Battery Box 2.0

A couple of years back, we saw that a team (unfortunately I don’t remember which team) made a post about a box they had built to manage their batteries. Inspired by that post, we built our own version. Ours is built from a plastic “Homer Box” from Home Depot - I think it cost $9.00. Here’s the description.

There are four battery chargers zip tied to the bottom of the box. They are all plugged into a power strip. I cut hole in the back bottom of the box to bring the plug from the power strip out.

Over the chargers, I built a simple shelf out of a piece of polycarbonate attached to two blocks of wood. The shelf is clear, so we can see the light on each charger.

On the shelf, my son built some 3D printed battery holder grippers. Also on the shelf are two small plastic boxes for AA batteries (attached with velcro). One is labelled “Charged” the other is labelled “To Be Charged”.

Into the lid of the box, we have an official 8-battery VEX AA battery charger. Also on the inside of the box, we attached a digital multimeter.

Finally, on the outside of the box, my son created a 3D printed cable holder, so the plug can be attached to the box for transportation.

Our team has found this a great way to manage our batteries. The portability of the battery box makes it perfect to transport between meetings and competitions.

I hope other teams might find this design useful.







Nice job! We have something similar, but not enclosed like the Homer box. We use a large food storage container, the ones used to ship fish and other food stuff. Inside we nest a small plastic shoe box for batteries being charged. Alongside there is a row of chargers and power strip. We also have another shoe box for “Charged Batteries” The although it takes more horizontal space, you can see the battery charging lights. All the charger ends are numbered so you can see which batteries are still charging. We charge six batteries this way, which is ample to supply the needs of ten teams (HS and MS) in our pit.

However, seeing the Homer Box solution, I am going to rethink this. Better for transportation.

You tend to see a lot of battery management systems at worlds, and the some of the ones that caught my eye were the systems that actively cool the batteries so that they come off the charger cold. This allows them to be used immediately, and with full power. When batteries (or motors) are hot, they perform worse than if they are cool or at room temp. I have also seen teams that have built in voltage meter so that they ensure that they use their best batteries for the final matches :smiley:

That would probably be my school :slight_smile: I can post a picture of it tomorrow for those of you that are wondering

For Worlds last year we had our chargers and cords built into the lid to our crate that we used for parts and tools.

This year, we are using a case like the one below, and attached the chargers, batteries, and some small tools using velcro, and a frame from VEX parts to organize the wires under. I can post a picture later.

You guys and team 21 :slight_smile:

This box is really cool, I’m going to make one :smiley:

Here are a few pictures of our battery board. The voltage meters read a little high because of the incoming current, but at least we know they are charged ~ 8.9V

Where can I buy those voltmeters?

You can get an inexpensive volt meter at almost any hardware or home store. I like the ones from Harbor Freight

Presently on sale for $5.99. I like them because if they get broken, lost, stolen, etc. I’m not as upset as if it was my Fluke meter.

For hard core battery checks I have one of these.

If you really want to prove out your battery selection for worlds, this device will let you load test the battery packs


But I’d start with the $6 dollar volt meter first.

You need to let the battery sit OFF the charger for about 15 minutes before checking the voltage. When it first comes off the voltage is much higher and will give you a false sense of “goodness”.](

The person at our school who built our battery board is on vacation, so i can’s tell you the exact one we used. That said, something like this: looks very similar.