My team in planning to use a LCD display but don´t know if we should code it to have the back light on due to battery consumption? How much voltage dose the back light really use?

How long were you thinking of using the LCD display? I figure most teams will only use it during their set up, turning it off afterward, so not for a long time. For that you shouldn’t notice much. But if you leave it on the whole competition, that’s a whole other matter. Of course, if it’s just for set up, you could keep a flashlight with you, too.

Also, as a technical point, telling you it uses the same voltage as everything else is rather meaningless but answers your question. You are really asking about the current or power draw, not the voltage. I don’t know the specific draw, though, and I don’t see any spec sheet on the VEX site, just information on what numbers give what characters.

Thanks, we were planning on having it on for the entire match

Oh. Are you able to read it while the robot drives around? I know there is no way I could. It’s not like you’re allowed to press buttons on it during the match. Or was it just making no plans to turn it off, as opposed to having a specific use for it?

If you have no plans to actively use it after setting up, I would finish the set up with a confirmation press on the LCD, then shut down the LCD prior to autonomous beginning. Then it’s only running for the minute or so of set up, when you need it.

I suppose you could test it. Check voltage with a multimeter, plug in and turn on LCD. Wait for 2 minutes, and check again. You could also use the battery reading from the cortex but I don’t know how accurate that is.

They draw very little power

They don’t draw much power; but, if you’re going to use it for a long period of time compared to the short amount of time for a match, it would just be best to leave it off for stuff like long debugging on the actual bot.