Is 7.4v 20c/3000mah reciver battery enough for Airsoft?

[ScooterVauto]

Just to make sure i dont burn my house down..
the pack in question has 2 red and 2 black.
the question is each "pack" is 2 x 3.7v lipos thus 4x 3.7
the packs are currently wired as 2x 7.4 (with 1 red and 1 black each)

when i wire it for use I'll want to basically combie the 2 red together
and the 2 blacks together which should give 7.4 @ 3000
correct?

if i wire them with 1 pack red to the other Black the outcome would be
14.8 @ 1500

now taht said it all depends on how the balancer is wired.
a 7.4 has 3 wires but a 14 has 5.

My charger uses the balancer to read the voltages and charges through the main power connector.

so I wonder if the balancer connector is going to be the crutch

[Kos-Mos]

NO.

Just use the leads marked as "DISCHARGE"

And charge through the balance port.

The packs are internally wired, you cannot decide what cells you want to use (except through the balance plug, but that is sub 1A usually)

[ScooterVauto]

Ive never understood how a lipo charges through the balancer,
forinstance, the TGH batteries state a 3 to 5 C charge rate.
on a 3000 mah battery its a 9amp charge.
how do the tiny little balancer wires hand 9amp of charging power?

also please define the No.
no i dont want to combine the 2 red and the 2 black wires (obviously in pairs not ALL together LOL)

no the balancer wont be a problem?

[XZIVR]

Yes, combine both of the leads. I don't think Kos-Mos is looking at the battery very hard. This is a reciever battery, which has TWO SETS of discharge leads. Typical thing to see on a reciever pack. Yes, both sets of discharge leads are soldered to the same place and yes by replacing the wiring, you are effectively combining them.

Here's a quick sketch of how the battery is wired inside. There's no way to wire it to get 14.8v unless you desoldered all the cells and stacked them in series.

Originally Posted by Kos-Mos

I will let you read that again...

Parallel = current doubles.
Serial = voltage doubles.

The "C" rating is a direct measure of the maximum current a pack can give.
In this case, the combined two packs are 20C, each pack will only give half of that maximum current. Otherwise they would mark the pack 40C since it would be better for marketing purpose. But it's not safe to run the pack at 40C...

Ugh. Let me try to take you through the math. Each cell is 1500mah. There are four cells. Take two cells and put them in parallel and you have 1s2p. Put that group of cells in series with a second group and you have 2s2p. With me so far?

Hope so. Now, if one cell has 1500mah and a 20C discharge rate, 1.5 amps x 20 = 30 amps. So each cell can pass current at 30 amps. Now let's put that beside another cell (ie in parallel). Now you have two cells that can each drop 30 amps. What's 30 + 30? 60? Correct. The two cells together can drop 60 amps. Now let's look at the battery as a whole, it's 3000mah 20c what's 3 amps x 20? 60? The same? holy fuck I think we're on to something!

I think you understand the general idea but the part you keep forgetting is that each cell is NOT 3000 mah, it's 1500mah. The two cells TOGETHER add up to 3000. That's WHY you make a pack like this. If each cell were 3000mah 10c as you seem to think, then they would be advertising the battery as 6000mah, not 3000. Understand now?

[ThunderCactus]

Its like $10 for a new, proper lipo. Just buy the correct battery before you set something on fire lol
And for shits, since its a 2s2p, would you have to charge it as a 4s battery?

[blackjack21]

Well first off I asked in this thread if this was a good battery, was told it was and ordered 2 of them. Second these are the ones that fit my gun. Third, hobby king still instists the pack is fine for my gun.

Scooter when I get the batteries in I will turn them over to you for a rewire, depending on cost.

[XZIVR]

Originally Posted by ThunderCactus

since its a 2s2p,

No, you charge it as a 2s. It could be configured as a 2s99942143984389324743p battery and you would still charge it as a 2s.



This might help some people too.. http://www.rchelicopterfun.com/rc-lipo-batteries.html

[ThunderCactus]

So as I understand it, you're balancing 2 parallel cells as one cell.
Then isn't it possible for those cells to be unbalanced between eachother?
I'm not understanding how it distinguishes between those 2 cells on the one balancing port

Like on parallel pack chargers, it uses a common main charging line for all the packs, but keeps all the cells separate. So 4 2s packs would be treated as an 8s battery.
But a parallel pack puts 2 cells on one port, so it charges a 4s like a 2s?
Unless there's some other science at work that seems incredibly dangerous...

[Kos-Mos]

Originally Posted by XZIVR

Yes, combine both of the leads. I don't think Kos-Mos is looking at the battery very hard. This is a reciever battery, which has TWO SETS of discharge leads. Typical thing to see on a reciever pack. Yes, both sets of discharge leads are soldered to the same place and yes by replacing the wiring, you are effectively combining them.

Here's a quick sketch of how the battery is wired inside. There's no way to wire it to get 14.8v unless you desoldered all the cells and stacked them in series.






Ugh. Let me try to take you through the math. Each cell is 1500mah. There are four cells. Take two cells and put them in parallel and you have 1s2p. Put that group of cells in series with a second group and you have 2s2p. With me so far?

Hope so. Now, if one cell has 1500mah and a 20C discharge rate, 1.5 amps x 20 = 30 amps. So each cell can pass current at 30 amps. Now let's put that beside another cell (ie in parallel). Now you have two cells that can each drop 30 amps. What's 30 + 30? 60? Correct. The two cells together can drop 60 amps. Now let's look at the battery as a whole, it's 3000mah 20c what's 3 amps x 20? 60? The same? holy fuck I think we're on to something!

I think you understand the general idea but the part you keep forgetting is that each cell is NOT 3000 mah, it's 1500mah. The two cells TOGETHER add up to 3000. That's WHY you make a pack like this. If each cell were 3000mah 10c as you seem to think, then they would be advertising the battery as 6000mah, not 3000. Understand now?

Yeah, had my math mixed up a bit.
However, that pack is still not suited for anything over 10A.
Read the reviews and forums about them. The Turnigy Nanotech are great!, however not when in 2p setups. They not only use smaller cells, but cheaper apparently (similar to their B-Grade series).

I have bought a LOT of LiPos from Hobbyking, around 50-60 as of now.
The packs that are parallel wired are known to be over-rated. I had two bloat on me (receiver packs that is), and one explode.

Their "main" batteries are really good though. Won't last 200-300 cycles, but they are cheap and deliver while they are fresh. That is the packs that use Xs1p setups.

Most receiver pack I bought have a diode and short circuit protection on the "Discharge" leads, to prevent failure in case of a faulty servo. If it is the case with theses packs, it means that connecting both leads will trigger the circuit and might just blow the pack. Unless you remove the shrink to make the changes, I would advise against jumping both leads.