Home Battery Systems
Whole Home Battery Comparisons
How to size a whole-home battery by energy, power and voltage, and how current systems from Tesla, FranklinWH and Enphase compare on published manufacturer specifications.
Starting 0.5 kW average, 3 kW peak and 24 h are hypothetical examples. 90% and 20% are Zaron planning assumptions, not universal constants. Units shown are for energy only; modular systems may add power as well, so confirm with the manufacturer or an installer. If startup is blank, verify manufacturer specifications.
Size my whole backup planInstalled home batteries, from official datasheets and product pages.
Published nominal or usable capacity per unit.
Assumed efficiency and sizing margin, shown with every result.
Portable or whole-home?
Three Ways to Back Up a Home.
Specific loads, flexible
Plug in what you need. Output and capacity are limited by the unit.
Broad, automatic backup
Connected to the electrical service by professionals, with a gateway or transfer equipment.
Start small, add later
A smaller installed system plus portable backup, or a modular system you expand.
Side by side
Whole Home Batteries, Compared.
Manufacturer-published figures. Prices and incentives are not shown because they vary: ask installers for current quotes. Specs can change by region and version.
| Spec | Tesla Powerwall 3 | FranklinWH aPower 2 | Enphase IQ Battery 5P |
|---|---|---|---|
| Energy per unit | 13.5 kWh (nominal, AC) | 15 kWh (usable, AC) | 5.0 kWh (usable) |
| Continuous power | 5.8, 7.6, 10 or 11.5 kW (configurable) | 10 kW | 3.84 kVA at 240 VAC |
| Peak power | Verify on manufacturer page | 15 kW for 10 s (per spec listing) | 7.68 kVA for 3 s; 6.14 kVA for 10 s |
| Voltage | 120/240 VAC split phase | 240 VAC (10 kW rating) | 240 VAC single phase |
| Solar coupling | Integrated solar inverter, up to 20 kW DC | AC-coupled | AC-coupled |
| Scaling | Up to 4 Powerwall 3 units | Up to 15 units per aGate (225 kWh) | Modular: add units (designed by installer) |
| Chemistry | Verify on manufacturer page | LFP (per spec listing) | LFP |
| Warranty | 10 years | 15 years or 60 MWh throughput | Up to 15 years or 6,000 cycles, over 60% capacity |
| Consider if | You want one unit with high continuous power and built-in solar. | You want 15 kWh and 10 kW per unit with a long warranty term. | You want to start small and add 5 kWh modules, with lower power per unit. |
Tesla and Enphase figures are from official datasheets; FranklinWH's headline figures are from its product page, with peak and chemistry from spec listings.
Capacity, Power and Voltage Must All Match.
kWh is how long a battery can supply energy. kW is what it can run at once. Voltage is what your appliances require. A large battery with low continuous power can't run a big load, and a high-power system with small capacity runs out quickly.
What to ask an installer
The Ten-Point Checklist.
Whole-home batteries must be installed by qualified professionals following manufacturer instructions and applicable electrical requirements. This page is not installation guidance. Never backfeed a panel.
Methodology
Numbers You Can See. Assumptions You Can Check.
90% and 20% are Zaron planning assumptions, not universal constants. Zaron compares published specifications and has not physically tested these products.
Evidence
Know Where the Numbers Come From.
Planning method
Energy = power × time (DOE). 0.90 and 1.20 are Zaron planning assumptions.
ENERGY.GOV →Common questions
Straight Answers.
What is a whole-home battery?
A permanently installed battery system, usually connected to the home's electrical service through a gateway or transfer equipment, that can power selected circuits or the whole home during an outage. It is different from a portable power station.
How much battery does a whole home need?
It depends on your loads and outage length. Estimate average kW × hours for raw energy, then apply Zaron's planning factors (÷ 0.90 × 1.20). Also check peak power and any large motor or 240V loads.
Can one battery power my whole house?
Sometimes, depending on your loads. The continuous power rating of the system must cover what runs at the same time, and its capacity must cover how long. Many homes prioritize essential circuits.
Do these systems need professional installation?
Yes. Whole-home batteries involve interconnection with the electrical service and must be installed by qualified professionals following manufacturer instructions and applicable electrical requirements. Never backfeed a panel.
Is a whole-home battery better than a portable power station?
They solve different problems. Portable stations suit specific loads and flexibility; whole-home systems suit broad, automatic backup with professional installation. See the 5 kWh systems page for the portable-class option.
Did Zaron test these batteries?
No. This page compares published manufacturer specifications. Zaron does not claim to have physically tested these products.
Keep sizing your backup
Build the Outage Load by Load.
Size the outage first
Stay Powered.
Build the Whole Backup Plan.
Add the appliances that matter, choose your outage duration, then compare systems against your real numbers.
Open full backup calculator →