I was on cheapbattery packs.com and I could get a 6 cell pack of 4500's elete with dean female and 12 guage wire in a side by side for 44.97 this seams to be a really good deal. How long of runtime would I get with them in my sv27. Would my duratrax digital piranha charger work? What would be some guidelines? How many amps do I charge them at? Are Ib4200's worth the extra $10 or are these better? Thanks