Most efficient way to convert DC to 110VAC - 3-5W

[jana]

Hi

This is slightly off topic, but I am sure there are some experts in this field here at the Endless Sphere

I am working on a product that needs 110VAC and have a power requirement of in the 3W to 5W range.

I plan to use a ebike battery to power this application for at least a week. I have considered this battery http://www.bmsbattery.com/24v/318-24v-19ah-lifepo4-ebike-battery-pack.html

What kind of inverter will give the least losses ( highest efficiency) when converting from 24VDC to 110VAC?

Will using a 48VDC battery be more efficient?

I am very grateful for your input.

/Jan

 

[amberwolf]

There's lots of 12V car inverters out there, very small, can do up to 80W with ones that are only 3"x3"x1" or less. Have seen some half that size with less capability. Some even have USB ports to run 5V devices, too.


What is the product you need to run off 110VAC? Does it not have it's own DC-input port you could just run a smaller DC-DC to?

 

[Kin]

If your device says "110-240v" there's a quite good chance you can run it very well off of 18-24s LiPo.


Are you sure your device is only 3-5 watts? At 110Vac that's less than a 20th of an amp. It pulls even less than my phone charger.

 

[jana]

Thank you very much for your input. The device is a version of Smart Glass . "electrically switchable glass or glazing which changes light transmission properties when voltage is applied" http://en.wikipedia.org/wiki/Smart_glass

110VAC is applied directly to the glass/film to make it transperant. That is the reason for the low power usage.
I am sure a standard inverter could be used, but I belive they are very ineffiecient at these power levels?

 

[Kin]

It appears you indeed need AC then. i guess you want a pure sine wave converter (http://en.wikipedia.org/wiki/Power_inverter) but I don't pretend to know much about it. I'm not sure if the cheap car inveters are efficient enough or not, but perhaps they are good enough for your relatively small needs.

 

[amberwolf]

You might want to check out inverters used on LCD backlights for laptops and monitors, to power the CCFL bulbs. IIRC they are often between 100 and 200V outputs, 5 or 12V input, and an analog voltage input to control them for "dimming" the bulbs. Sometiems also an enable line. I'm pretty sure it's AC output, too, as it doesnt' feel like 200VDC when I've accidentally put a finger across the output of one.



If you have an old dead laptop or LCD monitor around that doesn't have a backlight problem, you can determine the pinout of the input of that inverter board with a little multimeter probing while changing brightness, and then hook it's output up to the smart glass to see if it will run it.

 

[jana]

You might want to check out inverters used on LCD backlights for laptops and monitors, to power the CCFL bulbs. IIRC they are often between 100 and 200V outputs, 5 or 12V input, and an analog voltage input to control them for "dimming" the bulbs. Sometiems also an enable line. I'm pretty sure it's AC output, too, as it doesnt' feel like 200VDC when I've accidentally put a finger across the output of one.



If you have an old dead laptop or LCD monitor around that doesn't have a backlight problem, you can determine the pinout of the input of that inverter board with a little multimeter probing while changing brightness, and then hook it's output up to the smart glass to see if it will run it.

Thank you for this tip. Sounds a bit too complicated for my skill level, but a great to know about this possibility.

 

[dnmun]

it is not just a possibility, it is basically what you are looking for.

if you have dead laptop, the inverter is right under the screen, above the hinges in a strip about 1/4" thick, 1" wide and 5" long.

if you have dead laptops, take the screen apart and try it. the pin out is pretty easy to figure out.

 

[jana]

Ok, I'll try to check it out