3.0 Sirius Models

Training Overview Introduction to Greenfox Core Concepts of Sirius Different Sirius models Market Segments and Applications Sizing for solar applications Module Operation & Specifications

Breakthrough of Sirius In order to develop Sirius, there were three major challenges that had to be overcome. Supercapacitors lose energy when they are not in a state of charge/discharge Ohms law applies to supercapacitors in series. The cost/kW.h of supercapacitors is very high. Supercapacitors energy loss Any supercapacitor will lose energy when not in a state of charge/discharge. This also applies to Sirius. How this hurdle was overcome is to put all the capacitors in a constant state where they charge/discharge each other. This is a very complex algorithm that helps the supercapacitor retain its energy for 65 days. Capacitors in series “Ohms law for capacitors in series”. What is Ohms law… Ctotal = 1/(1/Cap1 + 1/Cap2 + … 1/CapN) That is the quickest way to reduce the capacity. A single low energy capacitor can reduce the entire stack of capacitors to zero if it fails. Ohms law for capacitors results in the total capacitance being less than the smallest capacitor. A matrix of capacitors are built inside Sirius, containing 1200 Supercapacitors per 3.5kW.h unit. Each capacitor is graded before being placed into a batch. The balancing algorithm plays a major role in this, where energy is transferred between capacitors on a continuous basis. Cost factor of Supercapacitors One of the biggest advances of Sirius is the ultra enriched graphene. This brought down the cost of Sirius to compete with Lithium based chemical technologies. With ultra enriched graphene the energy density was brought in line with lithium technologies, but the power density of supercapacitors are lightyears ahead.

Makeup of Sirius Static storage (capacitors) have the ability to absorb energy at a tremendous speed. The limiting factor is the transfer of electrons through the internal cables/PCB tracks and semiconductors of the balancing circuit. In order to store the energy successfully the internal cabling/tracks as well as the balancing should be designed to keep up with the energy transfer. Internal routing and semiconductor balancing are responsible for the losses of the unit. If the balancing can’t keep up, Ohm’s law for capacitors will find a lower energy capacitor and the capacity of all the units in series will reduce to less than the capacity of the smallest unit. The balancing is done through IGBT’s semiconductors, and their rating is important to keep up with the balancing. Capacitors as a whole have more than 1 Million cycles, that means that the energy storage part is probably the most robust part of the unit. The power electronics have been built in such a way that it can be replaced should it fail. Unlike traditional batteries that have dozens of factors that can damage them, Sirius only has three. Under-voltage – Below 2.2V per Capacitor the IGBT’s can’t balance the capacitors. If you draw a unit below minimum voltage the balancing stops working. If you keep drawing energy from the unit below Vmin the danger that one of the capacitors may reverse polarity and damage itself. Overvoltage – The capacitors are rated 2.7V per unit. So going above 2.7V per unit may damage the capacitor. Take equalization off any charger, make sure the capacitor voltage do not exceed 2.7V per unit. Overcurrent – The balancing circuit needs to be able to keep up with the energy flow. If the balancing can’t keep up the danger is that a single cap may overvoltage when pushing power into the unit, or reverse polarity when drawing power from the unit. Keep within the current limits of the unit that you have. The IGBT’s can also fail due to overcurrent, and permanently damage the balancing circuit. If you want to completely discharge the unit, discharge to 44.0V, then leave it. The charge retention circuit needs the balancing to work. Within a few days the capacitors will be 0V.

Unit Safeties Most of units currently in the country have theft protection. This is a feature that was requested in the telecommunications space and the production line added them to all the units that came into South Africa. The standard units will not have theft protection in future. How the safeties work (excluding theft protection). Using the 48V unit as example Overvoltage – Safety activates at 56.0V Internal bleeding resistor slowly discharges internal unit to 54.0V. Once internal voltage is at 54.0V it checks the voltage on the terminals 44.0V < Vt < 54.0V. If terminal voltage is in range it will reconnect automatically. Under-voltage – Safety activates at 44.0V Once this safety is activated it measures the terminal voltage 46.0V < Vt < 54.0V. Overcurrent – Safety activates at Imax + 50%. 150A for 100Aunit and 300A for 200A unit Attempts to reconnect after 60 seconds. If OC again within 10min it will reconnect 2 more times after 60 seconds. If third attempt failed, it will wait for the voltage to be within 1V of internal voltage.

Sirius Model 48V “Slow Charge”

Sirius Model 12V “Pole Mounted”

Sirius “Telecommunications”

Do’s and Don’ts with batteries Lead Lithium Sirius Leave Battery Empty No Yes Discharge 100% Store on concrete Transported by air Can be installed Sideways/upside down Max strings parallel (DC ripple) 4 5 10 Fire Hazard Explosion Hazard Valuable Raw Materials Temperature sensitive

Power Curve Please refer to IV & SOC profile white paper.