To charge any battery the voltage of the input must be more than the battery's output.
You can't charge the battery with those 245 watts unless they are being 'pumped into' the battery at a higher voltage than the battery puts out. If you can exceed the voltage of the battery, that 245 watts will definitely charge a battery.
1 watt will do the job.
You sure can! I charge a marine battery with a 75 watt panel and it goes from a fairly good discharged state to fully charged in about four days.
about 500watts/meters of irradiance
Well, isn't that a happy little question! To charge a 12V 180Ah battery, you'll need a solar panel with a wattage of around 180-200W. This should provide enough power to charge your battery efficiently. Just remember, it's all about finding the right balance between the size of your solar panel and the energy needs of your battery.
You need to provide many more details. So assuming that the panel voltage is reasonable, the panel is clean, it is sunny and the panel is pointed at the sun. Then it will take about 225/7 hours to charge the battery. About 300 hrs. But in fact charging is only about 85% efficient (charge at 14 V get energy out at 12V or so). This ups the charge time to maybe 350 hrs or so. Charging can be improved by inserting a MPPT charger between the battery and the panel. This bit of electronics decouples the battery voltage and the panel voltage allowing the panel to be operated at its' most efficient voltage. That might knock off 15% of charge time bringing you back to 300 sunny hours.
There is too much information there. Charging a 100 amp-hour battery fully would take 18 hours at 5.5 amps, or 6 hours at 16.67 amps. At 5.5 amps the power would be 12x5.5 or 66 watts, and this is the rating of the solar panel required. That would be about 0.4 of a square metre.
The power output of a solar panel is typically measured in watts peak (Wp) or kilowatts peak (kWp). For a typical residential solar panel, the power output can range from around 250 watts to 400 watts per panel. Commercial or utility-scale solar panels can have higher power outputs reaching up to 500 watts or more per panel.
The power output of a solar panel is typically measured in watts (W). A common residential solar panel has a power output ranging from 250 to 400 watts. Commercial solar panels usually have higher power outputs, up to around 500 watts or more.
The amount of watts that a solar panel system can generate varies depending on factors such as the size of the system, efficiency of the panels, sunlight intensity, and weather conditions. On average, a residential solar panel system can generate between 250 to 400 watts per panel.
For calculation purposes 1 HP is equal to 746 watts. So you have a total of 746 x 7 = 5222 watts. The amperage will be A = W/V = 7222/12 = 435 amps. You can not start the motor directly off of the solar panel. You would need a large 12 VDC parallel connected battery bank to obtain the amperage capacity to start the motor. The solar panels would be connected to the battery bank and used to charge the batteries after the start.
Yes, you can. The alternator on your boat is voltage regulated, so it will automatically taper off the charge current to maintain about 14.6 volts regardless of what the solar panel is doing. The panel is not regulated if you do not have a charge regulator installed between it and the battery, but at 5.5 watts, the most it will put out is about one half an amp. As a rule, you can take the current rating on a panel and divide it by 50, and as long as the amp hour capacity of the battery is not less than the resultant number, you do not need a charge controller, the panel will never put out enough current to overcharge the battery. If the sun is shining while the motor is running, the alternator will simply reduce its output enough to accomodate the panel, no other action is required. If you want to read more about this, look in the library for a book called, "The Complete Battery Book," by Richard Perez. Take care, Rudy