Why Sentinel exists, and who gets to use it.

1. Why we built an engineer’s tool, not a customer app

There are plenty of pretty dashboards that show a homeowner a graph of yesterday’s solar. That was never the gap. When GivEnergy went into administration, the thing that broke wasn’t the customer’s view of their own system — it was the engineer’s ability to reach it. No portal to log into, no support line to escalate to, no sanctioned remote path to a live inverter. An engineer who’d be on-site in a heartbeat suddenly had to drive across three counties to read a fault code they could have pulled in thirty seconds if they’d had remote access.

So Sentinel is built for the person holding the multimeter, not the person who owns the battery. You pair to a customer’s system with a six-character code, and you get the whole picture an engineer actually needs: live power flow, the full Modbus register map, EMS state, per-cell voltages, G98/G99 export behaviour — everything you’d see standing in front of the unit, read remotely. Most faults get diagnosed in minutes, and the ones that genuinely need a visit, you now arrive at with the parts already in the van.

That focus is why Sentinel is free to approved installers. The app is the tooling; the diagnostic and remedial work engineers do with it is the business. We’d rather put the tool in as many capable hands as possible than meter it.

2. Why access is application-only and 5★

A tool that can reach into a live installation in someone’s home only works if you can trust who’s holding it. Remote access to a customer’s inverter is not something we hand out at a sign-up form. So Sentinel is free, but it’s earned: access is by application, and we give it to installers who are consistently rated 5★ by the customers they serve.

This is a policy, not an algorithm — there’s no automated ratings feed deciding who’s in. We look at who you are, the work you do, and the track record you carry, and we make a call. It’s free, but it’s a privilege, and it can be withdrawn if standards slip. That’s the deal, and it’s deliberately a bit demanding, because the alternative — remote reach into homes handed to anyone who asks — is exactly the kind of thing that makes people distrust our industry.

If you install and service GivEnergy kit for a living and you hold that standard, apply for access. If you’re not there yet, we’re happy to tell you honestly what we’re looking for.

3. Why it’s read-only by default

Remote access to a battery inverter is a serious thing to hold, so Sentinel treats it seriously. By default the app reads — it pulls registers, watches power flow, surfaces faults — and it cannot write anything back. That’s the resting state, always.

When a fix genuinely needs a change to the inverter, the write never happens on your say-so alone. You arm an access window from the engineer side; the actual consent to write is given by the customer, on their own device, during that window. Nothing is changed on their system without them agreeing to it in the moment, in their own hand. And every write that does happen is recorded to a permanent, tamper-evident log — what changed, which engineer made it, and on which system — the moment it’s made, before it reaches the inverter, and no engineer can alter or delete it. Only the account owner can erase an entire system’s record (for example to clear a test), and every erasure is itself permanently logged, so there’s always an honest record.

Read-by-default plus on-device customer consent isn’t friction we’re apologising for. It’s the whole reason an engineer can be trusted with remote reach in the first place.

4. What we’ll never do with data

• We’ll never sell it. Not anonymised “market research”, not aggregated “industry insights”, not bundled into a research data set for some battery manufacturer’s ML model. The data your inverter generates is yours. Full stop.
• We’ll never advertise to you in-app. No banner ads, no promoted “recommended installer” cards, no third-party tracking. The dashboard’s only ads are the Solar Tech Support links — and those are written so you know exactly what they are.
• We’ll never lock you out of your own data. CSV export of every reading we’ve ever stored, downloadable at any time, even after you cancel.
• We’ll never share it with GivEnergy, even if they ask. The administration is what made this product necessary; we’re not handing over anything to the entity (or whoever buys the assets) that left their customers stranded.
• We’ll never email marketing junk. Transactional emails only — fault alerts, access notifications, security notices. No newsletter, no promos, no “we noticed you haven’t opened the dashboard in a while.”

5. Why we still tell customers to get other quotes

When Sentinel spots a fault on a system and the customer comes to STS, we’ll quote for the fix. Then we’ll suggest they get two other quotes from independent installers before deciding.

This isn’t fake humility. It’s self-interest. If a customer compares three quotes and picks ours, they bought with confidence and they’ll be a happy customer who tells their neighbours. If they pick a competitor’s quote because it’s cheaper or faster or they preferred the engineer, fair enough — that fault would have stayed undiagnosed without Sentinel, so the customer’s still better off, and the next fault they might give us another go. Either way they’re ahead of where they were with a system nobody could reach.

The alternative — “our tool found the fault, so you have to use us for the repair” — is what the solar industry has been doing for two decades. It’s why so many customers don’t trust solar installers. We’d rather opt out of that pattern entirely, and we’re open about the limits: if a feature isn’t ready, we say so, and every change we ship is logged publicly at /changelog/.

Who pays for this and how the books balance

Sentinel is a wholly owned product of RVTC LTD, a UK limited company. The same company runs Solar Tech Support, a solar diagnostic and repair service that has been operating since 2019, and Alectrona, a solar installation company. The accounts are public — Companies House filing 14XXXXXX.

Sentinel runs at a small loss in isolation, because it’s free to the installers who use it. That loss is more than offset by the engineer-services revenue those diagnoses drive into STS. We don’t have outside investors and we’re not trying to grow Sentinel to be acquired. The aim is for it to be a slow-but-stable source of trusted repair work for the next 10+ years.

If RVTC LTD ever gets sold or wound up, we’ve committed in the privacy policy to a 30-day notice window during which all telemetry data is exported and deleted — nobody’s data gets bundled into an acquisition.