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Utility room wall with a hybrid inverter, a home battery cabinet and neat conduit
Utility room wall with a hybrid inverter, a home battery cabinet and neat conduit
Home
Builds›Battery Retrofit

Utility-Room
Battery Retrofit

A 2022 roof in Aurora with no storage. The string inverter swapped for the hybrid, a Keeper battery on the utility-room wall — and a nine-hour storm outage three weeks later.

Battery Only
Aurora, CO
Completed June 2026
Outage carried
 
 
9hours

through the July storm: fridge, furnace blower, Wi-Fi and lights stayed on.

See the numbers
The story

A good roof that went dark with the grid.

Jorge Medina’s panels shut down in every outage — exactly when the family needed them.

Backup circuits
Grid use −55%
01
Challenge
A string inverter with no battery input, a utility room with one free wall and four circuits the family could not lose.
02
Solution
An engineer picked the four circuits from the house panel photos. The installer swapped in the hybrid inverter and hung the Keeper battery beside it in one day.
03
Result
Three weeks later a storm cut the power for nine hours; the fridge, furnace blower, Wi-Fi and lights never noticed. Grid use is down 55%.
Spec sheet

The build, line by line.

Figures from the order, the gateway and the owner, checked with them in October 2026.

Ask an engineer about it
Location
AuroraCO
Battery
13.5kWh Keeper
Inverter
Hybrid7.6 kW
Existing roof
7kW · 2022
Fitted by
Certifiedinstaller
Outage
9 hJuly storm
Backup
4 circuits
Completed
Jun 2026
Parts in this build

A battery, a new inverter and the gateway.

The Keeper battery, the hybrid inverter that runs it and the gateway — the roof stayed exactly as it was.

White wall-mount 13.5 kWh home battery cabinet on a light studio backdrop
1
Home Batteries
Keeper 13.5 kWh Home Battery
$6,450 $6,990
White hybrid solar inverter with a small display on a light studio backdrop
1
Inverters
Hybrid 7.6 kW Battery-Ready Inverter
$1,590 $1,690
White energy monitor gateway with two clamp-on sensors
1
Accessories
Sunbox Energy Monitor Gateway
$199
On site

One wall, one day, one storm.

The installer swapped the inverter in the morning and hung the battery after lunch; an inspector signed it off that week.

Electrician fitting a new breaker in a residential electrical panel
Electrician fitting a new breaker in a residential electrical panel
New breaker for the backup panel
Building inspector with a clipboard checking a new isolator while the owner watches
Building inspector with a clipboard checking a new isolator while the owner watches
Inspection day
Sunbox engineer with a headset answering a customer at a desk with a roof layout on screen
Sunbox engineer with a headset answering a customer at a desk with a roof layout on screen
Engineer picking the backup circuits
 

Grid power bought a year, before and after

−55% a year
Before
 
6.9k
After
 
 
3.1k
Monthly output of the 2022 roof · kWh
May–Aug in teal
560
 
J
660
 
F
870
 
M
970
 
A
1.1k
 
M
1.1k
 
J
1.1k
 
J
1.1k
 
A
920
 
S
760
 
O
560
 
N
510
 
D
The first year in numbers
9hours
carried through the July storm
4circuits
on backup: fridge, furnace, Wi-Fi, lights
1day
to fit the inverter and the battery
 
“The storm took the street dark for nine hours. We only knew because the neighbours came round to charge their phones.”
JM
Jorge Medina
Verified buyer · Keeper 13.5 kWh + Hybrid 7.6 kW
Same battery

Roof, but no battery?

The Keeper 13.5 kWh is on sale this week — and works with the hybrid inverter.

Shop the Battery
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