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yash101 08-08-2013 17:39

Driver station power
 
I am designing an advanced driver station for our team, and I was wondering if a car battery would be allowed as a power source. I would use a shunt connected to the mcu to monitor the battery conditions and see if it would be safe. Are car batteries allowed at the competition if they are not on the robot? If anyone is interested in the project, the homepage is at: http://devstuff.no-ip.biz:890

techhelpbb 08-08-2013 17:48

Re: Driver station power
 
From previous Q&A:
http://forums.usfirst.org/showthread...-Extra-Battery

Dragonking 08-08-2013 17:49

Re: Driver station power
 
I believe there are available power strips or individual sockets at each of the driver stations on all fields. I'm pretty sure they are available at all venues, if you need power.

yash101 08-08-2013 17:53

Re: Driver station power
 
I was wanting the cart to be portable, and I wanted two BAG motors aboard to help reduce the weight of many batteries; otherwise, the 15 amp outlet would be the best solution

BobbyVanNess 08-08-2013 17:55

Re: Driver station power
 
Quote:

Originally Posted by Dragonking (Post 1286517)
I believe there are available power strips or individual sockets at each of the driver stations on all fields. I'm pretty sure they are available at all venues, if you need power.

I believe there are connectors for the KOP driver station computers, however teams not running that computer can not benefit from them.

We wound up connecting a 12v robot battery to a 120v inverter, and powered the laptop charger directly. This saved us on a number of occasions, going into matches only to find that the driver station battery was about to die as we were setting up.

yash101 08-08-2013 18:01

Re: Driver station power
 
I am talking about a 2000 watt inverter connected to a car battery, breakered and fused. I am willing to place every safety feature possible, like current watch and temp watch. In my current schematic, I am having 250 amp MOSFETs powering everything so if too high of a current is detected, an automatic shutdown of that component for a set amount of time. It will also have a display and a usb-serial plug to the driver station and control EVERYTHING, even the power TO the motor drivers (victors)

EDIT: I am also thinking of placing the battery inside an ABS holder, because of it's resistance to acid spills. We would smell a spill before it becomes too late.

Joe Ross 08-08-2013 18:23

Re: Driver station power
 
Who is going to carry this monster?

Gregor 08-08-2013 18:56

Re: Driver station power
 
A robot battery and one of these should suffice.

yash101 09-08-2013 00:05

Re: Driver station power
 
This is kind of overkill, but this is what I was looking at. However, the price tag isn't the prettiest. However, we could start out with a small inverter to just start off with and if we decide to do something like charging robot batteries on the fly, maybe upgrading to something similar to this would be feasible. However, the inverter that Gregor linked to was the first one that I looked at. BTW, has anyone visited the site that I posted and think something is impractical?

techhelpbb 09-08-2013 06:03

Re: Driver station power
 
Quote:

Originally Posted by team1165wins (Post 1286571)
BTW, has anyone visited the site that I posted and think something is impractical?

Use solid state relays not MOSFETs.
Still not really sure why you have such high current requirements.

Also...

Propeller input + voltage divider = 5V tolerant input :)

Al Skierkiewicz 09-08-2013 07:21

Re: Driver station power
 
Quote:

Originally Posted by techhelpbb (Post 1286516)

This response was for a time when power was not supplied in the driver's station and this became the FRC recommendation for that year.

We are very concerned about safety in all areas of the competition and moving a heavy, liquid acid battery and high voltage source pushes the envelope on that precept. Additionally, there is very little floor space in the driver's station to place your equipment. There is no substitute to having the laptop battery charged before you come to the field. And while nice, most teams find there is no substitute for charging batteries in the pit prior to coming to the field.

More likely to be invoked is this...
4.1.11.4
R93
The OPERATOR CONSOLE must not exceed 60 in. long by 12 in. deep (excluding any items that are held or worn bythe DRIVERS during the match). There is a 54 in. long by 2 in. wide strip of hook-and-loop tape (“loop” side) along the center of the PLAYER STATION support shelf that may be used to secure the OPERATOR CONSOLE to the shelf. See Section2.2.9 for details.

techhelpbb 09-08-2013 07:45

Re: Driver station power
 
Quote:

Originally Posted by Al Skierkiewicz (Post 1286608)
This response was for a time when power was not supplied in the driver's station and this became the FRC recommendation for that year.

In 2011 Team 11 was given an approval to use batteries in flashlights at the driver's station

However I agree this seems extreme and of course rules change. Those flashlights would not exceed the driver's station dimensions but we scraped it early on. It was for a camera tracking system we did not need.

Considering that a laptop charger is usually < 150W and < 30V.
I do not understand why anyone would need the sorts of current listed at the link.
If you must charge a laptop from a battery why not get a universal laptop car charger and put an Anderson Power connector on the end for a FIRST approved robot battery?
At least then you should have plenty of opportunities to charge that robot battery.
Plus handling the robot batteries is typical for this competition.
Plus a laptop charger meant to work in the car will not put out wall socket voltages.
So there's much less risk of some unusual accident.
Plus 150W max is no worse that 2 CIMs dragging on that battery.
Finally the custom electronics power supply on the robot would work at the driver's station (with less issues).

Course again it is entirely at FIRST's discretion if they allow this in future years.

I will also add that in past years while in various volunteer positions I've had the crazed experience of trying to help a team find a replacement laptop battery at a competition (laptop batteries are not cheap and the software just takes hours to install). Lucky for those that got one I have several friends with computer stores and piles of questionable laptops they can part for a used spare. Usually my friends have been good enough to just give them the battery which is generous considering it's a zero notice demand and sometimes they've even delivered it (hey that was not 30 minutes or less :)).

I myself have a universal car charger with an Anderson power connector and a few tails just in case something like this happens. I come prepared (I even lately bring a spare dual core laptop suitable as a driver's station with most of the software and updates installed) and the mess stops with me. However I would never offer this up as a solution without confirming with the field crew they understand what is going on (even if the rules might allow it in any given year).

FrankJ 09-08-2013 10:23

Re: Driver station power
 
We have always plugged our laptop in the pits between matches. We have had close calls. Especially in the finals when you do not go back to the pits between matches. We are looking at putting power on our cart for this reason.

The FRC legal battery with a small inverter will keep your lap top charged. Since it is the same battery as the robot, you get a spare robot battery or you can use an older robot battery that doesn't have the umph for competition. A lot less likely to raise a flag with the safety people since there are 100s in the building already.

daniel_dsouza 09-08-2013 13:12

Re: Driver station power
 
you could also use a computer that has the same power requirements as the classmate.

Our Lenovo x61 laptop-tablet computer has a power adapter that uses the same connection just before the power brick.

Mark McLeod 09-08-2013 13:36

Re: Driver station power
 
Quote:

Originally Posted by daniel_dsouza (Post 1286650)
you could also use a computer that has the same power requirements as the classmate.

Our Lenovo x61 laptop-tablet computer has a power adapter that uses the same connection just before the power brick.

Please don't plan on unplugging parts of the field at your whim.
The field provides a barrel connector for a Classmate. It doesn't provide any other plugs.


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