RX8 on fire

[TekinTeamMgr]

I agree C rating isn't everything. However you're assuming the batteries can deliver this amount of current. Which with so many mfg's inflating their numbers, most don't.

[Ola]

These battery`s are rated 25C (150A) constant, and 50c (300A) burst of 10sec.

IIRC the logs i`ve seen on the 1515 2200kv i e-revo/flux, they usually pull 120-130A peaks, and more like 40-50A constant..
So even if my batteries isnt up to the specs, they should do the job?

Please enlighten me if not, and tell me more about what type of battery to run, if we cant trust any ratings.. (Just for the record, i`m not being sarcastic now.)

[TekinTeamMgr]

The issue stems from ripple current. Ripple current must be controlled by the caps in the esc. If the batteries cannot keep up with the load requirements of the system the caps will get over worked and fail. Again this is what we see more often than not on catastrophic failures such as yours.

Loose connections that can short ANY of the 2 wires together also cause this. This is usually a loose post on the unit caused by wires that have no "give" and pull the post out,etc.

Hard to say without the unit in my hand.

[Ola]

I know about ripple voltage..
But if my battery`s are to weak for my setup, i would like to know.. And i really would like a tip towards a brand/size battery that handles alot better..

Right now, i`m running the same batteries both 5s and 6s, on a cc1717 through a MMM esc.. That motor pulls alot more amps than a 1515, so this should make even worse ripple?

The cables was 100% secure, and everything was tight without pulling on eachother etc etc.. The esc wires was even re-soldered acouple days earlier due to the motor change to the 1515.. And yes, the soldering was done properly :)

Sh1t happends, i know.. And i`m not afraid of buying another RX8 in the future, if a sensored motor setup gets tempting to me again..

[TekinTeamMgr]

I'm not coming after you at all. I will ONLY recommend good quality batteries since I know I can stand by them. Protek RC, Thunder Power, SMC, are a few.

The smoked unit is all speculation until we see it. $98 will get you a brand new one. IF the tech's see blown caps they usually throw out a "battery check" note on the invoice.

Even a battery with one bad cell can cause this issue so it's tough to say without testing 'em.

[scarletboa]

i've seen, used and even own turnigy nano-tech batteries and i can say that the batteries are not the problem. of all my batteries, including my expensive neu-energy batteries, my nano-techs have the least voltage drop and the most punch. also, even in my most demanding setup that has heated and puffed some of my 30c batteries, my nano-tech battery was only luke-warm and solid as a rock. by the way, mine are only 5000mah and they are more than sufficient.

the batteries are not the problem. it could be anything else though such as a loose solder post or maybe a faulty component. i've had a MMM fail in less than 5 minutes due to a faulty part and i have MMMs with over a year of heavy use and a couple hundred runs on each.

edit: also, you mention that you recommend SMC batteries. i have a pair of their 9000mah 28c+ packs and they are some of my weakest packs. my turnigy 30c 5200mah packs have more punch and run cooler. i was pretty skeptical of turnigy batteries at first, but after i tried 1, i had to have more. now, i have about 20 turnigies and 8 name brand packs.

my best batteries are the turnigy nano-techs and my worst are maxamps. my maxamps are strictly for 1/10 use lol.

[TekinTeamMgr]

I don't recommend giant mah batteries though.

Let's get one thing straight. If a battery is only so large, you can either get punch and voltage, or you can get runtime and less punch.

Lipo batteries are simply electric gas tanks. You can either get a lot of power and less runtime, or less power and a lot of runtime. Take your pick.

Originally Posted by TekinTeamMgr

I don't recommend giant mah batteries though.

Let's get one thing straight. If a battery is only so large, you can either get punch and voltage, or you can get runtime and less punch.

Lipo batteries are simply electric gas tanks. You can either get a lot of power and less runtime, or less power and a lot of runtime. Take your pick.

not true im afraid
these batterys isent following any specefic size regulation so the larger capacity ones is also larger in size

the 6000 can deliver more power and amps than the the equal 5000 ones, it also have less resistance..
The turnigy nane tech is great, i have a bounch of lipos including hyperion and i can say the nanos have alot of power.

That a esc fail isent that uncommen for many reason but blaming somthing else is just not necesarry, it could have been many things like snow, water, wiring, connector, servo, heat, soldering ore perhaps even the esc failed becouse of years of stress ore faulty components.

[Ola]

Originally Posted by TekinTeamMgr

I don't recommend giant mah batteries though.

Let's get one thing straight. If a battery is only so large, you can either get punch and voltage, or you can get runtime and less punch.

Lipo batteries are simply electric gas tanks. You can either get a lot of power and less runtime, or less power and a lot of runtime. Take your pick.

Huh?!

Ofcourse, if you got a battery without enough capasity (constant amps) for youre system, it`s not good enough..

But why dont you recomend large mah lipo`s ?
I cant find 1 reason, except weight..

By choosing a large mah battery with enough amp delivery for youre system (mah X **C +headroom since you cant trust the manufacturers), you CAN have more runtime + maximum punch..

If i remember my lipo theory correct, **C is not an amount of power delivery, it`s a factor for calculating it..

[TekinTeamMgr]

C rating is calculated as you describe. You're missing my point. Large Mah packs are often 2 "other" packs in one case. All of this adds up to more resistance,etc.

Have you ever seen a 4s 9000mah 60c pack ? no

I know for fact that batteries can cause esc failures. We've tested it, and seen it. Even though your batteries are rated "here" they may not be performing "there".

Rx8's with blown caps are likely failed due to poorly performing batteries, period.

[BrianG]

Originally Posted by TekinTeamMgr

C rating is calculated as you describe. You're missing my point. Large Mah packs are often 2 "other" packs in one case. All of this adds up to more resistance,etc.

Have you ever seen a 4s 9000mah 60c pack ? no

I know for fact that batteries can cause esc failures. We've tested it, and seen it. Even though your batteries are rated "here" they may not be performing "there".

Rx8's with blown caps are likely failed due to poorly performing batteries, period.

I completely agree with all the except for the statement "Large Mah packs are often 2 "other" packs in one case. All of this adds up to more resistance". Large mAh packs are usually in 2p (or more) arrangement, which would decrease the resistance by half the amount of a "1p" pack.

But, yes, ESC failures where caps are overworked are definitely caused by the battery being pushed beyond its real-world rating, no matter what the C-rating, mAh capacity, or number of parallel cells. It doesn't necessarily mean the pack quality is poor; it could be a setup issue (geared too high, improper components for the vehicle, etc), or any number of other things.

And FWIW, I don't like 2p packs; more connections to have issues...

poor quality battery may also cause the fets not open\close as they should, atleast so have i heard. Turnigy is one of the more common batterys out there so i recommend tekin to get some suitable ones fore testing purpose.

As your affiliated with the manufacture and prob have allot of knowledge(atleas more than me) im surprised you are blaming the battery and claiming lower capacity ones can deliver more power than the bigger ones

dont think this thread was meant for blaming ore find the reason just for showing off like yes i burnt the rx8

[Ola]

I`m not going for blame war`s, that i can promise you.
But if you cant trust manufacturers ratings up to a certain point, then i dont know how any normal hobby RC driver could be able to find a suitable battery without spesific recomending from the ESC manufacturer..

I would really like to get a name (and type) for a battery above 4500mah, both 2x 3s and 1x 5s, than can be run in a MT with large wheels and heavy gearing, without making ripple voltage and burn my ESC..

And just for the record, Castle say the exact same words.. Batteries kills ESC`s the most.. But they will neither speak of what batteries that are good enough.. For MT`s, they only say "30c 5000mah minimum"..

Normal people dont even know what ripple is, and they for SURE havent got the gear to measure it..

[TekinTeamMgr]

As I said before, you get what you pay for with batteries. There's a reason some mfg's don't charge as much as others.

I personally have had no issues with Protek's or Thunder Powers.

[JERRY2KONE]

Tekin has been a pretty successful R/C company creating some of the best ESC's and motors in the business, so why don't you guys do a little expansion and come out with a line of GOOD Lipos in support of your great electronics? With the level of quality control already in place I bet you guys could kill in the Lipo market considering what your up against. I mean come one anyone can beat Maxamps working out fo some guys garage, and considering your race teams experience creating a line of Lipos in comparison to whats already out there should be a fairly easy business option. The only challenge would be doing it for a fair and reasonable price range. Being competitive and acquiring a fair market share would be the key. You guys already have a good reputation in the industry. So what do you say?