Any Failures on Li Fe Po4 cells?

Hi,

after reading detailed failures etc etc for the mmm i havent read of any with Ion Phosphate aka 123 cells?

anyone?

[Helly]

I know two MMM who die with A123, look here:

http://www.rc-monster.com/forum/showthread.php?t=14913

My MMM die on 6s2p A123 with a Neu 1515/2D (3day ago)
The other one was on 6s2p A123 too.

This is the battery who are recommended by Castle...

[tc3_racer_001]

keep in mind the % of people using them vs lipo is very important when assessing whether they are safer to the controller. if anything id say they have the potential to do MORE damage (a 6s2p pack weighs a TON and can supply a huge amount of power...)
my 5 cents :)

[Helly]

I agree with you, but it's always the same thing,

I am running 5s2p A123 on a MM without issues, MM who are rated for 3s lipo....
(5s2p A123 is ~800g)

So imo the probleme isn't A123 but MMM

[tc3_racer_001]

yeah of course - bad design! im sad i sold my mamba.. o well at least my MMM is working and im very happy with it!

ok thanks chaps i must have missed that one. i got some dewalts heading my way and will just try my luck. strange ,i would have associated "luck" with nitro's as opposed to electrics.

[gogglespaesano]

I've been running my e-aftershock on 5s2p A123 with a V1 MMM from mike's preorder with no problems. Keeping my fingers crossed though.

But most mmm's are failing on 6s....so why don't more people run 4s till the bugs are worked out?

[tc3_racer_001]

personally i dont agree... 6s will draw less amps. i would agree the 6s high speed setups may kill it, but perhaps the bec cannot step down adequetely, this may possibly be correct, but im sure they would have adressed that much before v2 came out!

[RBMike]

I've killed them on 5S A123 & 5S lipo in 2 different buggies with a 2000KV & 1700KV motors. I will have a hard time beleiving that my set-ups are killing MMM's it is just not putting that much load on it. Besides the A123 set-up never killed my MM.

[TruckBasher]

I Killed MMM on 6S2P A123 Internal BEC and other MMM run for 15mins UBEC (havent run more on it thou) This setup has been running on MM 6S2P A123 for 10 batt cycle...I also doubt its the setup but Im not speculating so I dont know what killed it....

[Sammus]

People say that your esc can blow caps if your cells are inadequate, because lower quality (lipo) cells are prone to a bigger voltage drop, and voltage drops translate to ripple voltage or ripple current or something that can destroy your caps.

Why do castle recommend using A123 on their monster then? Since A123 are renowned for huge voltage drop. I measured a 1V drop at 55A (23C) load the other day on my A123 cells for example. It's not a myth, its even written plain as day on the discharge graphs on the A123 website that they have substantial voltage drops. I imagine they would cause significant ripple current or voltage or whatever it is that blows caps...oh well, ive got a few big caps here I'll just add for safty anyway - just putting the idea out there for comment.

[suicideneil]

My comment: Has nothing to do with A123 cells, at all. I've been running them from day 1 and the MMM V1 works perfectly. I've used them with the hvmaxx 6.5 motor, and the 2 different 9XL clones, and the esc didnt bat an eyelid.

The key thing to bear in mind is that cheaper or lower spec (MA) lipos will drop their voltage just as much under load, and nimhs will drop their voltage even more so. My feeling is the issues are down purely to parts in the esc, bad layout or design of the esc, or just plain user related issues- poorly mounted esc being knocked about & using busted servos that overload the BEC spring to mind...

[snellemin]

My MM still run great on 6s A123 without issues. If the MMM blows with A123, then I say it's the MMM that is "bad". Could be bad boards, parts assembly or the parts themselfs. Can be pita to find the cause sometimes.

"'I've been running my e-aftershock on 5s2p A123 with a V1 MMM from mike's preorder with no problems. Keeping my fingers crossed though."

how have you found running the car with those config packs? i am about to do the same but even 1 5S pack looks cumbersome.