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› Can you discharge parallel connected lipos @ HIGHER DISCHARGE RATE?
01-12-2009 04:57 PM  9 years agoPost 1
iskoos

rrKey Veteran

Orlando, FL

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If you have two identical lipo packs, can you discharge them(without damaging the packs) faster if connected parallel?

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01-12-2009 05:54 PM  9 years agoPost 2
Pistol Pete

rrProfessor

Seffner, FL

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no...it will actually take twice as long since you doubled the amperage.

but THE fastest way is to actually fly them.

Why would you want to discharge them to begin with?

Storage? Just set ESC cut off to a higher voltage like 3.8 cut off per cell.

~~Enjoying the hobby one flight at a time~~

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01-12-2009 08:40 PM  9 years agoPost 3
iskoos

rrKey Veteran

Orlando, FL

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misundestanding...
I meant "Can you discharge at higher discharge rate"

It is correct that parallel connection would double up the total capacity. Since packs are rated as 10C, 15C, 20C etc. doubling the capacity makes it look like you can discharge the pack at higher discharge rate. But this is just math, it doesn't make much sense when you think about it.

And also when I said "Discharge", I didn't mean discharge through the charger. I meant discharge by using it on a model.

This is what got stuck in my mind:

A pack 3s 2000mah rated at 10C(say for continuous discharge) is safe when discharging up to 10x2=20amp.

If you take two of these packs and paralle them, you have now 3s 4000mah pack. At 10C discharge rate, you get 10x4=40amp.
Does that mean you can disharge the pack safely at higher(twice as much) rate safely?

Calculations show that way(unless I am making a mistake) but it really doesn't make much sense...

Am I clear now?

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01-12-2009 08:56 PM  9 years agoPost 4
QuantumPSI

rrElite Veteran

Atlanta, GA

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Yes, you can!

...now where was I, dh/dt = BS-dx/dt
I will fly you forever... till earth do us part

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01-12-2009 09:50 PM  9 years agoPost 5
iskoos

rrKey Veteran

Orlando, FL

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Himmm... Then the conclusion would be:
Connecting packs parallel not only does it increase the total capacity but also increases the safe discharge rate making it easy on the packs...

If anyone does not agree with this, please chime in (with the reasoning)

Thanks

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01-12-2009 10:37 PM  9 years agoPost 6
QuantumPSI

rrElite Veteran

Atlanta, GA

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Yes, if you're pulling the same current on two packs as you would with one, then yes it is easier on the packs. However, if you're pulling the max discharge rate for both packs, you're flying them just as hard. Lemme be clear...

If you have 1 pack, 2000mah 10C, that's 20amps. However putting another in parallel would give you 4000mah 10c, and max is 40amps. In either case you're pulling on each pack at their max ability.

...now where was I, dh/dt = BS-dx/dt
I will fly you forever... till earth do us part

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01-12-2009 10:48 PM  9 years agoPost 7
iskoos

rrKey Veteran

Orlando, FL

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Yes. My question was assuming the same load when packs connected in parallel. So it would make it easier on the packs.

But if I also increased the load (where I start pulling twice as much current for example), then it would be the same think as running a single pack at half discharge rate. So the only difference would be doubling the flight time...

It is good then what I was thinking is correct...

Thanks...

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01-12-2009 11:04 PM  9 years agoPost 8
QuantumPSI

rrElite Veteran

Atlanta, GA

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Yup no problem!

...now where was I, dh/dt = BS-dx/dt
I will fly you forever... till earth do us part

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01-13-2009 01:08 AM  9 years agoPost 9
HeliCSR

rrApprentice

Hesperia, Ca, US

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YES.

2 5000ma packs would be 10,000ma discharge.

I fly and then I fly some more.
If it don't glitch then I won't crash.

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01-13-2009 03:07 AM  9 years agoPost 10
iskoos

rrKey Veteran

Orlando, FL

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YES.

2 5000ma packs would be 10,000ma discharge.
Thanks HeliCSR but that wasn't the actual question... I got my answer though...

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