How my ~£530 portable battery + Tapo smart-plug setup uses Octopus Agile's overnight cheap rates (sometimes negative pricing) to shave my electricity bill by roughly 10–15% — no DNO paperwork, no MCS installer, no G99 application.
Transparency: links marked (*) are affiliate links — if you buy through them we may earn a commission at no extra cost to you. It doesn't change our recommendations.
Last updated: May 2026 · Product prices and ASINs last verified on 2026-05-22. Related guide: Build your own 2000W DIY solar setup.
Last Tuesday at 3 AM, Octopus Energy paid me 4 pence per kWh to use electricity. Not joking — that’s what plunge pricing on Agile means: when there’s so much wind blowing across Scotland that the grid can’t absorb it all, the wholesale rate goes negative, and Octopus passes that through to half-hourly customers like me. I had my battery scheduled to charge at exactly that hour. The whole 1 kWh storage filled up at a cost of minus 4p.
To be clear: I’m not running a fixed home battery installation. I’m using a £500 portable plug-and-play battery + a £15 Tapo P110 smart plug to do Agile arbitrage — charge during cheap-rate or negative-rate windows (typically 2–5 AM), discharge during the expensive 4–7 PM peak. (New to the tariff? Start with Octopus Agile explained.) No DNO notification, no G99 paperwork, no MCS-certified installer. Just a heavy box and an outlet timer.
⚠️ Safety disclaimer: This article shares my personal experience with a portable battery arbitrage setup on Octopus Agile. Descriptions may be incomplete or inaccurate, and tariff structures change frequently. You build at your own risk. Working with 230V AC outputs requires basic electrical awareness. All recommended units have RCD protection on their UK 3-pin BS 1363 outputs — never bypass that with long extension cords. For any installation tied to the main consumer unit (fixed batteries, hybrid inverters), G98/G99 compliance and an MCS-certified installer are required by ENA regulations.
| Your situation | Better choice |
|---|---|
| You’re on Octopus Agile or considering it | Portable battery + smart plug |
| You rent your flat / can’t drill walls | Portable plug-and-play |
| You want fastest setup (one evening) | Portable |
| You want to back up an EV charger or electric shower | Fixed installation (electrician needed) |
| You have existing solar PV and want to add storage | Hybrid: portable for peak shaving, fixed for full export |
| You want £8,000+ install with whole-home automatic transfer | Fixed installation with G99 paperwork |
| You’re on a standard fixed tariff (no Agile) | Battery arbitrage less valuable — wait for Agile signup |
| You’re worried about crimping wires | Portable (no wiring needed at all) |
Most renters, flat dwellers, and Agile customers end up on the portable side. The economics work out as long as you actually USE the scheduling (more on that below).
Goal: shift roughly 1–2 kWh of daily peak-hour consumption (4–7 PM, when Agile peaks above 28p) onto cheap-rate charging (2–5 AM, when Agile drops to 8–15p, sometimes negative). Setup comparison from Amazon.co.uk (May 2026):
| Feature | Anker SOLIX C1000 Gen 2 ★ Recommended | EcoFlow DELTA 3 Plus | Jackery Explorer 2000 v2 | BLUETTI AC180 |
|---|---|---|---|---|
| Price | ~£499 | £699 | £1,061 | ~£599 |
| Capacity | 1.02 kWh | 1.02 kWh (expandable to 5 kWh) | 2.04 kWh | 1.15 kWh |
| Continuous output | 1,800W (2,400W SurgePad) | 1,800W (X-Boost 2,400W) | 2,200W | 1,800W (2,700W surge) |
| Mobility | Portable (11.3 kg) | Portable (12.5 kg) | Portable (17.5 kg) | Portable (17 kg) |
| App scheduling | Anker app — schedules ToU | EcoFlow app + Tapo plug | Jackery app — basic scheduling | Bluetti app |
| Best for | Entry-level Agile arbitrage | Modular growth path | Bigger storage for multi-day | Best AC charging speed |
For most UK Agile customers, Anker SOLIX C1000 Gen 2 is the sweet spot. It’s affordable, has the deepest 4.7★ rating with 1,000+ reviews, and integrates with Tapo smart plugs for scheduling. If you want to grow to a 2 kWh+ system over time, EcoFlow DELTA 3 Plus is more modular (additional battery packs available).
Short answer: For Agile arbitrage starters, Anker SOLIX C1000 (£499, 1.02 kWh, 1,800 W with 2,400 W SurgePad for the kettle) is the value pick. For modular expandability up to 5 kWh as your usage scales, EcoFlow DELTA 3 Plus (£699, 1.02 kWh + stackable extra packs) wins. Both are LiFePO4 with sub-30 ms UPS switchover. Above 1 kWh you’re paying for headroom you only use if you cycle more than once per cheap window.
Both are LiFePO4. Both have similar capacity. Both work for Agile arbitrage. Key differences:
Short answer: A TP-Link Tapo P110 (~£15 single, ~£30 for a 4-pack) is the dead-simple choice. Built-in energy monitoring lets you verify the exact kWh you drew during the 2–5 AM cheap window — useful if you want to audit the savings against your Octopus account. Skip the battery maker’s own scheduler if it’s clumsy: Tapo + a Google/Apple Home routine covers 95 % of arbitrage cases without lock-in.
Without scheduling, you’ll forget to charge during the 2–5 AM cheap window. The Tapo P110 (4-pack £29.99) makes scheduling brain-dead simple:
The Tapo P110 also has built-in energy monitoring, so you can see exactly how many kWh you charged at off-peak and verify Agile savings in retrospect. £15 for a single, £30 for 4-pack — buy the 4-pack if you also have other devices to schedule (washing machine on Economy 7-style timing, EV charger off-peak, etc.).
Short answer: Only if you want whole-home consumption verification, not just battery monitoring. The Shelly logs every kWh in/out of your house at 1-second resolution and tags each to its Agile half-hour slot — so you can document exactly what you saved (or what Octopus paid you on plunge nights). For Agile data-geeks and audit-friendly savings tracking, yes. For a plain “charge cheap, use later” setup, skip it and put the £150 toward a bigger battery.
If you want to verify whole-home savings (not just battery savings), add a Shelly Pro 3EM 120A (£150) on your consumer unit’s DIN rail (a sparkie can fit it in 30 minutes). The Shelly logs every kWh in/out of your house in 1-second resolution, and you can see exactly which half-hour Agile slot you consumed in. Optional but powerful for Agile geeks — it’s how I documented the negative-pricing charges that ended up paying me to use power.
I bought the C1000 in week 1. Manually plugged it in to charge each evening. By the end of month 1: about £2 saved on Agile. Vastly underwhelming. I assumed I needed a bigger battery.
Wrong. The actual issue: I was charging at random times, not specifically during cheap-rate windows. Charging at 9 PM when Agile peaks at 30p means the battery cost me MORE per kWh than the grid I was supposedly replacing. Stupid.
The fix: £15 Tapo P110, scheduled to ON 02:00–05:00, OFF rest. Set it once on a Saturday morning. By month 2 (with the schedule): about £7 saved. By month 4: settling around £8/month — roughly the £90/year a 1 kWh battery can realistically shift. The battery hardware was never the bottleneck — my human inconsistency was.
Lesson: the £15 smart plug delivers more ROI than the £500 battery. Scheduling is not optional. Set it once on day 1.
Three cases where I’d recommend a proper installed home battery over portable plug-and-play:
For everyone else — flat dwellers, renters, Agile-curious homeowners — portable is the right entry point.
Everything I bought, with direct Amazon.co.uk links:
Availability note: If a primary pick is sold out, the alternatives in each component section are direct drop-in replacements. Links marked with (*) are affiliate links; no extra cost to you.
After 4 months of running an Anker SOLIX C1000 + Tapo P110 schedule on Octopus Agile:
You’re in for arbitrage if:
Go fixed install if:
For me, the £528 setup is on track to pay for itself in around 5 years through Agile arbitrage — quicker on the nights Octopus actually paid me to charge. Modest and steady rather than a windfall, but with zero paperwork and nothing to install, it’s the easiest win on Agile.
Anker
£498.99
Prices & availability may change.
EcoFlow
£699.00
Prices & availability may change.
Jackery
£1,061.00
Prices & availability may change.
TP-Link
£29.99
Prices & availability may change.
Shelly
£150.54
Prices & availability may change.
Yes, but be realistic about the scale. A 1.02 kWh Anker C1000 cycled once a day shifts about 1 kWh from peak to cheap-rate. Filling 1 kWh during the 2–5 AM window (≈8–15p/kWh) costs roughly 8–15p; using it in the 4–7 PM peak (≈28–42p/kWh) avoids about 35p. Net margin ≈ 25p per kWh stored — around £90/year for a 1 kWh battery, or ~£180/year if you run a 2 kWh unit and cycle it fully. Negative-price nights add a little on top. It's a steady saving, not a windfall.
A typical UK household uses 3–5 kWh during the 4–7 PM peak window. So a 1–2 kWh battery covers the most expensive part of your day. The Anker SOLIX C1000 Gen 2 (1.02 kWh, £499) is the entry-level pick. Jackery Explorer 2000 v2 (2.04 kWh, £1,061) doubles the storage. For multi-day arbitrage with negative-rate nights, 3 kWh+ is ideal — daisy-chain two C1000s or step up to a Bluetti AC180.
Yes — without scheduling, you'll lose 80% of the arbitrage margin. The Tapo P110 (£15 for single, £29 for 4-pack) plugs between wall outlet and battery, and lets you schedule 'Charge ON 02:00–05:00, OFF other hours' via the Tapo app. Some batteries (Anker SOLIX) have built-in time-of-use scheduling in their app, which is even better. The smart plug is the cheapest way to add this to ANY plug-in device.
Up front, portable is far cheaper. A grid-connected fixed home battery with an MCS installer + G99 DNO application runs £8,000–£15,000 including labour and paperwork (often 4–8 weeks for DNO approval). A plug-and-play setup is £500–£1,200, deployed in an evening, with no paperwork. The fixed install has a higher savings ceiling (whole-home auto-switching, EV integration) but a steep upfront barrier. For most households just starting with Agile, portable is the easier entry point — just keep the savings expectations realistic.
All recommended units (Anker SOLIX C1000, Jackery Explorer 2000 v2, EcoFlow DELTA 3 Plus) use LiFePO4 chemistry, which is far more thermally stable than the NMC lithium in phones and laptops — though no lithium battery is truly non-flammable. They output through UK 3-pin BS 1363 sockets, but most portable stations use a floating-neutral or Class II design rather than a built-in RCD, so don't assume the same RCD behaviour as a fixed installation. The main thing to avoid: running the output through long extension leads, which adds resistance and voltage drop. Use the battery's own sockets, in the same room.
Total kit: Anker SOLIX C1000 Gen 2 (£499) + Tapo P110 4-pack (£29) + optional Shelly Pro 3EM (£150) = £528–£678. Annual Agile arbitrage savings for 1 kWh/day shifted from ~35p to ~12p work out to about £84/year (≈£0.23 × 365). Payback on the basic kit is therefore roughly 5–6 years before round-trip losses — quicker if you run a larger battery, cycle it more than once on cheap days, or catch negative-price nights. The Shelly is for monitoring, not extra savings.
Amazon.co.uk is usually competitive and convenient for Anker SOLIX, EcoFlow, Jackery, and Bluetti portable units, and often runs below the manufacturer's direct price — but compare manufacturer stores and retailers like Argos and Currys before buying. Black Friday and Prime Day are the deepest discount windows: the Anker C1000 has been seen around £349 during sales. Buying through Amazon also gives a hassle-free UK returns path if a unit arrives faulty.
Perfectly. The whole point of plug-and-play is no installation, no permission needed. Battery plugs into any standard UK 3-pin BS 1363 socket. Tapo smart plug schedules the charging. You can take it with you when you move. The only thing not legal in flats: connecting to communal building circuits or feeding back into the building's grid — but for in-flat arbitrage (charging in your own meter zone, using in your own meter zone), it's fine.
Generally no — G98/G99 govern generation and storage that can operate in parallel with the grid and export. A plug-and-play battery that only charges and powers your own loads (never back-feeding) is treated as an appliance, so it typically needs no DNO notification or MCS installer. But if you ever connect it so it can export or run in parallel with the supply, ENA's G98/G99 process applies — and note ENA treats storage as generation in that process, so check the current guidance before any grid-tied setup.
Keep Reading
Power & Energy
12V or 24V for a 2000W inverter? We compare current draw (~170A vs ~85A), cable size in mm², cost and efficiency — and when 12V is fine vs. when 24V is the clearly better choice.
Mobile
The best budget smartphones in the UK for 2026: Google Pixel 10a (7 years of updates), Samsung Galaxy A57 (6 years), Nothing Phone (4a) Pro as the British-brand hero, and the £219 CMF Phone 2 Pro under £250 — with PSTI Act minimum-support-period context.
Power & Energy
What cable size for a 2000W inverter? At 12V the real draw is ~180–200A — we show why 50 mm² is the bare minimum (70 mm² is safer), how to size the fuse and voltage drop, and how to avoid cable fires.