Battery Rules Question

I’m very sorry if someone has already posted a topic on this issue, our team is just having trouble locating the right information.

We were just curious, does anyone know how much of the battery has to be supported on the sides? Do we have to go up the complete height of the battery, or are we able to leave it at, say, middle height or low height? If anyone knows the inches, or even a rough guesstimate we would be eternally grateful. Thank you in advance!

There are no rules governing how you must secure the battery. It is in your best interest, both for safety and performance reasons to make sure that whatever method you use will fully secure the battery and not allow it to tip or exit your robot.

In this game dead robots will be even more costly than in many previous games so I would caution you to evaluate your battery mounting very carefully.

well… there is one rule that you just have to make sure you don’t break and that is

<R59> The control system is designed to allow wireless control of the ROBOTS. The Driver Station, cRIO Mobile Device Controller, digital sidecar, breakout boards, power distribution module, speed controllers, relay modules, wireless bridge, batteries, and battery charger shall not be tampered with, modified, or adjusted in any way (tampering includes drilling, cutting, machining, gluing, rewiring, disassembling, etc.)

that means that any method of securing it which involves modifying the battery will not be allowed. just pay attention to that one rule and make sure that your battery doesn’t go flying when hit and you’ll be fine in competition.

just please make sure you secure it properly and make it convenient to change. Last season, our battery was not really thought of too much and was just a complete nightmare. It would slip out and sabbotage the whole round for us. it was also a complete nightmare swapping it out.

Us 2… one time we flipped the bot and the battery fell out and slammed the electronics…

This year we are laying the battery flat and securing it on three sides with aluminum KOP framing. Multiple Industrial-Grade velcro straps will keep it from moving. Not only will it be easy to change out, but held securely in place well within the bumper zone. Even if we are tipped and it becomes dislodged, it will not come in contact with the electronics.

I’m thinking now though we should add a thin steel safety plate under it to prevent puncture in case we are tipped and another robot slams into it.

Laura,

One way to determine how good your battery restraint needs to be is to do a little math.

A robot being driven with CIM motors via an AndyMark Toughbox transmission (12.75 gear ratio) can achieve speeds of 11 ft/sec.

This is the speed at which a robot could hit a wall or another robot (traveling at the same speed, bumper to bumper contact).

The equation for the velocity, v, of a falling object after it has fallen a certain distance, x, under a uniform acceleration (gravity), g, is:

v = sqrt (2gx)

Solving for x we get

x = (v**2) / 2g

So, for v = 11 ft/sec we get x = 1.9 ft

Now, an engineer will normally design for and test with “design margins”. That is, some value above and beyond the design point. It is convenient that most tables are 2.5 ft tall. This is 32% more than our design point.

DO NOT ACTUALLY DO THIS NEXT STEP WITHOUT CHECKING WITH YOUR MENTOR!

Now imagine putting your robot onto a table at school and pushing it off such that the bumper hits the floor first.

This is the shock that your robot can (and will have to) withstand in a typical match. Usually many times in each match… Note that even if your robot does not move that fast, the other guy probably will be.

Under this shock load, your battery must not come loose. Your bumpers must not fail. In fact, your entire robot must be able to withstand this shock load.

Now look at your robot’s design. Is it up to the challenge?

Regards,

Mike

Last year at Atlanta, on Archimedes, a bot, I cannot remember who it was, had their battery fell out, and ultimately got disconnected. This is not a good thing and take precautions against it. in the past we have gotten our battery secured with aluminum and then would put a piece of Velcro over the top of it.

what we did was took like a 2 x 4 peace of box aluminum and we cut in to it to fit the battary inside and then we took some sergical tubing and put s hooks on them and then we wraped it over the battery and put eye bolts in to the box to connect thhe s hooks to ----- hope this helps

Changing the battery our rookie year was a nightmare, so we thought about it and one of the students came up with this idea the next year. The nylon strap and buckle is available at the hardware store for about $5, it is attached securely to the bottom of the robot. Having a box for the battery to sit in gives it good support and makes changing it easy. With the battery sitting upright, and the box surrounding it on all sides, the strap isn’t under load…it’s there in case the robot falls over, or something wild happens.

We’ve seen a few robots dragging their batteries by the wires during competitions, it’s not something we ever want to see happen to our robot





good box i was just ryin to give ideas ours was made up on the spur of the moment

There are lots of ways to do it, the more ideas the better!