I'm building a photovoltaic plant for my car. I can tell you that the power (watts) of the inverter must be 5 to 7 times the absorbed load.|
This dimensioning is not necessary when using only bulbs (resistive circuits) but it becomes when connecting instruments using transformers (inductive circuits).
Transformers - such as those contained in battery chargers - are inductances that require a starting power of 5 to 7 times the declared power on the connected instrumentation: in the case of i2 battery charger (with input power of 194.54 Wh) a 1500 Watt inverter should be optimal. I use the conditional cause I'm waiting for a friend (really expert) to confirm my calculations.
Another important thing is the battery ...or the batteries. Car batteries are often used, but they are not suitable. The plant works the same but since they are not designed for the purpose they deteriorate quickly, and may have problems themselves. To avoid this, I have chosen - for my plant - the AGM one among the various, and more expensive, types of battery suitable for this purpose. They have a great ability to withstand the initial absorption of inductive devices and provide electricity for a good number of hours. Why do I say "number of hours"? Batteries suitable for photovoltaics have a parameter C (Capacity) that indicates the number of hours the power is released. This parameter normally is C10 or C20 and it means that the Ah (Amperes hours) are released in 10 hours for C10 and 20 hours for C20. For our purpose C10 is more than required.
Something about inverters. Buy pure sinusoidal wave inverters. If the manufacturer does not specify this feature then you are buying a square wave inverter ...which puts the connected devices in a tough work.
Finally, always FUSES between batteries and inverters. Batteries can be dangerous.
I realize that what I write does not say everything, but here it is not possible to give complete explanations. I recommend you search for information on photovoltaic websites.