Power electronics - Battery usage control

[saopaulo]

Hi there,

I'm working on a renewable energy source project for school and I have the following problem:

I have a battery that has been charged by the renewable source, and so I'd like to use it whenever I can. However, given that it will not be able to provide enough energy for the whole system all the time, I will also have to use the normal power network to complement the use of the battery.

The problem is I don't know which component I can use to control the power supply battery-network, favoring the battery. I have thought about a UPS, but I think that it's not quite right since on those the main power source is the network and usually the battery is built into it.

Thanks a lot, anything will help

 

[dselec]

Whats the problem ?
Y not build a pwr supply that will pwr the system and charge the batt too ?

 

[saopaulo]

I don't know, maybe that could work.

The thing is I don't know much about power electronics and I'd just like to know if there is a controller like the one I described, one that would allow to switch between the main network and the battery according to the charge of the last.

Is there?

Thank you for your answer anyway

 

[FoxyRick]

A grid-tie inverter is the sort of thing you are looking for, I think. They usually have an higher voltage input than a SLA battery though, 48V upwards generally I think.

They are really intended for connecting a renewable DC source like a photovoltaic array or wind turbine into the grid. When connected and given power, they basically become just another power source on the grid. If you charged a battery bank and connected it to the input, then that would be fed into the grid until the battery died.

Really though, a grid-tie inverter is probably a much bigger solution than you are looking for. I don't know of anything else off-the-shelf that does what you want.