Questions/builds thread.

Thanks guys! We won't be painting it, we'll just clean up the white and leave it at that. Don't think paint would stick very well anyway. We quite like the white, under studio lights it should almost glow. :)

As for batteries, if we replace them it's a matter of replacing them now. If we order today from ebay then we SHOULD get them here before the 31st. Maybe.

Would 3 of these in series be sufficient? http://www.ebay.co.uk/itm/6V-3300mAh-Su ... 5645b92771

Could we keep our current charger, the 18v drill one? And the discharge rate on those is just 30a, would that be enough? We're likely to be drawing quite a bit more than that.

It's a real bummer that our drill batteries may not work. Today we'll test drive it and time how long it lasts. If it starts fading after a minute, we may be in trouble. We hadn't predicted this of course, when we were testing it before it weighed 5kgs less, meaning the motors worked less hard, and so it could go for 4-5 minutes no problem.

Here's hoping, again!

3300mAh at 18V, I would say definitely. I drove Conker around uni for about 30 mins and only took 2000mAh out of my lipo. So even if I trebled the average drain it would still give me 10 mins drive time in combat!

(Though I would get someone else's thoughts to cos I have 0 experience in combat)

Out of Interest, will it run upside down with the back wheels touching the ground?

It's painful, but yes. On a smooth floor it should drive around enough to be considered active. When upside down we have little weight of the wheels and only 2 contact the ground anyway, so it's by no means perfectly invertible, but it does drive. Sort of.

Possible breakthrough: it just finished charging but after feeling the top panels, only one side is as warm as the batteries used to get when charging (alarmingly hot, but right). The other side is warm but hardly, whilst as I say the other side is too hot to touch.

Does this mean we're only properly charging the fully heated side? Or perhaps does it mean that the really hot side has a high resistance, maybe due to shoddy cells, and so it not only gets very hot but doesn't charge properly?

I feel more confident in saying it's the cooler side that is somehow wrong. Until now it has driven fine when both sides have been equally hot after charging. We may have a dodgy cell somewhere.

I can't diagnose it yet, but we may be running on half capacity, or more or less half. They're two 1.3ah packs in parallel, one side is hot, the other warm, any idea what that could mean?

What it means is you need to get some non-drill cells! Be a shame if that's what lets you down in combat, especially as it looks so good

You might just have to bite it and buy some racing packs just so you have quality cells, Ewan is right, it would be such a shame to see a brilliant design fail due to shoddy batteries.

Just spotted your second qualifier!

Inertia XL v Tormenta v NST

I have to fight them to but not at the same time! Talk about a baptism of fire!

Where are you staying when in the UK? It would probably be easier to buy cells from eBay/Vapextech when you're over here than try and get them posted out to Spain before the 31st. With two weeks between you arriving and the event, it could possibly lessen the rush.

It looks brilliant though. Don't worry about the wonky armour panels. I always used to try and get everything to match up and have no gaps or squint lines, but you don't really notice in the arena and no-one else is that bothered by it :)

I think you have made a really nice job of it, lets have more screws holding those side panels on, they might flex and absorb a knock that wont stop them being ripped off...........love the Design, more screws and could you also let us know the dimensions of the beasty!

Thanks for the comments and concerns.

I measured the voltages of the cells and they all measure the same. No issue there. We don't quite understand the issue of why one gets so hot and the other only warm.

I am looking at batteries, and:

Is 30a maximum discharge enough? The maths say 30a isn't enough, but our current batteries, although they get hot, seem to to the job, and I doubt they're designed to give 30a discharge as drill cells. Would paying double and going for 60a be worth it?

I can't seem to find a fast enough charging charger that doesn't cost more than the batteries themselves. Any help with this? Is there a golden charger that everyone uses?

What do you guys recommend we do? We could get 3x 6v batteries, put 'em in series and use our current charger, or buy two 9.6v packs and buy a new charger?

Decisions! All of them costly! :uhoh:

Thanks for the kind words guys, really!

If you can afford it the /best/ you're going to get will be li-po's, but they don't actually have to cost a huge amount, for example:

Charger for up to 6 cell 5amp charging http://robotbirds.com/catalog/product_i ... ts_id=6248 £20
Or if you don't have a power supply here's one with a supply built in http://robotbirds.com/catalog/product_i ... ts_id=6247 £40
And an 18.5V battery UK stock http://robotbirds.com/catalog/product_i ... ts_id=4892 £37

That's all just 2 minutes browsing, you could find a little cheaper if you looked.
For your machine 30A continuous output ought to be 'enough' in most scenarios though.