Added voltage readings

I'd def check them if you are planning to send them back, if they get them and they are showing 2 or 3 volts, I'd say you wasted your money on shipping them to them.

It most certainly is. Its speced for 4 THROUGH 6s, that means 4,5 or 6. You've just seen everybody pair their lipos and choose 4 or 6s.

You're into it this far, go up to 6s and reduce your gearing for the same top speed as your 4s setup, everything will run cooler and happier.

I know from running nitros how quick the little engines overheated running in grass, so I mostly avoid grass runs with my electrics. Good Luck!

I hate to say it, but it might just be the packs are crap, not just yours but all of them. My LHS has seen several sets of these packs do the exact same thing. Packs will be working fine, then one run they will randomly lose power and puff. My guess is that it's not necessarily your setup, but the cell chemistry SMC is using may be unstable.

Yeah, I have seen those SMC and other brands like it in hard cases just poof, more than usual. A guy that is sponsored at my local track says he is sponsored by SMC and of course says 'they are the best batteries'... I think to myself, boy how much did they pay you to say that?

If you want get some tough ass batteries, go for the Hyperion G3 packs, more than top notch performance, and very decent prices.

I put an eagletree up not that long ago showing that an lvc of 3.2 on the MMM still allows the pack to get under 6v under load. I have reset my LVC to 3.4 v / cell.

This graph shows pack voltage with a 3.2v/cell lipo cut off, it still drops below under load.

http://i212.photobucket.com/albums/c...rols/flux1.jpg

It may not kill the battery the 1st, 2nd or even 20th time but it all contributes until one time you reach the point of no return and it's puffin time!

why are you sending them back? Its not there fault.... Running in grass puts a HUGE strain on everything and obviously the batteries couldn't take it.. Theres no reason to blame a company for ur mistake..

I would try to get some sort of refund or comp. It is hard running, but if they are rated that high, they should not have puffed like that. I dumped an A123 pack (4S 4600 mah equiv) in 7 mins in the grass and they were rock solid.

FWIW, they are only rated 28C, that doesn't say burst or constant. Obviously not constant w. your experience...

$85 for a 2S pack is pretty pricey. For the money you spent, you could get a Neu pack and be sure of the spec (or hyperion or whatever...) or go cheap and get Zips for way less. Pretty disappointing really.

I thought SMC was a "good" brand of Lipos

I wish you experts would give a list as to what is and isn't a "good" brand.

Hmmmm.............10 week old Lipos. But you posted noticing some slight puffing after only having them 4 weeks?

http://www.rc-monster.com/forum/showthread.php?t=21373

I would say they've been on their way down for awhile now.

If your fan wasn't kicking in, IMO, you couldn't have been pushing the amp draw that hard.

My MMM fan cycles quite often really on 4S.

Thats just the thing, I was sitting in the grass driving it and I had the truck come up to me several times to check on it and I never heard the fan kick on once.

It is possible that the first episode caused some damage which slowly increased until this.


My MMM fan cycles a fair bit on 4s as well. It is possible that if your fan didn't kick in at all as you say, maybe the speedy wasn't getting the amps it needed from the pack, the pack gets overdischarged due to prior damage and then this.

If you really want details, here are some photos of the grassy area I was driving on when this occured. Sure as hell don't look like it would cause my batteries to fry like that but then again, anythings possible at this point I guess.

http://i100.photobucket.com/albums/m...Flux/area1.jpg

http://i100.photobucket.com/albums/m...Flux/area2.jpg

http://i100.photobucket.com/albums/m...Flux/area3.jpg

http://i100.photobucket.com/albums/m...ux/area4-1.jpg

How dare you run an offroad truck offroad!

WTF< now people are telling me 4S isn't good enough for these trucks?! At first it was 6S was to much and breaks shit and now its 4S isnt' enough!! This is really getting old. The electrical tape was their to prevent the battery trays from damaging the wires after I clipped them FYI.