a detailed design and schematic for a fee.

If you are interested complete this online enquiry:

* because energy is stolen from the engine's low efficiency, the effective efficiency can be argued at 100%+