// OFF-GRID HOLIDAY-LET MONITORING
Off-grid holiday lets and cabins on one dashboard
Run more than one off-grid let and the daily question is simple: has every property got enough power for the next guest? We build, host and support a single custom dashboard — drawing live from the official Victron VRM API — that puts every cabin’s battery, solar and alarms on one screen, so you can clear a changeover from your kitchen table instead of driving 200 miles to find out. Rated 4.9 on Google.
- ● Live demo on this site
- ● Built & hosted for you
- ● Worldwide
/01 — THE SHORT ANSWER
Portfolio-level monitoring for off-grid lets
If you run more than one off-grid holiday let — a cabin in Wales, a bothy in the Highlands, a gite in the Dordogne — the job on changeover day is to know every property’s power situation from one place, before a guest walks into a cold, dark room. We build, host and support a single custom dashboard, powered by the official Victron VRM API, that shows the state of every site side by side.
That means a drawn-down battery becomes a text on changeover morning rather than a phone call from a guest at 9pm. Each property gets its own tile — state of charge, solar in and out, load, last-seen and a plain traffic-light status — so a non-technical cleaner or manager can read it at a glance. It works whether you have two cabins or twenty, and it does not replace Victron’s own monitoring: it sits on top of it, tuned to how a lettings operation actually runs.
The rest of this page is honest about what VRM already does brilliantly for free, where its built-in fleet tools stop for a small distributed portfolio, and exactly what we add.
/02 — THE CHANGEOVER-DAY PROBLEM
The gap between guests is where it goes wrong
Off-grid lets have no mains to fall back on. Between guests, a fridge left running, an immersion left on, or a fortnight of flat winter light can quietly walk a battery down to the point where the next arrival has no hot water and no lights. When the property is 200 miles away — or in another country — you find out when the guest calls, which is the worst possible moment.
The people on the ground rarely help here. A changeover cleaner has ninety minutes and no way to judge whether a battery bank is healthy or on its last few percent. Logging into a separate Victron account per property, on a phone, in a hurry, is not a workflow anyone sustains.
What actually works is one screen you glance at on changeover morning:
- Every property in one view — green means go, amber means keep an eye, red means send someone before the guest arrives.
- History that earns its keep — weeks of state-of-charge and solar data show which cabin is chronically under-panelled, so you right-size the array once instead of guessing every winter.
- Alerts that reach a human — a warning that lands before the guest does.
That is the job this service is built around.
/03 — WHAT VRM ALREADY DOES WELL
Victron VRM is excellent — use it first
Credit where it is due: Victron’s VRM portal is superb, and it is free. Every site with a GX device gets live dashboards, deep historical logging, and — importantly for lettings — genuinely good automatic alarm monitoring. VRM watches a predefined list of parameters and will email you and push a notification to the VRM app when something enters an alarm state, with advanced per-parameter rules and hysteresis available if you want them. For a single cabin, that may be all you ever need, and if it is, we will tell you so.
Where it stops is portfolio presentation. The built-in installation overview is a table, not a branded at-a-glance screen; the richer Fleet Dashboard only appears once your account is linked to 10 or more sites; the stock per-site dashboard layout is fixed (only the Advanced tab is composable, and custom widgets are limited to about six parameters); and none of it is brandable — the long-promised white-label “Dealer ID” feature was confirmed by Victron staff to have never shipped.
Independence line: we are an independent service and are listed in Victron Energy’s Recommended Software Integrator Program — though not a Victron dealer, distributor or reseller. Victron and VRM are their trademarks. We build on top of the official VRM API; we do not replace it.
/04 — THE PORTFOLIO DASHBOARD WE BUILD
One screen, every property, plain English
Using the same official VRM API that streams our own demo, we build you one dashboard for the whole portfolio — and it works from the very first two sites, with no 10-site threshold to cross.
- A tile per property — state of charge, solar today, load, last-seen and a single OK / watch / act status, laid out the way you think about your cabins, not the way a table sorts them.
- Plain English, no login — the view we build is readable by a cleaner or manager with no Victron account and no training.
- Your branding — your name, colours and property labels, not a generic portal.
- Where you need it — on a phone for changeover mornings, an office monitor, or a wall-mounted kiosk; we can also embed a public view if you want to reassure eco-conscious guests.
Crucially, this is a layer on top of VRM, not a substitute. VRM keeps doing its own logging and alarming; our dashboard gives you the single, branded, changeover-focused view VRM does not. It is built, hosted and supported by us, so you are not maintaining a server or a Grafana stack yourself.
/05 — SEE IT RUNNING LIVE
Our own off-grid van streams live on this site
We do not ask you to take this on trust. Our own off-grid support vehicle — the 365 Crafter, running a Cerbo GX on Venus OS with MPPT solar and a lithium bank — streams live through the official VRM API on our custom dashboards page, in two completely different dashboard styles built from the same data.
On the same page there is a fleet-style demo that mirrors exactly what a holiday-let portfolio view looks like — several properties side by side — where only the van is a real, live system and the rest are clearly labelled as sample sites. That is deliberate: we would rather show you one honest live feed and label the demo tiles than fake a portfolio we do not have.
Open it, watch the van’s numbers move, resize your browser, and picture your own cabins in those tiles. If you have run Victron kit before, you will recognise immediately that this is the real API and not a screenshot. When you are ready, the same build can be pointed at your sites.
/06 — WHAT YOU NEED, WHAT WE NEED
Honest prerequisites
Straight about the prerequisites, because they matter:
- Victron kit is required. Each property needs a Victron GX device (a Cerbo GX, or a GX built into another unit) online and reporting to VRM. The dashboard is only ever as good as the kit fitted — and non-Victron sensors can only appear if they are wired through the GX.
- We need VRM access. You grant us read access to your sites at the right level — an installer link or a shared account — so we can pull each property through the API. You keep ownership; we simply read.
- Each site needs a connection. No connectivity, no data. If a remote cabin has no reliable link, we also do rural connectivity, Starlink and point-to-point wireless, so that is a problem we can solve rather than a dead end.
We work worldwide and remotely — your cabins can be in three different countries and it makes no difference to us. Where response times come up, we are honest that our office hours are UK Monday to Friday, 9 to 5 UK time; the monitoring and alerting run around the clock, but a human picking up the phone is during those hours. We sit alongside your existing installer, not in their place.
/07 — WHAT IT COSTS
Quote-based, and here’s what moves the price
Pricing is quote-based, because a two-cabin estate in Snowdonia and a fifteen-unit portfolio across France are not the same job. Rather than invent a number, here is what actually moves the price:
- How many properties we are pulling into the dashboard.
- How many views — a single manager screen, or that plus a public embed and a kiosk display.
- How custom the branding, property grouping and OK / watch / act thresholds need to be.
- Alert routing — who is told what, and how, when a battery drops.
- Hosting and support — we host and maintain it, so there is a modest ongoing element alongside the one-off build.
Typically it is a one-off build plus a small hosting-and-support arrangement, and we will put a firm figure in front of you after a short call about your sites — no surprises, no invented tiers. If, after that call, we think stock VRM already covers you, we will say so.
Ask for a quote and we will scope it honestly.
FAMILY-RUN SINCE 1995 · ★ 4.9 ON GOOGLE · 200+ COMPUTERS UNDER OUR CARE · NO FIX, NO FEE · SAME-DAY REMOTE SUPPORT
// GOOD QUESTIONS
Frequently asked
Does this replace Victron VRM, or do I still need it?
You still need VRM — and you keep it. Our dashboard is a layer built on top of the official VRM API, not a replacement. VRM continues to log data and run its own alarms; we add the single, branded, portfolio-wide view it does not offer, tuned to changeover day. If your kit reports to VRM, we can read it; nothing about your existing setup gets torn out.
How many holiday lets does this make sense for?
Even two, if they are far apart. Victron’s own Fleet Dashboard only unlocks once your account is linked to ten or more sites, so owners of two to nine off-grid cabins fall into an awkward gap — too many to check one-by-one, too few for Victron’s portfolio view. That gap is exactly where a custom single-screen dashboard earns its keep, though it scales happily to twenty sites and beyond.
Will this guarantee a guest never arrives to a flat battery?
No, and we will not pretend otherwise. Monitoring gives you the warning — a red tile and an alert before the guest arrives — but physics still applies: if a bank is genuinely depleted, someone has to act. What it removes is the surprise. You get the chance to send help, shed a load, or run a generator on changeover morning instead of hearing about it from an unhappy guest at night.
What does each cabin need for this to work?
A Victron GX device — typically a Cerbo GX — online and reporting to VRM, plus a working internet connection at the site. Monitoring is only ever as good as the installed kit, and any non-Victron sensor has to be wired through the GX to appear. If a remote cabin has no reliable connection, we also handle rural wifi, Starlink and point-to-point links, so that need not stop you.
Our cabins are in different countries — can you still do it?
Yes. The whole service is remote and worldwide — a cabin in Wales, a bothy in Scotland and a gite in France sit on the same dashboard with no difference to us, because we work through the internet-based VRM API. We are a UK firm and our phone hours are Monday to Friday, 9 to 5 UK time, but the monitoring and alerting themselves run continuously, wherever your properties are.
How up-to-date is the data on the dashboard?
It refreshes from the official VRM API, which is far more responsive than a VRM share link — those are read-only and only update at the logging interval, 15 minutes by default. Practical freshness still depends on how often each site’s GX logs to VRM and on its connection quality, so we are honest that it is near-real-time rather than instantaneous. For changeover decisions, that is comfortably fast enough.
Are you approved or certified by Victron?
No. We are an independent service and are listed in Victron Energy’s Recommended Software Integrator Program — though not a Victron dealer, distributor or reseller; Victron and VRM are their trademarks. We build on their official, published VRM API, which is exactly what it is intended for. We think being straight about that matters — you are hiring a specialist integrator, not a Victron reseller badge.
How do we get started?
Open the live demo first — watch our own off-grid van stream through the real API in two dashboard styles. If it looks like the answer, get in touch or call +44 1202 775566 and we will have a short conversation about your properties, then send a firm quote. No obligation, and no pressure if stock VRM already covers you.
Can my cleaners and managers read it without a Victron login?
Yes — that is the point. The view we build is plain-English and needs no Victron account or training: a tile per property with a clear OK, watch or act status. You can put it on a phone, an office monitor or a wall display. The technical VRM detail stays available to you and your installer; the people on the ground just see what they need.
Can the portfolio page live on the same website guests book through?
Yes, and it works nicely that way — a subdomain like monitor.yourholidaylets.co.uk means cleaners, managers and you all share one bookmark on the domain you already run. Your VRM token is stored in a single server-side file there, invisible in the page code, and we only ever hold FTP access to that subdomain’s folder rather than your booking site. Because it all sits on your own hosting, the dashboards remain yours for the long term — with room to add properties and features as the portfolio grows.
See it live, then let’s talk about your portfolio
Open the live van dashboards to see exactly what we build, then book a short call for a quote shaped around your cabins — worldwide, hosted and supported by us.
01202 775566 · help@365techies.co.uk · MON–FRI 9AM–5PM