I was right
if you wire the batteries is series wich is the only way people are going to be doing it for these cars for double voltage my rule of the lower current being the total is correct
trust me I learn't it in robotics I right ask anyone

i have one of my bits set up so it can be in series and parallel. in parallel you can charge on a normal controller then switch back to series for the power or have it off so the battery doesnt drain.

Yeah I'm going for power. Can I just put90 sec. timing capacitor inline on my charger? With like an led after to let me know when it's done?

no you cant you could do that if you were just upgrading the battery to 150mah but because of the extra cell you must up the voltage by either taking out the current limiter or by making an external charger
Just search for duel cell mods and you will get all the answers you need
I want to do a duel cell too but I cant find any batteries