Need some help choosing batteries
 

You guys have inspired me to go ahead with a conversion for an MBX-5. I've got Mike building a motor mount and I am going with a Mamba Max ESC w/ UBEC and a Neu 1512 2.5d motor with a 14/46 gear ratio. I want to run 4s Lipos and can't decide between 6000's or 8000's. I know glassdoctor has been having a lot of success with the Maxamps 2s6000 packs and I'm inclined to go with them because of the lighter weight. However, Mike recommends the 2s8000 packs for less stress on the batteries and longer run times. What I'm wondering is will the extra 6 oz's for 8000's turn the MBX5 into a lead sled or will that put it at the same weight as a nitro buggy?

Just FYI, you might need a larger pinion than a 14, depending on the diff ratio. I was planning to use 18/46 on my buggy with 4s Lipo and a Neu 1512 2.5D, and the diff ratio is 3.31:1.

A pair of 2s 8000mah packs wouldn't make it too heavy. You might need a bit more shock preload, but it would still be able to push itself just fine.

It has 40t rings and 12t pinions in the front and rear diffs, so I'm guessing that's a 3.33 ratio. I will use this strictly for racing on small to medium size tracks and not really concerned about blistering top speeds.

How long will the mains be where you race? If there will be some 30 minute mains I would recomend the 8000.

I don't think the 8000's will kill the car. 6 oz seems like a lot but it's only adding 5% to the total weight of the car. It will tip the scales over the 8lb mark though.

I like the 6000's cause the car comes in right at 8lbs or just under. But it's not a big deal and the extra weight hooks up anyway.

I have run 8000 in mine and can't say there's much difference in driving the car.

your setup sounds like a good one imo. You can always tweak the gearing a little once you get some wheel time. You won't believe the power this thing will have. :004: