li-po in hard case

[MetalMan]

Explosion isn't all that likely, especailly with Kokam cells.

[captain harlock]

Thanks, Man. I'll leave it for another time.

[RC-Monster Mike]

I am pretty sure a "bloated" cell would flex the plastic case, Metalman. It isn't a very thick case, and has some flexibility. I doubt a damage would go unnoticed truthfully.

[MetalMan]

But there is still the issue of heat. And if it is a thin case, then it could still be damaged in a crash

[RC-Monster Mike]

Well, anything can be damaged. The plastic is pretty thin, and would flex with a bloated cell for sure. I still think it offers a nice layer of direct protection for impact and flying rocks thrown by the spinning front tires, for example. Also, there is no chance of a small sharp stone lodging itself between the cells to cause future damage. I do get your point, but IMO, the Kokam cells are not likely to have problems, and the case/plastic packaging of the Orion batteries is a benefit. For one, they are shaped like a rectangular cube, whick makes holding them an easy affair. The fit damn near perfectly in place of a 6 cell pack, which is another nice feature.
The packs are rated for 70+ continuous amps, with bursts of twice that , so I don't forsee heat issues under normal use, either.

[gixxer]

they do look nice, the only issue I have with them is the price. i am not ready to spend $139 a pack right now.

[gixxer]

they do look nice, the only issue I have with them is the price. i am not ready to spend $139 a pack right now.

[MetalMan]

Originally posted by RC-Monster Mike
The fit damn near perfectly in place of a 6 cell pack, which is another nice feature.

What's that size like :L:

The packs are rated for 70+ continuous amps, with bursts of twice that , so I don't forsee heat issues under normal use, either. [/B][/QUOTE]

At their full rated discharge, they would probably hit ~150-160 deg. in open air (no air flow). At something lower (like car use), it should only get about 110. But encased in a package where heat cannot leave, there could be problems.

[RC-Monster Mike]

In my e-maxx, I would expect to get around 10 or so minutes runtime on my track(the kokam 3200s in 4s will last me around 7 minutes in race conditions), so my amp draw is nowhere near the full rated discharge. The rated 70 amp continuos current woudn't last a 5 minute race. Real world use will yield twice that or more(half the rated amp draw), so they are plenty in the safe zone. Just to get the cells to last a 5 minute race, the average amp draw would only be 2/3 of the rated capacity. The reality is that the cells in even an open design get very little airflow with the body on the vehicle.

[MetalMan]

I don't think we should be considering runtimes when trying to figure out the heat of a Lipo battery. My Rustler can get very good runtimes out of a 3300mah Lipo battery (like 15-20mins), yet somehow the battery comes out warm. This is due to the large amp bursts, and these are what need to be focused on (not average draw). For example, I was just running my Rustler with the Eagle Tree Micro Recorder hooked up doing some back-and-forth runs with normal gearing. My 3300mah battery is only rated at 33amps continuous, yet it was allowing spikes to 60+ amps. I hadn't been pulling too many amps during this 5min. run, since the GPS was on it, but not strapped in. As soon as I removed the GPS and started doing some wheelies and quick pulls of the throttle, the battery actually started to heat up. But even still, the average draw was most likely only ~15amps.

I realize that there shouldn't be a problem with these batteries, but you have to figure the worst case scenario. My personal opinion is that temperature is far more important that small dents (from rocks), as Lipo cells can take them (and the shrink wrap would take most of the force of the rock). For this reason, as well as the extremely high (IMO) price, this pack will never be sitting in any vehicle of mine.

mike, will you be selling lipo anytime soon? Or at special request?

[captain harlock]

He's already selling them. Just send him an e-mail: mike@rc-monster.com

[Batfish]

MetalMan - I think your points can be valid when considering very high-powered setups in bashing/racing situations, but it's almost invalid for normal setups in racing conditions.
If you're running a brushed or brushless setup appropriate for your racing environment, these packs would just about never be pushed to their continuous maximum, and barely ever have peak currents near their maximum capacity.
I'm pretty sure that Orion and Peak did not design these lipo packs with high-voltage brushless systems in extreme conditions in mind. As far as I am aware, they were designed to replace 6-cell nimh battery packs for 1/10th scale racing vehicles. In this application, they will exceed the nimh packs in performance and capability.

[MetalMan]

Originally posted by Batfish
MetalMan - I think your points can be valid when considering very high-powered setups in bashing/racing situations, but it's almost invalid for normal setups in racing conditions.
If you're running a brushed or brushless setup appropriate for your racing environment, these packs would just about never be pushed to their continuous maximum, and barely ever have peak currents near their maximum capacity.
I'm pretty sure that Orion and Peak did not design these lipo packs with high-voltage brushless systems in extreme conditions in mind. As far as I am aware, they were designed to replace 6-cell nimh battery packs for 1/10th scale racing vehicles. In this application, they will exceed the nimh packs in performance and capability.

I won't argue with you on that point. But for guys like me that run higher voltage in their 1/10 STs, this pack just won't do (too low voltage). It's a whole 'nother ballpark when you run 4s Lipo on a 3000kv motor in a Rustler ;).

[Serum]

You both have got a point.

it is clear to me, that metalman is not a fan of packing any lipo cell. I remembered about the same reaction on my post of the lipo packs from the UK..

I am curious if Kokam is going to launch these cells not only for the OEM's.