Miro has expanded on its Acconet solar solutions. We have just received a number of new products such as outdoor UV protected power cable, 150Watt monocrystalline solar panels and advanced 10/20Amp MPPT charge controllers.
IN-CBL-4 Outdoor UV protected DC Power Cable, AWG12, 4mm² (Per meter)
Miro currently stocks the both the male & female weather proof DC power connectors (IN-MC4-M, IN-MC4-F). These MC4 IP65 rated power connectors allow the installer to make their own power leads for solar applications. Miro now offers the solar power cable too. This is cable is specifically designed for high voltage outdoor solar applications. This means that the cable is UV resistant and has built in insulation for high voltage systems. Using both the cable and connectors one can create robust, long lasting, weatherproof power leads.
IN-SP12-150W Solar Panel, Monocrystalline, 150Watt, 12V (18V), 8.33A, 1480x675x35mm 11.5Kg Connection Box+Cable
The existing Acconet 130Watt Monocrystalline solar panel has been a firm favorite with most installers over the past two years. Fortunately the efficiency of solar panels is increasing. Typically one reads of these new performance milestones online but never gets to benefit directly from these gains. Thanks to recent improvements the existing 130Watt panel will be replaced by 150Watt panel. The new 150Watt model is exactly the same size & weight which allows installers to continue using the same mounting brackets.
Charge Controllers: Standard PWM vs MPPT
The existing 15 & 20Amp PWM charge controllers (IN-REG-15 & IN-REG-20) are cost effective however they are not efficient. This is not due to build quality issues etc. Rather this is due to the inherent design limitations of charge regulators at this price point. I will explain further.
The trouble is that solar panels typically operate at a higher voltage than what a standard 12 Volt battery does. A typical 12Volt battery voltage varies between 11.5V to 14.8V depending on its State of Charge.
This is unfortunately a necessary evil as the source or charging device needs to have a higher Voltage or pressure than the battery its charging. To use an analogy: If you are attempting to fill/inflate a balloon the air pressure in your lungs needs to be higher than that of the existing pressure inside the balloon in order to inflate it. This Voltage difference between the solar panels & the batteries/equipment creates waste. This is because the solar panels voltage is essentially pulled down to that of the battery’s. The lower the battery voltage (the more flat it is) the more the problem is exacerbated. This occurs at the time when your equipment needs power the most (when the battery is flat), the system performs at its worst. The battery voltage will never match the panel voltage therefore will always be a significant amount of waste.
Take the 50 Watt panel for example. If the voltage of the panel is reduced that of the battery then so will the total amount power created.
Watts = Volts x Amps.
50 Watt Panel = 20 Volts x 2.5Amps
28.75 Watt = 11.5 Volts x 2.5Amps
To use another analogy: This problem is similar to cars when looking an engine’s power curve. A cars engine will produce its maximum amount of power at a certain amount of revolutions per minute (RPM).
One could think of the RPM as Volts. Imagine trying to pull off in 2nd gear constantly, that is essentially the problem the standard charge controllers create. I have created graphs of the power that is lost due to this problem. The point being that you may purchase a 50 Watt panel but only get effectively 28 Watts out due to the standard charge controllers. On average only 70% of the solar energy created by our solar panels can be harvested with the standard charge controllers.
New MPPT Charge Controllers:
Now that you understand the problem with the standard charge controllers. Allow me to introduce our new MPPT (Maximum Power Point Tacking) charge controllers. These controllers are superior with regards to build quality, the quality of the components used, usability, manuals, packing and of course performance. These charge controllers have a built in DC-DC converters which allow both the solar panels & batteries to operate at their respective optimum voltages for maximum performance/efficiency. This results in a 30% increase in power (from the same panels)!
The IN-REG-10-MPPT & IN-REG-20-MPPT pay for themselves in terms of their performance gains. If you use an average of a 30% loss using the standard charge controllers then this is what it costs:
IN-SP12-50W R220 Lost
IN-SP12-80W R373 Lost
IN-SP12-130W R555 Lost
IN-SP24-200W R834 Lost
(This loss is calculated on a single panel)
In terms of general features these charge controllers have, dual timers, advanced 4-stage battery charging, different charging methods for different battery types, temperature adjustment etc.
Two features that standout is the optional LCD display & the high voltage input. Both controllers have a RJ45 port which allows you to attach an optional LCD display. The display will give the user much more detailed information about the whole system. The display also allows the user to configure the controller in an easier fashion via the buttons below the display.
With the standard controllers the panel setup needed to match the battery setup. For example if you were using 2 battery’s in series (12V+12V=24V) to power your MikroTik/Ubiquiti equipment you would need to connect 2 80W 12V panels in series (12V+12V=24V) as well. The problem comes in when you want to add more cameras, radios etc. The new equipment will need more power therefore more solar panels are require to meet the new power demand. In this scenario you can’t just add 1 more 80W panel, you must add a pair to equal 24v. The new MPPT charge controllers can accept up to 150V input from the solar panels. The power is then converted down to either 12/24v depending on how you have chosen to wire your batteries. In the scenario above the client could simply add one more 80W panel in series. The MPPT charge controller would then convert the 52Volts (17.5+17.5+17.5V) down to the batteries voltage & produce more current as a result charging the battery faster.
IN-REG-10-MPPT Solar Charge Regulator, 12/24V, 10Amp, Maximum Power Point Tacking, supports optional LCD Display
Max PV Input Voltage 150VDC, Max PV Input Power: 130W at 12VDC, 260W at 24VDC
IN-REG-20-MPPT Solar Charge Regulator, 12/24V, 20Amp, Maximum Power Point Tacking, supports optional LCD Display
Max PV Input Voltage 150VDC, Max PV Input Power: 260W at 12VDC, 520W at 24VDC
IN-REG-LCD LCD Display for 10/20Amp MPPT Solar Charge Regulators, Displays System Status and Parameters
1 12AH 12V Battery
The 4 50 panels were connected in series producing 91Volts (I expected 80V according to the specifications). The panels, battery & LCD interface were connected to the charge controller directly.
The charge controller reduced the 91Volts to 14.4Volts & initially achieved 7.8Amps when the battery was flat. Technically this setup could achieve up to 10Amps output if the panels are aligned correctly.