I’ve noticed that teams, (us included) have an unreasonably hard time of rigidly securing their batteries on their robots. How does your team secure your battery? Also, what are some funny stories from your team pertaining to securing your battery?
We’ve used the AndyMark battery box, sandwiched between polycarb plates, in conjunction with red velcro to secure it. This year it played a strategic part as the mount for our shooter motor.
I’m sure every team has a story like this, but at an offseason a few years ago, we had a very quickly-put-together robot. Of course battery placement wasn’t really thought out, so when we accelerated quickly, the battery would push the breaker in to the CIMs and turn off the robot.
I’ll open this one up by discussing what I’m looking for when I check a battery as an inspector. Then I’ll get to securing methods.
When I’m inspecting a robot for a secure battery, I’ll ask the team to make sure the battery is properly set up in their robot. Then I’ll grab the battery and try to get it out (sliding upwards, stuff like that). If it barely moves (or doesn’t move at all, even better), it’s good. If it can move enough to get a good jump on slamming into the securements, I’ll have a discussion on why you need to make sure that the battery isn’t moving. (Because, you know, having the battery dragging around is a great way to ruin your match.)
Generally, 1197 will build a box for their battery to sit in. After 2016, we learned to make that box accessible (inability to do a very quick change helped cost us a critical match). The box will be secured by a variety of methods depending on the robot…
My ideal: Build a box of wood, big enough for the battery but not quite as high. Add a hinged piece that goes over the top of the battery. Use hook-and-loop, bolt/wingnut, clever pin usage, or other solid securement to keep that down between the cables. Once it’s secured like that, your battery isn’t going much of anywhere.
we usually secure the battery with those long 2mm thick*20mm wide aluminum plates we have, and some lock mechanism that will help us to get it in and out easily.
at the houston champs (after 4 competitions without failing) our driver took a very sharp turn next to the feeder, and the rivets that held the aluminum plates disconnected, and battery flew off like 3 feet from the robot.
good times
Our team usually makes a small holder for the battery to sit snugly into, then secure it in place with velcro straps. Battery changes are super quick.
- Make an open-face box that snugly and securely holds the battery every direction except sliding in/out one way.
- Keep the battery from sliding out that one way.
- Last year (2017), we put four angle brackets on the aluminum plate we used for our climber, then secured the sixth direction with another piece of angle, two threaded rods, and wing nuts; we use a similar method on our air cannon.
- In 2015 and 2016, we used the AndyMark battery tray; works great with the end sheet of the AM14U2&3 if you can use that volume.
- In 2012-2014 we used wide velcro or friction straps as the final stage. This didn’t work quite as securely, not because of the strap came loose, but because we were missing the angles that kept the battery from moving sideways, and we were expecting the velcro to do two or three jobs instead of one, so the battery had a bit of wiggle room. Still, never lost a battery when the strap was tight.
My test these days is to lift the battery - the robot should move relative to the floor before/more than the battery moves relative to the robot. With our 2017 practice 'bot, we almost would have passed without the threaded rod - that box was TOO tight before we re-drilled some holes.
Edit: attached photos of our 2016 battery holder, taken the night we bagged. Top image is overhead view with battery removed; the battery sits in the 2" x 1/8" angle which mounts our winch, and is held in place at the base with three more aluminum angles, and is held in at the top with another angle. At the bottom is a picture with the battery in place, as we completed a test climb outside our shop; up is really up, and the battery is now horizontal.
Pretty much always, it’s a matter of straps and enough surrounding bits that movement is impossible.
The high-water mark might’ve been this year, when the battery slotted in the lower-left, then the sheetmetal bracket pivoted (to be a hook for the surgical tubing), then the bumper went on (and since it sat above the frame on 4" wheels, that constrained the battery further). Only problem was one match where our wires tagged the main breaker, but other than that it was painless.
I highly recommend the Vex Pro drive in a day battery box. It uses a strap to secure the battery. It kept the battery in every climb this past year (except when we accidentally didn’t secure it with the strap). 9/10
This year we riveted a battery box made of lightened 2x1 box tube to the rear cross member in our frame. We then ran a double sided velcro strap through the holes in the tube and over the top of the battery in it’s long dimension. The robot has since survived a fall, lots of brutal defense and maintenance involving inverting the robot with no issues.
We use a polycarbonate box that has a piece of PC that fits snug into the handles on the battery itself. We’ve done this since 2013 and have had no issues. Battery change takes anywhere from 5 to 20 seconds depending on where we locate it on the robot. The polycarb in the handles used the springiness of the material to hold the battery in place.
In 2013 we ran out of room and had to mount the battery from underneath. We got to the point where we could change it out in less than 30 seconds and faster than we ever thought we’d have to by the time we were in the semi finals at MSC. It turned out okay, but we try to avoid that if we can. That was also the last time we’ve used a fastener to retain the battery.
uhhh…strap?
This year we went a bit (too) overkill and had a pair of plates screwed onto the frame of the robot. When we wanted to change the battery, we’d flip the robot over and remove the bottom plate. It worked well but took a minute or two to change the battery out.
We usually (well, for the past 3 years) have built the chassis with a slot for the battery in mind, usually is such a place that it cannot be taken out without either a bumper being removed or a apparatus of the robot being moved/shifted. Usually the slot will be padded with rubber or some other material that acts as a dampener, but not something so soft as let the battery wiggle around, you want that battery to be bound to the frame as much as possible. Then we strap the battery in with Velcro (the nice and thick stuff, 2" wide, heavy duty) and we’re good to go. Having the battery in the frame protects it from hits, and prevents it from falling out, as the only way to remove it is to deactivate the bot. While this adds a slight downtime between matches, a trained pit team can get it done very quickly. The assurance that the battery wont be falling out or breaking is well worth the extra 15 seconds it takes to replace it.
We built a polycarb box with an open top and had the battery sit upright. After out first slam test (driving the robot into a wall at full speed- highly recommend it, we found a bunch of problems this way), the battery popped up and out of the robot, so we added a 2 inch wide vecro strap, and we’ve had zero issues over 7 competitions, while being able to swap the battery in <10 seconds.
As many have said previously, confine your battery to only moving in one direction, typically able to only slide up and out. Last year we used 1/8th Aluminum plate waterjet cut and CNC bent to allow the battery only to slide up. We used a cheap dollar store dog collar with a buckle to secure the battery. It ended up working great and we will be doing it again on our future robots. Furthermore we integrated bolt holes for the Anderson connector of the robot’s power cables to be firmly attached to the battery box. This made it super easy to connect and disconnect the battery from the robot.
I assume 125 is receiving their royalties for this use of their motto? 
One additional thing you might want to try is zip tying the battery connectors shut so that they won’t ever accidentally open and cause your robot to lose power.
We ended up adding a lot of things to keep our battery contained. At first we just had a plate with one of the molded plastic battery clips and a red velcro strap.
After the first time our battery fell out, we added a pair of aluminum angle pieces on both sided of the battery. The back part ended up needing to be re-riveted after the battery slid back into it and remove the rivets.
In addition, we held the Anderson connectors to the side of our fuel tank with a piece of dual lock and a bungee cord to keep the cable from hitting our main breaker.
I believe we also replaced the red velcro strap with a pair of industrial strength black velcro straps (regular sticky backed velcro, just with the plastic backing still on) at some point as well.
we didn’t secure ours well enough, it finally came out, first elimination round at the AZ state champs yesterday. Now we know.
We’ve used the same bent sheet metal battery box part in the last four or so robots. It’s a bent 0.125 50something sheet about four inches tall. It sits vertically against our bellypan, then a velcro strap over the top. We’ve never lost a battery.
You can see it in the top centerish of this picture:
