Lipo Protection in beetles

[daveimi]

Hi, if I move to a lipo in my new beetle will I need the 2mm metal plate under it?

[Eventorizon]

I kept trying to give a simple answer to this, technically the answer is a straight forward Yes, but I think its more complicated than that.

That rule was implemented to reduce the risk of a LiPo fire reaching the floor of a wooden arena, such as the Robots Live and Roaming Robots arenas, for HW's and FW's. (I believe that is correct, I may be wrong)
In beetleweights its less of an issue as 2 arenas already have thick metal floors, Stu and Dave's arenas, and ours has 1in thick wood which is treated to be self extinguishing (its old school staging and thus was required for heath and safety)

However, the main issue now isn't to do with it reaching the floor but the protection required on the sides to stop the big horizontal spinners such as Lynx and Spin Cycle reaching the LiPo by cutting though your armour and reaching it that way, rather than from the bottom up.

Given Lynx has been able to cut through 15mm of HDPE given the right hit, I would say 2mm on the bottom (if the robots base isn't that thick already) 2mm on the top and then 2mm on the sides with an additional 10mm of HDPE and probably an air gap too.

All that said though, if a robot has reached your LiPo in the first place a LiPo fire will probably be the least of your worries... your robot may well be spread far and wide across the arena by that point.

[RogueTwoRobots]

Any armouring of a lipo to prevent it getting damaged by a spinner should be down to the builder and not a part of the rules. I believe the 2mm metal base requirement was more to do with preventing a lipo fire from leaving a bubbling mess of plastic on the arena floor, especially in featherweights as a lot of bots use that for their bases.

I've not had 2mm metal in any of my beetles that have been using lipos and, as far as I'm aware, it's not actually in the rules in black and white, so you're perfectly free to run without any metal. If you don't want to make your entire base out of 2mm metal, you can always just put a localised piece under the lipo. I did this on Onyx and Reaver when I switched to lipos as they used polycarbonate and HDPE respectively for their baseplates.

[daveimi]

Ok that's great thank you. Yeah I can get a 3s lipo at less than a third of the weight of the nimh pack I have at the minute. I'd never really paid them much attention but the capacity vs. the weight is amazing. And how cheap they are??? Thought they'd be really expensive with them being the latest thing etc.

I want the weight for armour and weaponry, have shifted cash to paypal for some botbitz's, got myself mixing on the transmitter and have a new lightweight receiver. So with a lipo my electrical package will be as light as is humanly possible, just wanted to ask about the specifics before I order a charger and stuff at the same time.

[RogueTwoRobots]

Yeah the weight saving is great. Both my beetles use 3s 850mAh packs, which I get from Robot Birds for £9 each. I have four packs which cost £36, can't argue with that price. One pack lasts Flatulence an entire event and more, and Spin Cycle needs a fresh pack for each battle :P
Even chargers are a lot cheaper these days than when I started, making a battery setup for a beetle nice and low-cost.

[Ellis]

If you don't need high discharge: http://www.hobbyking.com/hobbyking/s...arehouse_.html

£9 is a rip off!

[mrsam]

Standard Turnigy packs (Non Nano tech ones) i've found to be fantastic, i used them in my feather at the champ this year and they were great especially considering how cheap they are. Granted for spinners they'd probably struggle but for anything else you can't really go wrong.

[Ellis]

Agreed, can recommend the regular light blue Turnigy range. A trio of well-used Ebay bought (well looked after, importantly) 5ah 20c packs run Tormenta 2 very nicely, some 50-70 cycles down the line. They're great value. Can't comment on the nano range yet, although T3's packs seem fine too.

[RogueTwoRobots]

£9 may be a ripoff compared to the Turnigy packs, but space is so tight inside Spin Cycle that any other pack that has different dimensions just won't fit. The £9 packs are Hyperion ones; I had one already from four years ago that lived in Flatulence, but transferred it across to Spin Cycle when I was first wiring it all up. I then ordered more of the same pack for the size reasons mentioned, but also to keep consistency battery-wise between the beetles. Means I don't need to have different batteries for different beetles or need to fanny about with my battery charger settings at an event.

[harry hills]

Spin cycle is a terribly designed robot. Absolutely horrible. How anyone thought any of the design choices were remotely good is beyond me.