Scouting Power System

[Kims Robot]

Seeing some of the issues we have had (http://www.chiefdelphi.com/forums/showthread.php?t=84823) in the past, we are looking into working up a power supply system for our scouting setup this year.

I know a few teams from that thread have worked with UPS's or other things, could you provide details on your power setup?

Here are my thoughts for ours so far...
Power Draw
1 Linksys Switch
6 IBM Thinkpads
1 Dell Lattitude D600
If my numbers are right, we need ~1100Wh supply to run for 9 hours

I would prefer to stick with DC, so DC-DC converters from a Marine Battery or from military BB590 Batteries (Harris has easy access to these).

It seems like a lot of teams do DC-AC-DC which is just so terribly inefficent that I don't want to lug around that extra power

Anyone do anything like this? Ideas?

[klmx30302]

When we need extra power we just take robot (or car) batteries and attach a power inverter. Yes is is rather inefficient but it is also simple. And you could stretch the power by using power saving settings on the laptop.

[foozie]

One of the reasons that the DC-AC-DC system is used is that the inverter and the rectifier-power-bricks for the laptops or whatever supply the system with a good level of regulation and signal-grooming. Take that away, and you may just fry a laptop or two. Be warned.

[klmx30302]

um... didn't read the part about 7 laptops. So lets see 1100wh/12v= 91ish amp hrs so that's 2 normal car batteries now take into account 80% inverter efficiency 91/.8= 113.5ah now say the laptop power bricks efficiency is around 80% 113.5/.8=142.5ah that means you would probably need 3 fully charged car batteries hooked up in parallel to get the appropriate amount of power which at this point would be 142.5x12=1700wh.
Unless of course you already took this into account in which case you should be fine with 2 car batteries.

[NullEntity]

My freshman year (Lunacy) we tried our UPS with our 7 laptops and a switch. The inverter couldn't handle any more than 3 laptops at a time, and the batteries instantly drained. It did NOT work for us at all. We evolved to essentially creating our own scantron. The best mix between paper and technology.