Inverter efficiency @ low load

Piwoslaw · 01-29-10, 05:26 AM

I'm on the lookout for a 150-250W grid-tie inverter for small projects, but the smallest I can find in my neck of the woods is 500W. I've read that inverters are most efficient close to max load, so any ideas how much I'd be losing if I put 50-150W through a 500W inverter? Would it be about the same as through a 1000W? If so, would it be better to buy the 1kW inverter now (anticipating future expansions), than 500W now and 500W later?

Also, is it true that an inverter's efficiency is higher when the input voltage is higher? Ie is a 1kW 24VDC->230VAC inverter more efficient than a 1kW 12VDC->230VAC inverter (all other parameters equal)?

Daox · 01-29-10, 06:09 AM

You'd really have to get those specs from the manufacturer. I would hope they have that data available.

Xringer · 01-30-10, 08:01 PM

They have 300W units on Ebay.. $99.99 shipped..

eBay Store - POWER INVERTER TRADE CENTRE: 12v pure sine wave inverter, 12v modified power inverter, 12v solar panel

600W for $199.99

Edit:
Sorry, I didn't see you were in Poland..

01-29-10, 05:26 AM	#1
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	Inverter efficiency @ low load I'm on the lookout for a 150-250W grid-tie inverter for small projects, but the smallest I can find in my neck of the woods is 500W. I've read that inverters are most efficient close to max load, so any ideas how much I'd be losing if I put 50-150W through a 500W inverter? Would it be about the same as through a 1000W? If so, would it be better to buy the 1kW inverter now (anticipating future expansions), than 500W now and 500W later? Also, is it true that an inverter's efficiency is higher when the input voltage is higher? Ie is a 1kW 24VDC->230VAC inverter more efficient than a 1kW 12VDC->230VAC inverter (all other parameters equal)?

01-29-10, 06:09 AM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	You'd really have to get those specs from the manufacturer. I would hope they have that data available. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

01-30-10, 08:01 PM	#3
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	They have 300W units on Ebay.. $99.99 shipped.. eBay Store - POWER INVERTER TRADE CENTRE: 12v pure sine wave inverter, 12v modified power inverter, 12v solar panel 600W for $199.99 Edit: Sorry, I didn't see you were in Poland.. Last edited by Xringer; 01-30-10 at 08:02 PM.. Reason: Poland