CyboEnergy v. Hoymiles Power Electronics — Dismissed With Prejudice (496 Days)
CyboEnergy, Inc. brought a patent infringement action against Hoymiles Power Electronics USA in the Eastern District of Texas, asserting two power inverter patents against Hoymiles’s inverter product line. After 496 days of litigation, both parties jointly stipulated to dismiss all claims with prejudice — each side bearing its own costs.
Power inverter IP clash ends in bilateral walk-away
On June 27, 2023, CyboEnergy, Inc. filed suit against Hoymiles Power Electronics USA, Inc. in the Eastern District of Texas (Case No. 2:23-cv-00311) before Judge Rodney Gilstrap — one of the country’s most prominent patent litigation jurists. CyboEnergy alleged infringement of two U.S. patents, US9331489B2 and US8786133B2, both directed to power inverter technology, asserting that Hoymiles’s commercial power inverter products embodied the patented claims.
On November 4, 2024, the parties filed a Joint Stipulation of Dismissal under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), and Judge Gilstrap accepted the stipulation the same day. All claims were dismissed with prejudice, meaning CyboEnergy is permanently barred from re-asserting these claims against Hoymiles on the same grounds. Critically, the order specified that each party bears its own costs, expenses, and attorneys’ fees — a standard bilateral walk-away structure consistent with a confidential settlement or licensing resolution.
The 496-day duration suggests the parties litigated through at least preliminary motion practice before reaching resolution, though the public record does not disclose whether a licensing arrangement, cross-licence, or other commercial agreement underpins the dismissal. The with-prejudice designation and mutual cost-bearing terms are consistent with a negotiated resolution rather than a unilateral concession. The underlying terms, if any, remain confidential.
Filing to Dismissed with Prejudice in 496 days
496 days — above the median for E.D. Tex. patent cases settled before trial
Dismissed with prejudice: what the joint stipulation means for both parties
Rule 41(a)(1)(A)(ii) dismissal with prejudice explained
A Rule 41(a)(1)(A)(ii) dismissal requires the signatures of all parties, making it a bilateral act. The ‘with prejudice’ designation is the critical qualifier: unlike a without-prejudice dismissal, it extinguishes the underlying claims permanently. CyboEnergy cannot re-file the same infringement claims against Hoymiles based on the same accused products and the same patents. The court’s role is limited to accepting and acknowledging the stipulation.
Permanent bar on re-filingCyboEnergy permanently closes this enforcement avenue
By agreeing to dismissal with prejudice, CyboEnergy surrenders the right to re-litigate these specific claims against Hoymiles. This outcome is consistent with either a licensing agreement that rendered continued litigation unnecessary, or a strategic decision to exit. The mutual cost-bearing clause suggests neither side extracted a one-sided concession. CyboEnergy retains the patents and may assert them against other parties.
Rights preserved vs. other defendantsHoymiles exits with prejudice — but public terms remain opaque
Hoymiles secures finality against CyboEnergy’s claims under US9331489B2 and US8786133B2. Whether that finality came at a licensing cost or through other commercial terms is not disclosed in the public record. The each-party-bears-own-costs clause removes any fee-shifting risk. Hoymiles’s inverter product line is no longer subject to re-litigation by CyboEnergy on these two patents.
No fee-shifting; product line clearedPower inverter sector: both patents remain live enforcement tools
The with-prejudice dismissal resolves only the CyboEnergy–Hoymiles dispute. US9331489B2 and US8786133B2 remain active patents in CyboEnergy’s portfolio and can be asserted against other power inverter manufacturers. Competitors operating in distributed energy, microinverter, and solar string inverter markets should treat these patents as live litigation risk. The E.D. Tex. filing signals CyboEnergy’s willingness to enforce aggressively.
Patents remain assertable vs. othersFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | CyboEnergy, Inc. | Company | Power electronics IP licensor — holder of US9331489B2 and US8786133B2Search in Eureka ↗ |
| Defendant | Hoymiles Power Electronics USA, Inc. | Company | Hoymiles Power Electronics USA — U.S. subsidiary marketing solar power invertersSearch in Eureka ↗ |
| Plaintiff counsel | Jacob Bruce Henry | Attorney | Counsel for CyboEnergy, Inc.Search in Eureka ↗ |
| Plaintiff counsel | William P. Ramey , III | Attorney | Counsel for CyboEnergy, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Blank Rome LLP (Houston) | Law Firm | Representing CyboEnergy, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Ramey LLP | Law Firm | Representing CyboEnergy, Inc.Search in Eureka ↗ |
| Defendant counsel | Andrea Leigh Fair | Attorney | Counsel for Hoymiles Power Electronics USA, Inc.Search in Eureka ↗ |
| Defendant counsel | Darlene Fae Ghavimi | Attorney | Counsel for Hoymiles Power Electronics USA, Inc.Search in Eureka ↗ |
| Defendant counsel | Matthew Alexander Blair | Attorney | Counsel for Hoymiles Power Electronics USA, Inc.Search in Eureka ↗ |
| Defendant law firm | K&L Gates, LLP | Law Firm | Representing Hoymiles Power Electronics USA, Inc.Search in Eureka ↗ |
| Defendant law firm | Miller Fair Henry PLLC | Law Firm | Representing Hoymiles Power Electronics USA, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Rodney Gilstrap | Judge | Texas Eastern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s order adopts the parties’ joint language verbatim, confirming dismissal with prejudice under Rule 41(a)(1)(A)(ii) and denying all pending relief as moot. The ‘with prejudice’ designation is legally significant: it operates as an adjudication on the merits for res judicata purposes, permanently foreclosing CyboEnergy from re-asserting these claims against Hoymiles on the same patents and accused products. The mutual cost-bearing clause is notable — it signals a negotiated bilateral resolution rather than capitulation by either side.
US9331489B2 & US8786133B2 — Power inverter architecture patents
US9331489B2 (Application No. 13/789,637) and US8786133B2 (Application No. 12/837,162) both sit within CyboEnergy’s portfolio of power electronics innovations. The patents relate to inverter architectures used in solar energy systems, covering configurations relevant to multi-string and microinverter topologies. US8786133B2, having the earlier application number, likely predates the ‘489 patent and may represent foundational inverter circuit claims upon which the continuation builds.
For the distributed solar and energy storage sector, these patents represent meaningful IP risk. As inverter technology evolves toward higher-efficiency multi-port designs and virtual power plant integration, claim coverage originally drafted for residential solar systems may read on next-generation commercial products. Hoymiles is a significant global microinverter supplier, making this dispute strategically important for the broader market. The patents’ continued validity and CyboEnergy’s demonstrated willingness to litigate in E.D. Tex. elevate FTO priority for any inverter OEM or distributor.
Should your team run an FTO against US9331489B2 and US8786133B2?
Any company designing, importing, or selling power inverters — including string inverters, microinverters, and hybrid storage inverters — for the U.S. market should assess its exposure to these two CyboEnergy patents. The demonstrated enforcement action against a major inverter brand like Hoymiles confirms that CyboEnergy actively monitors the market. Product teams planning new DC-to-AC conversion architectures or multi-port solar inverter launches should prioritise a claim-by-claim FTO review before commercial release.
PatSnap Eureka’s FTO Search Agent enables R&D and IP teams to run structured freedom-to-operate queries against US9331489B2 and US8786133B2, mapping your product’s technical features against independent and dependent claims, surfacing relevant prior art, and flagging design-around opportunities. Eureka’s litigation overlay also shows you whether CyboEnergy has filed further actions — giving your team the commercial intelligence to assess enforcement risk before it becomes a demand letter.
Run a freedom-to-operate analysis on US9331489B2 to assess your product’s exposure
Run FTO in Eureka →Similar power inverter patent cases in E.D. Tex. and federal courts
Cases involving solar power inverter patent infringement filed in the Eastern District of Texas, including comparable dismissal-with-prejudice outcomes and Rule 41 stipulations.
What this case signals for the power inverter IP landscape
A with-prejudice exit in E.D. Tex. after 496 days rarely happens without a commercial resolution — here is what it means for the sector.
E.D. Tex. remains the preferred venue for inverter patent enforcement
CyboEnergy’s choice of Judge Gilstrap’s docket in the Eastern District of Texas is consistent with established plaintiff strategy. The district’s patent-friendly procedures and experienced bench make it a high-pressure venue for defendants. Any power electronics company selling into U.S. markets should map its E.D. Tex. exposure before a claim arrives.
With-prejudice mutual dismissals typically signal a licensing event
When both parties stipulate to dismissal with prejudice and elect to bear their own costs, the structure is typically consistent with a confidential licence or cross-licence agreement. Product teams and IP counsel at inverter manufacturers should assume CyboEnergy’s enforcement programme is commercially active and budget-modelled accordingly.
CyboEnergy v Hoymiles — key questions answered
CyboEnergy, Inc. filed a patent infringement suit against Hoymiles Power Electronics USA in the Eastern District of Texas on June 27, 2023, asserting US9331489B2 and US8786133B2 against Hoymiles’s power inverter products. After 496 days, the parties filed a joint stipulation of dismissal with prejudice under Rule 41(a)(1)(A)(ii), accepted by Judge Gilstrap on November 4, 2024. Each party bears its own costs.
Dismissal with prejudice permanently bars CyboEnergy from re-asserting the same infringement claims against Hoymiles based on these two patents and the same accused products. However, the patents themselves remain valid and enforceable. CyboEnergy retains the right to assert US9331489B2 and US8786133B2 against other power inverter manufacturers in future proceedings.
The parties’ choice of with-prejudice dismissal under Rule 41(a)(1)(A)(ii) — which requires bilateral consent — is typically consistent with a negotiated resolution such as a licence agreement or cross-licence. A without-prejudice dismissal would have left the door open for re-filing. The mutual cost-bearing clause reinforces the inference that neither party made a unilateral concession, though the underlying commercial terms are not disclosed in the public record.
The Eastern District of Texas, particularly before Judge Rodney Gilstrap, is one of the most active patent litigation venues in the United States. It is frequently selected by patent plaintiffs for its experienced bench, established patent local rules, and historically plaintiff-friendly outcomes. CyboEnergy’s choice of this venue signals a deliberate, commercially sophisticated enforcement strategy targeting Hoymiles’s U.S. operations.
Yes. The with-prejudice dismissal resolves only the CyboEnergy–Hoymiles dispute. Both US9331489B2 and US8786133B2 remain active and enforceable against other parties. Any company designing, manufacturing, or distributing power inverters — including microinverters, string inverters, or hybrid storage inverters — for the U.S. market should consider a freedom-to-operate review against these patents, particularly given CyboEnergy’s demonstrated enforcement willingness in E.D. Tex.
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