Field Notes · Capture spec · Storage
What a battery adds to the site survey
Storage is not the panel survey plus one photo. It is a second electrical investigation, a dimensional rulebook, and often a second authority. Here is the list.
A battery changes the survey more than most installers expect. It is not the panel survey plus one extra photo. It adds a second electrical story, a second set of clearances, and a second authority with an opinion, and every one of those turns into a change order if the technician left the site without it.
This is the capture list we work from on a solar plus storage site. It is written for the person standing in the garage with a tablet, not for a spec sheet.
What the battery adds to the electrical survey
A panel-only survey answers one question about the service: can it carry the new solar breaker. Storage asks four more.
| Capture | Why it decides something |
|---|---|
| Main breaker rating and bus rating, photographed separately | These are frequently different numbers and the bus rating is the one that constrains you. The label is often behind the deadfront. |
| Meter-main versus separate meter and panel | Determines whether a backup arrangement can be done at all without a service upgrade, and whether the transfer equipment has anywhere to land. |
| Every existing double-tap, tandem, and open slot | Slot count drives whether partial backup needs a subpanel. Discovering this on install day is a return trip. |
| Service entrance conductor size and route | If the backup point has to go upstream of the main, this is the number that decides the method. |
| Grounding electrode and bonding path | Storage inspections fail on grounding more than on anything else. |
| Existing loads worth calling out: well pump, EV charger, mini-split, sub-panels | These set the backup load calculation, and the homeowner will assume all of them are backed up unless someone wrote down that they are not. |
The clearances nobody photographs until they have missed one
Batteries live under a dimensional rulebook that panels do not. The survey has to produce measurements, not impressions.
- Wall run available, measured, with obstructions marked. Hose bibs, dryer vents, and the garage door track are the usual three that kill a location after it was already sold.
- Floor to ceiling and floor to first obstruction. Storage units have working-space requirements and a shelf at the wrong height moves the whole install.
- Distance to the nearest door, window, and dwelling-unit opening. Some authorities restrict this. Capture it whether or not yours does, because the number does not change and the rule might.
- Distance from the battery location to the main panel, along the actual conduit route rather than in a straight line. Conduit runs get estimated on a straight line and then cost twice that.
- Egress path and whether the space is a means of egress. A garage that is the only route from a bedroom is a different question than a garage that is not.
- Ambient conditions. Unconditioned attic, west-facing garage wall in Phoenix, or a crawlspace that floods. Thermal derating is real and it is decided here.
The one that causes the most rework
Photograph the proposed battery wall from far enough back that the whole wall and both adjacent walls are in frame, then again with a tape measure held against it. A tight photo of a wall proves nothing about what is three feet to the left of it.
The second authority problem
On a panel-only job you are usually dealing with one building department and one utility interconnection process. Add storage and you can pick up a fire-code review, a separate electrical review, and in some jurisdictions a different inspector on a different visit. Those reviews ask for things a solar-only plan set does not contain: a battery location plan with dimensions, a placard and labeling schedule, and sometimes a listing document for the specific equipment.
None of that is hard. It is only expensive when the survey did not collect the inputs and the plan set has to be revised after the first rejection. We deliver stamped permit sets with the storage sheets included, and the arithmetic that makes that worth it is the same arithmetic in the build versus buy model: a revision cycle costs more than the survey did.
What a complete storage survey looks like when it comes back
Our storage surveys come back inside 48 hours of the site visit, with the roof and electrical captured in a single trip and a 3D roof model accurate to less than an inch. From that survey to a permit-ready plan set is six days. We have run more than 50,000 surveys over seven years, nationwide, and the storage sites are the ones where the capture spec earns its keep, because the failure mode is not a bad photo. It is a missing measurement that nobody knew to take.
Flat $275 per site. The reason that number holds on a storage job is that the capture list above is a checklist rather than a judgement call, which is the whole argument in two technicians, two roofs.
The short version
If you take one thing to your next storage survey: measure the wall and the conduit route, and write down which loads are not backed up. Those two omissions account for most of the storage change orders we see, and both take under five minutes on site.
Storage volume coming in 2027?
Bring a site that went sideways and we will walk back through what the survey should have caught.
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