The assessment
How it scores, by category
Market position
The data
DC-coupled battery
Stores DC energy and relies on system power electronics outside the battery product for household AC.
- Product role
- The published battery record covers the storage stack, controller and stated capacity range.
- Published range
- 10–20 kWh
- Phase
- Not recorded
- Backup boundary
- Installation-specific
Capacity guarantee: minimum retained at year 10
No year-by-year capacity schedule is published for this product - the manufacturer guarantees only this end-of-term minimum, not a specific decline curve. Capacity figure based on the sourced usable capacity of the base configuration; modular systems scale with additional modules.
Verification & sources
Market context
Global evidencechange in the site menu
Global benchmark. This scorecard is benchmarked globally. A global score does not imply local availability, certification, warranty coverage, or installer compatibility.
Benchmark anchor. The score uses the named exact German benchmark; larger stacks, paid states and nearby generations do not transfer evidence. Scored model: VARTA.wall 20 BM1 · checked 2026-08-16. Evidence.
Sources & references · checked 2026-09-01
Strong evidence coverage
13 of 13 scored criteria link directly to a published source.
Values marked estimated, derived, or not found remain visible on the audit sheet and do not carry the same evidential weight as a linked source. Coverage measures direct links, not an independent guarantee that a claim is correct.
How far the evidence reaches
- OutputManufacturer claim3 rows
- EnduranceManufacturer claim4 rows
- SafetyManufacturer claim4 rows
- Warranty & backingManufacturer claim2 rows
- FitNot assessed for batteries
- FootprintNot assessed for batteries
Rings, outside in: manufacturer claim, certified or regulator-listed, third-party source. The centre is review.solar's own measurement, empty for every product today. How the evidence puzzle works
Record revision. VARTA.wall BM1 German datasheet and March 2026 operating manual checked 2026-08-16. First-market US overlay review 2026-09-01: official United States catalogues recorded; existing Australian and German overlays and scores unchanged. Exact BM1 online manufacturer warranty effective 2026-03-16 recovered 2026-10-05; applies only to systems commissioned on or after its effective date. PV-only and non-PV limits, nominal-capacity basis and partial labour coverage are kept separate; no full-product or market revalidation.
- Sourced valuesData card →
- Cell provenance & traceabilityManufacturer ↗
Show 2 more
- Financial strength & warranty backingManufacturer ↗
- Financial strength & warranty backingManufacturer ↗
Product record history
4 changes to this record · 3 products changed in this update
3 changes to this record · 6 products changed in this update
Financial strength & warranty backing: Evidence sources
- Before
- https://www.varta-ag.com/de/ueber-varta/news-presse/details/varta-gruppe-tobias-wahl-zum-vorlaeufigen-insolvenzverwalter-bestellt
- After
- https://www.varta-ag.com/de/ueber-varta/news-presse/details/varta-ag-verkaufsprozess-laeuft-planmaessig; https://www.varta-ag.com/de/ueber-varta/news-presse/details/varta-gruppe-tobias-wahl-zum-vorlaeufigen-insolvenzverwalter-bestellt
US Evidence sources
- Before
- https://www.varta-ag.com/de/konsument/produktkategorien/energiespeicher/vartawall; https://www.varta-ag.com/us/
- After
- https://www.varta-ag.com/de/konsument/produktkategorien/energiespeicher/vartawall; https://www.varta-ag.com/us/; https://www.varta-ag.com/us/navigation/products.navi
US Support Note
- Before
- varta-ag.com/us is a CAPTCHA and does not retrieve VARTA.wall BM1. BM2 is a different chemistry and is not transferred. Held is not unavailable.
- After
- The 1 and 6 September 2026 reviews recorded varta-ag.com/us as presenting a CAPTCHA that did not retrieve VARTA.wall BM1. A fetch on 9 October 2026 returned the regional home page and product navigation without a challenge page. Those pages list microbattery, hearing aid, power pack and application products and do not list VARTA.wall BM1. They do not state that the product is unavailable in the United States. BM2 is a different chemistry and is not transferred. Held is not unavailable.
5 changes to this record · 10 products changed in this update
20 changes to this record · 1 product changed in this update
DE Warranty conditions
- Current text
- labour: Section 2.4: repairs in the first five years are at VARTA Storage cost, but onsite reimbursement is voluntary under agreed service allowances. After five years labour and additional services are excluded; no unconditional full-term labour entitlement.; registration: Qualified/certified installer registers system/modules/commissioning. Customer or written-authorised installer must register warranty within eight weeks. Technical online services must be used promptly from commissioning; internet outages must not exceed four consecutive weeks. Conditions also apply across prior owners.; remedy: Warrantor VARTA Storage GmbH chooses repair or depreciated-value compensation. Repair may use new/reconditioned modules or parts and restores the stated nominal-capacity threshold; compensation depreciates original price monthly over ten years. No warranty restart or extension.; removal reinstallation: No unconditional removal/reinstallation entitlement is established. Section 6 may charge examination, labour and removal/reinstallation when a claim is inapplicable, subject to the stated exception where the customer could not recognise inapplicability.; transferability: Section 1.3 covers qualifying current owners, including acquisition from prior owners. All prior owners must have met continuous online/operating conditions; this is conditional transfer, not an unrestricted transfer right.; transport: Section 2.4 expressly covers transport with replacement parts/equivalent equipment after five years. No unconditional freight entitlement for every claim or declined claim is inferred.
The previous text is not reproduced here: both versions run to a full research paragraph. Both are in the JSON record linked below.
DE market evidenceWarranty throughput+4 in JSON recordWarranty assurance: Evidence status
- Before
- reviewed_absence
- After
- sourced
End-of-warranty retained capacity (%): Evidence status
- Before
- Not previously recorded
- After
- sourced
Warranty degradation guarantee: Evidence status
- Before
- Not previously recorded
- After
- sourced
DE Evidence sources
- Before
- https://www.varta-ag.com/de/konsument/kontakt/storage-kontakt-faq?tx_faq_targetgroups%5Bcategory%5D=35&tx_faq_targetgroups%5Btargetgroup%5D=2; https://www.varta-ag.com/de/konsument/produktkategorien/energiespeicher/vartawall; https://www.varta-ag.com/de/ueber-varta/news-presse/details/varta-gruppe-tobias-wahl-zum-vorlaeufigen-insolvenzverwalter-bestellt; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Betriebsanleitung_VARTA.wall.pdf; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Datenblatt_wall_BM1_DE.pdf
- After
- https://www.varta-ag.com/de/konsument/kontakt/storage-kontakt-faq?tx_faq_targetgroups%5Bcategory%5D=35&tx_faq_targetgroups%5Btargetgroup%5D=2; https://www.varta-ag.com/de/konsument/produktkategorien/energiespeicher/vartawall; https://www.varta-ag.com/de/ueber-varta/news-presse/details/varta-gruppe-tobias-wahl-zum-vorlaeufigen-insolvenzverwalter-bestellt; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Betriebsanleitung_VARTA.wall.pdf; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Datenblatt_wall_BM1_DE.pdf; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
End-of-warranty retained capacity (%): Evidence sources
- Before
- Not previously recorded
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
Warranty degradation guarantee
- Before
- Not previously recorded
- After
- End-point only: minimum capacity at end of warranty term
Warranty throughput
- Before
- Throughput terms not published
- After
- 2.5-5 MWh warranted per kWh usable
Warranty throughput: Evidence sources
- Before
- https://www.varta-ag.com/de/konsument/kontakt/storage-kontakt-faq?tx_faq_targetgroups%5Bcategory%5D=35&tx_faq_targetgroups%5Btargetgroup%5D=2; https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Datenblatt_wall_BM1_DE.pdf
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
Warranty assurance: Evidence sources
- Before
- https://www.varta-ag.com/de/konsument/kontakt/storage-kontakt-faq?tx_faq_targetgroups%5Bcategory%5D=35&tx_faq_targetgroups%5Btargetgroup%5D=2
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
Source revision
- Current text
- VARTA.wall BM1 German datasheet and March 2026 operating manual checked 2026-08-16. First-market US overlay review 2026-09-01: official United States catalogues recorded; existing Australian and German overlays and scores unchanged. Exact BM1 online manufacturer warranty effective 2026-03-16 recovered 2026-10-05; applies only to systems commissioned on or after its effective date. PV-only and non-PV limits, nominal-capacity basis and partial labour coverage are kept separate; no full-product or market revalidation.
The previous text is not reproduced here: both versions run to a full research paragraph. Both are in the JSON record linked below.
Primary datasheetDE Warranty scope
- Before
- Germany; VARTA publishes ten years only after portal registration and permanent internet, otherwise two years. Exact remedy and capacity terms remain unresolved.
- After
- Germany; recovered online policy effective 16 March 2026 applies to systems commissioned on or after that date. Ten-year master/base defect coverage; BM1 battery modules: ten years or 4,000 full cycles for PV-only use, otherwise 6.9 MWh per module, whichever occurs first. Battery defect threshold is below 80% total nominal capacity. Online-service, registration, installation and operating conditions apply. Earlier commissioning dates require their own instrument; no offline manufacturer term inferred.
Warranty degradation guarantee: Evidence sources
- Before
- Not previously recorded
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
Warranty period (yrs): Evidence sources
- Before
- https://www.varta-ag.com/de/konsument/kontakt/storage-kontakt-faq?tx_faq_targetgroups%5Bcategory%5D=35&tx_faq_targetgroups%5Btargetgroup%5D=2
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Herstellergarantie_VARTAwall.pdf
Warranty throughput: Evidence status
- Before
- reviewed_absence
- After
- sourced
5 changes to this record · 152 products changed in this update
US Support Note
- Before
- Not previously recorded
- After
- varta-ag.com/us is a CAPTCHA and does not retrieve VARTA.wall BM1. BM2 is a different chemistry and is not transferred. Held is not unavailable.
Source revision
- Before
- VARTA.wall BM1 German datasheet and March 2026 operating manual checked 2026-08-16
- After
- VARTA.wall BM1 German datasheet and March 2026 operating manual checked 2026-08-16. First-market US overlay review 2026-09-01: official United States catalogues recorded; existing Australian and German overlays and scores unchanged.
US Evidence sources
- Before
- Not previously recorded
- After
- https://www.varta-ag.com/de/konsument/produktkategorien/energiespeicher/vartawall; https://www.varta-ag.com/us/
US Status
- Before
- Not previously recorded
- After
- not_reviewed
1 change to this record · 9 products changed in this update
DE Grid and installation context
- Before
- Not previously recorded
- After
- The BM1 battery's IEC 62619 and VDE-AR-E 2510-50 evidence is battery-safety evidence, not standalone German grid approval. Final grid conformity belongs to the site's power-conversion equipment, settings and network approval; no cross-product suitability is inferred.
8 changes to this record · 78 products changed in this update
Value
- Before
- Not previously recorded
- After
- Reviewed 2026-08-25: no exact-product battery/DC round-trip efficiency with a complete measurement boundary was established in the reviewed primary source set. This is a scoped reviewed absence, not proof that the value has never been measured.
Evidence sources
- Before
- Not previously recorded
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Datenblatt_wall_BM1_DE.pdf
Evidence sources
- Before
- Not previously recorded
- After
- https://www.varta-ag.com/fileadmin/varta/consumer/downloads/energy-storage/varta.wall/Datenblatt_wall_BM1_DE.pdf
Value
- Before
- Not previously recorded
- After
- Reviewed 2026-08-25: no exact-product cycle-life result to exactly 70% retained capacity was established in the reviewed primary source set. Warranty limits and other or unstated endpoints are not converted. This is a scoped reviewed absence.
1 change to this record · 13 products changed in this update
Product record
kind: battery; brand: VARTA; name: VARTA.wall BM1; model: VARTA.wall 10 / 15 / 20 (BM1, NCA); scored reference VARTA.wall 20; score: 49.3
Primary datasheet
This is review.solar's publication history. It does not claim the product changed on the recorded date, and it excludes compatibility, system pairing, installation suitability and relative leaderboard prose. Open the complete JSON record.
Evidence timeline
Recorded verification events for this scorecard. These are evidence checks, not historical score snapshots.
- Core scorecard evidence checked
- US market evidence checked
- DE market evidence checked
- Series benchmark evidence checked
Scored by Solar Analytica Research
Further reading from Findings
Stay across the benchmark.
New scorecards, score changes and market signals, published as they happen.
Our reading
VARTA.wall BM1 scores 56, placing 71 of 76 in the Performance & Value class against a class average of 63.6. Its strongest scoring dimension is power & efficiency (63). Energy Ecosystem scores 40, the lowest pillar for this product. The class average on energy ecosystem is 48. Key specifications: 10.5 kW continuous output.
Dietreich Farquharson · review.solar