lipo mah vs. weight vs. heat vs. c rating

[DrKnow65]

Another lipo question, but not the same ole' question...

Those of you guys with multiple lipo's and rigs (lincpimp types), when you chose your lipo's for a rc set-up which way do you tend to go;

1) big mah, heavy, low C rating (single pack)
2) small mah, light, high C rating (single pack)
3) option 1 with multiple packs
4) option 2 with multiple packs

I didn't list specific vehilces or mah's as each rig will dictate the needs (amps & voltage), but if we need to be more specific, I'm one of the many waiting on the MMM to put first into a converted hyper7 (custom motor mount above the diff, custom trays) then later on to a direct-to-diff-revo. I'm looking at doing 6S lipos in both rigs (mabey even the same lipos) with an 8xl or the castle/neu if it isn't toooooo far off.

[aqwut]

I'd love to go single packs and highest possible C rating... but it's hard running single packs when you want to run Higher voltage... 6S - 12S+.. also have to consider the weight & location of the batteries... I try to match the batteries so they can give the same output as the motor and ESC..

[neweuser]

I too like a good C rating, but it also depends on racing vs bashing. I usually bash now, so I really don't care and go for run time, durability/dependability, and of course customer service. ;) But I would think a C rating to be important regardless. Good quality is a must just as with NiMh. I think that the application and what you are looking for is a big deal also when choosing lipos.

[sikeston34m]

This really depends alot on the application.

I try to go with the largest mah cell that I can justify the weight of.

If you pack in enough Lipo to weigh the same as Nimh, you're going to get twice the amount of runtime and even with 10C Lipo, beat the crap out of the best discharge rate that Nimh has to offer.

I think Amp Draw should be estimated first. Or at least have a rough idea of what your setup is going to demand from your batteries. Then add 25% to that. Pick some Lipo's that are going to deliver THAT kind of amperage.

I have ran 10C, 15C and 20C cells. The higher the C rating, the more expensive they are.

The 10C cells performed GREAT, but the amp draw of the application they were in, fit their ability.

In the same application as the 10C, the 15C had more punch, but weighed slightly more.

Mah per ounce, you will find that the higher the C rating, they more they weigh. It might not be much, but for certain applications, such as airplanes, the people that pay attention to detail do take the time to figure all of this into the equation.

In my experience, the 20C cells will deliver enough amperage to take you right up to, or beyond the mechanical limits of your drivetrain even with upgraded parts. I can only imagine what the 25C or 30C cells will do performance-wise.

Just remember, Mah rating and C rating work hand in hand.

For example, a 4S 2500mah 20C pack will deliver the same amps as a 4S 5000mah pack built with 10C cells.

Space, weight, amperage requirements AND budget all should be considered when choosing the right Lipo for your application.

[BrianG]

I think it depends somewhat on use.

If you want max performance for shorter runtimes (or if you don't mind a battery swap), you probably want something lighter, yet not sacrifice performance. For that, you need lower capacity cells for the weight and high C rating to get the amperage you need.

For just bashing around, you probably want long runtimes. This means the cells will have higher capacity. And since the capacity is higher, max discharge current is easier to reach with lower C ratings.

[jhautz]

Racing.... The highest C rateing you can get with just enough mah to get you through the race. The smallest pack you can run and still finish comfortably.

Bashing. I dont mind more weight to get mor mah for extended run times. The longer it runs the happier I am.

That said. In most buggy, truugy and lighter MT applications you need a battery capable of 80A constant at a minumum for your typical 4s, 5s setups. More than that if you have a very heavy vehicle. 11lbs+. I have found that I have toasted lipos, it was always ones that were on the small side for the application amp wise.

If you decide to run very high voltage you can get away with batteries that are less capable as far as current, but you will need more cells to get the higher voltage. Its all trade off.

[DrKnow65]

Sweet guys. Sikes, thanks for taking the time to write that post up.

I knew the higher C rating would put out the amps better without heating up, but never really considered they had less voltage drop-i.e. better performance.

I'll be bashing for the most part but if I get the opportunity to hit a track I don't want a dog in the corners.

I'm considering the 25-35C zippy lipo's, 2 packs of 3S 4000mah (100amps and 392grams) they are only $60 each.

or get a pair of the 20-30C 5000mah's @ 100amps and 392grams

A good example of weight vs. C rating...