Battery and inverter matching.

[Saggys]

A 420 amp hour battery bank that is lead acid at a C/8 discharge rate into a 24 volt inverter tells me I can only power a 1260 watt inverter at a continuous output. I know that is not typical but what is the rule for matching a battery bank to an inverter?

[Sunking]

No real rule. Depends on battery type. There are some AGM batteries that can deliver 1C or greater discharge. Problem is the battery is done in 20 minutes or less. Batteries are sized to deliver 20% of their charge in a 24 hour period, then immediately recharged. So if done like that the inverter battery size ratio is not an issue. That 420 AH 24 volt can deliver up to 2 Kwh/ day. If th eload is constant for a 24 hour period, the load is 2000 wh / 24 h = 83 watts or a 100 watt inverter. No problem.

[Mike90250]

...what is the rule for matching a battery bank to an inverter?

Large inverters need a large battery bank, for 2 reasons,

prevent voltage droop under load
buffer AC ripple induced on battery from inverter (while the inverter is creating the sine wave)

Larger inverters usually have this spec in their data sheet.

[SunEagle]

Large inverters need a large battery bank, for 2 reasons,

prevent voltage droop under load
buffer AC ripple induced on battery from inverter (while the inverter is creating the sine wave)

Larger inverters usually have this spec in their data sheet.

I understand that the larger the inverter the more non load losses occur. Is the function of buffering the AC ripple the reason for the higher loss or is it other circuitry in the inverter that consumes?

[Saggys]

Thanks guys, I wasn't sure if it was crtical or not. A 2,400 watt 24volt inverter should be fine with a 420 amp hour battery bank.

[Mike90250]

I understand that the larger the inverter the more non load losses occur. Is the function of buffering the AC ripple the reason for the higher loss or is it other circuitry in the inverter that consumes?

Not always true, my standby losses in my 6KW inverter, is 28 watts. here's the chart from the manual.