Question about carts
 

So to start things off, let me explain, for a little off season project, i thought that having a multi-purpose workbench/tool-chest/battery station is much more practical then chargers on the floor, using the totes as tool chests, and other problems that were had in my teams rookie year, (2013 was 4519's first season).

From all that i was wondering if there are regulations in place against having say a deep cycle battery on the cart that can provide power to power bars, battery chargers, and so on.

I was thinking that the cart would be designed to fit in a 36" doorway, and to be a couple feet long, 3'-6' perhaps. my design for the cart would all start with a main power in, a power cord, running from the main cart battery to an outlet for recharges. at that point there would be the battery, for that i would plan to have a master switch that when flipped cuts all power on the cart, both to and from the battery (in case of sudden problems, and for overnight situations), i would plan for it to also have a little information panel easily accessible that would display the battery's current charge and such.
From there the battery would just run to appropriate transformers to make the power safe for being hooked up to power bars, the classmate DS, and battery chargers

Apart from all electrical, it would just have some drawers of a cupboard with all the super important tools that would need easy access.
back to the original question, Is there anything governing the use of large battery's on carts?

also if anyone has any ideas or tips for improvement of the cart design, please leave a comment, Thanks!

Have a great day everyone!

-Connor

Re: Question about carts
 

I can't think of any rule about having a deep cycle battery on a cart per se. However, the one caveat on that is that safety is going to be probably your #1 driving requirement, even above having all the appropriate space. (Not that space will be an issue, necessarily.) The main breaker that cuts the battery out of the system is an excellent start.

Now, the question then becomes: Where do you plan to use this cart, primarily? Obviously, in the pit, which has a power drop (thereby making the large battery unnecessary); where else do you anticipate using the cart (and what are the odds of a power outlet being nearby)?

Re: Question about carts
 

20 has a robot cart that helps to carry a toolchest, batteries, and other necessary tools. And while it seems nice and convenient (and it sometimes is), it's very heavy and difficult to push around to matches.

Now even if it were to be just a setup for your pits, you have to figure out how to transport the cart to the venue. Our cart is somewhat tall, so the shelving and handle detach for transporting it to events.

I would recommend a separate lightweight, maneuverable cart, a separate tool chest, separate battery charging stations (easy enough to make out of wood), and a separate driver's station. You could set up the drivers station charger in your pits. You could also attach a robot battery and inverter to your drivers station in order to charge your laptop in a clinch.

If the totes aren't working for you as tool chests, try out different ways to store your tools. Partition your totes, use excessive labeling. If you have the funds, purchase a sliding drawer tool chest or build one.

I feel like I'm being rather unhelpful toward what you were asking, but from our team's experience, an all-in-one cart sounds good, but it can be implemented poorly very easily.

I'd love to see you have some success with this, and if you do, post pictures!

Re: Question about carts
 

Well the cart would of course be in the pit, and around my school the majority of our testing is done in our gym, which is not an idea distance to be running back and fourth for things like battery's, and also for the space we have in the school, we have to keep everything in the smallest area possible, (we have a small classroom as a workshop).

To your point on the pits having power, making the battery a little redundant, and event that happened at the regional my team attended was one of the power power lines failed because the generator died, and where our pit was there were not other close by power sources, so we were powerless for about 4 or 5 hours, so its basically a better safe then sorry feature.

If you want to have a "cart" like pit setup, I would do some research on wheels, and wheel setups. You need to have the right wheels for the amount it will carry(a lot) and it should not be able to easily drift(don't do 4 casters). One tip I would give is make sure you have breaks. So if someone worked on the workbench, it wouldn't move away into the next pit. :) Also, with any electrical work you do, make sure it is safe enough to pass safety in the pits and is weather proof.(you never know when a thunderstorm is coming) As for maneuverability, I would look into a pull cart kind of system. And if you plan on buying this cart and modifying it, most of the above is redundant. :)

Re: Question about carts
 

There are those that would tell you that 2 steering and 2 fixed is good for large-ish, heavy-ish rolling devices. Let's just say that I heartily disagree, from experience, and suggest 4 casters, all locking. You may need a second person either pulling or pushing, but it'll be a lot easier to manage in a tight space, say the pit aisles or the classroom, if you have the ability to go side to side. And if they're all locking, trying to move the cart will be made very difficult, even if you can't get to one or two to lock them.

Make sure you can go over a large cable protector in any case--figure about 2-3 inches vertical and about the same or maybe a little longer horizontal.

Re: Question about carts
 

well being able to support the weight is something im not too too worried about, because mcmaster carr has some very heavy duty wheels for a good price, (can hold a few thousand pounds)


When i do electrical, i do everything in my power to make sure, its safe, perfect, and also pretty, because ugly wiring is ugly, and the weatherproofing is also not much of an issue, but the battery will have some form of leak-proof box, for weather reasons as well as battery spills.

Re: Question about carts
 

In what situations would you need to use the battery you want in the cart? In your build space or gym, you should be able to get to an outlet, even if you need an extension cord. In the pits, power is provided for you. Personally, I don't think the possible gain from having the battery is worth the headache of safety concerns.

That said, here are a few pictures of our battery cart:
http://www.chiefdelphi.com/media/photos/35787
http://www.chiefdelphi.com/media/photos/35786
http://www.chiefdelphi.com/media/photos/35785

Features:
- Charging for both robot and drill batteries
- Main power switch that kills power to the entire cart
- Relays between the chargers and the Anderson connectors to prevent draining the batteries when the power is off (the chargers will slowly drain the batteries otherwise!)
- External power strip
- Lockable wheels to give a sturdy base (two fixed, two caster)
- Bolted down vice
- Sturdy work surface - you can really pound on something here, unlike on the tables usually included in the pits at events.
- Not only fits through standard doors, but it can be laid flat on its back to fit in the storage compartment beneath most coach buses (this was really important, until we got our trailer).
- Additional storage room, sized to fit a standard FRC tote, on end (generally PR stuff for the stands goes in here to be carried up later)
- It's heavy. Very heavy. Fully loaded, it takes 4 adults to lift it into the trailer.

Note that we have a foll-sized tool chest (on wheels) for all of our tools that gets wheeled in everywhere with us, as well as a set of cabinets (on wheels) that holds other tools and supplies (The cabinets come apart when we get to the pits and go in either corner, and include supports for our pit banners).

Re: Question about carts
 

You will want to design it for a 30" door opening. While 36" is the standard for exterior doors, many interior doors are 30" or 32". That one time you need to go through a narrow door, you'll be thankful.

I agree with the points about not having an unnecessarily complex charging system on the cart. Just get some battery chargers and extension cords. You should never be without wall power. Safety inspectors may tell you to disconnect a charging system for a deep cycle battery in the pits.

I also agree with others' statements regarding separate carts. Don't try to have a single cart for everything; instead, separate it out into mechanical, electrical, and battery charging. These don't need to be massive carts. Electrical may only need an 18"x18" table top and chest of drawers.

A good project for sure!

Re: Question about carts
 

The one thing that I would caution is having motorized wheels on the cart. If the motors or batteries die mid-competition then you will have to manually push the cart. We used to have a motorized one until we had this happen; from what I heard it was not a fun experience for the whole weekend at championships. Our current cart is really versatile (parts can be shifted quickly, it is light, and allows access to the under-side of the bot) but does not house anything besides the robot.

Re: Question about carts
 

I suppose if in doubt make the cart modular.
If you show up and get told to remove something then you can just do it.

Then if you want the battery but can't use it you can just remove it.
If you make it somehow motorized you can just undo it.

Just make sufficient cavities for the desired accessories.

Re: Question about carts
 

if you don't mind my asking, what did did you use for the top of the cart, and also the internal support?

Re: Question about carts
 

One thing i should clear up, is that this cart will mostly stay in the pit, so pushing it around is not too much of a concern.

it has been designed to fit through through a 30" doorway, if i remember correctly the design is 28" wide.

after some thinking about what everyone has been saying about the battery not really being needed, I have decided to remove it from the design.

i should clear up that this would basically be my teams tool chest as we currently do not have one. Also there would be a different cart for the robot transportation. (basically some plywood with support on wheels.

Re: Question about carts
 

Deep cycle batteries are not allowed in the event. Some regionals don't care but the one I was a safety advisor at, one team wanted to use one and we had to end up taking it from them.

Re: Question about carts
 

I have decided to remove the battery from the design for the reason of having plugs around 90% of the time.

Let me thank you for clearing this up, because i have heard about some teams having them on carts, but it is good to receive clarification from someone that has been an inspector!