Which would be better?

[mattsdragons]

Bit of background info, my featherweight set up needs altering as currently the motors (12v) and the batteries (2x8.4v packs) get very hot after a 3 min fight

2 options but which will come out with a more reliable system?:

1 - Buy some 18v rated motors and change to a 24:1 ratio which will give the same speed but less torque
2 - Drop my battery power slightly down to 15.6v overall and change to the 24:1 ratio

[Ellis]

One of your options includes overvolting, the other doesn't. It's not difficult lol.

[maddox10]

Buy a 4S LiPo pack. Cheapest solution I can see.

[mattsdragons]

Charger?

[plargen]

if you have the space you could always add these to the motors

http://www.ebay.co.uk/itm/Ansmann-Racin ... 3cc12b17cf

not sure how effective they will be

[mattsdragons]

No space for additional fans so need to figure the best way of taking the strain out

[maddox10]

This battery
combined with
Imax B6


Total pricetag. £ 35.97 +P&P

Cheaper than any other good solution for your overheating drives. And it will free a lot of weight and space for future upgrades.
Yes, the machine will be slower and will have less torque. But will run a lot more controled and with less maintenance problems.
I know I like the less maintenance situation. It's rather frustrating making emergency repairs during an event on a machine that didn't get any battledamage.

[Ellis]

t's rather frustrating making emergency repairs during an event on a machine that didn't get any battledamage.

Indeed it is!

[mattsdragons]

What about all the lipo safety bits as well?

[Ellis]

You need a fuse which is safely below the peak of the pack, so around 100a for the battery Mario posted, though the lowest you think you can get away with is obviously advisable.

Such a fuse can be found on Technobots but is probably cheaper on Ebay. Something like this, you might save a a few pennies if you search deeper: http://www.ebay.co.uk/itm/2-X-100-AMP-1 ... 3f1b0ee5af

And a fuse holder, for example: http://www.ebay.co.uk/itm/Maxi-Blade-Fu ... 2ec1bce2c5

I'd also suggest a Lipo Alarm, though I don't think that's in the rules.

You need to mount it securely, though with shock absorption, and with at least 2mm of metal between it and the arena floor.