Onderzoek: rendement van vaste thuisbatterijen

Per fabrikant nagetrokken wat er werkelijk over rendement, bruikbare capaciteit en garantie gepubliceerd is — inclusief wat níét vermeld wordt.

Dit is het onderzoeksdocument zoals het is vastgelegd, ongewijzigd overgenomen uit docs/battery-catalog/fixed-rte-research.md. Het is in het Engels geschreven.

Roadmap item: A5 companion research · Researched: 29 July 2026 · Scope: eleven fixed-install records in catalogue.json · Status: research input only, not independent verification. A second reviewer must confirm every claim against the linked source before any catalogue value is marked verified.

Question: do the manufacturers publish a product-specific round-trip efficiency, explicit usable capacity, and complete warranty limits for these eleven fixed-install products?

Upfront negative result: Huawei LUNA2000-7-S1, Huawei LUNA2000-14-S1, sonnenBatterie 10 performance 11, AlphaESS SMILE-S5/B5, all three EcoFlow PowerOcean configurations, and Tesla Powerwall 3 publish no value explicitly labelled “round-trip efficiency.” Tesla publishes a different conversion-path figure — “Solar to Battery to Home/Grid Efficiency” — which is preserved under its own label below. Only the three BYD HVS records publish a line labelled “Round-trip Efficiency”; its AC/DC boundary and whether it is a rated or maximum figure are not stated.

No figure below is inferred, multiplied, squared, or normalised. NOT STATED means that the requested value was not found in the cited manufacturer document.

1. Findings per product

Product	Round-trip efficiency	Usable capacity	Warranty	Research conclusion
Huawei LUNA2000-7-S1 (`huawei-luna2000-7-s1`)	NOT STATED. The manufacturer datasheet contains no efficiency or round-trip-efficiency field. HUAWEI-D	Exact label and value: “Battery usable energy¹” — “6.9 kWh”. Footnote: “Test conditions: 100% depth of discharge (DoD), 0.2C rate charge & discharge at 25℃, at the beginning of service life.” The same table separately says “Battery module capacity” — “6.9 kWh”. HUAWEI-D	Years: “15 years (5 years basic warranty + 10 years advanced warranty): Europe, Australia, Japan”. Throughput/retention for the “Battery Expansion Module (6.9 kWh Pack)”: “15 years (5 years basic warranty + 10 years advanced warranty) or 28.84 MWh@60% EOL: Europe, Australia, Japan”, “whichever comes earlier”. Warranted cycles: NOT STATED. HUAWEI-W	Usable capacity and the per-pack warranty limit are explicit. RTE is unavailable. The 15-year advanced term is conditional on connectivity; the policy says it is void after more than six months disconnected or if never connected after power-on.
Huawei LUNA2000-14-S1 (`huawei-luna2000-14-s1`)	NOT STATED. The manufacturer datasheet contains no efficiency or round-trip-efficiency field. HUAWEI-D	Exact label and value: “Battery usable energy¹” — “13.8 kWh”. The table also states “Battery module capacity” — “6.9 kWh” and “Number of battery modules” — “2”. Footnote: “Test conditions: 100% depth of discharge (DoD), 0.2C rate charge & discharge at 25℃, at the beginning of service life.” HUAWEI-D	Years: “15 years (5 years basic warranty + 10 years advanced warranty): Europe, Australia, Japan”. The throughput is published only for a “Battery Expansion Module (6.9 kWh Pack)”: “15 years (5 years basic warranty + 10 years advanced warranty) or 28.84 MWh@60% EOL: Europe, Australia, Japan”, “whichever comes earlier”. A configuration-level 14-S1 throughput is NOT STATED and is not created by multiplying the module value. Warranted cycles: NOT STATED. HUAWEI-W	Usable capacity is explicit. RTE and configuration-level warranted throughput are unavailable.
BYD Battery-Box Premium HVS 5.1 (`byd-battery-box-premium-hvs-5-1`)	Exact label and value: “Round-trip Efficiency” — “≥ 96%”. AC-to-AC or DC-to-DC basis: NOT STATED. Rated or maximum: NOT STATED; the source expresses a lower bound and does not use either label. BYD-D	Exact label and value: “Usable Energy [1]” — “5.12 kWh”. Footnote: “DC Usable Energy, Test conditions: 100% DOD, 0.2C charge & discharge at + 25°C. System Usable Energy may vary with different inverter brands.” BYD-D	Years: “ten (10) years”. Retention: “retain sixty per cent (60%) of its Usable Energy for ten (10) years from the Warranty Start Date; or (ii) reach the Minimum Throughput Energy, whichever comes first”. Table: “HVS 5.1 5.12 15.41” under “Usable Energy (kWh)” and “Minimum Throughput Energy (MWh)”. Warranted cycles: NOT STATED. BYD-W	The only explicit RTE found, but its boundary and rating class are missing. It must not be relabelled AC-to-AC or treated as a rated whole-system value.
BYD Battery-Box Premium HVS 7.7 (`byd-battery-box-premium-hvs-7-7`)	Exact label and value: “Round-trip Efficiency” — “≥ 96%”. AC-to-AC or DC-to-DC basis: NOT STATED. Rated or maximum: NOT STATED. BYD-D	Exact label and value: “Usable Energy [1]” — “7.68 kWh”. Footnote: “DC Usable Energy, Test conditions: 100% DOD, 0.2C charge & discharge at + 25°C. System Usable Energy may vary with different inverter brands.” BYD-D	Years: “ten (10) years”. Retention: “retain sixty per cent (60%) of its Usable Energy for ten (10) years from the Warranty Start Date; or (ii) reach the Minimum Throughput Energy, whichever comes first”. Table: “HVS 7.7 7.68 23.12” under “Usable Energy (kWh)” and “Minimum Throughput Energy (MWh)”. Warranted cycles: NOT STATED. BYD-W	Same limitation as HVS 5.1: explicit RTE label, undocumented boundary and rating class.
BYD Battery-Box Premium HVS 10.2 (`byd-battery-box-premium-hvs-10-2`)	Exact label and value: “Round-trip Efficiency” — “≥ 96%”. AC-to-AC or DC-to-DC basis: NOT STATED. Rated or maximum: NOT STATED. BYD-D	Exact label and value: “Usable Energy [1]” — “10.24 kWh”. Footnote: “DC Usable Energy, Test conditions: 100% DOD, 0.2C charge & discharge at + 25°C. System Usable Energy may vary with different inverter brands.” BYD-D	Years: “ten (10) years”. Retention: “retain sixty per cent (60%) of its Usable Energy for ten (10) years from the Warranty Start Date; or (ii) reach the Minimum Throughput Energy, whichever comes first”. Table: “HVS 10.2 10.24 30.82” under “Usable Energy (kWh)” and “Minimum Throughput Energy (MWh)”. Warranted cycles: NOT STATED. BYD-W	Same limitation as HVS 5.1: explicit RTE label, undocumented boundary and rating class.
sonnenBatterie 10 performance 11 (`sonnenbatterie-10-performance-11`)	NOT STATED. The datasheet instead publishes two maximum component figures: “Max. Wirkungsgrad Wechselrichter 97,2%” and “Max. Wirkungsgrad Batterie 95,9%”. Neither is labelled round-trip; the conversion boundary is NOT STATED. They are explicitly maximum figures and are not combined. SONNEN-D	Exact label and value for 10p/11: “Nutzbare Batteriekapazität in kWh” — “10”. The same table separately says “Nominale Batteriekapazität in kWh” — “11”. SONNEN-D	Manufacturer guarantee: “the end of the 10th year after commissioning”, “up to 10,000 full charge cycles”, or “a maximum energy flow of 8,500 kWh per kWh of the net capacity of the battery (kWh flow added up for discharge processes)”; “Once one of the conditions (10 years, 10,000 full charge cycles, 8,500 kWh) is exceeded, the premium guarantee ends.” Claim threshold: “the capacity of the battery modules falls below 70% (seventy percent) of the nominal capacity”. No total-system throughput is derived. SONNEN-W	Capacity is explicit; RTE is not. The exact warranty is conditional and expressed per kWh of net capacity, not as a published total-kWh figure for this configuration.
AlphaESS SMILE-S5/B5 (`alphaess-smile-s5-b5`)	NOT STATED. The current manufacturer datasheet contains no round-trip-efficiency entry. ALPHA-D	Exact label and value: “Usable Capacity” — “4.79 kWh”. Separate fields: “Module Capacity” — “5.04 kWh” and “Depth of Discharge (DoD)” — “95%*”. Footnote: “Test Condition: Max. 0.5C charge & discharge at 25+2°C.” ALPHA-D	Product warranty: “AlphaESS provides 5 years warranty” and explicitly includes “SMILE-BAT-5P” and “System SMILE-S5/SMILE-B5”. Performance term: “AlphaESS warrants the Battery performance for 120 months”. The general precondition says: “The Throughput Energy per kWh should be lower than 3.11MWh and SOH (State of Health) should be lower than 70%”. Warranted cycles: NOT STATED. The datasheet’s “Cycle Life 6000” is a lifecycle specification, not warranty wording. ALPHA-W ALPHA-D	Capacity is explicit; RTE is not. The warranty document does not state one unconditional end-of-warranty retention/throughput pair; its internal scenario table must be preserved, not collapsed.
EcoFlow PowerOcean 5.1 (`ecoflow-powerocean-5-1`)	NOT STATED. The battery table has no efficiency field. The inverter table separately says “Efficiency Maximum Efficiency >96% >96.5%” and “European Weighted Efficiency >95% >96% >95.5% >96% >96%”; these are inverter figures, not labelled battery round-trip efficiency. ECOFLOW-D	“Battery Usable Capacity (kWh)*² (95% Depth of Discharge)” — “4.8”. Separate nominal field: “Battery Nominal Capacity (kWh)” — “5.1”. ECOFLOW-D	“15 years or 6000 charge/discharge cycles, whichever comes first”. Retention: “minimum nominal capacity of 70% after 15 years of use or 6000 charge/discharge cycles”. Warranted throughput: NOT STATED. ECOFLOW-W	Usable capacity and warranty are explicit. RTE and throughput are unavailable.
EcoFlow PowerOcean 10.2 (`ecoflow-powerocean-10-2`)	NOT STATED. Same battery and inverter distinction as PowerOcean 5.1. ECOFLOW-D	“Battery Usable Capacity (kWh)*² (95% Depth of Discharge)” — “9.7”. Separate nominal field: “Battery Nominal Capacity (kWh)” — “10.2”. The table identifies “EF BD-5.1-S1 x 2”. ECOFLOW-D	Same battery warranty: “15 years or 6000 charge/discharge cycles, whichever comes first”, with “minimum nominal capacity of 70%”. Warranted throughput: NOT STATED. ECOFLOW-W	Usable capacity and warranty are explicit. RTE and throughput are unavailable.
EcoFlow PowerOcean 15.3 (`ecoflow-powerocean-15-3`)	NOT STATED. Same battery and inverter distinction as PowerOcean 5.1. ECOFLOW-D	“Battery Usable Capacity (kWh)*² (95% Depth of Discharge)” — “14.5”. Separate nominal field: “Battery Nominal Capacity (kWh)” — “15.3”. The table identifies “EF BD-5.1-S1 x 3”. ECOFLOW-D	Same battery warranty: “15 years or 6000 charge/discharge cycles, whichever comes first”, with “minimum nominal capacity of 70%”. Warranted throughput: NOT STATED. ECOFLOW-W	Usable capacity and warranty are explicit. RTE and throughput are unavailable.
Tesla Powerwall 3 (`tesla-powerwall-3`)	No value is labelled round-trip efficiency. Exact published label and value: “Solar to Battery to Home/Grid Efficiency” — “89%”. Basis: “Typical use case with energy produced by PV and stored in battery and then released to loads or the grid.” Test condition: “Values provided for 25°C (77°F), at beginning of life. 3.3 kW charge/discharge power.” It is neither labelled AC-to-AC nor DC-to-DC, and neither rated nor maximum. TESLA-D	Explicit usable capacity: NOT STATED. The datasheet instead says “Nominal Battery Energy” — “13.5 kWh AC”. This is retained as nominal and is not relabelled usable. TESLA-D	“free from defects for ten years following its initial installation date”. For the Netherlands and listed uses, “80% at 10 years following initial installation date” and “Unlimited cycles”. For an unlisted use or combination, “80% at 10 years following initial installation date” and “37.8 MWh of aggregate throughput”, with throughput “Measured at the battery AC output.” TESLA-W	Tesla supplies a useful path-specific efficiency, but it is not the requested AC-to-AC or DC-to-DC rated RTE. Usable capacity is not explicitly published. Warranty cycles/throughput are application-dependent.

2. Findings

2.1 Only BYD uses the requested RTE label — but the number is still not comparable

The three BYD rows are the only records for which a manufacturer datasheet contains the exact field “Round-trip Efficiency”. The value is “≥ 96%”, but the datasheet does not state:

whether the test boundary is DC-to-DC or AC-to-AC;
which compatible inverter, if any, is inside the boundary;
whether the figure is a rating, a typical value, or another class of claim.

The adjacent footnote explicitly calls usable energy “DC Usable Energy” and warns that system usable energy varies by inverter. That does not prove the efficiency is DC-to-DC, so this research does not assign it a boundary. Under a policy requiring rated AC-to-AC RTE, all eleven records remain ineligible from manufacturer documentation alone.

Tesla’s 89% is more fully conditioned, but it covers a different path: PV generation into the battery and then to loads or the grid. It must remain under Tesla’s exact “Solar to Battery to Home/Grid Efficiency” label, not be silently renamed round-trip efficiency.

2.2 Usable capacity is explicit for ten records

Huawei, BYD, sonnen, AlphaESS, and EcoFlow all state usable capacity explicitly. BYD is the only manufacturer here that also specifies the usable-capacity boundary as DC. Tesla states “Nominal Battery Energy 13.5 kWh AC” but does not state usable energy, so its usable capacity correctly remains NOT STATED.

No usable-capacity value in this file was calculated from nominal capacity and DoD. Where both are published, both are quoted separately.

2.3 Warranty limits are not interchangeable

Huawei publishes 28.84 MWh per 6.9 kWh pack, not a 14-S1 configuration total. This file does not multiply it for the two-module record.
sonnen publishes 8,500 kWh of discharge flow per kWh of net capacity. This file does not turn that ratio into a configuration total.
AlphaESS publishes throughput per kWh and several conditional SOH scenarios, not one simple system-level throughput warranty.
Tesla uses unlimited cycles for the listed residential applications but a 37.8 MWh AC-output limit for other applications.
BYD publishes model-specific minimum-throughput figures and defines them as output energy recorded in the control module.
EcoFlow publishes years/cycles/retention but no warranted throughput.

2.4 Manufacturer contradictions and document risks

sonnen retention conflict across current official Netherlands pages. The product page says: “De gegarandeerde opslagcapaciteit van de module is na 10 jaar of 10.000 laadcycli nog steeds minimaal 70%.” SONNEN-P The December 2025 manufacturer guarantee also uses a below-70%-of- nominal-capacity claim threshold. SONNEN-W However, sonnen’s separate Netherlands FAQ says: “De gegarandeerde opslagcapaciteit van de modules bedraagt na 10 jaar of 10.000 laadcycli minstens 80 procent.” SONNEN-FAQ The research does not resolve this conflict; the controlling contract and applicable version require independent review.

AlphaESS contains multiple claim scenarios in one warranty document. Its general precondition uses “＜3.11MWh” and “＜70%”, while the table in the same document also lists:

“Claim Scenario-1 25℃ to 28℃ ＜2.92 ＜80%”
“Claim Scenario-2 -10℃ to 50℃ ＜2.39 ＜80%”
“Claim Scenario-3 -10℃ to 50℃ ＜3.11 ＜70%”

The table extraction also places repeated “AND” markers beneath these columns. The document does not supply one plain-language rule that safely collapses those scenarios, so no single derived throughput-kWh or retention value is asserted here. ALPHA-W

EcoFlow naming mismatch. The current datasheet identifies the battery as EF BD-5.1-S1 and publishes 5.1 kWh nominal capacity. The current European warranty names PowerOcean-Battery-5kWh-DE. The warranty is clearly for the PowerOcean LFP battery family, but the exact SKU alignment should be confirmed by the independent reviewer rather than assumed. ECOFLOW-D ECOFLOW-W

3. Recommendation

Keep round-trip efficiency unset for Huawei, sonnen, AlphaESS, EcoFlow, and Tesla. Tesla’s 89% may be displayed as a manufacturer path-specific metric, but not fed into a field defined as rated AC-to-AC RTE.
Do not enter BYD’s ≥96% into an AC-to-AC engine field until BYD or an independent reviewer confirms the test boundary and the figure class.
Send narrowly worded manufacturer questions:
- Huawei, sonnen, AlphaESS, EcoFlow, Tesla: “Do you publish a rated AC-to-AC round-trip efficiency for this exact product/configuration, with test conditions?”
- BYD: “Is ‘Round-trip Efficiency ≥96%’ measured DC-to-DC or AC-to-AC, and is it a rated, minimum, typical, or maximum figure?”
Put the sonnen 70%/80% conflict and AlphaESS scenario table on the independent reviewer’s explicit checklist.
Treat this file as evidence collection only. It does not change catalogue.json, engine constants, or any verified field.

4. Source register

All sources are first-party manufacturer documents or pages. All were retrieved on 29 July 2026.

HUAWEI-D — Huawei, LUNA2000-7/14/21-S1 Technical Specification, version 01-202411: official PDF
HUAWEI-W — Huawei, Residential Smart PV Warranty Policy (Global), V2.1: official PDF
BYD-D — BYD, Battery-Box Premium HVS Technical Parameters, V1.0, 2024-06-26: official PDF
BYD-W — BYD, Battery-Box Premium HVS&HVM Limited Warranty — Europe, V1.2: official PDF
SONNEN-D — sonnen, Technische Daten sonnenBatterie 10 performance, February 2024: official PDF
SONNEN-W — sonnen, Manufacturer’s Guarantee, Netherlands endpoint, as of December 2025: official PDF endpoint
SONNEN-P — sonnen Netherlands, sonnenBatterie 10 performance: official product page
SONNEN-FAQ — sonnen Netherlands, FAQ — sonnenBatterie 10 performance: official FAQ
ALPHA-D — AlphaESS, SMILE-S5/B5 Datasheet, V03, 2023-06-01: official PDF
ALPHA-W — AlphaESS, Warranty Conditions for the AlphaESS Residential Product Series, manufacturer-hosted 2024 document: official PDF
ECOFLOW-D — EcoFlow, PowerOcean Single-phase / PowerOcean LFP Battery Datasheet: official PDF
ECOFLOW-W — EcoFlow, Warranty Policy for Home Solar Battery Solutions in Europe B, V1.5, valid from 2025-11-03: official PDF
TESLA-D — Tesla, Powerwall 3 Datasheet, 2025, English European/UK version: official PDF
TESLA-W — Tesla, Powerwall Warranty — European Warranty Region, Rev. 1.16, effective 2025-12-03: official PDF