Running your Lipos in series or parallel?

[Blackjack-sven]

I dont think you double your "C" rating. I think you double your Mah. When in parallel

CORRECT

[Jesse J]

I like A + B. Series then parallel, or vice versa. Find the voltage you want (that won't make no smoke), then put that much voltage in series and you have fast for a long time.

When your capacity doubles, so does your C rating as you have twice the amperage so by definition you have twice the C rating. Its like two fire hoses, speed of water stream being voltage and diameter of hose being amperage, double the cross sectional area and you have twice the volume.

[line6]

No the c doesnt change the mah does. The way you are saying is they both double. That would mean you have 4 times the max amp rating that is wrong. Look up it was said how it works

[Jesse J]

Fine, you are right. C rating is an inherent quality of each pack.

1 pack with 5000mAh 20C battery is good for 1000A (20 x 5000mA/1000). (edited to correct math)
2 packs with total of 10000 mah are good for 2000A (20 x 10000ma/1000).

Don't want to spread incorrect information, thanks Line6 for keeping thing right.

[Rusty_Noob]

The C rating wouldn't double but because the capacity doubles you can pull the same C rating thus doubling the amps availible, in parallel.

For example we'll pretend we have two 7.4v 5000mah 20c batteries to give us an easy to work out 100amp constant for each battery running in series to give us a 14.8v 5000mah 20c.

If you're running series and your ESC is drawing 100amps of power you will have to pull the 100 amps from each battery as each one is giving 7.4v at full power.

If you ran the same batteries in parallel you would have a 7.4v 10000mah 20c battery meaning you can deliver 7.4v at 200amps.

If you're running parallel and your ESC is drawing 100amps of power you will have to pull 50 amps from each battery as each one is giving 7.4v but because they are working together they can share the amp load.

In other terms 2x 7.4v 5000mah 20c batteries in Series = 14.8v 5000mah with 100amp max load
2x 7.4v 5000mah 20c batteries in parallel = 7.4v 10000mah with 200amp max load

What I want for my boat is 2x 14.8v 5000mah 20c batteries running in parallel for 14.8v with10000mah and 200amp max load.

[Chilli]

Your C rating of your set up does double if you run parallel as does battery capacity. In a high amp set ups, one of the benefits of running parallel packs is you cut the amp draw of each pack in half. This lessens the stress on batteries packs and the chance of the dreaded ripple current that can distroy your ESC.

C rating has to do how fast you can suck energy out of the battery, mAh is about how much energy you have to suck out. If you run one 5000 30c battery, you can draw 150 amps, If you run two in parallel, you can draw 300 amps.

[Rusty_Noob]

Your C rating does double if you run parallel. In a high amp set ups, one of the benefits of running parallel packs is you cut the amp draw of each pack in half. This lessens the stress on batteries packs and the chance of the dreaded ripple current that can distroy your ESC.

C rating has to do how fast you can suck energy out of the battery, mAh is about how much energy you have to suck out.

Your C rating stays the same, but because the capacity has doubled it essentially is doubling the C rating.

If you take my example of a 5000mah 20c (100amp) battery and use your logic/post above, you are saying the C rating doubles in parallel, therefore you are saying the battery is a 10000mah 40c battery, which it isn't, as it would then be able to deliver 400amps.

If the C rating stays the same it works out as a 10000mah 20c battery which can deliver 200amps.

[Jesse J]

I have switched sides of the C rate change debate. I remain on the "it don't change" side. How can you increase the rate at which you can remove energy from a battery simply by the configuration? Good point, in parallel you draw half as much from each battery, thus being easier on your batts. I am now even more convinced and am glad I was corrected that C rating does not/cannot change with any configuration.

Please provide documentation/data that states otherwise.

[Jeff Wohlt]

If your packs can pull 40 amps each and you para them then they can pull 80 amps. (but you do not want to do this) I would never pull more than 75% amp rating on any pack.

You should not buy cheap 10C cells and put 4 togther thinking you can pull craploads of amps thru them. Remember, some cells have CHEAP tabs and soldering and small wires....you will fry them anyway.

Rusty is correct.

[Rusty_Noob]

If your packs can pull 40 amps each and you para them then they can pull 80 amps

Just to clarify, they can pull 80 combined, not 80 each.

[Jesse J]

Yep, just double, not quadruple. I think we are arriving on a consensus. Combining increases the amount that can be drawn thus giving the extra margin for high draw motors or providing extended run times.

[Jeff Wohlt]

That is correct...in para makes the pack for total...not each pack then.

It is very simple guys.

[Chilli]

I think we all got hung up over "C" terminology. It's all good.

[Jeff Wohlt]

I think you are right. C rating is the right term for any cell. This goes for charging as well.

[Jesse J]

That is correct...in para makes the pack for total...not each pack then.

It is very simple guys.

Just like anything, its simple once you understand it!