Technical Lipo Q's.....Mamba
12-23-2005, 10:22 AM
#1
Technical Lipo Q's.....Mamba
I just got a 6800 Mamba brushless and I am looking to buy some 7.2v lipo batteries for it.
Does anyone know what kind of discharge rates I should be looking for? There are several batteries with 12C continous to 16c burst discharge rates and some pretty expensive liops with 16C cont. with 20C burst.
Do I need that kind of discharge for my mamba? Part of me says "oh yeah baby, bring the power" The other part says "yeah right, like you could control that" LOl
Any help is really appreciated!!!
Does anyone know what kind of discharge rates I should be looking for? There are several batteries with 12C continous to 16c burst discharge rates and some pretty expensive liops with 16C cont. with 20C burst.
Do I need that kind of discharge for my mamba? Part of me says "oh yeah baby, bring the power" The other part says "yeah right, like you could control that" LOl
Any help is really appreciated!!!
12-23-2005, 12:36 PM
#2
You have to look at the discharge rate AND the capacity.
Example - a 500mAh Lipo at 10C constant discharge can only give 5A - not enough for the Mamba.
BUT a 2000mAh Lipo at 10C will give 20A - plenty.
Look for 15-20A continuous as a current from your Lipos, I believe "Apogee" are the packs used by Castle Creations themselves - perhaps contact them to find the exact cells they prefer.
Example - a 500mAh Lipo at 10C constant discharge can only give 5A - not enough for the Mamba.
BUT a 2000mAh Lipo at 10C will give 20A - plenty.
Look for 15-20A continuous as a current from your Lipos, I believe "Apogee" are the packs used by Castle Creations themselves - perhaps contact them to find the exact cells they prefer.
12-23-2005, 05:48 PM
#3
Lipoly packs don't come in 7.2 volts.
As far as which pack you should purchase. The "C" ratings only tell you how much power the battery can put out, not what they will put out. A 10C 1500 Mah lithium can put out 15 amps. However it will only put out as many amps as your power system draws. So if your power system draws only 10 amps, then puting in a 15 amp capable pack won't mean that it will put out 15 amps... only 10.
I typically don't like to draw more than 6 - 8C, that usually gives me run times (flight times) of 7 - 10 minutes. Any less than that and I'm usually left unsatisfied; any more than that and I get bored. Since most packs are now designed to be capable of delivering 10 - 20 C, almost any pack that will give you 10 minutes of runtime will be fine.
The biggest advantage of buying cells with a high discharge capability is that they hold their voltage under load better than simillar capacity, low discharge rate cells. They're also less likely to be damaged by sudden spikes in amp draw (like if you try to plow over a curb).
I prefer Kokam (FMA) packs myself. I like the way they're constructed. They solder the cell tabs to a PC board, giving a more robust pack thats less likely to be damaged. I can't stand Thunder Power packs because the tabs are soldered to the other cell's tabs, which creates a very weak point in the pack construction.
If I were in your place I would probably choose the Kokam 1250's in a 3 cell pack (11.1 volts). It can handle up to 18 amps, and the higher voltage will give you more speed/power; and when geared down a little will give you more runtime (along with more speed/power).
-Frank
As far as which pack you should purchase. The "C" ratings only tell you how much power the battery can put out, not what they will put out. A 10C 1500 Mah lithium can put out 15 amps. However it will only put out as many amps as your power system draws. So if your power system draws only 10 amps, then puting in a 15 amp capable pack won't mean that it will put out 15 amps... only 10.
I typically don't like to draw more than 6 - 8C, that usually gives me run times (flight times) of 7 - 10 minutes. Any less than that and I'm usually left unsatisfied; any more than that and I get bored. Since most packs are now designed to be capable of delivering 10 - 20 C, almost any pack that will give you 10 minutes of runtime will be fine.
The biggest advantage of buying cells with a high discharge capability is that they hold their voltage under load better than simillar capacity, low discharge rate cells. They're also less likely to be damaged by sudden spikes in amp draw (like if you try to plow over a curb).
I prefer Kokam (FMA) packs myself. I like the way they're constructed. They solder the cell tabs to a PC board, giving a more robust pack thats less likely to be damaged. I can't stand Thunder Power packs because the tabs are soldered to the other cell's tabs, which creates a very weak point in the pack construction.
If I were in your place I would probably choose the Kokam 1250's in a 3 cell pack (11.1 volts). It can handle up to 18 amps, and the higher voltage will give you more speed/power; and when geared down a little will give you more runtime (along with more speed/power).
-Frank
07-13-2009, 04:30 PM
#5
Hmmm... lately old threads are being dug up on all the message boards I post to...
I prefer 3 cells for a number of reason. A) I already use a lot of 3 cell packs in planes, so they can be used for multiple applications. B) A high-voltage/low amp system is more efficient than a low-voltage/high-amp system. C) More power is almost always a good thing.
You can always gear down if it's too much power for you.
-Frank
I prefer 3 cells for a number of reason. A) I already use a lot of 3 cell packs in planes, so they can be used for multiple applications. B) A high-voltage/low amp system is more efficient than a low-voltage/high-amp system. C) More power is almost always a good thing.
You can always gear down if it's too much power for you.
-Frank
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