FoxESS Hybrid Inverters with Second-Life EV Batteries

FoxESS (Wenzhou, China, founded 2019) builds one of the more affordable hybrid inverter portfolios. Its H-series (DC-coupled hybrid) and AC-series (AC-coupled battery-only) share a Pylontech-compatible CAN protocol at 500 kbit/s and a matching HV battery window.

Short version. Four FoxESS families are relevant: H1/AC1 (single-phase, 3.7–6 kW), H3/AC3 (three-phase residential, 5–12 kW), H3 Smart (three-phase residential, 10–15 kW, LFP-friendly) and H3 Pro (commercial three-phase, 20–30 kW). All models expect a Pylontech-compatible battery over CAN at 500 kbit/s and operate in a 80–500 V DC battery window (per fox-ess.com datasheet H1/H3 series). BMS-EV emulates the Pylontech HV master and forwards the EV pack's SOC, current, temperature and limits.

Supported FoxESS families

Model familyPhaseAC powerBattery DC rangeMax DC currentCoupling
H1-3.7 / H1-4.6 / H1-5.0 / H1-6.01-ph3.7–6.0 kW80–500 V25 ADC hybrid
AC1-3.7 / AC1-4.6 / AC1-5.01-ph3.7–5.0 kW80–500 V25 AAC-coupled (battery only)
H3-5.0 / H3-6.0 / H3-8.0 / H3-10.0 / H3-12.03-ph5.0–12.0 kW80–500 V26 ADC hybrid
AC3-5.0 / AC3-8.0 / AC3-10.03-ph5.0–10.0 kW80–500 V26 AAC-coupled (battery only)
H3 Smart 10.0 / 12.0 / 15.03-ph10.0–15.0 kW80–500 V30 ADC hybrid, LFP-friendly firmware
H3 Pro 20 / 25 / 303-ph20.0–30.0 kW180–800 V (Pro-800 variant)50 ADC hybrid, commercial

CAN protocol

FoxESS speaks Pylontech HV Force H2 dialect over CAN at 500 kbit/s. The essential frame set is compact:

BMS-EV publishes these six frames at 1 Hz. The inverter's heartbeat timeout is 5 s; the controller opens its pack contactor on any loss of the vehicle BMS heartbeat within 100 ms.

Wiring topology

┌──────────────┐ ┌─────────────────┐ │ EV battery │ │ FoxESS H1/H3/ │ │ pack │ │ Smart / Pro │ │ │ HV DC 90–500 V │ │ │ DC+ ────────┼───► fuse ─► contactor ─┼──► BAT+ input │ │ DC- ────────┼───► shunt ─────────────┼──► BAT- input │ └──────┬───────┘ └────────┬────────┘ │ CAN (vehicle BMS) │ CAN 500 kbit/s │ │ (Pylontech HV) └──► BMS-EV controller ───────────────────┘ (Pylontech emulator, node 0x0000)

DC voltage matching

EV batteryNominal VOperating VFoxESS model fit
Nissan Leaf 40/62 kWh350 V300–405 VH1, H3, H3 Smart (all fit)
BMW i3 33/42 kWh355 V260–400 VH1, H3, H3 Smart
Tesla Model 3/Y350–360 V260–405 VH1, H3, H3 Smart
VW MEB 58/77 kWh400 V310–450 VH3, H3 Smart (top edge)
Hyundai Kona 64 kWh356 V250–410 VH1, H3, H3 Smart
Porsche Taycan / e-tron GT 800 V800 V610–835 VH3 Pro-800 variant only

Known limitations

Recommended EV battery pairings

EV batteryUsable capacityBest-fit FoxESS modelNotes
Nissan Leaf 40 kWh36 kWhH1-5.0 / H1-6.0Single-phase, residential
BMW i3 33 kWh27 kWhH1-4.6 / H1-5.0Compact match
BMW i3 42 kWh37 kWhH1-6.0 or H3-5.01-ph or 3-ph
Tesla Model 3 SR+ (55 kWh)50 kWhH3-8.0 / H3-10.0Three-phase
Tesla Model 3 LR (75 kWh)70 kWhH3-10.0 / H3-12.0H3 Smart 12/15 for higher C-rate
VW ID.4 77 kWh72 kWhH3-10.0 / H3 Smart 12.0Top of DC window at 100 % SOC
Hyundai Kona 64 kWh60 kWhH3-8.0 / H3-10.0
Porsche Taycan 93 kWh (800 V)84 kWhH3 Pro-25 (Pro-800 variant)Requires the 800 V SKU

FAQ

Should I choose H1/H3 (DC hybrid) or AC1/AC3 (AC-coupled)?

H1/H3 if you are installing PV plus battery on one inverter — DC coupling is more efficient (no PV → AC → battery conversion) and reduces component count. AC1/AC3 if you already have a PV inverter from another manufacturer and want to retrofit storage — the AC-coupled unit sits parallel to the existing PV inverter on the AC bus.

Does FoxESS work with Nissan Leaf modules (48 V build)?

Not natively. FoxESS residential inverters have no LV (48 V) input. To reuse Leaf modules at 48 V you either need a different inverter (SolaX X1 Hybrid LV, Growatt SPH LV) or you must reassemble modules into a 90–500 V pack — practical only for whole-pack reuse.

Is the H3 Smart different from the regular H3?

Yes. H3 Smart has higher continuous current (30 A vs 26 A on H3), a lower minimum battery voltage floor (60 V vs 90 V on some SKUs), LFP-optimised charge curve firmware and larger PV MPPT window. It is FoxESS's newer generation; H3 remains in production alongside.

What does FoxCloud show about the battery?

FoxCloud reports pack SOC, voltage, current, temperature, cycle count and alarm bitmap — everything the Pylontech HV protocol carries. Cell-level voltages and per-module temperatures remain on the BMS-EV controller's local web UI.

Can I run two EV batteries in parallel on one FoxESS?

No. FoxESS accepts one cluster on the BAT port. To parallel two packs, either run two H-series inverters or physically parallel the packs at DC (advanced — inter-pack balancing at the BMS level required).

What is the H3 Pro's 800 V option?

H3 Pro is available in two DC-front-end variants: standard (180–500 V) and Pro-800 (180–800 V). Confirm the SKU before ordering — the higher-voltage variant is the only FoxESS product compatible with Porsche Taycan and Audi e-tron GT packs.

Does FoxESS need a DC breaker on the battery side?

Yes. Per FoxESS installation manual, a DC breaker or fuse-disconnector rated for the battery Vmax (500 V or 800 V DC) and the maximum current (25/26/30/50 A depending on model) is mandatory between the battery and the inverter. Use HV DC-rated components — an AC breaker will not extinguish a DC arc.

Order a FoxESS-compatible BMS-EV controller
Pre-configured Pylontech HV firmware for your battery + FoxESS H1, H3, Smart or Pro
Last updated: 2026-09-18
Current firmware: 15.0.14
Technical author: BMS-EV engineering team (Clima Boost sp. z o.o., Poland)
Reviewer: Jakub Lipiński, founder/lead engineer BMS-EV
Revision: 2026-09-18 — aligned with firmware 15.0.14, SOFAR 180–800 V DC verification, Kia EV6 + SOFAR HYD 15KTL case study reference
Related: All inverters · Compatibility Matrix · Integration guides

Sources and references

ParameterValueSource
H1/H3 battery voltage range80–500 V DCFoxESS Hybrid Inverter product page
H3 Pro (800V variant) range180–800 V DCFoxESS H3 Pro datasheet
CommunicationPylontech HV Force H2 dialect, CAN 500 kbit/sFoxESS BMS communication protocol