Micro T questions

[eovnu87435ds]

So I picked up a micro T, and when looking around on sites like atomic mods, etc. The truck runs for 7-9 minutes on a 180mah nickel pack. I have also seen that the losi micro xcelorin speed controller is rated for 5 amps continuous, 9 amps burst. I'd think that the stock motor/esc would be less.

What I was thinking, was to take a pair of cellphone batteries, rated at 850mAh, and wire them in series for a 2s li-ion pack. Do you think the batteries will hold up to the stock setup? has anybody ever tried this before?

Or does anybody know the general rating of cellphone li-ion batteries? specifically those from motorola/nextel phones?