REhub MPPT : Add Solar to existing Inverters

REhub MPPT enables the addition of Solar PV to existing power back up solutions

With REhub MPPT add Solar PV to existing back up solutions without the expense of replacing the UPS/Inverter and Batteries and upgrade to Solar!

REhub MPPT controls the charging of the batteries from from two sources - the grid (charging by the existing UPS/ Inverter) and the installed Solar PV.

Adding Solar PV is the logical way to extend the back up hours and reduce electricity bills- but must be done the right way. Add too little PV Watts-the Solar addition does not really serve the purpose of long back up. Size up your day time loads and add at least enough Solar PV to take care of day time loads. However, here is the nub, if you add enough Solar PV to take care of day time loads, the power available from the PV panels can exceed the safe charge rate to the batteries. The charge rate to the Lead acid batteries MUST be limited to 10-15% of the battery AH and REhub does this while providing sufficient power to the loads.

REhub MPPT provides the right combination for adding Solar PV. REhub MPPT intelligently controls the charging process in a way that keeps the batteries safe and therefore extends their life. They allow the maximal use of Solar power.

The unit is based on an high efficiency MPPT charge controller that maximizes the extraction of energy from the PV panel.

REhub Keeps Batteries Safe

When the energy from the Solar panels are servicing the loads or when both the sources of energy (Solar and Grid through the Inverter) are charging the batteries, the charge current to the batteries can be higher than what is safe for the batteries. With its unique NET CURRENT to battery monitoring and control REhub MPPT ensures that the charge rate to the batteries is maintained at all times within its safe limits, preventing premature failure of the batteries.

REhub MPPT Maximizes Solar PV Without Excessively Cycling The Batteries

REHub MPPT provides a hub like interface for the connected PV panels, the existing Inverter, the utility grid and the batteries.

REHub MPPT controls the flow of power from the available sources to the connected loads through the inverter. REHub MPPT exercises this control to maximize the usage of Solar energy while making sure the back up needs are not compromised.

Its easy to maximize Solar Power utilization by drawing power from the batteries even when the grid is available. The issue is that the batteries are 'cycled' and the life of the batteries are compromised. Further, back up may not be available when its really needed.

REhub MPPT minimizes the cycling of the batteries and gives priority to keeping the batteries charged to make sure back up is available when needed.

REhub MPPT Solar Charging is High efficiency MPPT Based

MPPT stands for Maximum Power Point Tracking. Extracting power from the panels using MPPT can deliver up to 30% more energy compared to PWM chargers. Using MPPT also allows for the use of economical larger PV panels which are produced in volumes for MW plants on rooftops. REhub's power electronics design also does power conversion at better than 95% efficiency.

REhub MPPT Lowers System Costs

REhub MPPT's innovative Power electronics design allows for a very high Input to Output ratio of Voltages without loss of efficiency. This translates into the ability to wire the PV panels in an all series arrangement for 12V systems and a Series parallel arrangement for 24V systems- reducing system costs.

There are savings in

Wiring costs: Input Voltage can be much higher than the battery system Voltage and therefore the size of the wire can be smaller = Lower costs in wiring.

PV Panel costs :On a per Watt-Peak (Wp) basis larger PV panels (More cells- more commonly used in MW installations) cost lesser than Smaller PV Panels ( Lesser cells).

Lesser BoS - BoS : Balance of systems like lesser connectors, lesser civil works, lesser structures because of smaller Panels, simpler wiring result in Lower costs.

REhub MPPT 12V/24V 40A

Technical Specifications


Operating principle

High efficiency MPPT Based Solar Charger to enable addition of Solar PV to existing home inverters. Monitors the net battery current to ensure optimal charging rate and maximizes the usage of Solar

System Specifications

Battery System Voltage



Solar module STC Wp



Output Current Continuous , Max



PV Open Circuit Voltage (VOC)



PV MPPT Voltage range



Input Current PV ( Max)


Power Conversion Efficiency (typical)

95% typ

95% Typ

Full load output voltage

Same as battery voltage

Float Mode Charge Voltage

13.5 V ( Factory Configurable)

27V (Factory Configurable)

Bulk Mode Charge Voltage

14.4 V ( Factory Configurable)

28.8V (Factory Configurable)


Ambient temperature range

0C to 50C


1 terminal for PV input separate Negative,1 Common terminal for PV Positive & Battery Positive,1 terminal for Battery Negative,1 terminal for connecting Inverter's Battery Negative,1 15 A Socket and 1 1.5Sqmm 3 core cable with 3pin 15A Plug, 1 mtr long. 1 Port for external temperature sensor and 1 RJ45 port for data


135X253X106, IP20


~ 2 Kgs


16 X2 Backlit character LCD to display system
state, Instantaneous Power and cumulative
energy generated from Solar PV

16 X2 Backlit character LCD to display system
state, Instantaneous Power and cumulative
energy generated from Solar PV


Battery Reverse polarity

Electronically protected

Over voltage protection

System shutdown, recovers with a timeout

Over current protection

System shutdown, recovers with a timeout

Over temperature protection

System shutdown, recovers with a timeout

Short Circuit

System shutdown, recovers with a timeout


Adding Solar PV to existing power back up solutions is now easy with REhub MPPT. REhub stands for renewable energy hub - and will function as the back up hub in your home or office. Connect the incoming grid, the output of the UPS inverter, battery terminals and Solar PV to REhub MPPT and you are ready to enjoy long and a safe back up supplemented with Solar energy

Access the cable compartment after removing the L Plate. 

Cable entry is through the slots provided. Close the L Plate after the terminals are sufficiently tightened and all the connections are checked for correctness. 

Panels / array configuration for your installation

With REhub MPPT, you can connect panels in an all series arrangement with Voc maximum of 90V for both 12V and 24V battery system voltages.

REhub MPPT Wiring diagram

Double check with a multimeter the Voc of the array before connecting the wires : The Voc must be below 90V. The unit starts up as soon as the battery connections are made. Unlike other charge controllers, the battery negative of the Inverter is connected to REhub. At the battery positive terminal, there would be two wires , one from REhub and the other from the Inverter. The battery negative terminal however will have only one wire, from REhub.

Installing REhub MPPT

Installing REhub MPPT is simple. Note how its different from other MPPT charger installations though. 

Key Steps in the Installation

  1. Wire Panels in an ALL SERIES arrangement or a Series Parallel arrangement.
    Note the input Voc (Open circuit Voltage of the PV panels) limit - you can wire up to a maximum of 90V Voc for both 12V and 24V Systems and input current limit of REhub MPPT.

  2. Make sure Battery Voltage Matches REhub MPPT output
    Check the installed Battery Voltage. REhub MPPT delivers 24V Or 12V output

  3. Make the wiring connections
    Carefully check the polarity before connecting the wires. Connect the wires in the appropriate ports as show in the picture.
    • Disconnect the AC input 'Live' from the Inverter. Connect to AC Socket of REhub MPPT. Now connect the AC wire with Plug from REhub to the Mains supply. CAUTION : Do not connect the AC wire to any of the DC ports. REhub MPPT WILL be destroyed beyond repair if you do so. DO NOT SWITCH ON MAINS TILL REHub does the Auto detection if Battery Voltage
    • Disconnect from the battery terminal the NEGATIVE output of the Inverter and connect to the Battery monitoring port of REhub MPPT. Connect one more wire of similar cross section to the battery terminal from the other terminal available on REhub MPPT
    • Connect the PV wires to the PV ports of REhub MPPT
    • Connect to common +Ve terminal the Solar + Ve and Battery +ve wires.

  4. Check to make sure REhub MPPT has been installed correctly
    If REhub MPPT is installed correctly the LCD will switch on, and will auto detect the Battery system Voltage and start functioning. Make sure the correct Battery Voltage is detected
    Now Switch on the Mains.

    Other products in the REhub Family

REhub PWM : Upgrade to Solar

Amberroot's Renewable energy hub (REhub PWM) provides a cost effective way to add Solar PV to extend back up in homes for small solar installations.

REhub PWM includes a display that makes its easy to know the power generated, the availability of Grid power and to control the usage of Grid power thereby maximizing the usage of Solar energy.

REhub MPPT Eco: MPPT REhub for small Solar installations

REhub MPPT Eco is a 25A, 12V/24V Solar MPPT charger to add Solar to existing Inverters.

REhub MPPT Eco allows you to install 72 Cell or 60 Cell PV panels even for 12V systems, thereby reducing the amount you spend on a per Wp basis for Solar Panels. Get all the benefits of MPPT charger with ability to upgrade to Solar PV at a lower total system cost.

1316/E, Ist Floor, 9th Cross Road,
JP Nagar II Phase,
Bangalore 560078
Phone: +91 (80) 26588022