volts time amps equal watts dudden it?

[UGT]

I have (3) 24 volt 200ah batteries from LiTime. Very pleased with them. Paage on their website states that the usable energy from one of these batteries is 5120 watts. I thought Volts x Amps=Watts. So wouldn't this be 4800 watts for one of these 24 volt batteries? How do they get 5120 watts? Is this accurate or are they just messing with numbers to make the batteries appear to have more watts? Jus' wonderin'. Thanks, George in Austin The page I am referring to

 

[SparkyJJO]

A "24V" LFP battery is nominally 25.6V (3.2V/cell, 8 cells).

 

[sunshine_eggo]

I have (3) 24 volt 200ah batteries from LiTime. Very pleased with them. Paage on their website states that the usable energy from one of these batteries is 5120 watts. I thought Volts x Amps=Watts. So wouldn't this be 4800 watts for one of these 24 volt batteries? How do they get 5120 watts? Is this accurate or are they just messing with numbers to make the batteries appear to have more watts? Jus' wonderin'. Thanks, George in Austin The page I am referring to

Per @SparkyJJO , 25.6V nominal for LFP:

8 * 3.2V * 200Ah = 5120Wh

 

[UGT]

Well further investigating and looking closer at the specs it states the voltage of these 24 volt batteries is 26.5 which is the nominal voltage. So 26.5v times 200ah equal 5120 watts. So when figgering how long my batteries will give energy to my stuff do I use the 4800 watts figure or the 5120 watts? When I charge these up they hit 28.5 plus volts. When my victron shunt ap shows 100% charge my inverter shows 28.5 plus volts. So am leaning toward using the 5120 watts figure to make calculations.

 

[UGT]

A "24V" LFP battery is nominally 25.6V (3.2V/cell, 8 cells).

Yeah, I just discovered that. Thanks. Guess I got more juice than I thought.

 

[Mattb4]

Well further investigating and looking closer at the specs it states the voltage of these 24 volt batteries is 26.5 which is the nominal voltage. So 26.5v times 200ah equal 5120 watts. So when figgering how long my batteries will give energy to my stuff do I use the 4800 watts figure or the 5120 watts? When I charge these up they hit 28.5 plus volts. When my victron shunt ap shows 100% charge my inverter shows 28.5 plus volts. So am leaning toward using the 5120 watts figure to make calculations.

Take with a grain of salt the 5120wh (note: not watts) figure. More likely you will not fully charge and discharge the battery if you want a long life from it. Plus which depending on the rate you discharge it will also affect if you can even reach full ah due to the chemistry involved.

Personally I like using around 70% of rated to use as a working number.

 

[sunshine_eggo]

Well further investigating and looking closer at the specs it states the voltage of these 24 volt batteries is 26.5 which is the nominal voltage. So 26.5v times 200ah equal 5120 watts. So when figgering how long my batteries will give energy to my stuff do I use the 4800 watts figure or the 5120 watts? When I charge these up they hit 28.5 plus volts. When my victron shunt ap shows 100% charge my inverter shows 28.5 plus volts. So am leaning toward using the 5120 watts figure to make calculations.

Watts are power.

Watt-hours are energy/capacity.

The smart shunt wants Amp-hours.

 

[UGT]

Thank you. My system is mostly a backup system for my house in case the grid goes down. I am using it a little on sunny days to run a couple freezers and refrigerator through my transfer switch and some nights which only takes them down to 80-85%. Most likely willl never fully discharge the batteries.

 

[wattmatters]

Well further investigating and looking closer at the specs it states the voltage of these 24 volt batteries is 26.5 which is the nominal voltage. So 26.5v times 200ah equal 5120 watts. So when figgering how long my batteries will give energy to my stuff do I use the 4800 watts figure or the 5120 watts? When I charge these up they hit 28.5 plus volts. When my victron shunt ap shows 100% charge my inverter shows 28.5 plus volts. So am leaning toward using the 5120 watts figure to make calculations.

The stated energy capacity is generally a guide as in reality it varies depending on use case.

Just keep in mind the battery's voltage is not constant. As a battery is discharged, its voltage drops. As load is applied, voltage drops. The higher the load the greater the voltage drop. When load is removed, voltage rises. When the battery is charging, voltage rises.

As a result, how much energy capacity they can actually supply is variable depending on how they are used, and the conditions they are used in.

LiFePO4 is however pretty resilient and will deliver a similar capacity over a wide range of usage scenarios.