Legal battery chargers this year.
 

My team was wondering about what chargers are legal this year. We have heard that in past years there has been a 6 amp limit but this year we cant find anything talking about chargers in either the game or administrative manual.

Does anyone have any clarification on this rule?

Re: Legal battery chargers this year.
 

You can not charge a battery at a rate higher then 6 amps, (about the max charge rate of the batteries we use) This is stated in the safety manual.

This is generally enforced by limiting chargers to a max rate of 6 amps. However certain special conditions could allow a charger with a max rate greater then 6 amps to be used.

Re: Legal battery chargers this year.
 

http://www.chiefdelphi.com/forums/sh...3&postcount=11

Re: Legal battery chargers this year.
 

Thanks for the help.

My team is also wondering how many batteries your team brings to competition. We have a 6 CIM drivetrain and are worried about not having enough batteries fully charged.

Re: Legal battery chargers this year.
 

I consider 6 batteries to be an absolute minimum for a competition. Now that we are a district, with 12 matches (at least) per event, this became an even more solid conviction. We have a charger cart with four chargers that makes us comfortable with 8 batteries. This partly due to doing only one match per battery and monitoring the battery state after each match just before it joins the charging cycle. At matches we set the charge rate to 4a.

Giving each battery a name will also help you keep track of the good versus the marginal performers and allow a cogent cycle of use to be formed for them. We use a battery beak to monitor the battery state. They are pricey, but the beak helps you manage your several hundred dollar investment in electron storage and feel confident that your robot has as decent a chance at getting through a match as you can give it. You also get the chance to see which of your stable of energy may only be suitable for practice or control system testing.

Re: Legal battery chargers this year.
 

With 6 CIMs, you'll most likely want a new battery every match. This will come up most in eliminations. There are extra batteries available for teams in eliminations that need to play back to back matches, but plan on having at least 6 batteries fully charged and ready to go for eliminations.

Re: Legal battery chargers this year.
 

We have a 3-charge bank and bring plenty of batteries. I think we bring 10-12ish, but I am not sure. We change the battery before every match.

Re: Legal battery chargers this year.
 

I think the amount of batteries will depend on how you use them. Previous years with us not using pneumatics, 4-6 batteries with two chargers was very adequate.

If you have a lot of pneumatics and plan on pre charging a bunch of tanks in queue you could need quite a few batteries and chargers to keep up.

This year we are using a lot of pneumatics and are bringing 10 new batteries and some of our previous years batteries for pit demos (LED shows and such for the pit visitors). We will be bringing 5 (6amp) chargers as well. We also plan on using the previous matches battery for the pneumatic pre charging and swapping in a fully charged battery when the robot is ready to load on the field.

Good luck this season,

Aloha!

Re: Legal battery chargers this year.
 

You might want to be worried about tripping the main breaker. At least two teams in Wisconsin tripped multiple times with a six motor drive train.

Re: Legal battery chargers this year.
 

We were kind of worried about this being an issue. I hope it doesn't end up being a huge problem.

Re: Legal battery chargers this year.
 

Oh, is that why 2481 kept dying during eliminations? I know in at least two (maybe it was three) matches, they dropped dead in the middle of the field (no signal light), after a rough pushing match.

Re: Legal battery chargers this year.
 

Yes in between SF 1 and SF 2 we switched out the main breaker. After that it never flipped again. We were also cooling it between matches. Realize we had 8 motors for our swerve drive. 4 CIMs and 4 BB RS775(I think). The wires between our battery and PDB were getting quite warm so we are planning on lowering the gauge for nationals to better handle the current.

Re: Legal battery chargers this year.
 

I saw three robots with tripped main breakers at the Boilermaker regional. In each case, only one of the wires was warm. The apparent cause was not too much current, but simply too much heat from a poor connection caused by a loose nut where the wire connects to the breaker.

Loose main power connections -- on battery terminals, SB-50 connectors, main circuit breakers, and/or Power Distribution Board inputs -- were unfortunately very common. It'll be interesting to see if the logging feature of next year's PDB will help convince certain teams that their general animosity toward "the FMS" is misplaced, and that their loss of robot control on the field can usually be prevented with a bit more attention in the pits to checking and maintaining the robot's electrical system.

Re: Legal battery chargers this year.
 

I didn't realize teams did anything different.

Re: Legal battery chargers this year.
 

Kyle,
I think the drivers just became a little less aggressive in the subsequent matches as I had suggested. If you go back to the old ways, this problem will revisit you. You know I have a vested interest in keeping you guys running, you gifted me and I am returning the favor.