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Fox ESS PQ Series 8kW Stackable All-In-One with Heating Function
Fox ESS PQ Series 8kW Stackable All-In-One with Heating Function
Fox ESS PQ Series 8kW Stackable All-In-One with Heating Function
Fox ESS PQ1 Series — An all-in-one that stacks: inverter, battery and heating in one floor-standing tower.
The PQ1 is not a wall-hung inverter with a battery next to it. It is a single floor-standing unit that contains the inverter and stacks battery modules underneath, with the cabling between them made at the factory rather than on site. For an installer that removes the battery cabling, the comms cabling and most of the commissioning; for a customer it removes a second box from the wall.
About the Fox ESS PQ1 Series
The heating function is the detail that matters in a British winter. Lithium cells cannot be charged below 0 °C without damage, and an unheated outdoor battery in an unheated garage will refuse to charge on the coldest mornings — exactly when the tariff is cheapest. The PQ1 warms its own cells.
It runs from 3.68 kW to 12 kW with two to four MPP trackers, IP66 for outdoor use, and up to three units in parallel. Maximum battery charge power is 12 kW across the range, and depth of discharge is 90 %.
Which battery does this inverter take?
This inverter takes High voltage Fox ESS stacks.
This model has a battery voltage window of 80 – 500 V, a maximum charge or discharge current of 50 / 50 A.
A stack is one master module, which carries the BMS, plus matching slave modules of the same type. Module types are never mixed in one stack. These are the counts this inverter is listed for — Product Compatibility Fox ESS UK 2026, the module count range for this inverter family:
What we stock that fits this inverter:
String design, battery limits and what is in the box
The details that decide whether this unit suits the job:
- Battery is EQ5000 modules, 80 – 500 V, 2 to 6 per system. Fox's compatibility matrix lists only the EQ5000 against PQ1 — the CQ7 is not a supported pairing.
- Note the minimum battery voltage at full AC load: 78 V on the 3.7 kW rising to 247 V on the 12 kW. A two-module stack will not deliver full output on a 12 kW unit.
- Maximum battery charge power 12,000 W across the range; discharge matches the AC rating. 50 A charge and 50 A discharge.
- 3.7 and 5.0 kW have two MPP trackers; 6.0 kW has three; 8.0 kW and above have four. 8,000 W per tracker, 20 A, 25 A Isc.
- AC input up to 14.5 kVA and 63 A on the 7 kW and above — configurable on the platform.
- EPS load start capability is 122 A for 2 seconds, with bypass to 63 A.
- Floor mounted, 570 × 420 × 380 mm and 35 kg for the power module. IP66.
- 3.7 to 6.0 kW are convection cooled under 35 dB; 7 kW and above use fans at under 50 dB.
- Battery warming function and AFCI are both optional. DC switch is fitted.
- The datasheet's grid regulation row quotes AS/NZS 4777.2:2020 and IEC 62619:2022 for the battery. For a UK G98 or G99 application ask us for the current Fox certificate that matches your firmware and we will send it with the order.
Where this hybrid earns its place
The PQ1 Series is specified most often for these jobs.
Things worth knowing about this listing
- Battery compatibility: 2 to 6 × Fox ESS FE-HV-EQS-5000 modules.
- Register the installation with Fox ESS at fox-ess.com to activate the 10-year warranty. Unregistered, the cover is 5 years.
Fox ESS PQ1-8.0 technical data
Ordered with this inverter more often than anything else
A hybrid is the middle of a system, not the whole of it. These are the parts our customers add most often:
Questions we get asked about this inverter
Why does battery heating matter in the UK?
Lithium cells cannot be charged below 0 °C without permanent damage, so an unheated battery simply refuses to charge on a frosty morning. That is exactly when an off-peak tariff is cheapest and when you most want a full battery. A heated stack keeps working.
Which battery does it take?
Fox EQ5000 modules, two to six of them. Fox's UK compatibility matrix does not list the CQ7 against the PQ1, so do not plan on one.
Can I start small and add modules?
Yes, from two to six. But check the minimum battery voltage at full AC load for your model — on the 12 kW it is 247 V, so a small stack will limit output.
Is it really all-in-one?
The inverter and battery are one stacked unit with factory-made interconnects. You still connect PV, AC and comms.
Indoors or outdoors?
Either. It is IP66 and rated −25 °C to +60 °C, with derating from +45 °C.
How many can I run together?
Up to three in parallel.
Documents, advice and trade pricing
Every datasheet, certificate, installation manual and warranty document we hold for this product is in the Documents tab below. See the rest of our hybrid inverter range, our batteries and our solar panels, or email sales@clearraysolar.com if you would like us to check a battery pairing or a string design before you order.
Three figures govern it, all in the Technical Specifications: the MPPT voltage range, the maximum input voltage and the maximum DC power. Tell us which panel you're pairing it with and we'll confirm the string layout.
G98 covers installations up to 3.68kW per phase and is notified to your DNO after commissioning. Anything larger needs G99 approval agreed beforehand. We can flag which one your design falls under.
A hybrid inverter takes a DC-coupled battery directly. A standard string inverter needs an AC-coupled battery alongside it. The Technical Specifications show which type this unit is.
Yes, up to the maximum DC power figure in the specifications. Modest oversizing is normal practice - it lifts output in winter and at either end of the day, at the cost of brief clipping at midday peak.
An MPPT tracks the optimum operating point for a string of panels. You want one per roof orientation or pitch, because panels facing different directions on a single tracker drag each other down.
The standard manufacturer warranty is listed under the Warranty tab. Extended cover is available on most brands - see Warranty Extensions.
Build your complete solar system
Everything you need in one place.
- Inverters
- Batteries
- Mounting Systems
- Cabling & Accessories
- Protection Devices
Delivery times vary by region:
- UK — 1-2 business days
- Highlands & Islands — 1-2 business days
Returns accepted within 14 days of delivery for unused items in original packaging.
