Save BOS Cost

We're consistently told how easy we are to install, and how much we save people in labor and materials.

  • Plug and play design allows for easy installation and replacement if needed
  • Array installation crew can do all but AC home runs
  • Connectors are certified means of AC and DC disconnect
  • No special Rapid Shutdown equipment
  • No cranes or lifts to get equipment to roof-top

 

Learn more from these customer-costed case studies against competitors.

Case Study: 480V & 208V installations

Reliability by Design

We've taken a new approach to solar inverters, one that has focused first and foremost on enhancing reliability. Examples of the careful design are:

 

No electrolytic capacitors. These electronic components are very common in many household items as well as most solar inverters. It is well-documented that with time and heat they tend to dry out and fail, often in only 5-7 years. They are a leading cause of failure in inverters, which is why we have avoided them completely.

 

Automotive-grade components. Cars tend to be hostile environments and require tough and long-lasting electronics. Unlike any other inverter we've heard of, we only use automotive-grade components inside our inverter. One example of why we do this is their extended operating temperature range of -40 to +105 °C, making us feel confident in our overall inverter operating range of -40 to +65 °C.

 

One single-sided circuit board. Two of the most common causes of failure in electronic systems are connectors and cabling. We've seen the inside of some leading inverter models with 7 or more separate circuit boards and many, many cables and connectors - a likely cause of future problems. We've kept each of our units to one board, and consequently a bare minimum of cables and connectors.

 

Sealed, with convection cooling. Many people have experienced failures with the electric fans that cool their computers, and its the same with inverters - fans are another common cause of inverter faults. In addition, they tend to suck dirt and dust into the enclosure which is not desirable. One of many advantages of being fully sealed, waterproof and NEMA6 certified is that dirt cannot get inside, and we don't use fans.

Lab Tested

We've worked with Reliant Labs to put the product through Highly Accelerated Life Testing (HALT) to make sure it really is tough and reliable. Our unit was subjected to repeated cycles of thermal shock, and vibration at 25g, at the same time, and passed. Read more in the lab report.

Graph os temperature and vibration from thermal shock HALT testing; inverter in test chamber

Advanced Monitoring

HiQ inverters have extensive monitoring derived from many built-in sensors that keep track of the operation and external conditions. The data produced is useful from the commissioning process onwards for the life of the plant, allowing performance to be observed in real-time.

Kiosk summary page for a site showing useful summary graphs, physical map location and greenhouse gasses offset
Graph showing array output during one day, with the measured cloud cover also displayed
Inverter production comparison graph showing variation across the site
Graph showing comparison of production from multiple inverters over several days

NEMA6 Rugged

We've driven a Subaru WRX over a HiQ inverter with no problems, the unit continues to work just fine. We've tested it underwater. We have had units mounted in a desert environment for several years with no ill effects. Our inverters are uniquely suited to hostile environments such as desert, high altitude and coastal regions with salt air.

PV solar inverter with a car on top of it, demonstrating how rugged the inverter is
PV solar inverter shown operating in a tub of water with a Nemo fish toy floating in it

Mountable Anywhere

HiQ Solar inverters are sealed, waterproof, silent, rugged and reliable. They can be mounted just about anywhere.

HiQ Solar PV inverter mounted face down under a PV array. Inverter can be mounted in any orientation
Inverter mounted under a low profile roof-mounted array

Easy Rapid Shutdown

If your inverter is designed to hang on a wall, it's hard to force-fit it onto a roof, with the poor thing forced to lie almost on it's back. It's a lot easier if your inverter was designed from the ground up to be array-mounted, like the HiQ TrueString inverter. Tuck it out of the way, safe in the knowledge that it's easily within the 10 foot and even the 1 foot area specified in the NEC.

HiQ Solar inverter mounted under a PV solar array complying with NEC Rapid Shutdown

Cradle Compromises or Purpose-Designed Solution?

The HiQ Solar TrueString inverters were designed from the outset to be array-mounted. Below is a quick comparison of our approach with the large 3-phase string inverters that are increasingly common.

3-phase String on a Cradle HiQ TrueString Mounted Under the Array
1. Satisfies 2014 NEC 690.12 Rapid Shutdown 10’ rule? When installed correctly and within 10 feet of the array, yes When installed correctly and within 10 feet of the array, yes
2. Satisfies 2017 NEC 690.12 Rapid Shutdown 1’ rule? Possible, but awkward - not designed for this When installed correctly and within 1 foot of the array, yes
3. Ease of designing with Requires extra wide walkways or takes up space in mandated walkways Sits under the array, but easy to access unlike micro inverters
4. Ease of installation Typically weigh more than 150 lb., hard to lift, requires more than one person. Requires extra effort and cost to buy and assemble the cradle Weighs 24 lb. Easy to lift, easy to install, easy to carry spares.,Easy to install by one person.,Connector-based electrical connections.
5. Reliability LCDs, fans etc. require maintenance and regular replacement. Often these inverters use electrolytic capacitors. Sits in full sun. Not being used as originally intended NEMA6, no electrolytics, no display, no fans. Maintenance-free. Robust, single circuit board, automotive grade components. Being used as intended
6. Ease of replacement later 150 lb.+, hard to get replacement units onto a roof later, requires several people in the crew to do so Tuck one under your arm, climb a ladder. Unclick the connectors, click in the new one. Easy
7. Other Usually strings are paralleled, making poor granularity of monitoring, fault-finding and arc detection Each string has separate MPPT, monitoring. Single string arc detection, placed next to the modules, makes arc detection reliability better, and reduces occurrence of false-positives

AFCI per String

Solar PV systems are known to cause fires. This is not surprising given that typical installs are comprised of many, many high voltage connections, arising from the stringing of PV modules serially together. The combination of high voltage (up to 1,000Vdc) and many manual installation steps where the probability of imperfect connector mating is high, makes arcing a real and frequent risk. To protect against this, US rules require PV systems to have arc detection. However recent fires demonstrate that there is a gap between product compliance, and the detection of real-world arcs in the field.

 

Reliable detection of real arcs is a very difficult engineering problem. It is easier for an inverter with single strings, and placed close to the array than for large string inverters placed long distances away from the array and with strings paralleled together. These large string inverters, and also central inverters, may turn to the use of combiner boxes, which separate the strings and do arc detection per string. These devices must then communicate with the inverter to shut off when an arc is detected. Clearly this entails a lot more hardware, more failure points, more headache, more costs.

 

The TrueString architecture of HiQ Solar solves this problem simply and reliably.

 

The video below, and the photos to the right show results from some customer testing of a real-world arc produced by a test fixture positioned in the middle of a string of PV modules. A variety of AFCI-compliant string inverters were tested, and none detected the arc except the HiQ Solar TrueString.

Upper photo:
AFCI compliant inverter failing to detect & extinguish a real-world  arc

 

Lower photo:
Arc being detected and extinguished by a HiQ TrueString inverter

Light Weight

The TrueString 480V packs an impressive 8 kW into just 24 lbs. Not just light in weight, but also very small; a guiding design principle of our inverters is that they should be liftable and capable of being carried under your arm. This makes installation easier, and usually achievable by just one person. No OSHA safe-lifting limits to worry about.

Ideal for Retrofits

  • Usually don't need to lay out the roof again, work with the existing design even if the modules are old
  • Reduce the footprint of inverters - easy to site at the array
  • Suited for 600V and 1,000V installations
  • Easy to comply with recent rule changes such as Rapid Shutdown
  • 200-850V MPPT voltage range for 600V and 1,000V systems
  • High MPPT efficiency even for 600Vdc systems
  • Powerful integrated powerline communications & analytics – no additional wiring
  • Integrated measurement equipment for troubleshooting and performance metrics
  • Connectorized DC & AC for install or replacement
  • No annual maintenance; no fans; no electrolytics; no mounting orientation requirements
  • Waterproof

Using HiQ TrueString Inverters to replace the existing central inverters  liberated valuable space inside the building