Our picks

The parts we choose,
and why.

Every part on this page is one we fit on our own sites. Our best option for most projects is a Huawei inverter with LONGi back-contact panels, protected by ABB, CHINT and SUNTREE switchgear and wired in copper from Yazaki and LINK. Below is the reason behind each choice, and the alternatives we trust.

Looking for prices? Members can download the price list. Not a member yet? Ask through a consultation.

Inverters

We install all sorts of brands: Huawei first, with five alternatives we trust

The right brand depends on the site: roof shading, phase balance, battery plans and budget.

The inverter is the heart of a solar system.

It turns the DC power from the panels into the AC power your home or business uses, decides when to charge the battery or draw from the grid, and shuts the system down safely when something is wrong. It is also the part most likely to need attention over 20 years, so we choose on service first and price second.

Hybrid inverter with stacked battery, mounted on a steel frame at a Solar ESS site
Hybrid inverter with battery
Inverter and AC/DC combiner box on a steel mounting frame with conduit
Inverter and AC/DC combiner box
Inverter and distribution box installed indoors above a wireway
Indoor installation over a wireway

Our first choice · 5 kW to 100 kW

Huawei

Huawei is the inverter on most of our sites. What we love most is the service system behind it. We can submit a ticket directly to Huawei, no matter where your installer or supplier is, and you are treated as Huawei's own customer.

If a unit has to be claimed, Huawei delivers the replacement to your door and collects the faulty one for investigation.

Homes with uneven loads

Solis

We love how it supports an unbalanced system at home, where the three phases carry different loads, and its practical remote app.

Microinverter

Enphase

A long-term warranty and a worry-free option for owners who want to fit it and forget it.

Microinverter

ATMOCE

We love its safety and durability. Each panel has its own small inverter, so there is no high-voltage DC cable running across the roof.

All-in-one storage

Sigenergy

Inverter, battery and energy management in one modular stack. Battery modules can be added as needs grow, with an EV charger option in the same system.

Shaded and complex roofs

SolarEdge

We love the optimizers, which let every panel work at its own best, and the long warranty. The monitoring app is excellent.

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Solar panels

Back-contact panels from LONGi and AIKO

The newest step in a long line of improvements. Here is how panels got to this point.

Each generation of solar panel has turned a little more of the same sunlight into electricity.

  1. Amorphous and thin filmA thin layer of silicon or another material laid on glass or a flexible sheet. Cheap and light, and familiar from pocket calculators, but low in output, so a roof needed a large area for little power.
  2. MonocrystallineCells cut from a single silicon crystal. More power from the same area and a longer life, which made mono the standard for rooftops.
  3. PERCA reflective layer added to the back of the cell sends unused light back through the silicon for a second chance at being absorbed.
  4. BifacialGlass on both sides, so the panel also collects light reflected from the ground or roof onto its back.
  5. Back contact (HPBC and ABC)All the metal wiring moves to the back of the cell. Nothing on the front blocks the light, and the whole face of the cell works.

Our standard panel

LONGi HPBC

HPBC stands for Hybrid Passivated Back Contact, the technology in LONGi's Hi-MO X10 range. With no busbars on the front, more light reaches the cell and the panel has a clean, all-black face.

It gives high output per panel, so the same system needs fewer panels, fewer roof fixings and less cable. It also copes better when part of a panel is shaded by a tree, a pole or a neighbouring roof.

Also installed

AIKO ABC

ABC stands for All Back Contact, used in AIKO's Neostar range. Both the positive and negative contacts sit on the back of the cell, leaving the front completely clear.

It is among the most efficient panels available for rooftops, and handles partial shading well, which suits small or awkward roofs where every square metre counts.

Compared · October 2026

AIKO or LONGi?

On technology the two are almost a tie. Both lose 0.26% of power per °C, age at the same rate and carry the same 15-year product and 30-year performance warranties. In the same size frame, the AIKO sold in Thailand gives 670 W against 650 W for the LONGi.

On price there is no clear winner: in Thai shops both cost about the same per watt. LONGi is the larger company, shipping about three times as many panels. We choose between them by roof space and the supplier price on the day.

Download the full comparison (PDF, English)

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Battery

Intellihome, LV Topsun G4, Flex Core ID and Dyness

Sized to your evening load and the backup you need, not the biggest box on offer.

A battery is only as good as its conversation with the inverter.

What we fit

Chemistry
LiFePO4 (lithium iron phosphate)
Brands
Intellihome, LV Topsun G4, Flex Core ID, Dyness
Pairing
Checked against the inverter maker's approved battery list for each project

Why we pick it

  • LiFePO4 is the safer lithium chemistry and keeps its cycle life in Thai heat.
  • An approved pairing means the battery and inverter talk to each other properly, so charging, backup and warranty all work as they should.
  • Sized from the site's real evening and night consumption, read from the meter data.
  • Installed in shade, ventilated and off the floor, with its own DC breaker.
Ask for a price

Breakers

CHINT MCCB, ABB and IPG

Sized to the cable and the inverter on every circuit, DC and AC.

A breaker is cheap until the day it has to work. This is the wrong place to save money.

What we fit

AC breakers
ABB, IPG
DC breakers
SUNTREE
DC fuse holders
SUNTREE
MCCB, main and changeover boards
CHINT

Why we pick it

  • Each breaker is matched to the cable it protects, so the breaker trips before the cable overheats.
  • DC circuits get breakers rated for DC. An AC breaker on a DC string cannot be relied on to break the current.
  • Labelled and laid out in the box so the next electrician can see what each one does.

DC combiner box: SUNTREE fuse holders and breakers

Every solar string comes into the DC box through a SUNTREE fuse holder on both the positive and negative lines, then a two-pole SUNTREE DC breaker, before it reaches the inverter.

DC combiner box with a row of SUNTREE fuse holders, two-pole SUNTREE DC breakers, surge protection devices and an earth bar
DC combiner box: SUNTREE fuse holders and two-pole DC breakers, one set per string
  • The fuse protects the string cable and panels if another string back-feeds a fault into it.
  • The two-pole DC breaker isolates each string on its own, so one string can be worked on while the rest keep producing.
  • Fuse holders open safely for checking and changing a fuse, with no live parts exposed.

Moulded-case breakers (MCCB)

On the main feeders of a hybrid or backup system (the grid, inverter, backup and bypass circuits) we fit CHINT moulded-case circuit breakers. They carry the full feeder current, from about 63 A to 160 A and above, where small DIN-rail breakers stop.

Changeover board with CHINT MCCBs labelled Grid, Inverter, Back up and By pass, and a 4-pole automatic transfer switch
Changeover board: grid, inverter, backup and bypass MCCBs with a 4-pole ATS
  • A high breaking capacity, so a short circuit is cleared safely instead of welding the contacts shut.
  • Earth-leakage versions on the inverter and backup circuits, for protection against electric shock as well as overload.
  • Four-pole models where the neutral must switch with the phases, as on a changeover board.
  • Every breaker is labelled, and a bypass breaker with written switching steps keeps the building supplied while the ATS or inverter is serviced.

RCBO: one-way or two-way?

An RCBO combines earth-leakage, overload and short-circuit protection in one unit. In a solar home, the direction power flows through it matters.

Unidirectional
Built for power in one direction only, from the supply (Line / In) to the circuit (Load / Out). For ordinary lighting and socket circuits fed only from the grid.
Bidirectional
Certified by the maker to work safely with power flowing either way. For any circuit that solar, a battery, a generator or a V2G charger can feed.

How to tell them apart

  • A unidirectional RCBO has terminals marked Line / Load or In / Out, or an arrow, on the case or the front diagram.
  • A bidirectional RCBO has no fixed supply side, or its datasheet states that it is suitable for power flowing in both directions.
  • If the datasheet does not say bidirectional, we treat it as unidirectional.

How we wire them

  • A unidirectional RCBO only ever takes the supply on its Line / In terminals. An inverter, battery or generator is never connected to its Load side; fed backwards it may not trip, can be damaged, and can leave its electronics live during a fault.
  • On circuits that solar, a battery or a generator can feed, we fit RCBOs the maker certifies as bidirectional, wired to the maker's diagram.
  • Where the neutral must be switched, we use double-pole devices.
CHINT MCCBs labelled GRID-INV and GRID
CHINT MCCBs labelled GRID-INV and GRID
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Fuses

SUNTREE gPV fuses on every string

Solar-rated DC fuses in touch-safe holders.

The fuse is the cheapest part in the DC box, and the one that stops a string fault becoming a fire.

What we fit

DC fuses
SUNTREE, gPV class, rated for the system DC voltage
Fuse holders
SUNTREE, touch-safe

Why we pick it

  • gPV fuses are made to clear the low fault currents a solar string produces. An AC fuse is not.
  • Fitted on both the positive and negative lines where strings run in parallel.
  • The rating is chosen above the string current and within the panel maker's maximum series fuse rating.
  • Holders open safely to check or change a fuse, with no live parts exposed.
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Surge protection (SPD)

SUNTREE surge protection on both the DC and AC sides

Fitted in the DC and AC boxes, with a proper earth.

An inverter is electronics. Surge protection costs a small fraction of the inverter it saves.

What we fit

SPD
SUNTREE, DC and AC

Why we pick it

  • Thai storm seasons bring lightning surges down both the roof cables and the grid line. Protecting one side only leaves the inverter exposed.
  • Installed close to the equipment with a short, direct earth connection, which is what makes the device effective.
  • Checked at every maintenance visit.
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Automatic transfer switch (ATS)

An ATS rated for the full load, chosen per project

Used where a site has backup power, a generator or more than one supply.

The ATS is a safety device as much as a convenience. We size it to the site, not to a price list.

What we fit

ATS
GEYA, CSQ, SUNTREE

Why we pick it

  • Switches the load between sources by itself, so the lights come back without anyone going to the board.
  • Breaks one source before making the other, so solar or generator power can never feed back into the grid line.
  • Rated for the full current of the circuits it carries, with margin, not for the average load.
  • Laid out with a manual bypass so the site can still be run by hand during service.
GEYA 4-pole ATS with its own controller, mounted in the changeover board
GEYA 4-pole ATS with its own controller, mounted in the changeover board
Changeover board: CHINT MCCBs, ATS and labelled terminals
Changeover board: CHINT MCCBs, ATS and labelled terminals
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Cable and fuses

Yazaki copper on the AC side, solar-rated cable on the DC side

Copper throughout, sized to keep losses low.

Cable is hidden once the job is finished, which is exactly why it is the first place cheap installations cut.

What we fit

AC cable
Yazaki, copper
DC cable
LINK, Phelps Dodge, HELUKABEL
DC fuses
SUNTREE

Why we pick it

  • Solar-rated DC cable is double insulated and built for years of sun, heat and rain on a roof.
  • We size cable by the length of the run, not by the minimum that will pass, so less of your solar power is lost as heat.
  • Fuses on the DC strings protect the cable and panels if one string develops a fault.
  • Run in conduit and wireway, clipped and labelled, with nothing left loose on the roof.

AC cable

Yazaki copper from the inverter to the main board, sized for the inverter's full output and the length of the run.

  • We keep the voltage drop small. A long, thin AC cable raises the voltage at the inverter, which can make it trip off on high grid voltage.
  • Run in conduit or wireway and labelled at both ends.

DC cable

Solar-rated, double-insulated copper cable (LINK, Phelps Dodge, HELUKABEL) from the panels to the inverter.

  • Built for UV, heat and rain on a roof for the life of the system.
  • Positive and negative are run together and kept short to reduce losses and surge pickup.
Yazaki THW copper cable, IEC 01, 450/750 V
Yazaki THW copper cable, IEC 01, 450/750 V
Yazaki THW in phase colours for the AC side
Yazaki THW in phase colours for the AC side
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Wiring

Neat, labelled and built to be serviced

How the cables are run matters as much as which cables we buy.

Most faults we are called to on other installers' systems start at a connector or a loose terminal.

What we fit

Connectors
Genuine MC4-type connectors from the same maker on both halves
Conduit and wireway
UV-resistant on the roof, metal where cable could be damaged
Labels
Every cable, string and breaker

Why we pick it

  • Mixing connector brands is a common cause of hot joints and arcing, so both halves always come from one maker.
  • Connectors are crimped with the correct tool and terminals are tightened to the stated torque.
  • Cables are clipped off the roof surface and kept away from sharp edges and standing water.
  • AC and DC are run separately, and polarity is checked before anything is connected.

See our research report on overheated joints on the Technical page.

Control box: every wire on a labelled terminal, run in wireway
Control box: every wire on a labelled terminal, run in wireway
Operating instructions fixed inside the board door, in Thai
Operating instructions fixed inside the board door, in Thai
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Grounding system

One earth, measured and recorded

Panel frames, rails, boxes and the inverter all bonded to a tested earth.

Surge protection and leakage protection only work if the earth behind them is real.

What we fit

Earth rods
Copper-bonded ground rods
Earth conductor
Green/yellow copper, sized to the circuit
Bonding
Every panel frame, rail joint and metal box

Why we pick it

  • Bonding the frames and rails means a fault cannot leave exposed metal live.
  • Surge protection drains a lightning surge to earth through a short, direct path.
  • Earth resistance is measured at commissioning and recorded, with a target of 5 ohms or less.
  • The solar earth is joined to the building's main earth so there is no difference in potential between them.
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Smart meter

The inverter maker's own meter, at the grid connection

Needed for zero export, battery control and accurate self-consumption figures.

The inverter can only control what it can measure.

What we fit

Meter
The meter specified by the inverter maker, single-phase or three-phase to match the supply
Location
At the grid connection point, after the PEA meter

Why we pick it

  • Zero export and export limits depend on it. A meter in the wrong place makes the system export, or hold back solar for no reason.
  • Three-phase sites get a three-phase meter, so the inverter sees each phase on its own.
  • It gives the monitoring app real consumption figures, not estimates.
  • Wiring, direction and phase order are checked at commissioning.

See our zero-export case studies on the Technical page.

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Sensors

Current transformers and monitoring sensors

The small parts that tell the system, and us, what is really happening.

One CT clipped the wrong way round can make a good system look broken.

What we fit

Current sensors (CT)
The inverter maker's own CTs, sized to the main breaker
Monitoring sensors
Irradiance and panel-temperature sensors on larger plants, on request

Why we pick it

  • Each CT goes on the right conductor, facing the right way, on its matching phase.
  • Split-core CTs let us fit them to an existing board without cutting the supply.
  • Irradiance and temperature readings let us judge output against the weather, for example before deciding whether panels need cleaning.
  • Readings are logged in the monitoring app, with alarms when something drifts.
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Enclosures

KJL steel boxes

For the AC and DC combiner boxes beside the inverter.

The box keeps water, dust and hands away from live parts for the life of the system.

What we fit

Enclosure
KJL, steel

Why we pick it

  • Steel stands up to heat and knocks better than plastic, and gives a solid earth point.
  • Sized with room inside, so breakers and surge protection run cool and can be serviced.
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Test instruments

Hioki and Fluke

What we measure with matters as much as what we install.

Every system is tested before handover and at each maintenance visit.

What we fit

Instruments
Hioki, Fluke

Why we pick it

  • Insulation, earth and string measurements are recorded at commissioning, so later readings have something to be compared against.
  • Thermal checks on boxes and connections find a loose terminal before it becomes a fault.
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Supply

Buy the same materials from us.

Installers and owners can order any of these parts through Solar ESS, with advice on sizing included. We do not publish prices here. Members can download our current price list with their password. Not a member yet? Book a consultation and ask for one.

Member price list

kris@solar-ess.org
063 151 6694 · 089 429 6832

Integrated price list

Integrated price list

The full Solar ESS price list is available here with a password. Ask us for the password through a consultation request.

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