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How to connect a solar panel kit

Updated: October 2026

You have the box open beside a leisure battery in a van, caravan, or shed, and the sheet names the plugs without saying which lead goes on first. How to connect a solar panel kit, on these 12 V sets, is a sequence. The controller sits between the panel and the battery, the battery goes on first, and the panel stays covered until that side is done. The steps follow the kits in our [Solar panel kit comparison](/hub/electrical-equipment/solar-panel-kit). If you are still choosing a controller, use the [solar panel kit buying guide](/hub/electrical-equipment/solar-panel-kit/sub/solar-panel-kit-buying-guide) and come back with the leads in your hand.

You have the box open beside a leisure battery in a van, caravan, or shed, and the sheet names the plugs without saying which lead goes on first. How to connect a solar panel kit, on these 12 V sets, is a sequence.

Our top picks

ECO-WORTHY ECO-WORTHY 240W solar panel kit

Best overall

ECO-WORTHY ECO-WORTHY 240W solar panel kit
8.5/10about £164.49
View offer
KOLLNIUN KOLLNIUN 240W solar panel kit

Best value

KOLLNIUN KOLLNIUN 240W solar panel kit
6.0/10about £129.99
View offer
Hoysicy Hoysicy 30W 12V solar panel kit

Rank 3

Hoysicy Hoysicy 30W 12V solar panel kit
5.9/10about £39.99
View offer
On this page
  1. 1.What you are connecting
  2. 2.Order and the fuse
  3. 3.Battery profile and series wiring
  4. 4.When this is no longer a DIY clip

What you are connecting

The panel produces the voltage, the controller passes it on, and the battery stores the charge. None of these kits includes the battery or a household plug, so you are charging a battery you already own. The plugs change with the kit. Hoysicy 30 W uses alligator clips and ring terminals, ECO-WORTHY 25 W uses an SAE plug, and larger ECO-WORTHY kits use MC4 connectors with Y leads. DOKIO mixes SAE, XT60, and alligator clips. A clip that slips can spark, so it is a weak permanent joint. Match the MC4 symbols before you push the plugs home, and leave that joint on the panel cable. A Y lead joins panels in parallel and does not stack voltage the way series wiring does. A gland and sealant for a van roof sit on the solar panel kit for a campervan page.

Order and the fuse

Connect the controller to the battery before you connect the panel. The KOLLNIUN sheet and the other controller notes in this cluster do the same. Panel-first wiring can blow the protection inside the controller, because it expects a battery and instead sees an open, live input. Keep the panel covered, or face-down, until the battery side is finished. Put the fuse on the positive lead, close to the battery, so a short cannot use the battery as a welder. Two controller manuals in this cluster place that fuse within about 15 cm of the positive post. If your sheet gives another distance or another rating, follow the sheet. These kits often leave the fuse out. If the case heats up or you smell burning, disconnect and stop.
ECO-WORTHY ECO-WORTHY 240W solar panel kit

Testsieger

ECO-WORTHY ECO-WORTHY 240W solar panel kit
8.5/10about £164.49
View offer

Battery profile and series wiring

Set the chemistry the controller lists once the battery is connected. A wrong profile holds lead-acid at the wrong voltage, or it charges lithium on a lead-acid curve. Hoysicy 30 W mentions AGM, flooded, and gel, and a review says that controller does not suit lithium. The KOLLNIUN reviewer set B1, B2, or B3 only after the battery was connected. Match the code to the chemistry in that manual. The 12 V on the box is the battery system, and panel voltage sits higher than that label. One KOLLNIUN reviewer reports an input limit of about 23 V on the 12 V setting and paralleled the two panels instead of series-connecting them. Y leads on the larger ECO-WORTHY kits are the parallel join when that input limit is too low for series. If you replace the controller, that choice sits on the PWM or MPPT page. Battery and fuse come first, then the profile, then the panel.

When this is no longer a DIY clip

The load terminals are a small 12 V output. A 230 V inverter draws more than those pins allow, so fuse it at the battery if you fit one. Sockets fed from that inverter are a different job from clips on a leisure battery. These kits have no BS 1363 plug and do not go into a wall socket. In England and Wales, Part P and BS 7671 cover fixed wiring in a dwelling, not clips on a van battery. Stop for a new circuit, a house roof, or export to the grid, and use a competent person. These kits do not export unless a grid-tied inverter is added.

Common questions

Do I connect the battery or the solar panel first?
Connect the battery first, with the panel covered or face-down. The controller needs to see the battery before it charges. Panel-first wiring can blow the internal protection, which is the mistake the KOLLNIUN sheet is avoiding. Fit the fuse on the positive lead in that same step.
Where does the fuse go, and why is it often missing from the kit?
Put it in the positive cable, as close to the battery as your manual states. Two manuals here use about 15 cm, and your sheet wins if the distance or the rating differs. The fuse protects the cable from the battery's fault current.
What if the amps stay at zero?
A covered panel, an unset profile, and reversed polarity all show no charge. Larger ECO-WORTHY orders often arrive as two parcels, so a missing box leaves half the leads elsewhere. Confirm polarity and both parcels before you uncover the panel.
Can I plug the kit into a wall socket?
No. There is no BS 1363 plug on these kits, and adding one to feed a kitchen socket puts a source on house wiring.
Can I run a 230 V inverter from the controller's load terminals?
No. Those pins are a small 12 V output. Fuse an inverter at the battery if you fit one, and leave it off the controller. Sockets after the inverter need a competent person.
When do I stop and call an electrician?
Stop if you smell burning or the case is too hot to leave. One UK Hoysicy 30 W review reported a fire during installation. Also stop for a new circuit, household sockets, a house roof, or any export to the grid. In England and Wales, fixed home wiring is under Part P and BS 7671.

Related pages

Solar panel kit

Best solar panel kit for a 12 V battery in Britain

How to choose a 12 V solar panel kit for a battery

Solar panel kit for a campervan roof or your pitch

PWM vs MPPT for your 12 V solar panel kit controller

Sources

Public UK sources and the amazon.co.uk listings used for this comparison. Prices and star ratings are the listing lines from 19 October 2026.

  1. GOV.UK: Register energy devices in homes or small businesses (retrieved 19 October 2026)
  2. legislation.gov.uk: GPDO 2015 Schedule 2 Part 14 (retrieved 19 October 2026)
  3. GOV.UK: VAT Notice 708/6, energy-saving materials (retrieved 19 October 2026)
  4. GOV.UK: VAT on energy-saving products (retrieved 19 October 2026)
  5. National Grid: G98 microgeneration (retrieved 19 October 2026)
  6. Electrical Safety First: solar panels (retrieved 19 October 2026)
  7. MCS: why certification matters (retrieved 19 October 2026)
  8. Azeco: PWM versus MPPT charge controllers (retrieved 19 October 2026)