Re: Where to mount the battery?
 

Mount the battery underneath the robot. It is pretty fun to deal with.

/sarcasm

Re: Where to mount the battery?
 

The battery is capable of 600 amps fully charged, even a 100 amp 12 volt power supply will not be enough to get four motors turning.

Please NO!!!

Please be sure to insulate the terminals at all times, whether on or off the robot, in a box or not. 600 amps is capable of welding metal.

Re: Where to mount the battery?
 

Actually, even upside down is perfectly fine. Just do not charge it upside down, because of the overpressure vents on top. During use the battery won't need to vent making orientation irrelevantI have seen several robots with the battery mounted right to the bottom center of the robot. To change the battery, they just tip the robot on its side, exposng the battery mount.

Re: Where to mount the battery?
 

It really is too early to start "planning" on where the battery will go. There has been some great advice on here, but keep in mind that every game is different! For example, if you were climbing the tower this past year, depending on design you might not have wanted your CG to be in the middle of the robot... battery placement for many teams might have been a key component of getting the robot to hang correctly!

As others have alluded to, there could also be obstacles on the field or other rules that affect how you build your robot. For example, in BreakAway bumpers had to be fairly high, and pretty much every team used a riser kit to elevate the frame off the floor. This potentially gave you significant space underneath your main frame to put stuff!

As for location of your main mechanism, We've had ours all over the place! Our rookie year, we had mechanisms on the front and back of the robot. Over the years, we've built two "fork-lift" style elevators, where one was on the front and one was on the back. In BreakAway, we even had a mechanism that was primarily on the side of the robot!

When designing a robot, you really need to look at the entire thing. You can't design part here, part there, and mash it together and get something good. There's a lot of give and take as you build it up, a lot of planning that goes into making sure you have room for everything where you need it. If you want to practice for the next few weeks before kickoff, take last year's game/rules, and design a robot for that!

Re: Where to mount the battery?
 

I'd be concerned with the pressure on the vents from sustained inversion. Erring on the side of caution when it comes to batteries is a good principle.

Re: Where to mount the battery?
 

We actually did that last year. It was a pain to change out the batteries when we had back to back matches in eliminations.

Re: Where to mount the battery?
 

Sorry to be a bit off-topic, but why go for this configuration? You'll have very little scrub preventing you to turn, therefore making the robot very hard to drive. Why not just go with the standard kitbot, 6-wheel, dropped centre?

As for the battery mounting, just remember that your battery can be used as a form of "ballast" to move your CoG to somewhere else. Other than that, as long as you can securely mount the battery (using tools such as the Battery Base Mount linked earlier from Andymark) and can access it easily, your battery should be fine as long as it is properly maintained.

P.S. While we're talking about batteries, zip tie the leads. They're the next most likely thing to come lose.

Re: Where to mount the battery?
 

Not to make a grudge, but I dislike zipties and batteries because they are only single use. They can also look bad. I think heat-shrink would be a good choice for what to insulate the wires with. If done correctly, it will hold the wire together with quite some strength. You could possibly hold the battery with the wires (though not the best idea) with the strength if done correctly. Also, does anyone solder the connections to the battery?

Re: Where to mount the battery?
 

Where would you expect such pressure to come from? There's no gas production when a SLA battery is being discharged.

I have no problem with this.

Re: Where to mount the battery?
 

The battery mount should be light, simple, and functional. (Along with everything else on the robot)

When putting the battery in, be sure to secure it well. Ziptie the connectors for the battery to the connector. Use reusable zip ties if you would like.

If you are securing the battery to the robot, make sure it doesn't go anywhere. A few zipties may seem like enough, but if your robot is going over bumps or falling over, a simple strap may be a better option.

A previous poster mentioned holding a battery by the wires. Don't do this. Stress on the battery terminals is a bad thing. Besides for ripping the tab straight off the battery, the performance and safety of the battery will be reduced.

Re: Where to mount the battery?
 

If the choice is between a disposable zip tie and an immobile robot due to the connector coming loose, I think paying the two cents for the zip tie is a good deal.

If your complaint is that they might not look nice, then take the time to make them look as nice as you want.

Huh? Battery wires aren't going to swell or pop from the electron pressure. What are you proposing the heat-shrink tubing would hold the wire together against?

Using heat-shrink on the battery connections is okay. The only problem I would have with it is that it can make checking the quality of the connection difficult.

NO.

NEVER lift a robot battery by its wires. EVER. You'll put stress on the interior connections and risk irrevocable physical damage. But how would heat-shrink affect how strong the wire-to-battery connection is?

That would be a Bad Idea. The amount of heat you'd have to apply to the terminals would be likely to deform the plastic case, and has the potential to warp the plates.

Re: Where to mount the battery?
 

I am superstitious. I prefer my batteries to be upright. The UPS sitting next to me uses the same type battery. One battery of the pair spends its life upside down. Go figure.

While zip tying the anderson connector is a good idea, if it is that loose, one of the connectors are bad. Could be a source of electrical gremlins. Better to strap it some way so that it does not flop around. We put in under the same Velcro strap we use to secure the battery.

We used Velcro tape to secure the battery one year. Bad idea. Very secure. Difficult to change.

Re: Where to mount the battery?
 

Gravity

Re: Where to mount the battery?
 

IFI/VEXpro have a very nice battery cradle as part of their 2013 Drive in a Day Chassis Kit.

Item 217-2966 for US$25, shown at the bottom of this page.



We just picked one up and will almost certainly use it for our 2014 robot.
It is formed out of 1/8" aluminum, so it is very sturdy, but not particularly heavy.

Cheers,
- Dean

Re: Where to mount the battery?
 

That seems like a good battery mount. However, as of what I understand, it is made of Aluminum, so I think it may be a short hazard!

I prefer upright battery mounts because these batteries have a grip that helps you replace them. The battery holder depends on your robot's size/design/CoG. Place it to center your CoG. Also, make it so that replacing the battery is easy. If you can replace the battery within thirty seconds, you have done well! Also, your robot's shape really matters. We didn't really worry about where we placed the battery because we had a very stable robot already. If the robot was like our 2012 robot for rebound rumble, that easily fell over, the battery must have been placed in the bottom center.

This is off topic, but not worth making a thread for:
Many robots won't reach the weight restriction. Are we allowed to place dense materials, like a block of lead or steel, etc. in places on the robot to reduce the CoG?