can this charger be used safely with series 1 batteries?
No, it cannot.
1.2 amps is 1C for Series 1 batteries... 1C is considered to be the fastest safe charge rate for NiMh.
Whatever it is I just typed... could be wrong.
No it can't , Hears the specs for the 2930 charger . http://traxxas.com/sites/default/fil...arger-Inst.pdf
1 Rusty VXL + Slash 4x4 Platinum