Battery Cart for Transport/Charging

Link to the full album with original resolution photos:http://imgur.com/a/wSD3s

So somewhere around September, I decided that our existing battery cart was too large and carried too little and that I was finally going to fix it. Hence this design was born. It was initially inspired by the general principle of server racks.

http://i.imgur.com/6vY2TEy.jpg

Cart Info:
The entire build sits on a two-wheeled dolly. The structure itself was modeled in Autodesk Inventor and then cut out in parts on a CNC. The Cart is made to hold a total of 16 batteries at once, six of which can be charging (Inside rows, from the top, first three compartments). Each battery compartment has a whiteboard door so that charged batteries can be covered and wrote on (ex. Date/Time/Voltage of charge). There are brackets at the top and bottom of each column which allow one to insert restraining bars to keep the doors to the compartments closed (This is to keep things from moving during transportation, whether its around an arena or on a trailer).
The center column contains six compartments for battery chargers. Each one has restraining wings on the sides to prevent the charger from coming out. However these can be lowered to remove the charger (This is where the server rack idea comes into play). Each charging compartment is permanently wired to Anderson connectors attached to certain walls as well as AC power. This allows one to plug in or remove a charger, so that it can either be used individually or as part of a whole unit (Helps remove wire clutter when used in the cart. Also makes it easy to remove and use individually).

http://i.imgur.com/HA6AwxK.jpg

Charger Info:
For this particular design, each charger is just a gutted Black and Decker charger. Each box was CADed and cut out of a CNC in parts, mainly to create a slightly more compact unit with a more consistent shape (Rectangular as opposed to trapezoidal). This was inspired by my attempt at creating battery charger cubes last year (If anyone remembers those. Looked cool but ended up being larger then the original). Every box keeps the active cooling system that was in the original (Mesh over inlet, Fan for output) and has a bracket holding the wires to prevent them from being pulled out. The input and output wires to the charger were cut on the ends and replaced with Powerpole connectors. As mentioned earlier, this allows the charger to be connected to the cart or removed easily. The original cable lengths were kept and are stored in a bucket next to the cart (As of right now, no exact place has been established. working on that) so that if one wants to use the charger individually, all they have to do is disconnect it from the cart, pick up both cables, connect the Powerpoles, and be on their way.

In comparison to our previous battery cart, this is a significant improvement. On the same dolly, we used to only be able to fit six batteries and three chargers. Although realistically removing chargers from a cart is usually not done, at least the possibility to do so is there (If you dont feel like carrying around a giant cart to charge a couple batteries). Both the charger boxes and the battery/charger compartments were CADed in Inventor so if anyone is interested I can post those files. Otherwise, thanks for reading! Any feedback is appreciated.

A nice design, neatly executed.

The retaining bars are a great idea. The one our team built this spring did not have this feature. The cart hit a bump in the floor and some batteries fell out and were damaged.

Better than the battery cubes…

Can we see into the back (behind the curtain)? I am always concerned with safety and cooling.

Sure! I assume you are referring to the boxes the chargers are in.
Full Resolution Photos: http://imgur.com/a/OO07g

The active cooling is still in place, and the boards themselves are elevated just a bit off of the surfaces.

Thanks, Andrey. Just don’t let the wood get wet and you should be OK. There is no way to keep the MDF from becoming conductive when it is wet.

Thanks for the tip. On the outside, we covered the whole structure and the boxes with a clear coat enamel, but i’m actually considering taking apart these chargers to cover the insides as well, probably better then straight up MDF.

You may want to mount the main circuit board using 1 inch long standoffs .

With your current set up, it looks like the circuit board is very close to the MDF. If a component on the board overheats, it may cause the MDF to char and become conductive. I have had this happen with FR4 circuit board material.

Ill definitely consider it. With the space available, I don’t think I could fit a one inch standoff but I could definitely fit at least half an inch. Thanks for the tip!

Very cool design! Could you be more specific with what battery charger you used (provide a link if possible) along with the display screen if that was separate. I’m having a hard time finding it. Thanks!!!

Mind if I get a closer look next week at Orlando? I like it. Looks really well done.