The Franklin aPower 2 home battery: whole-home backup, built to last 15 years.

Rate hikes are accelerating

Ameren raised rates 12% in June 2025. Liberty Utilities rates phase up another 11 to 13% over three years starting after the January 2026 PSC settlement. Evergy Missouri Metro filed for 14.9% effective January 2027. Every utility-rate increase makes solar-plus-battery economics better because your stored sunshine displaces increasingly expensive grid power.

Grid outages are getting worse

Missouri and Kansas sit in tornado alley with severe ice storms in winter and supercell thunderstorms through summer. Liberty Utilities reports an average outage duration of 170 minutes per event. The aPower 2's IP67 weatherproof rating and -4°F cold start mean it keeps working when the grid goes down, even in extreme weather.

Time-of-use rates reward storage

Evergy Missouri put all customers on time-of-use rates in October 2023. Peak rates from 4 to 8 PM run approximately 38 cents per kilowatt-hour in summer. A battery charges from cheap off-peak power (or solar) and discharges during peak hours, capturing roughly 29 cents per kilowatt-hour in arbitrage value on top of net metering credits.

A fourth reason worth noting: the federal residential solar Investment Tax Credit (which had covered 30% of battery cost when paired with solar) expired December 31, 2025. The 2026 federal incentive landscape is more limited, which makes the underlying economics of higher-rate states like Missouri and Kansas matter more in the payback math.

Pricing is per battery, fully installed at your home. The math is simple: $15,500 + $12,800 × (N − 1) where N is the number of units. Maximum stack is 15 units per aGate controller, totaling $194,700 for a 225 kWh system (typically off-grid or small commercial scale). Try the Solar Assure cost calculator with the battery configurator to see your specific system size, expected backup runtime, and total project cost in about 60 seconds.

These prices are for battery-only installs or batteries added to an existing solar system. When pairing with new solar at the time of original installation, the integrated quote may have small efficiencies that reduce the marginal battery cost. All pricing is subject to in-person verification of your electrical panel capacity, mounting location, and any local permitting variations.

The honest takeaway: all three are solid LFP-chemistry batteries from reputable manufacturers. Tesla Powerwall 3 wins on continuous and peak output and round-trip efficiency, but loses on warranty length and stacking flexibility. Enphase IQ Battery 5P wins on modularity (smaller 5 kWh increments) but gets expensive when scaled to whole-home capacity. The Franklin aPower 2 wins on storage per unit, warranty length, scaling capability, temperature tolerance, and operates fan-less for silent operation.

For Solar Assure customers using Enphase microinverters on the solar side, the AC-coupled Franklin aPower 2 is the natural pairing because it handles the storage side at lower cost than scaling Enphase IQ Battery 5P units to equivalent capacity. Customers who would otherwise need 3 Enphase IQ Battery 5Ps (15 kWh) get the same capacity for less in a single Franklin unit. This is why Franklin is Solar Assure's recommended battery for whole-home and off-grid configurations.

Most Common

Essentials backup, 1 unit

For homeowners who want to ride out storm-related outages without losing the fridge, freezer, lights, internet, or sump pump. Includes one window AC unit running occasionally. Most common configuration in the St. Louis metro and Kansas City suburbs.

· 15 kWh · ~12 hours essentials ·

Whole-Home

Whole-home backup, 2-3 units

For homeowners who want central HVAC, kitchen, and large appliances running through extended outages. Common in southwest Missouri (Liberty territory, ice storms) and Kansas tornado alley. Three units handles 36 hours of full-home use without rationing.

· 45 kWh · ~36 hr essentials ·

Off-Grid

Off-grid living, 4-6 units

For homeowners on rural acreage who want true grid independence. Sized to cover 2 to 3 days of full-home consumption to ride out cloudy stretches. Common pairing for new builds in rural southwest Missouri or off-grid cabins in the Kansas Flint Hills.

· 75 kWh · ~2.5 days off-grid ·

Daily arbitrage cycle · summer weekday on Evergy MO Standard Peak Saver

This is on top of the underlying solar production savings. Annualized including shoulder seasons (lower peak rate differential in spring and fall, milder winter peak), the typical TOU arbitrage benefit on Evergy Missouri runs roughly $1,000 to $1,500 per battery per year. Stacked against the $15,500 first-unit price, that means the TOU arbitrage value alone delivers a 10-to-15-year payback on the battery, with whole-home backup, EV-charging support, and 15-year warranty bundled in. Customers on flat-rate utilities (Ameren Missouri, Evergy Kansas, Liberty Utilities Missouri) have less daily arbitrage opportunity but stronger backup-value justifications because of higher outage frequency in those service territories.

Note: this example assumes the Standard Peak Saver default rate plan. Evergy MO offers four TOU options and the math varies by plan. Solar Assure models expected battery savings against your specific historical usage and rate plan during the in-person quote, so you see realistic dollar figures rather than marketing averages. For more on Evergy Missouri's TOU rates and how solar interacts with them, see our Evergy Missouri Solar Guide.

If you have Enphase microinverters

Most Solar Assure customers do. The aPower 2 pairs natively with Enphase microinverters because both are AC-coupled architectures. The Franklin sits at the home's electrical panel rather than between the panels and the inverter. Your existing Enphase App continues monitoring solar production while the FranklinWH app handles battery state-of-charge and outage management. Two apps, but each does what it does best.

If you have a string inverter

Also fine. AC-coupled architecture means the aPower 2 attaches to the AC bus downstream of your existing string inverter. Compatibility verified across most major string inverters including SolarEdge, SMA, Fronius, and others. The retrofit electrical work is similar to a new battery install: the aPower 2 ties into the main electrical panel, and the aGate controller handles the islanding logic when the grid goes down.

If you have no solar yet

The aPower 2 can install standalone as a grid-charged battery. This works particularly well on Evergy Missouri's TOU rates where peak vs off-peak arbitrage delivers daily value even without solar. However, pairing solar at the time of original installation is more economical because solar provides daily zero-marginal-cost charging. For a fresh installation, Solar Assure typically recommends the integrated solar-plus-battery quote rather than battery-only.

If you have a generator

The aPower 2 plays nicely with backup generators. The aGate controller can prioritize battery discharge first, then start the generator only when the battery reaches a configurable lower threshold. This extends generator runtime and reduces fuel consumption during extended outages. Useful for rural homes in Liberty Utilities Missouri or Evergy Kansas Central territories where grid outages can last 24 hours or longer.