Renewable Energy · 03

Battery storage that keeps the lights on.

Battery energy storage systems (BESS) for new or existing PV installations across Puerto Rico and the USVI. Whether you're adding outage coverage to an existing array or designing a hybrid system from scratch, we engineer the integration end-to-end — solar, batteries, generator, and grid coordinated through ATS controls.

Configuration
AC-coupled, hybrid & DC-coupled
Chemistry
Lithium-iron-phosphate (LFP)
Scope
New build & retrofit
Integration
PV, generator & ATS coordination
Battery Storage · Why JDR

The integration is the engineering.

The hard part of battery storage isn't the battery — it's the logic. How does the system prioritize between solar, battery, generator, and grid as conditions change? How does it island cleanly when the grid drops? How fast can it transfer critical loads without dropping electronics? These are the questions that separate a system that works from one that fails the first time it matters.

JDR's storage practice combines two decades of electrical systems engineering with active PV installation experience. We design hybrid systems holistically — not by bolting batteries onto someone else's PV design.

  • Critical-load analysis and battery sizing for real autonomy targets
  • AC-coupled retrofits to existing grid-tied PV
  • Hybrid inverter conversions for tighter integration
  • DC-coupled systems for new builds
  • Generator-aware logic with ATS retransfer coordination
  • Seamless <20ms transfer for sensitive electronics
  • Multi-day autonomy designs for high-resilience sites
  • Commercial demand-charge management configurations
  • Code-compliant installation per NEC 706 and UL 9540

The result: a system where everything actually talks to everything else, and the lights stay on when the grid goes down.

Three Scenarios

How storage typically fits in.

01

Retrofit: Add Storage to Existing PV

You already have grid-tied solar but it shuts down during outages. We assess the existing inverter and add AC-coupled batteries (or replace with a hybrid inverter) for full islanding capability.

02

New Hybrid: PV + Storage Together

Starting fresh? Hybrid systems engineered from the design stage are tighter and more efficient than retrofits. Single integrated platform, single point of control, single warranty path.

03

Three-Way: PV + Storage + Generator

For full hurricane-grade resilience. Solar covers daily loads, batteries handle short outages and overnight, generator kicks in for extended events — all coordinated through ATS retransfer logic.

How We Work

From critical loads to commissioning.

Phase 01

Load & Architecture

Identify your critical loads, quantify autonomy targets (hours? days?), and choose the right architecture — AC-coupled, hybrid inverter, or DC-coupled — based on existing equipment and goals.

Phase 02

Engineering

PE-stamped single-line including battery sizing, inverter selection, ATS configuration, generator coordination logic, and battery enclosure or location design with thermal considerations.

Phase 03

Installation

Self-performed install under PE oversight. Critical-load subpanel work, battery commissioning per manufacturer protocols, and integration testing with existing PV and any generator.

Phase 04

Commissioning

Full islanding test with measured transfer time, simulated outage scenarios, generator-aware logic verification, owner training, and a complete as-built and operating procedures package.

Technical Standards

The codes & standards we engineer to.

Storage Code
NEC Article 706 (Energy Storage Systems) — current edition. Sizing, disconnect requirements, working space, and signage all per code.
Safety Standards
UL 9540 energy storage system listing and UL 9540A thermal runaway testing for batteries installed in occupied spaces or near them.
Chemistry
Lithium-iron-phosphate (LFP) preferred for thermal stability in tropical climates. NMC chemistry available where energy density requirements justify the additional thermal management.
Inverters
Hybrid inverters with grid-forming capability and seamless transfer (typically <20ms). UL 1741-SB (grid-support) certification for code-compliant interconnection.
ATS Integration
Coordination with existing or new automatic transfer switches (ASCO 185-series, Generac, Kohler, and others), including retransfer logic and generator shutdown sequencing.
Interconnection
Net metering applications with LUMA Energy where applicable; behind-the-meter storage for sites with no export.
Common Questions

FAQ · Battery Storage

Almost always yes. The path depends on your existing inverter: AC-coupling allows storage to be added without replacing the PV inverter, while replacing with a hybrid inverter offers tighter integration but more disruption. We assess both options during the discovery phase and explain the tradeoffs honestly.

Lithium-iron-phosphate batteries are rated for 6,000+ cycles in moderate climates. The Caribbean's heat is the limiting factor — proper enclosure design with ventilation (or AC-conditioned battery rooms for larger systems) significantly extends real-world lifespan. We factor thermal management into every design.

We start by identifying which loads need to stay powered during an outage — typically refrigeration, lighting, communications, and medical equipment — and quantifying how long you need them. Most residential systems target 8–24 hours of autonomy for critical loads; high-resilience sites target multiple days with generator backup.

Yes — that's the whole point. Once islanded, the battery powers the critical-load subpanel directly. If solar production is also reduced (cloudy storm conditions), autonomy depends on battery capacity and load discipline. For longer events, a generator extends operation indefinitely.

Yes — generator-aware logic is part of every three-way (PV + battery + generator) system we design. The generator can recharge the battery during extended outages, with the battery providing the seamless transfer when the generator starts and stops.

Commercial storage for peak-shaving and demand-charge reduction is a growing application. The design priorities are different from resilience-focused systems — discharge cycles are more frequent and lifecycle economics matter more. We engineer commercial storage with that economic model in mind.

Start your storage project

Ready to add real outage coverage?

Tell us about your existing system (if any) and what you're trying to protect. We'll respond within one business day with next steps and, where appropriate, a no-obligation feasibility recommendation.

  • Retrofit existing PV or design hybrid from scratch
  • Generator-aware logic with ATS coordination
  • LFP chemistry for tropical-climate reliability
  • Seamless transfer measured at commissioning

Battery storage inquiry

One business day response.