why are lipos rated the way they are
#16
Eric , i have to put ya on the spot .
what is the best way to test packs to find out 2 things :
1)instant current flow? (like on the start of a race, high amperage demand )
2) how long it can handle said amps ?(which im thinking would show quality of the cells)
i would think a adjustable dummy load and a volt meter.
what is the best way to test packs to find out 2 things :
1)instant current flow? (like on the start of a race, high amperage demand )
2) how long it can handle said amps ?(which im thinking would show quality of the cells)
i would think a adjustable dummy load and a volt meter.
#17
There are a lot more than just two battery manufactures. And within each manufacture you can get different "grades" of cells in your packs. Some choose the cheaper cells to make more $$ and some use the higher grade cells for better performing packs. Just all up to how much each company wants to spend on their packs.
EA
EA
#18
Tech Elite
iTrader: (1)
#19
#21
Team EAM
iTrader: (79)
Eric , i have to put ya on the spot .
what is the best way to test packs to find out 2 things :
1)instant current flow? (like on the start of a race, high amperage demand )
2) how long it can handle said amps ?(which im thinking would show quality of the cells)
i would think a adjustable dummy load and a volt meter.
what is the best way to test packs to find out 2 things :
1)instant current flow? (like on the start of a race, high amperage demand )
2) how long it can handle said amps ?(which im thinking would show quality of the cells)
i would think a adjustable dummy load and a volt meter.
I've seen mod oval cars able to dump a 7000 1s pack in 3 minutes. Do that math and you'll see some serious amp draw numbers.
Numbers are irrelevant anyway. What maters is what's fast on the track first.
EA
#22
There are a lot more than just two battery manufactures. And within each manufacture you can get different "grades" of cells in your packs. Some choose the cheaper cells to make more $$ and some use the higher grade cells for better performing packs. Just all up to how much each company wants to spend on their packs.
EA
EA
out the good lower IR cells to sell as brand X.
Is this true??
#24
The only way to test c rating is to destroy the pack. No other way. But you can put a data logger in a tc or any other car and watch the amp draw spikes and see that mod cars on high load will pull 70+ amps.
I've seen mod oval cars able to dump a 7000 1s pack in 3 minutes. Do that math and you'll see some serious amp draw numbers.
Numbers are irrelevant anyway. What maters is what's fast on the track first.
EA
I've seen mod oval cars able to dump a 7000 1s pack in 3 minutes. Do that math and you'll see some serious amp draw numbers.
Numbers are irrelevant anyway. What maters is what's fast on the track first.
EA
Draw spikes are one things, continuous current is another. How long is that spike? 1/100 second? 1/1000 s? You need to quantify it somehow.
I challenge you to show us a data log from those cars that allegedly dumped a pack in 3 minutes.
#25
Team EAM
iTrader: (79)
I did, and I haven't seen more than 50A continuously (for less than five seconds).
Draw spikes are one things, continuous current is another. How long is that spike? 1/100 second? 1/1000 s? You need to quantify it somehow.
I challenge you to show us a data log from those cars that allegedly dumped a pack in 3 minutes.
Draw spikes are one things, continuous current is another. How long is that spike? 1/100 second? 1/1000 s? You need to quantify it somehow.
I challenge you to show us a data log from those cars that allegedly dumped a pack in 3 minutes.
I dont have to show a data log of it. I witnessed at the Snowbirds last year. Also saw several melt the bullet connectors off of the speedo wires from the current draw as well.
Anyone here thats good at math figure up what amp draw it takes to dump a 7000mah battery pack in 180 seconds.
EA
#26
Team EAM
iTrader: (79)
I have a chassis dyno here for Oval racing that helps tune motors. On it using 3.8V as supply voltage to the dyno during a dyno run a 13.5 Open motor will pull around 40 amps (Constant no a spike or peak) when setup properly. So go to a 3.5 motor and the amp draw ill increase drastically.
Every oval racer usually has a chassis dyno to get motors to repeat a 4 minute run on the track and tune them to run better. Most also use what they call free rev amp draw to start with. Usually its around 20 amps free rev (No load).
Just FWIW
EA
Every oval racer usually has a chassis dyno to get motors to repeat a 4 minute run on the track and tune them to run better. Most also use what they call free rev amp draw to start with. Usually its around 20 amps free rev (No load).
Just FWIW
EA
#27
Why all the confusion guys??? Just get Thunderpower, and call it a day....ok.... Also if these oval guys were dumping 7000mah packs in three minutes, then either the packs were not really 7000mah or their setups were too power hungry, and generated too much heat....
I dont have to quantify anything to anyone. If you want to know ask several of the top Oval racers in the country that did it at the Snowbirds.
I dont have to show a data log of it. I witnessed at the Snowbirds last year. Also saw several melt the bullet connectors off of the speedo wires from the current draw as well.
Anyone here thats good at math figure up what amp draw it takes to dump a 7000mah battery pack in 180 seconds.
EA
I dont have to show a data log of it. I witnessed at the Snowbirds last year. Also saw several melt the bullet connectors off of the speedo wires from the current draw as well.
Anyone here thats good at math figure up what amp draw it takes to dump a 7000mah battery pack in 180 seconds.
EA
#28
Tech Champion
iTrader: (17)
Why all the confusion guys??? Just get Thunderpower, and call it a day....ok.... Also if these oval guys were dumping 7000mah packs in three minutes, then either the packs were not really 7000mah or their setups were too power hungry, and generated too much heat....
As far as buy one battery brand and call it a day, why? I know a guy who designs battery specs for Johnson controls and not into RC at all. He sends his specs out to multiple mfgs for bids. He has to. Every generation of battery that comes out is an improvement on the last. The key is to find good batteries and keep the best for racing packs. Maybe just approach Kokam with your specs and have a battery of your own.
#29
Running offroad i can agree thunderpower is probably the best to use . They can be banged around and not cared for (as much) and hardly ever give any issues with puffing or build quality . But when it comes to onroad SPEC racing their are other companies that will outpreform them if cared for properly
#30
Tech Champion
I did, and I haven't seen more than 50A continuously (for less than five seconds).
Draw spikes are one things, continuous current is another. How long is that spike? 1/100 second? 1/1000 s? You need to quantify it somehow.
I challenge you to show us a data log from those cars that allegedly dumped a pack in 3 minutes.
Draw spikes are one things, continuous current is another. How long is that spike? 1/100 second? 1/1000 s? You need to quantify it somehow.
I challenge you to show us a data log from those cars that allegedly dumped a pack in 3 minutes.
C rating is a very common and very useful rating method for batteries overall, has been for a long time and will continue to be. Relatively new to RC is all.