Whole-home battery backup in California — without complex wiring or panel replacements
The ConnectDER IslandDER meter socket adapter simplifies installing whole-home backup with battery storage. It builds the microgrid interconnect device and consumption sensors into the meter socket itself, so installers can skip the expensive panel modifications that traditional backup installs typically require — no main panel replacements, no sub-panel rewiring, no circuit relocations.
Connect California helps homeowners and installers in California connect with certified IslandDER installers using compatible battery systems from leading partners.
At a glance
| Product | ConnectDER IslandDER (meter socket adapter) |
| Purpose | Whole-home and partial-home battery backup |
| Service rating | Up to 200A continuous |
| Built-in | Microgrid Interconnect Device (MID) + consumption CTs |
| Install | 15–30 minutes behind the utility meter |
| What it eliminates | Modifications to the existing combo panel, sub-panel installs, circuit relocations, separate MID/CT installs |
| Certifications | UL Listed, UL 414 SA/SB/SC, UL 1741/3141/9741 system ready, NEMA 3R |
| Pricing | Text or talk to a specialist — varies by installer and project |
What it does
IslandDER installs in the meter socket — between the utility meter and the home — and provides two functions in one device:
- Microgrid Interconnect Device (MID): safely disconnects the home from the grid during an outage so a battery can power the home without back-feeding the grid.
- Consumption sensing: built-in current transformers (CTs) measure household usage so the battery system knows what to power. No field-clamping CTs around service conductors required.
Combined, these two functions are what battery backup systems require to do whole-home backup safely. Traditionally they’re installed in the main panel itself or in a separate enclosure mounted nearby — and in California, that usually means modifying the meter-main combination panel on the exterior wall of the home, sometimes replacing it entirely. IslandDER puts both functions in the meter socket, so the existing panel doesn’t need to change.
Compatible battery partners
IslandDER works with a growing list of leading residential battery storage systems. ConnectDER coordinates with each battery partner on the controller hardware and integration.
Installing now
- FranklinWH aPower 2 and aPower S (with MAC controller)
- Lunar Energy Lunar System (with Meter Socket Adapter Controller)
Coming 2026
- EcoFlow OCEAN Pro
- Fox ESS PowerQ Series
- SolarEdge Nexis (digital ethernet variant; no separate MSA controller required)
If you’re already considering a specific battery system, we can confirm IslandDER compatibility and connect you with an installer who works with that battery. Tell us which battery you’re looking at →
Why this matters for whole-home backup
Most California homes have a meter-main combination panel — the meter and main breaker integrated into a single enclosure mounted on the exterior wall. Adding a traditional microgrid interconnect device and whole-home consumption CTs to a combo panel is difficult or impossible without major rework, and the fix is often a full breaker panel replacement plus utility-side service modifications — adding thousands of dollars and weeks of permitting and utility coordination to the project.
By putting the MID and CTs in the meter socket itself, IslandDER bypasses the combo-panel problem entirely. The install happens at the meter in 15–30 minutes, with no modifications to the existing combo panel — no replacement, no circuit relocations, no service-side changes.
For homeowners
- Whole-home backup with a battery, without a main breaker panel replacement
- Faster, cleaner install — the work happens at the meter socket, with no modifications to your existing combo panel
- Compatible with leading residential battery brands (above) — your installer picks the system that fits your home and budget
- Works in newer or older California homes (200A or smaller service)
For installers
- Cuts 4–8 hours of panel-modification work per backup install (per ConnectDER’s published installer data)
- No main breaker panel replacement, no sub-panel install, no field-clamping consumption CTs
- 15–30 minute install behind the meter
- Available through leading distribution partners; contact ConnectDER for installer training and certification on a specific battery partner’s system
If you’re a licensed California electrician or solar installer interested in adding IslandDER to your backup workflow, contact us → and we’ll connect you with the right ConnectDER and battery-partner resources for your market.
Frequently asked questions
What is IslandDER and how is it different from a regular battery backup install?
IslandDER is a meter socket adapter from ConnectDER that integrates the microgrid interconnect device (MID) and consumption sensing CTs directly into the meter. Traditional whole-home battery backup installs put the MID in the main panel or in a separate enclosure — often requiring a panel replacement or significant modifications to the existing meter-main combo panel. IslandDER puts that hardware at the meter instead, in a 15–30 minute install.
Which battery systems work with IslandDER?
Installing now: FranklinWH (aPower 2 and aPower S, with MAC controller) and Lunar Energy (Lunar System, with Meter Socket Adapter Controller). Coming in 2026: EcoFlow OCEAN Pro, Fox ESS PowerQ Series, and SolarEdge Nexis. Tell us which battery you’re considering and we’ll confirm fit.
Is IslandDER approved in California?
ConnectDER lists California as one of its approved IslandDER markets, with three utility territories cleared. We confirm utility approval for your specific address before recommending an installer. Call us at (858) 367-3617 with your address and utility, and we’ll check current status.
Does IslandDER do whole-home backup or only critical loads?
Both. IslandDER supports whole-home backup as well as partial- or critical-loads-only configurations. The choice depends on your battery’s continuous output capacity, your home’s typical load, and your preferences — your installer will help size the system.
Will I need a main electrical panel upgrade or replacement?
In most homes, no. The main reason traditional whole-home backup installs require breaker-panel work is to fit the MID and consumption CTs inside the panel — IslandDER puts both at the meter, so the panel typically doesn’t need to change. Your installer will confirm fit based on your specific service equipment.
How long does the install take?
The IslandDER itself installs in 15–30 minutes behind the meter. Total project time also depends on the battery installation and any required utility coordination — typical whole-home backup projects with IslandDER are completed in a few days rather than the multi-week timeline of traditional installs.
Do I need utility approval to install IslandDER?
For behind-the-meter installation (the most common configuration), yes — utility approval is required. ConnectDER also offers a separate standalone socket method that often does not require utility approval. Your installer will determine which method applies to your project.
Can I keep my existing solar system?
Yes. IslandDER is designed to integrate with new or existing solar plus a compatible battery. Your installer will confirm compatibility with your current solar inverter and any planned upgrades.
Is this for new construction or retrofit?
Both. IslandDER works for retrofit projects (where it’s most valuable, since it avoids the panel-replacement work traditional installs require) and for new construction.
How do I find an installer?
Text or call us at (858) 367-3617, or use our contact form. Tell us your address, what battery system you’re considering (or that you’d like a recommendation), and what kind of backup you want (whole-home or critical loads). We’ll connect you with a certified California installer working with the right battery partner for your project.
Get connected with a California installer
Tell us your address, your battery preferences (or that you want a recommendation), and what kind of backup you want — and we’ll match you with a certified California installer who works with the right battery partner for your project. Free, no obligation.