MPP voltage: how much power you get from your panels.
Dreh den Regler: Wie viel Leistung bringen deine Module?
Nadel mit der Maus ziehen – oder Pfeiltasten benutzen
Ungefähre Heizleistung
Grenze: Die Leerlaufspannung (Voc) deiner Module darf höchstens 50 V betragen.
[grafik:tacho]
Key points
- The MPP voltage (Vmpp) on your panels' datasheet determines how much heating power the 1 kW solar immersion heater reaches.
- For the full 1,000 W you need at least around 43.5 V. Below that, the power drops.
- The open-circuit voltage (Voc) must not exceed 50 V – this is the safety limit.
- Always connect panels in parallel.
When it comes to solar panels, most people look at the wattage first. For the 1 kW solar immersion heater, another figure is at least as important: the MPP voltage. It decides whether your heater reaches its full 1,000 W – or only part of it.
What is the MPP voltage?
MPP stands for "maximum power point" – the operating point at which a panel delivers its highest output. The voltage at this point is called the MPP voltage. You'll find it on every panel's datasheet, usually as Vmpp or "maximum power voltage".
The MPP tracker in the 1 kW solar immersion heater finds this point automatically and gets the most out of your panels.
Why the voltage limits the power
The 1 kW solar immersion heater draws a maximum current of 23 amps. Heating power is voltage times current. So the full 1,000 W is only possible from an MPP voltage of around 43.5 V.
If the MPP voltage is lower, even the best MPP tracker can't make up for the missing voltage. At 40 V you still get around 920 W, at 35 V about 805 W. The heater still works – your water just warms up a little more slowly.
Common panels with an open-circuit voltage of up to 50 V usually have an MPP voltage of around 38 to 42 V. That gives you roughly 870 to 970 W.
More panels bring more current. But full power needs the right voltage.
Already have panels?
Check the datasheet and set the MPP voltage on the dial above. You'll see right away what heating power you can reach with your existing panels. Even with a little less than 1,000 W, the 1 kW solar immersion heater is worth it – you put panels to use that would otherwise sit idle.
The limit: 50 volts open-circuit voltage
The MPP voltage determines the power. For safety, another figure counts: the open-circuit voltage (Voc). This is the voltage a panel delivers with nothing connected – it is always slightly higher than the MPP voltage. The electronics of the 1 kW solar immersion heater are designed for an open-circuit voltage of no more than 50 V.
That's why the panels are always connected in parallel: the voltage stays the same, only the currents add up. In series, the voltages would add up – 45 V would become 90 V.
Checklist for your datasheet
- MPP voltage (Vmpp) from around 43.5 V for the full 1,000 W.
- Open-circuit voltage (Voc) no more than 50 V.
- Connect in parallel, never in series.
- Not sure? Send us the datasheet – we'll check it for free.
