What do the numbers mean?
The first number is the max voltage open circuit allowed into the regulator
The second number is the max charge current out of the regulator
What is Voltage open circuit?
The voltage open circuit is found on the panel, usually;
22voc for a 12v panel
44voc for a 24v 72 cell Panel
37voc for a 60 cell (250w)
How does this relate to the MPPT regulator input?
When you put panels in series it adds the voltage, this cannot exceed the rating on the regulator eg.
A 100/30 MPPT allows 100voc input, this is;
4 x 12v panels (88voc)
2 x 24v panels (88voc)
2 x 250w 24v 60 cell panels (74voc) note 3x 250w would be 101voc which exceeds the 100v rating.
How does MPPT differ from PWM?
MPPT is max power point tracking
PWM is Pulse width modification
MPPT uses a different algorithm to track the maximum voltage power point (Vmp) resulting in up to 30% more efficiency
A PWM uses the available ‘seen’ voltage and discards the rest.
MPPT→ PV Array(Watts)18 Volts=Max Charge current (Amps)
PWM→ PV Array(Watts)15 Volts=Max Charge current (Amps)
So a 200w panel will put out a maximum of 11.1amps with a PWM and 13.3 amps with an MPPT.
*For a 24v battery the charge voltages are 36v for a PWM and 30v for
*For a 48v battery the charge voltages are 72v for a PWM and 60v for an MPPT.
The MPPT will find the ‘knee’ at any given time achieving the highest watts (blue line). This is in relation to the DC-DC ratio (Array Voltage Battery Voltage) depending on the array voltage (taking into account temperature) and the battery voltage at any one time.
Can I charge 36v?
Yes, however this needs to be a 150voc in MPPT controller or higher and requires reprogramming.
What about 48v battery banks?
You need a 150voc in or higher to do a 48v battery bank, this does not require programming.
What is the current limiting?
An MPPT will current limit at the given rating, you can go over this rating but it will be limited, eg. Putting 45amps into a 30 amp controller will still charge at 30amps.
How do I monitor the regulator?
There are a few ways to monitor your regulator, via Bluetooth dongle, MPPT control, BMV or Colour control, all these plug into the VE-direct cable port on the bottom of the regulator, it is a 4-pin white port.
Bluetooth dongle – uses local Bluetooth to talk to your smart phone or tablet. This does not require WIFI to work and has a range of 10m local to the device from the port. This tells you voltage, current in and out and keeps a 30 day history. You can also change charge/float/absorption voltage settings- $76.50
MPPT Control – has its own screen which tells you voltage and current, you can adjust some settings and it keeps a 30 day history. $125. This also requires a cable to connect, they come in lengths of 30cm,90cm, 1.5m, 3m, -$30
Colour control – The CCGX is a highly sophisticated piece of communication, monitoring and control equipment for multiple connected Victron devices (Fronius devices and some other Battery monitor systems are also supported). This unit can connect to, monitor and control almost any piece of Victron gear, so is incredibly useful for larger systems, consolidating all elements to one full colour control screen. The unit can log and monitor nearly all data on a system, and can even be connected to a modem for online reporting, and connecting to Victron VRM Portal. This unit allows for remote monitoring and control of a system from anywhere in the world via the units internet capabilities!
This unit has too many features to discuss them all here - check out hte Datasheet for more specific information -
How do I manage by batteries?
Proper battery management is essential to ensure the long life and correct operation of any off-grid/hybrid system. Victron offer a range of gear for battery management.
BMV-700- The Victron Battery monitor system is a the best way to simply monitor and protect your battery banks state-of-charge (SOC).
A shunt connected to the negative terminal of your battery bank measures all the incoming and outgoing charge, keeping all the checks and balances of your power generation/charging vs. your power consumption.
The BMV - 700 has user definable limits (total battery capacity, maximum depth of discharge, low and high voltage triggers) to sound alarms, or start an auto-start genset or charger via a relay switch (or VE Direct communication) to begin charging if battery capacity is detected as going too low and cease when desired voltage is achieved.
Where monitoring on a Solar charge controller can show only the power harvested from a solar array and power used from the load outputs, and an inverter can only report on the power it has consumed, the BMV-700 can show both power harvested and power consumed for more accurate monitoring of a battery's SOC.
The unit comes with a display screen, the screen has a VE direct port for interface with any of the VE direct communication cables/devices, including the bluetooth dongle or CCGX Color Control.
How can I ensure balanced charge with multiple batteries?
Multiple batteries connected in parallel or series can face issues with balanced charging. Small differences in charge factors such as resistance, health and temperature can cause some batteries to receive more or less charge than others, which can damage an expensive battery bank and affect the system’s overall performance. The Battery balancer solves this by monitoring the difference between two series batteries or a parallel bank and can move charge across to equalize the charge state between the batteries. Multiple devices can be connected together to monitor multiple batteries/sets of batteries.
Can I run a 12v load from a 24v or 48v battery bank?
Orion DC-DC Converters:
DC-DC converters have a wide range of applications, where a battery voltage is different to an application voltage and step-down or step-up conversion is required. An example of this could be a small 12v system such as lighting or a fridge running off a 24v bank, or a 12v battery that requires charging off a 24v system (or vice versa). The Orion convertors are very efficient and multiple units can be used in parallel to meet higher load demands. The output voltage can be adjusted for various applications such as battery charging and to compensate for voltage drop. This unit is available as an;
a non-isolated converter:
And high power, non-isolated converter:
How can I protect my batteries from going flat?
The Battery protect is a device that will disconnect any connected loads if the battery hits a determined low voltage value, and will reconnect when the battery is recovered. The unit is useful to prevent over discharge of a battery by connected loads, and can also sound a warning alarm via relay to report low battery voltage
There is also a model for 48v systems
How can I charge two separate batteries with one source?
Argo Diode/FET Battery Isolator:
The Argo Diode/FET Battery Isolator allows for two batteries or more to be charged simultaneously, but discharged separately. This is useful where an alternator is needed to charge multiple batteries on separate dedicated systems (such as to charge a starter battery and an auxiliary battery). The FET isolator incurs very little voltage loss, which can be an issue for lower power alternators and/or long cable runs.
Cyrix battery combiners:
Similar to the Agro Diode/FET Battery Isolator, this unit allows for a single charge source (such as an alternator) to simultaneously charge two separate batteries, but isolates the batteries for discharge (this device is commonly used in dual battery systems, where a vehicle’s alternator is required to charge both the starter and auxillary battery, but the parallel connection must be broken so only the starter battery energizes the starter motor)
Also available for Li ion batteries:
...and for high current loads:
Can I run a load directly from regulator?
Only the 75/10, 75/15 and 100/15 have load outputs and these are only for small DC loads, so no motors, induction or reactance power as the current peak would blow the fuse.
Do they come with fuses?
Only the 75/10, 75/15 and 100/15 have fuses, they are small blade fuses, the larger units have fuses inside which need to be sent back to manufacturer for replacement.
Can I run more than on MPPT?
Yes you can run MPPTs in parallel, though it advised to seek more advice to ensure max efficiency.
What is an inverter?
An inverter is used to create 240v AC power (the kind that comes from the grid) out of a battery bank. A crucial piece of equipment in off-grid systems, as most domestic applications run off 240v AC.
Victron manufacture a wide range of high quality, industry leading pure-sine wave inverters. They produce a very clean and constant load, perfect for running sensitive equipment like computers and electronics (“dirty” power from modified sine wave or cheap inverters can fail to run, or even damage sensitive equipment)
The range is too wide to discuss in detail here, but in short there are 3 kinds of inverter made by Victron available in 3 separate voltages for a given power rating (12v, 24v and 48v).
Phoenix Inverter (and V.E. Direct):
These inverters occupy the lower end of the power range, from 180W to 1200W and 250W to 800W (V.E Direct models utilise the V.E Direct communication port for monitoring and control (V.E Direct/VictronConnect is discussed elsewhere in this FAQ)
What type of Inverters are available?
We have a range of victron phoenix inverters;
All come in 12v, 24v and 48v models.
All inverters can peak at twice their rating; it is advised to not draw more than 85% nominally
Eg. A 1000w inverter can peak at 2000w for a split second but do not run more than 850w at any one time.
What is a Multiplus?
A Multiplus inverter charger both charges your batteries with up to 3 AC inputs and inverts the DC Battery bank to your AC Load. By Default they are configured to prioritise AC input for you load, only using the battery bank when there is no AC or the load exceeds the AC capabilities. You can hook up to 99 of these together.
These can be programmed to prioritise DC via a VE Direct to USB port and a computer; this can be involved and requires further advice.