Maybe someone on MR has such knowledge?

I've been caring for this silver maple (Acer saccharinum) seedling
which I brought in from Illinois last September. It's the only one
out of four that didn't vanish in the floods of October (7 ft. deep
inside the house), and it has doubled in size since then... but now
is beginning to show signs of stress.

Summer heat is REALLY on, and I tried to keep the soil and roots
cool, by using a DIY styropor chillbox with a TEC (Peltier) module,
both ends heatsinked with fans:


The fans and TEC module were powered (in parallel) via AC-DC
adapter, and it worked, cooling the chillbox interior, for all of 55
minutes, before the adapter MELTED.
The fans and TEC module still work, post testing with a 9v battery,
but I could really use help choosing a proper power source...
or confirming where I went wrong, lol... (I thought a 1A transformer
would cut it... argh).
The devices:
Heibei TES1-12703 (DC Vmax 15.4v; Imax 3A)
http://www.hebeiltd.com.cn/peltier.datasheet/TEC1-12703.pdf
CPU fan TM-CF04 (DC 12v; 0.12A)
CPU fan TM-CF07 (DC 12v; 0.12A)
The failed power source was:
NEWSTAR NA-1000RS (output 1.5 to 12v selectable; Imax 10000mA)
I know that this species isn't supposed to survive here in tropical
Philippines, but I really want to give it a shot.
Thanks

h.