12V/24V 600W Immersion Heater – Make the most of your solar energy
Your solar panels often generate excess energy that goes to waste when your batteries are full. Instead of losing that power, put it to work by heating your water. This 12V/24V immersion heater, crafted from durable SUS304 stainless steel, is a simple and efficient way to store your surplus solar energy as hot water, with no complex components required.
Note: The unit includes two 300W heating elements, providing a combined total of 600W. You can configure the voltage (12V or 24V) by adjusting the wiring—parallel for 12V or series for 24V.
Why choose this model? (Key Benefits):
- Corrosion-resistant SUS304 stainless steel — built to withstand constant water contact for years without rusting or degrading.
- Dual-voltage versatility (12V/24V) — one heater covers both common off-grid system voltages without the need for additional adapters.
- Standard 1-inch BSP thread — designed for direct installation into most standard water heaters and boilers without modifications.
- 600W total power — powerful enough to heat an 80-100L tank within a few hours of good sunlight.
- Lower current at 24V (~25A vs ~50A at 12V) — allows for thinner cabling, reduced power loss, and easier installation.
- Compact design (220 mm length, 8 mm diameter) — fits easily into existing setups, even in tanks with limited space.
Performance and Specifications
The heating elements are constructed from SUS304 stainless steel, an alloy specifically chosen for its excellent resistance to corrosion and high temperatures, ensuring reliable, maintenance-free operation. The two 300W elements can be wired differently depending on your system voltage: in parallel for 12V, or in series for 24V.
When wired in 24V series, each element receives 12V, reducing the total current to ~25A. This allows you to use 6 mm² cabling and 30A fuses, compared to the 10 mm² and 60A required for 12V setups. You get the same heating performance with a safer, more cost-effective installation. The 1-inch BSP thread ensures a secure, leak-proof fit on standard European electric water heaters.
| Parameter | Value / Detail |
|---|---|
| Element Material | SUS304 Stainless Steel |
| Total Power | 600W (2 x 300W elements) |
| Operating Voltage | 12V DC (parallel) / 24V DC (series) |
| Current Draw at 12V | ~50A |
| Current Draw at 24V | ~25A |
| Element Length | 220 mm |
| Element Diameter | 8 mm |
| Flange Thread Type | 1-inch BSP |
| Primary Applications | Solar boilers, hot water tanks, off-grid systems |
| System Compatibility | Off-grid PV, 12V/24V battery banks, surplus energy diversion |
Configuration and Installation Guide
- Check your system voltage (12V or 24V) before connecting.
- For 12V: Connect both elements in parallel—each element receives 12V, with a total current of ~50A. Use at least 10 mm² cabling and a 60A fuse.
- For 24V: Remove the bridge between the elements and connect them in series (positive to one terminal, negative to the other, with the junction in the middle). Total current is ~25A; 6 mm² cabling and a 30A fuse are sufficient.
- Ensure the elements are fully submerged in liquid before powering on—dry firing will cause irreversible damage.
- Use an energy diverter or relay to automate activation when your panels produce excess power.
- Tighten the BSP thread using the included gasket to ensure a watertight seal.
Package Contents
- 1x Heating element with 1-inch BSP flange (2 x 300W SUS304 stainless steel rods)
- 1x BSP thread sealing gasket
Frequently Asked Questions
Can I connect this directly to solar panels without a battery?
Yes. It can operate without a battery when connected directly to 12V panels. The power output will fluctuate based on solar intensity. For maximum efficiency and protection, we recommend using an energy diverter or an MPPT controller.
How do I know if I should wire in series or parallel?
It is straightforward: use parallel for 12V systems and series for 24V systems. The total power remains 600W in both configurations; only the current draw changes.
Will this fit my water heater?
The 1-inch BSP thread is the standard size used on the vast majority of electric water heaters in Europe. Please check your heater’s port; if it is a 1-inch BSP, this will be a direct fit with no adapters needed.
What cable size do I need?
For 12V (~50A): use at least 10 mm² cable with a 60A fuse. For 24V (~25A): 6 mm² cable with a 30A fuse is sufficient. Keeping cable runs as short as possible will minimise power loss.
Can this be used for radiators or other tanks?
Yes. Beyond standard boilers, it can be used in electric water or oil-filled radiators, thermal storage tanks, and any application requiring 12V or 24V DC heating from renewable sources.
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