Sorbari A's posts

I am looking to buy an inverter which could plug into the wall (using utility power) and can also connect a battery for backup. And if there is utility power, that would be used to power the inverter and in addition to providing AC current, the inverter would also be charging it’s back up battery. Then when there’s utility power failure, the inverter could automatically switch to its backup battery for power until there is utility power again when it goes back to charging its battery.

Can all inverters perform this function? That is, have a switch to connect into utility power, charge it’s back up battery and switch between utility power and battery power without causing any power failure? If not, what are the other accessories I have to look at.

I need a 3000 watt pure sine inverter that can perform all these functions. Anyone know any good one?

Thanks in advance for any help.

Thanks for the reply, Dave.

It is a "paper" project at the moment. My friend and I are relatively new to renewable energy and we are really excited about it. So at the moment we are swapping ideas to see if we can build one, a “useful“ one. But yeah, I understand what you mean about the book title...

Anyway, I wanted to ask another question.

Can a 12 volt 1400 AH battery plugged into a 1500 watt inverter take 5.4 hrs to fully charge from its 40% discharge state when it is not in used (switched off)?

To get the charge time, I used the formula you used above.
12 V x 1400 AH = 16,800 watt hour
At 40% discharge state = 6,720 watt hours used
6,720 x 1.2 = 8,064 to recharge to full state
8,064 needed / hours = 1500 watts
Hours = 8,064 / 1500
      = 5.4 hours

Is this correct?

P.S. I don’t understand why you multiplied the watt used by 1.2. What is the 1.2? And what is the answer gotten? Amp hour?

Furthermore, I don’t understand what you meant earlier about 80% chemical conversion. How do I reduce my result now from it's 80% to 50%.


Thanks in advance for any help

 

I’m planning to hook up some rechargeable batteries to power an inverter where solar power will act as the only rechargeable source for the batteries. I have the battery amp hour for my battery bank as 999AH at 200Volts on a 40% DoD. So I wanted to calculate what kind of solar panel will be able to fully charge the battery from its 40% DoD to full power at 5 sun hours.

After a bit of research, I found somewhere on the internet that to know how long it takes to charge a battery with a given supply of current (amps) the commonly used formula is
 
Charge time = 1.2 x Amp hours (of the battery being charged) / charge current

From my own understanding, this formula is to charge the battery from it fully discharged state to it’s full power. If so, I assume, the formula to charge the battery from a 40% discharge state would be:

Charge time = 0.4 (1.2 x Amp hours (of the battery being charged) / charge current)

Is this formula correct?

Furthermore, I assume the charge time that will be gotten from using this formula represents that of a battery that is idle. Will the formula (ie charge time) be the same as when the battery is being charged while it's in use? If not, can you please give me the formula for charge time when the battery is in use? As the solar power never powers the inverter directly but all its power is always used to recharge the batteries.

Thanks in advance for the help.