Official opening: VICTRON-Competence Centre, Klagenfurt

A little over a year ago Victron Energy in association with Austrian Victron Energy dealer E-BOX Off-Grid Power Systems, together with HTL1 Lastenstraße and their headmaster Dr. Michael Archer forged a partnership to utilise Victron Energy products for their varied educational program – to build a ‘Competence Centre’.

As a result on Thursday, 5th December 2018, the new VICTRON-Kompetenzzentrum (VICTRON-Competence Centre) for ‘Renewable Energy and Storage Technology’ was opened at the school.

HTL1 Lastenstraße is a Higher Technical Institute in Klagenfurt, southern Austria, with around 1100 students and 120 teachers. The school trains engineers in the fields of mechanical engineering, electrical engineering and mechatronics. It has around 34 workshops and laboratories as well as several competence centres. Another focus is ‘Land und Umwelttechnik’ (agricultural engineering and environmental technology).

This all makes HTL1 a unique training centre, not only for students from Carinthia but southern, eastern and western Austria. With the new VICTRON-Competence Centre training courses will specialise in the fields of energy storage technology, photovoltaics and energy management. Besides these courses Victron Energy have also been welcomed to run their own special courses at the school. In addition, interested companies will also have the opportunity to use this modern infrastructure for their own education and training events.

HTL1 Lastenstraße – The school is equipped with many different, modern photovoltaic-systems.

The school were particularly pleased to receive a visit from Victron Energy sales manager Leo Yntema  for the opening. Here’s a brief video (in German) of that visit and a few photos from the opening event.

https://youtu.be/r9wasVuZIUU

From left to right: Manfred Hartner – Managing Director of  E-BOX Off-Grid Power Systems, Dr. Michael Archer – Principal of HTL1 Lastenstraße and Leo Yntema of Victron Energy.

A student explains one of the 5 Workstations and its components at the opening.

From left to right: Andreas Albel, the teacher who is responsible for the VICTRON-Kompetenzzentrum and Leo Yntema of Victron Energy.

Equipment utilised

There are 5 workstations utilising Victron Energy equipment. Each workstation is equipped with its own separate 3kWp photovoltaic-system, plus each of the panels can be switched on and off separately.

Workstation 1: components / power storage / 3-phase
  • 3 x MultiPlus 48/3000/35-16
  • 1 x Color Control GX
  • 1 x Battery Monitor BMV-700
  • 4 x LiFePO4 battery 12.8V/90Ah – BMS
  • 1 x Battery Management System VE.Bus
Workstation 2: components / power storage / 1-phase
  • 1 x MultiPlus 48/3000/35-16
  • 1 x Color Control GX
  • 1 x Wall mount enclosure for Color Control GX
  • 1 x Battery Monitor BMV-700
Workstation 3: components / power storage / 1-phase
  • 1 x ECOmulti 24/3000/70-50 2,3 kWh LiFePO4
  • 2 x LiFePO4 battery 12.8V/90Ah – BMS
Workstation 4: Components / power storage / DC coupled
  • 1 x BlueSolar MPPT 150/85 CAN-bus
  • 1 x Wall mount enclosure for Color Control GX
  • 1 x Battery Monitor BMV-700
  • 1 x Venus GX
  • 24 x OPzV 200 Batteries
Workstation 5: Components / power storage / DC coupled
  • 1 x EasySolar 48/3000/35 MPPT 150/70 with Color Control GX built-in
  • 24 x OPzV 200 Batteries

Conclusion

It’s great to see the new VICTRON-Competence Centre now open and we trust it will serve as a valuable resource for the school and the young engineers of tomorrow.

This artcle was orriginally published on the victron blog by John Rushworth on January 31st, 2019

Links

Interview with Dr. Archer – https://www.victronenergy.com/blog/2017/11/13/back-to-school-with-victron-energy/

HTL1 Lastenstraße Klagenfurt Website – http://htl1-klagenfurt.at/index.php/en/

HTL1 Lastenstraße Klagenfurt on Facebook – https://www.facebook.com/HTL1.Klagenfurt/

E-BOX Off-Grid Power Systems Website – http://www.e-box.co.at


Lead acid battery charging in cold weather

This blog covers lead acid battery charging at low temperatures. A later blog will deal with lithium batteries.

Charging lead acid batteries in cold (and indeed hot) weather needs special consideration, primarily due to the fact a higher charge voltage is required at low temperatures and a lower voltage at high temperatures.

Charging therefore needs to be ‘temperature compensated’ to improve battery care and this is required when the temperature of the battery is expected to be less than 10°C / 50°F or more than 30°C / 85°F. The centre point for temperature compensation is 25°C / 77°F.

Cold weather also reduces a battery’s capacity. This is another factor that needs to be taken into consideration, along with the load and charge rate compared to the battery capacity (Ah). Both of these factors affect the correct and consequent sizing of a battery for your particular application.

Battery capacity in Ah is usually quoted as a 20 hour capacity rating at 25°C. The discharge rate or load can be written as 0.05C where for example C is the load factor of the 20 hour rated battery capacity at 25°C.

Worked examples: If a 100Ah 20hr rated battery then a 0.05 load would be 100 x 0.05 = 5 Amps or 100/20 which is also a 5 Amp discharge rate over that 20 hour period. A 10A load on a 100Ah 20 hour rated battery would therefore be a 0.1C discharge rate, a 0.2C discharge rate on a 200Ah would be 40A and so on. C ratings also relate to charge rates as well as discharge rates.

When buying a battery you may see its Ah quoted at 20 (the standard rate), 10 and 5 hour rates so you can see how load ‘shrinks’ the Ah. Some even quote at 25 hour rates, which often fools people into thinking they are getting a bigger battery than standard.

To recap – capacity reduces at low temperatures, as it does for higher discharge C rates above the 0.05C 20 hour rate. This reduction in capacity due to higher discharge rates is due to Peukert’s Law.

Graph showing the effect on battery capacity due to temperature and load:

Lead acid battery differences

Lead acid batteries come in a variety of types:
  • Wet lead with the ability to top up each of the six cells with de-mineralised water.
  • The so called ‘sealed’ wet lead leisure or rather maintenance free battery. These cannot be topped up and often have a green go or red no go cell inspection indicator.
  • AGM (Absorbent Glass Mat) valve-regulated lead-acid (VRLA), where the electrolyte is absorbed in a glass mat.
  • Similar to the AGM, but the electrolyte is held in a Gel.

All of the above are however lead based (as opposed to lithium) technology. Besides lithium batteries Victron Energy sell VRLA AGM and Gel monoblocs (6 x 2V cells in series) due to their superiority over wet lead monobloc types. Victron’s range consists of:

  • Gel (Better cycle life than AGM).
  • AGM (Better than Gel for higher loads and well suited for use with inverters).
  • AGM Telecom. Designed primarily for Telecom applications, but also excellent ‘footprint space savers’ for marine and vehicle applications.
  • AGM Super Cycle (Best if frequent discharge to 60-80% DOD is expected).
  • Lead Carbon Battery (Improved partial state-of-charge performance, more cycles, and higher efficiency).

Additionally Victron also sell specialist lead acid type batteries.

  • OPzV 2V individual battery cells. Long life, high capacity gel.
  • OPzS 2V individual battery cells. Long life high capacity flooded tubular plate batteries for specialist solar applications.

Temperature compensation and charging

Now we know about the kind of batteries, capacities and loads we are dealing with, we need to put some numbers together for temperature compensation and charging.

The recommended temperature compensation for Victron VRLA batteries is – 4 mV / Cell (-24 mV /°C for a 12V battery).

Besides accounting for cold weather charging the charge current should preferably not exceed 0.2C (20A for a 100Ah battery) as the temperature of the battery would tend to increase by more than 10°C if the charge current exceeded 0.2C. Therefore temperature compensation is also required if the charge current exceeds 0.2C.

How to achieve temperature and voltage compensated charging

There are a range of Victron products to achieve this.

With our range of inverter/chargers and since VE.Bus firmware version 415 was released some time back this has ensured that:

– Temp compensation continues down to -20C

– This is for all voltage set-points, except for float, storage and the start of bulk charging

– As soon as the temperature goes below -30C, the compensation mechanism is disabled (normal charge voltages are applied) and a warning is shown.

For systems that don’t use an inverter/charger – we can use Smart Battery Sense to ensure that charging sources provide optimal voltage and temperature compensated charging to your batteries, by wirelessly transmitting accurate battery voltage and temperature values to your Solar Charge Controller or Smart battery charger.

This information is then used to set the ideal charging parameters, resulting in more complete, faster charging – improving battery health and therefore extending battery life.

The Victron Toolkit app allows you to calculate cable sizes and voltage drop. Here’s an example where cable length is the round trip of the positive and negative battery charging cables. This is so you get an idea of what Smart Battery Sense automatically takes into account to ensure the correct charge voltage goes into the battery, by ensuring the charge voltage is compensated for and corrected due to any cable losses.

Victron’s range of SmartSolar MPPT Charge Controllers all work with the Smart Battery Sense. In fact I’ve just fitted one to my motorhome, along with the required Smart Battery Sense, due to the fact the leisure battery temperature location when compared to the location of the controller can have a difference of up to ten degrees. Definitely a case for ensuring accurate temperature compensation.

Other products can be connected too by using what we call ‘VE.Smart Networking support’. See the VE.Smart Networking page.

Conclusion

With the above solutions I know I’ll be happier now that my batteries are getting exactly the right charge due to optimal temperature and voltage compensation.

Why not make sure you are doing the same…

John Rushworth


The Kruger National Park is home to a third of the world’s remaining Rhino – a fact which makes the park attractive to poachers who kill Rhino just for their horns.Rhino Poaching Surveillance in the Kruger National Park

In order to try to prevent the Rhino from becoming extinct – Park Rangers have to be constantly on the lookout for poachers in a wilderness which extends to 2 million hectares. That’s an area equivalent to a box whose sides measure 140km/90miles – you can’t be everywhere at once, so the Rangers have installed some discreet technology to help.

Saving the Rhino is a race against time because the growth in poaching has been alarming: In 2007, 13 Rhino were poached in South Africa …by 2014 that figure had increased 9000% –  1215 animals were illegally slaughtered in that year alone.

Powdered Rhino horn has become more valuable than cocaine – fuelled by the misguided belief, particularly in the East, that it has medicinal value. When prices rose recently, Rhino became a target-interest of international organised crime – turning what was then localised illegal activity into something of global industry.

In order to maximise their policing, Kruger National Park Rangers have set up a number of radar detection systems, strategically installed to offer wide area surveillance, both day and night. Three or four units allow them to cover half the park area. The radar detects movement and plots it on a map. Remotely operated camera’s allow the operators to distinguish between  ‘Animal’ and ‘Human’ movement. Suspicious activity is then intercepted by truck or helicopter.

Financed mainly by charitable donations the surveillance installations are highly mobile, frequently moved, and can be packed for deployment by truck – or even slung under a helicopter and flown-in to new surveillance sites.

These mobile installations need reliable off-grid power source – for which Lithium battery specialist BlueNova located in Cape Town led the system design. Lithium Batteries are an ideal solution to frequently-relocated installations – amp for amp they’re almost 80% smaller and lighter than their Lead/Acid equivalents. And amongst a topography of scrub and boulder, PV panels offer discreet power-generation. They do not impinge on the visual amenity which is so important to wildlife tourists on safari; and they remain undetected by would-be poachers.

The power plant features 26V-8kWh BlueNova Lithium Ferro Phosphate battery (LiFePO4)

24V 3kVA Victron Multiplus

2 x BlueSolar Victron MPPTs  Solar Chargers to regulate the six-panel PV array.

 

Currently, three Rhino’s are killed illegally every day. At that rate the animals will soon face extinction. All that can be done to slow the decline should be done. Against armed poachers, the Kruger National Park Rangers are carrying-out a dangerous job with utter commitment to conservation – this technology helps them reduce the slaughter.


The hardware in Victron Energy Multiplus inverter/charger range has been improved: it can now switch much faster from inverter mode to mains mode. Combined with our high peak power ratings, this makes it possible to switch to mains mode before shutting down in an inverter overload alarm. This is especially useful in Self-consumption Hub-1 and 2 installations: it allows using an inverter/charger with a nameplate power below the system power. Multiplus inverter improved: faster switching to grid

The old hardware will take approximately 8.5 seconds to switch from inverter- to charger-mode, the new hardware can do it within half a second. Some notes:

  • single phase installations will be even faster than the half a second mentioned;
  • fast switching is only possible in the 3xx firmware versions. The difference between 3xx on one hand, and 1xx and 2xx on the other hand is approximately another 0.5 second in the worst case scenario: slightly differing frequency, and inverter being 180 degrees out of sync with the grid;
  • all larger models, 3kVA and upwards, already have fast-switching since a long time;
  • do not forget the other limit to using an ‘undersized’ Multiplus Compact in an installation: the AC transfer capacity. Max system load may never exceed the transfer switch capacity;
  • the load-shedding functions in the self-consumption hub-1 and 2 Assistants give options to further undersize a Multiplus Compact: use an external relay which is controlled via the Auxiliary output;
  • mentioned switching delays have not been measured exactly;
  • for parallel and three-phase operation, please check the Disqus comments below.

Lots of little details, but all together the conclusion is that this significantly reduces the chance of a Victron switching off in overload condition.Multiplus inverter improved: faster switching to grid

Availability

Despite stock and production logistics, all different models are shipping with the new hardware. Below table gives an overview of the current situation, from our main warehouse DSV in the Netherlands.