I think there's a little bit of misconception here.
You quoted 240 volts @ 5 amps, this gives you a total of 1200 watts. Again you quoted 12 volts @ 30 amps, this gives you a total of 360 watts, and the wattage rating is the crucial factor. There is no chance of overheating being cause by the brushes. You will find the same brushes in a mains powered drill as in it's battery operated counterpart.
I think the reason for Chas's comment if not so much the brushes but the thinner braid connection between the cable and the brush, this is the weak point. IMHO I think they should be OK.
Anyway this is going to be a case of suck it, not *uck it, and see.
posted on: 23/01/2015 20:05:16