Battery Charging Station

[pwnageNick]

I was aiming at continuous monitoring and a readout updated a couple times a second!

For what purpose?

Don't get me wrong, I have over-complicated plenty of modules on robots in the past, but when it comes to off-season projects like a battery cart, where it is something that your team will use for a long time, it's better for your team to have a lot of things like that, instead of using all of its time and resources on a project that while partially useful, is also not helpful to a point and over the top.

That being said, if you have a ton of people, a ton of time, and plenty of money to make such an elaborate system, then full steam ahead. However I know most teams would benefit from having a battery cart as well as other items such as various other pit space items (i.e. a solid workbench with storage, a quality robot cart, a display that showcases its robot and chairman's qualities), or some robot prototypes that can be built upon and benefited from for years to come.

-Nick

[yash101]

Here's my project page. It is kinda overkill, so beware! The way how I typically build things makes sure that they have a long lifespan. I use something like a Propeller and MCP3204s, to do all the sensing and other things! Even though I use open circuit boards, even decent-sized shards that fall into the controller won't damage it. It will stay shorted out until I fix it, then recover!

[Mr V]

Originally Posted by sst.thad

Would we be able to bring our own generator and run it in the parking lot? I could see a decent chunk of teams doing that if allowed.

If you are talking about using a generator in the parking lot and running a cord to your pit I would bet that would not be allowed.

Originally Posted by Alan Anderson

That's not a lot of power. I assume you've tried to obtain the use of a generator large enough to support what teams are used to?

I'm just the messenger, I did not participate in deciding what size generator to rent to supply pit power. I can tell you that how running 5 or 6 pits off of 1 20a circuit at the WA Girl's Generation was taken into consideration when deciding the power needs. It did not present a problem there until someone plugged in their Leaf into one of the circuits.

Originally Posted by Mark McLeod

I figure our typical pit power draw as a team to be ~7amps.

You'd better hope no one plugs a vacuum cleaner in (~12amps).

Something like a vacuum cleaner will not be allowed to be brought in and certainly would not be allowed to be used.

Originally Posted by sst.thad

Doing the math puts charging 3 batteries between 150 and 220 Watts. Add a 50 watt laptop, a 30 watt cordless drill charger, and a few other accessories, plus losses and teams are gonna push that 400 watt limit real quick. I hope they can find a way to increase it, even if its only to like 6 amps per team instead of 4.

The current plan is to only allow charging 2 batteries per team at a time.

Again I'm just the messenger. If the power proves to be woefully inadequate the size of the rental generators will likely be revisited.

[Al Skierkiewicz]

A few things...
The six station charger is available in 120 volt version. We have used one for years and they work great. Why this one is listed at 220 volts is beyond me but it may be for an intended audience whose country is at 220 volts. The manufacturer is right here in Illinois. While the chargers are listed as 5 amps per station, they do not supply 5 amps continuously. The output current is varied for a variety of conditions dependent on cell voltage and time. These smart chargers switch charge current on and off while they are testing the battery condition.
I would suggest to event coordinators that teams be encouraged to remove their batteries each night to be charged back at their hotel. Please be advised that precautions need to be followed as charging batteries do have a chance of releasing hydrogen and on occasion, batteries have failed during the charging process. I recommend that charging be monitored by adults and that batteries be disconnected during sleeping hours. I would also like to recommend that event coordinators have a charging station somewhere for teams playing in finals.

[yash101]

Al, you know better than me, but I an just thinking, but isn't it safe to have a lead-acid slow-charging at night? I don't see any problems with it, especially when I have a battery on my desk that charges continuously! (Harbor Freight Charger)

[Al Skierkiewicz]

Dev,
I like to err on the side of safety and I have seen batteries self destruct at competitions before. I would not want a battery in a student's room start leaking or worse.

[yash101]

Originally Posted by Al Skierkiewicz

Dev,
I like to err on the side of safety and I have seen batteries self destruct at competitions before. I would not want a battery in a student's room start leaking or worse.

So talking about that, should I be keeping the battery in the garage instead of right next to my bed? I use it when I need sparks of power (100AH). Other than that, it is a paperweight

[Al Skierkiewicz]

There is a better choice somewhere between those two. Batteries don't like temperature extremes but next to your bed? Maybe we should talk....

[yash101]

Originally Posted by Al Skierkiewicz

There is a better choice somewhere between those two. Batteries don't like temperature extremes but next to your bed? Maybe we should talk....

Yeah! But talking about that, making sure the batteries stay at an optimal temperature in a cart is an important thing to do!

[Mark McLeod]

Sounds like they are renting something like a 16kw diesel generator for the school gym district events.
Maybe there are space limitations that preclude renting two, or maybe the power distribution system isn't there yet.
There are likely startup financial reasons for having to limit power and purchase $ (Northern Tool has a sale on a 25kW towable for $22,000).
Maybe that restriction will loosen up in seasons to come.

Non-battery powered pit tools will also be off the list (one 3/8" hand drill would be 4amps, the entire team maximum), so teams will just have to take better advantage of any machine shop facilities. I assume that there will be a mobile machine shop that travels around to each event?

[Chris_Ely]

Originally Posted by sst.thad

Would we be able to bring our own generator and run it in the parking lot? I could see a decent chunk of teams doing that if allowed.

5.5.2.6 T11
At events, Teams may only produce FABRICATED ITEMS in the pit areas or provided machine shops, as defined in
the Administrative Manual, Section 4.8, The Pit.

Working in someplace other than your pit was not allowed in 2013, and I don't see that changing anytime soon for liability reasons.
My experience in FiM has been that there always was enough power for everyone. The only problems that I have seen were on Thursday night when the bugs were still being worked out.

[yash101]

Joke: At times, a large capacitor bank could be useful, especially when someone turns on a spot-welder, shutting down the breaker!

Now, back on topic, how much energy would the most energy-consuming machine used at competition take? Would it be a mill, consuming 500 Watts, drill consuming 60 Watts or something along those lines? Has anyone brought a UPS with them to give power as soon as power goes out accidentally?

[pwnageNick]

Has anyone really run into a situation where they did not have enough power in their pit? I mean seriously, are you running a concert inside your pit or what?

-Nick

[Invictus3593]

For powering the large charger mentioned before, it might be helpful to use one or two marine 12v batteries and this. If this doesn't work, I'm sure you can find one like it that has the right specs. Not very expensive either

[yash101]

Wow! That's cheap. I was looking at a 4kW one at Costco for about $200! Positive reps for you!