Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p??

Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (Full Version)

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simplecj -> Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/10/2008 9:02:08 PM)
Ok, I have been doing alot of homework on the subject of building A123 packs but it seems alot of what's talked about out there are 3s packs or higher (mainly aviation packs). My esc is rated to a max of 9.4v so I can't put the M1's in a 3s without changing my esc/motor combo. I'm fine with what I have and am going with a 2s setup. I just bought a DeWalt 36v pack and want to make use of all 10 cells. It would make sense to go with two packs, one 2s2p and another 2s3p for longer run times. I realize packing these into my Rustler might be tricky, but with some velcro strapping I should be able to accommodate both packs without too much trouble. My question is, if you can get about 4600mAhs from 2p then why not add two more cells (2s3p) to get about 6900mAh's?? Are there any drawbacks to this vs sticking with two 4600mAh packs and one 2300mAh pack with the remaining two cells?? I haven't seen anyone say they've made a 2s3p pack and with the 10 cell DeWalt pack being such a popular source it makes me wonder why! I've only seen discussion on 2s1p and 2s2p packs for a 6.6v application. More mAh means longer run times right? Plus since their lighter than NiMh going up to 6 cells shouldn't be any different on handling compared to the 4 cell NiMh I'm currently running (4600mAh Venom pack). It'd be nice to have two packs to take out on a nice day. I'm figuring between the two I should have almost an hour of play before it's time to head home. Any suggestions? 10 cells => Either 1-2s2p + 1-2s3p OR 2-2s2p + 1-2s1p ??? 2s5p??? PS - I'd love to sport some A123 decals on my RC & battery packs if anyone knows where I can find some!!

snellemin -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/10/2008 10:01:28 PM)
The power to weight ratio is just not worthed in my opinion running 3p, since you are just running brushed. But it does make for long playtime for sure.

simplecj -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/11/2008 5:30:28 AM)
If the A123's are so much lighter than the NiMh's I've been using, then there shouldn't be much difference between my 4 cell NiMh and a 6 cell M1 pack right? Therefore, power to weight ratio would be about the same, but with roughly 50% longer run times and maybe more if people are right that the M1s are underrated on capacity specs... kind of a no-brainer isn't it? Also, I'm not racing (no local track), just buzzing around off-roading, maybe some jumping... Running light isn't as important to me as running endurance. My 4 Cell NiMh (4600mAh = 412g A123 M1 Cells = 70g each 6 M1 Cells (6900mAh) = 420g Plus, we'll say 10g, for wiring & shrink wrap = 430g Percent weight gain = 4.4% Percent capacity gain = 50% Not to mention the fact that there's no noticable voltage sag with the M1's! Damn, I think I just answered my own question huh? Just for further iteration while I'm at it... 4 M1 Cells plus 10g for wiring and shrinkwrap = 290g ==> 30% loss in weight (from 4 cell battery pack alone) and equivalent capacity and better performance. That's awesome!

simplecj -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/11/2008 5:59:16 AM)
Actually to put this power to weight ratio business into perspective we'll include the weight of my vehicle (1.69kg) ... Traxxas Rustler XL-5 with 6 cell NiMh = 2.102kg Traxxas Rustler XL-5 with 6 cell M1 = 2.120kg Overall percent weight gain = 0.8% With 4 cell M1 = 5.8% loss With 2 cell M1 = 12% loss Assuming roughly the same power output (although the M1s maintain output throughout use, NiMh doesn't), it actually comes down to what's more important to the user, lighter weight racers only needing a good 5-10 minutes would benefeit most with the two cell pack. Running for fun people who appreciate not changing batteries every 10 minutes would benefit most from the 6 cell pack. Either way, the M1s will give you almost full performance for the entire run while my NiMh noticeably drops off after a few minutes of driving... 6cell - 0.8% weight gain - 50% increase in capacity 4cell - 5.8% weight loss - same capacity 2cell - 12% weight loss - 50% decrease in capacity

Metallover -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/17/2008 8:01:33 PM)
you're going to want 3sxp because 6.6v isnt much power. 9.9 is more like it.

simplecj -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/17/2008 9:35:47 PM)
I'm running an XL-5 brushed Titan 12T. The esc is rated to a max 9.4v. If I went to 3s I'd either need to change out the esc and maybe upgrade to brushless, OR I could just drive it till I burned it all up and be forced to upgrade. I've already built the two 2s packs and they perform great! It literally doesn't start to bog down till the last 30 seconds of operation, almost full speed the entire run, plenty fast for me!!! Got my battery supplies from cheapbatteries and the dewalt pack the same day, had to buy a better solder gun, everything went together very slick. I've even installed a custom velcro strap which holds the packs down just fine. I can post some pics if anyone's interested...

simplecj -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/23/2008 8:41:54 PM)
As an added note, my fully charged 6 cell pack gives me nearly a solid half hour of runtime, it's awesome! The two packs charged up will let me run for almost an hour which will make trips out in the desert worth it and no need to quick charge from my car.

SS Pede -> RE: Building packs for Traxxas Rustler XL5 - 2s2p or 2s3p?? (2/26/2008 5:33:36 AM)
quote: ORIGINAL: Dime666 you're going to want 3sxp because 6.6v isnt much power. 9.9 is more like it. Some people do just fine on 2s...it depends on your application. [8D]

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