The design philosophy behind SunTrunk is to provide an easy to setup and easy to use package. Solar energy goes in, and useful electricity in three voltage levels comes out. You don’t have to be an electrician, or an engineer to set up and use the SunTrunk systems. Just lock the panels in place and plug in.
All components for the SunTrunk systems have been chosen to give the highest efficiency performance, and provide useful operation for many, many years. High efficiency reduces the size and weight of the system. Quality equipment and materials give this product a 10 to 20 year life. There is no need to change out battery packs every 2 to 3 years.
The key features of the sub-systems that make a complete SunTrunk power system are presented below. I think you’ll see that in each area the SunTrunk excels in performance and quality, compared to lower cost – less efficient systems.
Max Power Point Tracking
Maximum Power Point Tracking (MPPT) gives you 10-30% more energy from your solar panels. These controllers are connected between the solar panel and batteries like any charge controller, but sophisticated electronics allow the controller to operate the solar panel at its maximum power level, while supplying the battery with the most efficient voltage for charging. This results in significant gains in energy collected over the course of the day.
MPPT controllers extract the most power possible from your panel in nearly any condition; hot or cold temperatures, different light levels, partially shaded panels. They even take wiring losses into account. The actual power gain will vary with conditions, and may be anywhere from 0-40%, with 10-30% being typical. Highest power gains come with discharged batteries, cold temperatures, and low light conditions – like the hours during dusk/dawn when the sun is at a low altitude.
Lithium Iron Phosphate Batteries (LiFP) are the next generation of Lithium Ion chemistries. They have a high practical capacity of 165 mAh/gram compared to 50 mAh/gram for lead acid batteries. They are therefore; small in size, and light in weight – about 1/3 the weight and volume of lead acid, or nickel metal hydride batteries of the same capacity.
They also have an extremely safe and stable chemistry with high intrinsic safety. They will not explode or catch fire under collision, over charge, or short circuit conditions. They have a high thermal stability of phases up to 500C. LiFP batteries are environmentally friendly with non-toxic and non-contaminating materials. They contain no rare metals.
They have high rate capability, and can deliver high amps for all high power output applications. They can be fully charged in a very short time – 2C fast charge within a half hour. Unlike lead acid batteries, LiFP batteries do not produce hydrogen, or other gases when charging.
LiFP batteries have an extraordinary Long Cycle Life. The best can be up to 2000 cycles versus 400 cycles for lead acid batteries. Service life would be over 5 times the life of lead acid, and 3 times the life of other Li-ion batteries. For the Suntrunk systems – a service life of 10 to 15 years can be expected, before a battery change out is needed.
They have a wide working temperature range from -4 F to 150 F (-20 C–+70C). Extremely cold and extremely hot weather will not affect its performance, and no temperature compensation is needed in the charging systems. (The solar and AC charger used in the Suntrunk systems are designed for LiFP batteries. You cannot use lead acid battery chargers for these batteries.)
They have no memory effect, and can be discharged 80% to 90% without significant reductions in cycle life. This gives much more usable storage than lead acid batteries that are typically discharged to only 50% of capacity. They also have a very high charge and discharge efficiency of around 95%. This is much greater than lead acid batteries, which can lose 15% to 30 % of the power during the charge and discharge cycle.
Finally, they have a very low or slow self-discharge when not in use. Shelf life when in storage can be 8 to 12 months. (If storing for long periods, the battery voltage should be checked every 6 months, and maintained at about 12.5 volts or higher.)
Pure Sine Wave Inverters
Pure Sine Wave inverters have many advantages over modified sine wave inverters. The output voltage wave form is like utility supplied power with very low harmonic distortion, and at a precise 60 hertz frequency. Inductive loads like microwave ovens and motors run faster, quieter, and cooler. Audible and electrical noise in fans, fluorescent lights, audio amplifiers, TVs, game consoles, fax machines, and answering machines are greatly reduced. This can prevent crashes in computers, printer/copier problems, and glitches/ noise in monitors.
Pure sine wave inverters can reliably power the following devices, which may not
work well with modified sine wave inverters.
- Laser printers, photocopiers, magneto-optical hard drives
- Certain laptop computers (you should check with your manufacturer)
- Some fluorescent lights with electronic ballasts
- Power tools employing "solid state" power or variable speed control
- Some battery chargers for cordless tool
- Some new furnaces and pellet stoves with microprocessor control
- Digital clocks with radios
- Sewing machines with speed/microprocessor control
- Home automation systems
- Medical equipment, such as oxygen concentrators
Pelican and Seahorse cases are used by the military and industry for the most demanding storage and transport jobs. For the SunTrunk systems, they provide a protection cocoon for the solar panels, batteries, and control equipment. They also form a solid base when the solar panels are in the deployed position. For ease of handling, the larger SunTrunks have comfort grip handles and rugged steel bearing wheels. With the built in wheels and handles the Suntrunks can be easily moved and positioned by one person.
The lid and body are molded in one piece; each from lightweight, high-impact polyethylene. They have molded-in, tongue-in-groove gaskets on the parting lines for splash resistance, and tight seals – even after impacts.
The corners and edges are reinforced for additional impact protection. Other features include; recessed hardware for extra protection, positive anti-shear locks to prevent lid separation after impact and reduce stress on hardware, molded-in ribs and corrugations for secure non-slip stacking, columnar strength with added protection, patented molded-in metal inserts for catch and hinge attachment points which provide strength, and spread loads to the container walls.