SolarEdge Home Battery vs Tesla vs Enphase Calculator

3-way comparison: SolarEdge 10 kWh (94.5% RTE, DC-coupled) vs Tesla Powerwall 3 (13.5 kWh, integrated inverter) vs Enphase IQ Battery 5P (96% RTE, most modular). Enter your existing solar brand, backup goal, and capacity — get a side-by-side table and recommendation.

kW
3-way battery comparison
Recommendation
Tesla Powerwall 3 — largest single-unit capacity (13.5 kWh), integrated inverter reduces install cost, highest continuous power (11.5 kW)
MetricSolarEdge Home Battery Tesla Powerwall 3 RecommendedEnphase IQ 5P
Capacity per module10 kWh13.5 kWh5 kWh
Modules needed2 modules1 unit3 modules
Total capacity20 kWh13.5 kWh15 kWh
Installed cost (before ITC)$16,500$9,200$16,500
Net cost after 30% ITC$11,550$6,440$11,550
$/kWh stored (net)$578/kWh$477/kWh$770/kWh
Continuous power output15.2 kW11.5 kW11.52 kW
Round-trip efficiency94.5%90%96%
Coupling typeDCAC (built-in inverter)AC
Requires specific inverterYes — SolarEdgeNo (any inverter)No (any inverter)
Modular (add later)YesYes (up to 4)Yes (any time)
Max system capacity30 kWh (3 modules)54 kWh (4 units)40 kWh (8 modules)
Ecosystem lock-inRequired: SolarEdge HD-Wave inverter ($1,500–$3,000 if not installed)AC couples with any inverter; built-in inverter for new solarNo separate inverter needed; best with Enphase IQ microinverters
Warranty10 years10 years10 years
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How to Use This Calculator

Enter your existing solar setup

Start with your existing solar system size (enter 0 for a new install) and brand. This matters more for home batteries than most people realize: SolarEdge Home Battery requires a SolarEdge HD-Wave inverter — if you already have one, there's no compatibility surcharge. Enphase IQ Battery works with any inverter but integrates most seamlessly with Enphase IQ microinverters (no additional gateway device required). Powerwall 3 includes its own inverter and AC-couples with any existing solar system.

Set backup hours and capacity target

The calculator uses both inputs to determine units needed: it takes the larger of (backup hours × 1.5 kW essential load) and your explicit capacity target. This ensures you meet both the time goal and the storage goal. SolarEdge modules come in 10 kWh increments (max 30 kWh), Powerwall 3 in 13.5 kWh (max 54 kWh), and Enphase IQ 5P in 5 kWh increments (max 40 kWh across 8 modules).

Select your scenario for a recommendation

The scenario dropdown drives the recommendation badge. "Existing SolarEdge owner" recommends the SE Home Battery because DC coupling is more efficient and no additional inverter is needed. "Existing Enphase owner" recommends IQ Battery 5P for seamless system integration. "New install max capacity" recommends Powerwall 3 for its integrated inverter and largest single-unit capacity. "Modular expansion priority" recommends Enphase for its add-one-at-a-time flexibility.

The Formula

Backup kWh Needed = max(Capacity Target, Backup Hours × 1.5 kW essential load) Modules Needed = ⌈Backup kWh Needed ÷ Module kWh⌉ (capped at product max) Total kWh = Modules × Module kWh Installed Cost = Modules × Cost per Module Net Cost = Installed Cost × (1 − 0.30 ITC) $/kWh Stored = Net Cost ÷ Total kWh TOU Arbitrage = Total kWh × RTE × (Peak Rate − Off-Peak Rate) × 365 days

Key spec differences drive the comparison: SolarEdge leads on round-trip efficiency (94.5% — best of the three) because DC coupling avoids an extra DC-to-AC-to-DC conversion. Enphase leads on modularity and also achieves excellent RTE (96%) through distributed microinverter architecture. Tesla Powerwall 3 leads on continuous power output per unit (11.5 kW) and is the only option with a fully integrated solar inverter, reducing new-install labor cost.

Example

Sarah — Existing SolarEdge 9 kW system, wants 20 kWh backup

Sarah has a 9 kW SolarEdge system in California with TOU pricing ($0.40 peak / $0.12 off-peak). She wants 20 kWh of backup to cover 12 hours during wildfire outage season.

Existing solar9 kW SolarEdge
Backup target20 kWh / 12 hours
TOU rates$0.40 peak / $0.12 off-peak
ScenarioExisting SolarEdge owner

Side-by-side result

SolarEdge: modules/cost2 × 10 kWh = 20 kWh / $11,550 net (no extra inverter)
Tesla: units/cost2 × 13.5 kWh = 27 kWh / $12,880 net
Enphase: modules/cost4 × 5 kWh = 20 kWh / $15,400 net
Round-trip efficiency94.5% (SE) vs 90% (Tesla) vs 96% (Enphase)
TOU savings/yr$2,009 (SE) vs $1,971 (Tesla) vs $2,217 (Enphase)
RecommendationSolarEdge — no new inverter, DC-coupled efficiency, lowest cost

For Sarah, the SolarEdge Home Battery is the clear winner: she already has the required SE inverter, so there's no compatibility surcharge. Two modules give exactly 20 kWh at the lowest net cost ($11,550 after ITC), and the 94.5% RTE captures strong daily TOU arbitrage on California's spread between peak and off-peak rates.

Ecosystem Lock-In: What You Need to Know

SolarEdge Home Battery

The SolarEdge Home Battery is DC-coupled, meaning it connects directly to the DC output of your solar panels before the inverter. This is the most efficient architecture (one fewer conversion = 94.5% RTE), but it requires a SolarEdge HD-Wave or Energy Hub inverter. If you don't have one, add $1,500–$3,000 for a compatible inverter to the total cost. For the roughly 30% of US residential solar owners who already have SolarEdge, this is a non-issue — and a significant advantage over the alternatives.

Tesla Powerwall 3

Powerwall 3 is the most flexible: it includes its own integrated solar inverter (can directly connect new solar panels DC) and also AC-couples with any existing inverter. For a new combined solar + battery install, Powerwall 3 reduces total cost because you don't need a separate string inverter. For existing solar owners with any brand, just AC-couple — one installation appointment. The trade-off: no official third-party battery expansion; you're in the Tesla ecosystem for future additions.

Enphase IQ Battery 5P

Enphase batteries are AC-coupled and designed to work with any inverter, but they integrate most seamlessly with Enphase IQ microinverter systems. With an existing Enphase system, batteries connect through the existing IQ System Controller 3 with no additional hardware. With other inverters, you may need an additional gateway. The standout advantage: add one 5 kWh module at any time without a system redesign — making it the most flexible long-term expansion path of the three.

FAQ

The SolarEdge Home Battery is a DC-coupled 10 kWh LFP battery designed to work exclusively with SolarEdge Energy Hub or HD-Wave inverters. Its key advantages: 94.5% round-trip efficiency (highest of the three, due to DC coupling), 7.6 kW continuous output per module, and seamless integration with SolarEdge's StorEdge monitoring ecosystem. It costs $7,500–$9,000 per 10 kWh module before ITC. The critical limitation: you must have a compatible SolarEdge inverter — making it ideal for existing SolarEdge customers but adding cost for everyone else.
Yes. Powerwall 3 AC-couples with any solar inverter including SolarEdge and Enphase systems. AC coupling means Powerwall connects to your home's AC electrical panel, not directly to the solar panels — so it works regardless of what inverter brand you have. For new installations, Powerwall 3's built-in inverter can directly connect solar panels (DC-coupled for new solar), potentially eliminating the need for a separate solar inverter. This makes Powerwall 3 unique: it functions as both a battery and a solar inverter in new builds, which can reduce total system cost.
Enphase IQ Battery 5P leads with 96% RTE, followed by SolarEdge at 94.5%, then Tesla Powerwall 3 at 90%. However, the efficiency story is more nuanced: Enphase achieves 96% through its distributed microinverter architecture with minimal conversion losses. SolarEdge achieves 94.5% through DC coupling — but only has this advantage if solar DC connects before the inverter (not in AC-coupled configurations with non-SE solar). Powerwall's 90% is for all configurations. For daily TOU arbitrage with 365 cycles per year, Enphase's 6% efficiency advantage over Powerwall adds up to hundreds of extra kWh annually per module.
Enphase IQ Battery 5P wins on expandability — you can add one 5 kWh module at any time without a system redesign or new compatibility checks. Start with one module ($5,500) and add more as budget allows, up to 8 modules (40 kWh). SolarEdge supports up to 3 modules (30 kWh) and additions require a compatible SE inverter. Tesla supports up to 4 Powerwalls (54 kWh) but each addition requires a separate Tesla installation appointment. For phased expansion over 5–10 years, Enphase's architecture is the most future-proof.
Adding a battery to existing solar makes financial sense in three situations: (1) your utility has TOU pricing with a meaningful peak/off-peak rate differential ($0.15+/kWh spread) — batteries can arbitrage this difference daily; (2) your area has frequent outages lasting 4+ hours; (3) your utility has reduced or eliminated net metering, meaning excess solar production has low value without storage. If you're in a state with robust net metering (e.g., NEM 3.0 grandfathered California accounts), the financial case is weaker — but backup value alone often justifies the investment for reliability-focused homeowners.

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