Another Quark Question

does lipo packs increase speed too or just run time?im kinda new on electric and specially 1/8 or 1/10 bl set ups..i bought a quark 125 also,can i run my batts in series with this ESC? after i fried my mtroniks that i got used im afraid to even connect the batts when i get the new ESC..about the mtroniks idk what happened but when i got it, the seller made a y-connector so i can ran my batts in series making it run 12cells of ib3800s..aside from that i connected the esc to another y harness that connects also to the brake servo.as i was setting my th/br on the radio the esc started to sizzle..will those connections can cause this?can someone pls post a pic on how u run batteries in series?i have a pic also that ill post and pls tell me if its right..u may have seen my post on other forums but they were left unanswered.the seller told me the connectors are done right another friend said its good too but idk y i fried my esc?pls help thanks guys..