Cheap vs Expensive Lipos
08-11-2008, 01:16 PM
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Cheap vs Expensive Lipos
If someone who has experience with both in the same vehicle could please post-
Is the performance of an expensive Lipo worth the 2x price? For Bashing? I am not a competative racer and do not need to squeeze every bit of performance out.
I have a Slash and and 2 Losi DT (between a few of us! not just me!). Have one set-up with velineon, and probably going to buy a second velineon or a sidewinder for brushless.
How do you select a Proper Lipo? My understanding is that you should select a 4000mah or more, and have at leaset 80amp continuous rating.
How do I know how many amps I am drawing? Do I need watt meter? Does the manual CORRECTLY state expected amp draw? I realize with stupid gearing or doing things the manual states not to do (running in tall grass/pulling/pushing stuff, etc), you will draw more amps. But if you are running around on pavement and dirt, what kind of amp draw should I expect so I can properly select a LIPO?
thanks
Is the performance of an expensive Lipo worth the 2x price? For Bashing? I am not a competative racer and do not need to squeeze every bit of performance out.
I have a Slash and and 2 Losi DT (between a few of us! not just me!). Have one set-up with velineon, and probably going to buy a second velineon or a sidewinder for brushless.
How do you select a Proper Lipo? My understanding is that you should select a 4000mah or more, and have at leaset 80amp continuous rating.
How do I know how many amps I am drawing? Do I need watt meter? Does the manual CORRECTLY state expected amp draw? I realize with stupid gearing or doing things the manual states not to do (running in tall grass/pulling/pushing stuff, etc), you will draw more amps. But if you are running around on pavement and dirt, what kind of amp draw should I expect so I can properly select a LIPO?
thanks
08-11-2008, 03:34 PM
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RE: Cheap vs Expensive Lipos
I'll try to find a couple of graphs that are overlaid (one cheapo and one decent) , but since you are operating at close to the max current of the battery then Yes, it will be noticeable. I generally use the biggest one that will fit in chassis and then shop for that size.
Someone can probably list the max current of the velineon in a slash or DT. Many of the ratings on batteries need to be cut in half to be realistic.
For starters if you know the length of your fastest run and the cpacity used it weill tell us the average current draw.
Someone can probably list the max current of the velineon in a slash or DT. Many of the ratings on batteries need to be cut in half to be realistic.
For starters if you know the length of your fastest run and the cpacity used it weill tell us the average current draw.
08-11-2008, 03:46 PM
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RE: Cheap vs Expensive Lipos
From my experience of lipos (mostly from RC helis) the cheaper lipos are matched as well and usually have highly inflated C ratings. Since the amps the battery can put out is = C rating x Capacity, you can see how a low C rating will affect the battery and the entire system.
08-11-2008, 04:02 PM
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RE: Cheap vs Expensive Lipos
The green is an old used one I bought and is the best one for voltage , yet the lowest capacity.
The black is a 20 C maxamps HV that I bought new and I don't rubn it over 10C.
The red is a generic rc smart e-bay pack that has the most capacity , but isn't even what I consider a good 10C battery.
All these are pulled at 10 amps which is quite low , but may illustrate the diffwerence between quality of packs. I use them all regularly.
The black is a 20 C maxamps HV that I bought new and I don't rubn it over 10C.
The red is a generic rc smart e-bay pack that has the most capacity , but isn't even what I consider a good 10C battery.
All these are pulled at 10 amps which is quite low , but may illustrate the diffwerence between quality of packs. I use them all regularly.
08-11-2008, 04:08 PM
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RE: Cheap vs Expensive Lipos
I guess the advise is to use the best you can get until you are very sure of the actual limits of the system AND battery.
A case in point is my Rusty just qwent to the el-cheapo chinese 3Sx3900 rc smart battery that I got a deal on and although it isn't the best neck snapping performance of some better batts, it suits the vehicle perfect since it made the acceleration just a tad soggy as to control traction and wheelies better. Once the vehicle is up to speed it is unloaded to a point where absolute top speed isn't compromised with the gearing I have.
If you are racing or top speed running then the advise is also go for the best most that'll fit in the chassis.
A case in point is my Rusty just qwent to the el-cheapo chinese 3Sx3900 rc smart battery that I got a deal on and although it isn't the best neck snapping performance of some better batts, it suits the vehicle perfect since it made the acceleration just a tad soggy as to control traction and wheelies better. Once the vehicle is up to speed it is unloaded to a point where absolute top speed isn't compromised with the gearing I have.
If you are racing or top speed running then the advise is also go for the best most that'll fit in the chassis.
08-11-2008, 04:34 PM
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RE: Cheap vs Expensive Lipos
Thanks for the help guys.
by length, do you mean distance or time?
Traxxas Velineon system
Regarding motor capabilities- it states-65A continuos, 100A burst
ESC- literature states 200A cont/ 320A burst
I have a Zippy Lipo, 2S 4150MAH rated at 20C, so supposedly it has apx 80A continuous capability?
guver, are those graphs taken from a sophisticated charger? Also, the graphs are done at 10A? I'm guessing the only way to tell whats really going on in the model is to use a watt meter?
I'm think of getting a cellpro 10s, or bantam, in that class. I think those chargers have PC interfaces- can they produce the graphs you have produced? I have a ripmax prodigy 2, non-balancing charger, but i noticed it has lipo discahrge ability- though i never knew what it was for. I wonder if the ripmax can produce the same data as you are showing?
ORIGINAL: guver
For starters if you know the length of your fastest run and the cpacity used it weill tell us the average current draw.
For starters if you know the length of your fastest run and the cpacity used it weill tell us the average current draw.
Traxxas Velineon system
Regarding motor capabilities- it states-65A continuos, 100A burst
ESC- literature states 200A cont/ 320A burst
I have a Zippy Lipo, 2S 4150MAH rated at 20C, so supposedly it has apx 80A continuous capability?
guver, are those graphs taken from a sophisticated charger? Also, the graphs are done at 10A? I'm guessing the only way to tell whats really going on in the model is to use a watt meter?
I'm think of getting a cellpro 10s, or bantam, in that class. I think those chargers have PC interfaces- can they produce the graphs you have produced? I have a ripmax prodigy 2, non-balancing charger, but i noticed it has lipo discahrge ability- though i never knew what it was for. I wonder if the ripmax can produce the same data as you are showing?
08-11-2008, 05:10 PM
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RE: Cheap vs Expensive Lipos
sorry, Time. If it's 20 minutes then it is averaging 3C , if it's 6 minutes then it is 10 C average.
The figures you listed are all "max" values and the motor/esc numbers can be trusted. The battery pack , well I don't know. The graphs are produced with a CBA battery tester.
I think the battery would do fine in the slash or DT.
It is exactly as you stated i your first post about grass, pulling/pushing, ect. and the only way to tell exactly is to use the data logger/watt-meter. I'm not sure if the chargers can produce a graph with discharge load.
The figures you listed are all "max" values and the motor/esc numbers can be trusted. The battery pack , well I don't know. The graphs are produced with a CBA battery tester.
I think the battery would do fine in the slash or DT.
It is exactly as you stated i your first post about grass, pulling/pushing, ect. and the only way to tell exactly is to use the data logger/watt-meter. I'm not sure if the chargers can produce a graph with discharge load.
