Yea I think C rating on batteries is actually very similar to horsepower and kv ratings on nitro engines and motors respectively. And RPM ratings on mass produced brushed motors fit in there as well. Some could be measuring no load RPM/kv and using more volts than the others are, so you never know what you're getting. Same with nitro engines. They make flywheel dynos, sure. But they aren't made to adhere to any specific standard. It's not like the automotive industry where manufacturers are forced to dyno all of their engines using the same net horsepower figures, and the process is standardized by the SAE requiring them to dyno all the engines sold in the US exactly the same way. Cold cranking amps on car batteries are similarly rated by a standard and almost always supply the rated power. Imagine buying a battery for your RV or worse yet your bass boat that was rated like RC batteries are only to discover that it can start the engine, only if everything else is turned off because it can't hit the required amps. It's a shame the RC industry isn't like the automotive industry in that manner. I agree with you, though. I too hate convos about power plants and batteries/nitro fuel for RC usually. They just never seem to go anywhere and people never actually answer anything, just argue their ideas are right and everyone else is wrong. I take to finding stuff out on my own these days when it comes to engines, motors, fuel, and batteries. I bought the ones for the Revo because they are the only smaller LiFe packs that will fit in it and have larger gauge wire for use with ground vehicles instead of RX/TX packs with 20ga wire on them.
Now, what I meant by cherry picking is that they receive the bulk shipment of cells from China, and test them once they are at the assembly shop and pick the best of the bunch, possibly just canning the weaker cells and the ones that won't take a full charge. This is what I think you pay for with high end batteries that usually cost more. Also, when dealing with Maxamps you have support that is based in the US, so if you have issues you can get meaningful help, another thing that adds to the cost. I've heard all too many times of cheap no name packs that arrive with horribly out of balance cells, and ones that have cells that simply never will balance out properly. For cheaper packs, it seems to be a lottery of sorts. That said, I just got 2 Zippy Flightmax 2S 2100mah 30C LiFe packs for use in my newly built Lunchbox that ran $15 each, $9 less than the 1050mah packs for the Revo. So far, they have been perfect. Balancing out just as well as my Maxamps 2S packs for the Revo. One major difference though is that the Zippy ones cannot be charged as fast. They have a max charge rate of 2C, while the Maxamps ones are good for 15C. I can't hit that with my charger, but I do charge them at roughly 6C (max for my charger is 6 amps) and they take the same mah as a 1C charge and are fully charged from dead (2.8-3.0v per cell) in about 10 to 12 minutes. I'm a little more careful with the Zippy packs and only charge them at 3.5-4 amps at the highest. But usually give them a 1C charge if I'm not in a hurry. I do always balance charge every time though, even though I don't think you have to with LiFe.
All that said, I have seen videos of 4S? LiPo RC batteries being used to start cars, so they must have a decent burst rating of at least a few hundred amps and be able to hold at least 12-13 volts, or that would never happen. That is however, just as you said, a burst test scenario and not at all a sustained test. I'd bet if the car's starter was left on for 20 seconds it would cause the battery to grenade. I wonder if one could build their own device to pull heavy amounts of constant amperage and test batteries with a good multi meter?
Last edited by Maxximize; 04-17-2016 at 01:58 AM.