Tired of team members lifting batteries by their cables? Tired of telling them to not lift by the cables only to watch them do it again? Well, worry no more. A small group of rookies and veterans on Team 1294 Pack of Parts decided that for their first solo cad project they wanted to solve this exact issue and made a wonderful battery handle to help lift batteries.
This battery handle is a two-part, 3D printed design that screws together around the top of your battery to help provide a good, solid grip and an easy to lift handle without crushing your wires. We used these handles throughout our season and had zero failures with them. They make life so much easier, be it allowing for a good spot to tie the battery down from (Velcro looped around the handle), or some nice and easy hot swaps at comp. But obviously, the biggest bonus is that they prevent people lifting batteries from the wire by providing an easier to use option.
Here are some pictures of them from CAD and the link if people want to create some for themselves. I’ll add some Irl pictures for them later once I take some.
If the OnShape link above doesn’t work, then you can just search up “Battery Handle V4” in the public documents on OnShape and look for the file made by a “Charlotte Gruian”
This is my first topic on CD so forgive me if I did this wrong.
We used to use PVC insulated battery cables which are stiff but strong, but over the past year and a half we’ve begun to switch over to EPDM insulated battery cables which are much more flexible. So now EPDM insulated battery cables will probably be our standard from year to year.
Hope that answers your question!
I created a Battery Bag using material left over from our bumpers and as a training project to help students learn how to sew our reversible bumper design. The project guide is at 00 FRC Project Guide-Battery Bag - Google Docs.
It has been a while since I’ve worked on this document and it needs some updating. Since June is Bumper Month, I’m hoping to get in and build a couple more Battery Bags. I’ll update this guide as I make progress.
It is competition legal as it doesn’t modify the battery but rather just adds on to it without any drilling or such. We were also allowed to use them at all competitions we attended (PNW Bonney Lake, PNW Sammamish, PNW District Champs)
As for the weight concern, none of the RI’s really asked us to weigh the handles/count them as part of robot weight, but then again, our robot was extremely underweight <100lbs, and the handles being 3D printed and being filled with <50% infill are pretty light. But that being said, we always did carry a set of unattached handles should an RI ask us to weigh them separately. I
TLDR, the handles are legal but don’t weigh too much so unless your robot is near the weight limit don’t worry about them but carry an unattached pair just in case an RI wants proof, they won’t cause the bot to go over.
I’d argue the handle to be part of the battery assembly and shouldn’t count towards overall robot weight end of story. Plenty of teams have other zipties, clips, fabric straps, connector handles, etc in their battery assemblies that aren’t explicitly legalized and also aren’t getting accounted for at weigh-in.
…Pushing the envelope with billet steel handles would probably get this stance revisited unfortunately.
you’re probably right. I couldn’t say for sure since none of the RI’s at our events really asked much about them. But ya, billet steel handles would definitely be pushing it a bit
Not to be a stickler here, but your device needs to be evaluated for it’s ability to properly vent gases. During both charge and discharge, any over pressure that builds in the battery vents through six valves under the door/panel at the top of the battery. This action prevents the battery from exploding and the design also allows the hydrogen that is part of that gas, from collecting in a flammable/explosive concentration.
You bring up an interesting point. I never really thought about that. I’ll be sure to let our designers know about this so they can re-iterate on the design to accommodate for this. Thanks for letting us know!
The Yuasa Applications Engineer who supported us at a previous job (manufacturer of industrial uninterruptible power supplies) told us gas should be coming out very slowly. The only time it should come out quickly is when the battery is exploding. Thus any minute gap between the handle and the battery should suffice.
Of greater concern to me is the bend radius of the two battery cables. A rule of thumb is that the bend radius should be greater than 2-1/2 to 3 times the outside diameter of the cable, including the jacket/insulation. If the cables are bent too sharply, some of the strands can break, reducing the effective cable size.
