Battery Charging Station

[Ether]

Originally Posted by Hugh Meyer

The battery charger information says it needs 220v input. That might be kind of hard to get in the pits. Is this the right link?

http://test.autometer.com/productDet...D=54&isKi t=0

I'm wondering why it is 220v. Is it monumentally inefficient? I figure max output power is around 450 watts with all 6 stations going full bore.

[Mr V]

Looking back through the thread I see the OP is from OR which throws a big wrench into the plans for a charging station.

Since we are in High School aux gyms for most of the events power to the pits is severely limited. We will be running on generator power for the pits and 5 or 6 teams will have to share 1 20a circuit. Because of this teams will be limited to the use of 2 chargers or one 3 station charger with no more than 2 batteries charging at a time. Also note that when the pits close power will be shut off to the pits so making a plan to take your batteries with you and charge them off site on Fri night is going to be a good idea.

Also it is important to note that you will not be allowed to plug ANYTHING into anywhere except your designated spot in the spider box in the pit.

[Thad House]

Originally Posted by Mr V

Looking back through the thread I see the OP is from OR which throws a big wrench into the plans for a charging station.

Since we are in High School aux gyms for most of the events power to the pits is severely limited. We will be running on generator power for the pits and 5 or 6 teams will have to share 1 20a circuit. Because of this teams will be limited to the use of 2 chargers or one 3 station charger with no more than 2 batteries charging at a time. Also note that when the pits close power will be shut off to the pits so making a plan to take your batteries with you and charge them off site on Fri night is going to be a good idea.

Also it is important to note that you will not be allowed to plug ANYTHING into anywhere except your designated spot in the spider box in the pit.

Really? I never would have guessed that power would be that limited. I'll make sure to pass that on.

[Mr V]

Originally Posted by sst.thad

Really? I never would have guessed that power would be that limited. I'll make sure to pass that on.

Yes that is what Kevin Ross announced during the most recent district model informational webinar.

It was announced as a blanket rule, however since we did not have limits on pit power at CWU and EWU in the past at those venues power may not be limited to 3-4 amps per team, but until there is an official ruling from Kevin otherwise, assume you'll be limited to that 3 amps at those events as well. I have no idea what the power situation might be at the OSU event since we've never had an official FRC event there before.

At the district CMP things will be as there were in the past at the Autodesk Oregon Regional since we will be in the same venue.

I can see some potential problems in the eliminations rounds at the district event. There will be no place to charge near the field and about 2/3 of the teams will be in the quarter finals meaning there won't be a lot of batteries to loan, nor teams with chargers that aren't in use to charge your batteries with.

[Thad House]

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.

[Alan Anderson]

Originally Posted by Mr V

We will be running on generator power for the pits and 5 or 6 teams will have to share 1 20a circuit...

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?

[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).

[Thad House]

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.

[Ether]

Originally Posted by sst.thad

Doing the math puts charging 3 batteries between 150 and 220 Watts.

What did you use for charging amps and voltage for that calculation?

[Thad House]

Originally Posted by Ether

What did you use for charging amps and voltage for that calculation?

Using 6 amps per battery and 12 volts gave 216 Watts. Not counting losses.
The 3 slot charger cannot individually change amp ratings, so it would most likely draw between 4-6 amps per battery, plus losses, puts the numbers right around 160-220 watts

[yash101]

I think it might be wise to bring a marine-cycle battery and a powerful inverter. Teams bringing all sorts of generators seems very inefficient and loud. Since teams aren't using power continuously, generators may be overkill without a battery to store and shut down the generator automatically! Also, a battery and inverter would probably cost less than a generator. Generators are for when you need LOTS of power, typically kilowatts. For every KG of gasoline, you can get a max of 5kw/kilo, which is the reason why most generators are rated for at least 750 watts continuous!

[pwnageNick]

While I did not read this entire thread, I skimmed through most of this, and I guess I'm just wondering why it is so important for this battery cart/station to be self-sustaining. You're supplied with power in your pit, specifically so teams can charge their batteries and driver station. I completely understand wanting to make an organized, well put together station for charging and storing your batteries, but the necessity for it running off a generator seems over the top.

Also, as far as making it able to drive, I see even less of a reason for this. Being able to drive the robot cart would make more sense then this, although I know I do not think that is a good idea, and I know many volunteers who have worked the queue at a competition would agree.

While I know that with all of the batteries, chargers, frame, etc. the cart will weigh a lot, I guarantee it will still be easy to push/pull.



Our team built a battery cart 2 years ago and it works great. Currently able to charge 9 at a time but could easily switch those 3 single bank charges to 2 three bank chargers. While it is heavy, we never have an issue being able to push it, and often times have other boxes on top of the cover when we are moving into our pit at the beginning of a competition.

https://www.facebook.com/media/set/?set=a.349869318365793.90542.109248172427910&type= 3

There are more pictures of it at this link and I would be more then happy to ask any questions you have about it.

-Nick

[yash101]

Originally Posted by pwnageNick

While I did not read this entire thread, I skimmed through most of this, and I guess I'm just wondering why it is so important for this battery cart/station to be self-sustaining. You're supplied with power in your pit, specifically so teams can charge their batteries and driver station. I completely understand wanting to make an organized, well put together station for charging and storing your batteries, but the necessity for it running off a generator seems over the top.

Also, as far as making it able to drive, I see even less of a reason for this. Being able to drive the robot cart would make more sense then this, although I know I do not think that is a good idea, and I know many volunteers who have worked the queue at a competition would agree.

While I know that with all of the batteries, chargers, frame, etc. the cart will weigh a lot, I guarantee it will still be easy to push/pull.



Our team built a battery cart 2 years ago and it works great. Currently able to charge 9 at a time but could easily switch those 3 single bank charges to 2 three bank chargers. While it is heavy, we never have an issue being able to push it, and often times have other boxes on top of the cover when we are moving into our pit at the beginning of a competition.

https://www.facebook.com/media/set/?set=a.349869318365793.90542.109248172427910&type= 3

There are more pictures of it at this link and I would be more then happy to ask any questions you have about it.

-Nick

That looks nice. I was thinking of overcomplicating things, and building a BMS (Battery Management System), to automatically pick the best battery, and to automatically do battery diagnostics!

[pwnageNick]

That looks nice. I was thinking of overcomplicating things, and building a BMS (Battery Management System), to automatically pick the best battery, and to automatically do battery diagnostics!

So basically what a Battery Beak does:

http://www.crosstheroadelectronics.com/Beak.html

We have one on a lanyard attached to the cart at all times. Works really well and is super simple to use. It is also made and sold by Cross the Road Electronics, which was started by Mike Copioli, who is very involved with FIRST. They also make the Talon motor controllers that many teams in FRC use.

-Nick

[yash101]

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