34LikesWARNING - LiPo "C" Discharge Ratings are INVALID!
12-19-2018, 12:44 PM
#121
Currently the only OEM's I know of in surface are Gens Ace, Max Amps and SMC. Those companies have their own factories for producing lipos and at least Gens Ace is OEMing for other brands.
12-19-2018, 02:20 PM
#122
Super expensive, mega powerful pro racing packs. C ratings are still false but if you compare the C ratings to average packs, the true amperage output scales very closely to the same. But that doesnt mean their chemistry is vastly different from a normal LiPo, they just pay top dollar for the most badass cells and then that cost is passed onto you as the consumer. There are single MaxAmps batt packs that cost more than an entire new 1/10th scale brushless truck, ouch!
12-19-2018, 05:54 PM
#125
Coincidentally a buddy dropped off some new SMC's at work today so I could add xt60 connectors then cycle them at home. Things have pretty low IR.
12-19-2018, 07:32 PM
#126
I actually had one, and while I do admit they screw up in certain ways, they do a fantastic job in others. Is it worth the price you pay? Hell no, Ill never do it again. But they are seriously powerful packs. I had a race edition 8000mAH 4S 150C pack for a 1/8th Truggy. What a beast of a pack, it came with 1.2 IR and 1.3 IR on all the cells, thats astounding! This means the batt is capable of a true 192 continuous amps when new. That is one HELL of a battery. It held its voltage right at the top all the way down to the very last few mAH of capscity. They seriously use the best cells I have ever personally seen. But, now for the screw-ups.
First of all, when I ordered mine, there was only one choice of connector: Deans. Really? 60 Amp connector on a nearly 200 amp battery? How noob does somebody have to be to make that mistake? Then I get the battery and I realize I forgot to look into what wire guage it comes with because it was 12AWG. 100 Amp wire on a batt that can max out 10AWG. I was sitting there like "OMG, are you ****ing serious?" But since I was running it on 1/8th scale I figured the wire would be ok and I could just change the connector to an XT90. It worked great and for a few years, probably around 350 cycles. Not bad lifetime at all considering back then I did not know a whole lot about techniques to extend a LiPos lifespan.
So yea, they might use the absolute best cells around but they seem to make some pretty seriously noob mistakes. They still make these mistakes to this day! So in raw power, they are number one, but would I ever buy from them again? Not a chance, leave that to the spoiled rich kids.
Now you can determine their true amperage capabilities. Endure they are charged to full 4.2V per cell, unplug them and let them sit for an hour or longer to ensure they are at room temperature. Then, plug them back in, retake that IR rating and plug the highest cell IR number (1.6 for pack one and 1.7 for pack two), along with capacity in mAH into the LiPoly Objective Performance Calculator linked in the OP. Be sure you do NOT pick up the batts after they have settled to room temp. The heat transfer from your skin to the battery alone is enough to give you an innacurate IR measurement. The number at the bottom is the battery's TRUE continuous amperage output capacity.
12-20-2018, 02:05 AM
#127
Random Fun Fact: Did you know you could use an Amps/Volts/Ohms/Watts calculator to determine an actual maximum horsepower rating for a battery?
Once you have determined a LiPos TRUE continuous amperage rating, you have the information you need. Plug the true amperage and full-charged voltage of the pack into the calulator and you will get your wattage. Covert the wattage to Horsepower and wala!
The 149 Amp 7400mAH SMC LiPo in 4S is a 2.96 continuous British Horsepower battery!
Once you have determined a LiPos TRUE continuous amperage rating, you have the information you need. Plug the true amperage and full-charged voltage of the pack into the calulator and you will get your wattage. Covert the wattage to Horsepower and wala!
The 149 Amp 7400mAH SMC LiPo in 4S is a 2.96 continuous British Horsepower battery!
12-20-2018, 08:56 AM
#129
As far as charging as it relates to life span those are old myths that have been debunked in the drone world. I charge everyone of my packs at 4 - 5c and they do last hundreds of cycles. There's also no need to charge below capacity. It's when you continually charge to HV that you dramatically reduce a packs life.
Going back to our heart pump battery, we did learn that we drastically increased cycle life by only charging to 80% capacity of the battery. It made a very large difference. We are only using about 60% of our rated capacity. We use a 3S lipo, so you'd think it's 11.1v but our label says 10.8v. It's because we don't use the top 20%. We also don't try to use the bottom 20% of rated capacity but that's not from a battery life perspective but rather a human life perspective. Alarms are screaming at a patient when it hits that point telling them to change batteries. They carry 2 btw. We did this because a person might be out and about and may have forgotten their spares at home. Then they get to a point where they need to change them because power is too low but they don't have it with them. They've got a built in reserve of 20% to get them back. We don't tell them this though! What happens if they get home and the replacements aren't charged? That's why we chose 3C to charge.
I know the instant response is that we are using some ultra high quality medical grade battery cells or that we are using lithium but not lipo. Not true. There's no point in spending all that time and money in battery development when something already exists that does what you need it to. We merely tested several manufacturers cells until we found the best for our needs. Anyone can buy those cells . They are Samsung 16650's. That's it. That's the big secret. Off the shelf components. They are packaged for us by Inspired Energy with a digital meter, the plug we need, and the case size we require but the cells themselves are off the shelf lipos. They are highly durable. Lives literally depend on them.
12-20-2018, 09:09 AM
#130
I'm a heart pump designer by profession. I have a heart pump that implants in the human body inside the left ventricle of the heart. The pump is actually a 6 pole brushless motor. I've got a patent on an improvement there but that's for another topic. It is powered by lipos. We fully intend to implant a small lipo in humans soon. A couple of years ago when working on the power improvements, I worked on batteries. We are moving to a much smaller and lighter battery pack since our power consumption is going down. We had 100 battery charging/discharging stations setup that would do nothing but charge and discharge at different rates to determine max longevity. Obvously we don't pull the current that any rc applications do so that isn't what is going affect battery life for us. We focused on charge rate and capacity. What we found is that charging at 1/2C-1C gave the most cycle life BUT we ultimately chose 3C. If 1/2C -1C was better, why charge faster? It wasn't much better. A few cycles on paper is a technical improvement but functionally if it only means that a battery gets replaced a few days earlier, it's not an issue. The big thing for us is that people's lives literally depend on their batteries. If it's time to replace their batteries but they forgot to put the old one on the charger in wait, we like the safety of being able to charge one in 20 minutes as opposed to waiting an hour, which they might not have. We did notice appreciable cycle life degradation above 3C. I personally charge my batteries no faster than 1C but my life doesn't depend on it and I'm in no hurry. Since I don't run my cars everyday, I charge them to storage level after use.
Going back to our heart pump battery, we did learn that we drastically increased cycle life by only charging to 80% capacity of the battery. It made a very large difference. We are only using about 60% of our rated capacity. We use a 3S lipo, so you'd think it's 11.1v but our label says 10.8v. It's because we don't use the top 20%. We also don't try to use the bottom 20% of rated capacity but that's not from a battery life perspective but rather a human life perspective. Alarms are screaming at a patient when it hits that point telling them to change batteries. They carry 2 btw. We did this because a person might be out and about and may have forgotten their spares at home. Then they get to a point where they need to change them because power is too low but they don't have it with them. They've got a built in reserve of 20% to get them back. We don't tell them this though! What happens if they get home and the replacements aren't charged? That's why we chose 3C to charge.
I know the instant response is that we are using some ultra high quality medical grade battery cells or that we are using lithium but not lipo. Not true. There's no point in spending all that time and money in battery development when something already exists that does what you need it to. We merely tested several manufacturers cells until we found the best for our needs. Anyone can buy those cells . They are Samsung 16650's. That's it. That's the big secret. Off the shelf components. They are packaged for us by Inspired Energy with a digital meter, the plug we need, and the case size we require but the cells themselves are off the shelf lipos. They are highly durable. Lives literally depend on them.
Going back to our heart pump battery, we did learn that we drastically increased cycle life by only charging to 80% capacity of the battery. It made a very large difference. We are only using about 60% of our rated capacity. We use a 3S lipo, so you'd think it's 11.1v but our label says 10.8v. It's because we don't use the top 20%. We also don't try to use the bottom 20% of rated capacity but that's not from a battery life perspective but rather a human life perspective. Alarms are screaming at a patient when it hits that point telling them to change batteries. They carry 2 btw. We did this because a person might be out and about and may have forgotten their spares at home. Then they get to a point where they need to change them because power is too low but they don't have it with them. They've got a built in reserve of 20% to get them back. We don't tell them this though! What happens if they get home and the replacements aren't charged? That's why we chose 3C to charge.
I know the instant response is that we are using some ultra high quality medical grade battery cells or that we are using lithium but not lipo. Not true. There's no point in spending all that time and money in battery development when something already exists that does what you need it to. We merely tested several manufacturers cells until we found the best for our needs. Anyone can buy those cells . They are Samsung 16650's. That's it. That's the big secret. Off the shelf components. They are packaged for us by Inspired Energy with a digital meter, the plug we need, and the case size we require but the cells themselves are off the shelf lipos. They are highly durable. Lives literally depend on them.
12-20-2018, 09:30 AM
#131
Some people think that we aren't using lipo's so it's not valid. We only use lipo's. We used to use NIMH. We tested 100 batteries over a year and a half period so we know what happens and what doesn't with charge rates and capacities. I trust our data more than I trust people that merely say how long something lasted for them. Without a frame of reference and large sample size, that's not very useful information. The fact that we don't have a high amp draw means that we don't have any useful test information as to how battery life is affected by higher current draws but it would stand to reason that a faster discharge rate would be a detriment to life as a faster charge rate is.
12-20-2018, 03:17 PM
#132
Random Fun Fact: Did you know you could use an Amps/Volts/Ohms/Watts calculator to determine an actual maximum horsepower rating for a battery?
Once you have determined a LiPos TRUE continuous amperage rating, you have the information you need. Plug the true amperage and full-charged voltage of the pack into the calulator and you will get your wattage. Covert the wattage to Horsepower and wala!
The 149 Amp 7400mAH SMC LiPo in 4S is a 2.96 continuous British Horsepower battery!
Once you have determined a LiPos TRUE continuous amperage rating, you have the information you need. Plug the true amperage and full-charged voltage of the pack into the calulator and you will get your wattage. Covert the wattage to Horsepower and wala!
The 149 Amp 7400mAH SMC LiPo in 4S is a 2.96 continuous British Horsepower battery!
Doing it as you say: 149 amps times 16.8V is 2503 watts. 2503 divided by 745.7 is 3.357
1 British HP = 745.7 watts
https://www.sizes.com/units/horsepower_british.htm
https://www.quora.com/What-is-the-di...ake-horsepower
12-20-2018, 03:27 PM
#133
Assuming that was correct in principle (which it is not) the number you mention is doesn't come out of the calculation you describe.
Doing it as you say: 149 amps times 16.8V is 2503 watts. 2503 divided by 745.7 is 3.357
1 British HP = 745.7 watts
https://www.sizes.com/units/horsepower_british.htm
https://www.quora.com/What-is-the-di...ake-horsepower
Doing it as you say: 149 amps times 16.8V is 2503 watts. 2503 divided by 745.7 is 3.357
1 British HP = 745.7 watts
https://www.sizes.com/units/horsepower_british.htm
https://www.quora.com/What-is-the-di...ake-horsepower
12-21-2018, 06:23 AM
#135
Nope. They won't. It'll fall. Don't nitpick. No one pulls that much current for that long anyways. Anything less than an XT150 connector would unsolder itself with that load for that time by then anyways.