11.1v to 14.8v system - different mah?

[704Authentic]

I have two 4000mah 3s 25c & two 2200mah 3s 40c lipos. Would like to run an extra one cell
battery in a series to get to 14.8v. Really hard to find a 1s battery that matches those. I suppose the "c" should match, but does the mah have to match or how close does it need to be? Not to concerned about run times, but don't want to hurt anything.

I'll be using this in a Aquacraft Wildcat EP with a Leopard 3650 2450kv, Proboat 60amp esc and a 1.6X2.6 s.s. prop.

In a perfect world, someone say they have some 1s, they have no use for :)




Mystic 29

[devo]

As far as I have seen running different batteries at the same time causes the proboat 60 esc to release the magic smoke. If you want to run 4s run 2 of the same batteries in series, and if you want to run 5s run 5s batteris, not a 3s and 2s in series, you are asking for trouble if you do this. Others may have different opinions but I've seen it 1st hand, unmatched batteries will cause your esc to pull harder on one battery than the other causing failure.

[Chilli]

The C rating and mAh capacity together give you the amperage output of a pack. If the output of all the cells are not the same, bad things can happen. Play it safe and get matched packs.

[704Authentic]

Is there a problem running a 3cell battery with a 1cell battery in a series to get to 14.8v, as Devo suggests.

Where are all the "senior witty" guys when you need 'em? :)

Thanks,

[lenny]

No,
But they need to be all the same kind and all the same C rating and all the same Mah.

[704Authentic]

When you say "kind" you don't mean the same brand do you? Or do you? Cause, I found a 1s, SMC battery, same C & Mah.
The other battery is a Rhino. Will that work?

Thanks,

[lenny]

Yes brand,
Everything the same,
They all have to be the same !
Except the volts can be different to make what you want to run on.

[devo]

The problem with the whole set up your trying to do is that when you put different batteries Together the speed control is going to pull harder on one battery then another calling all kinds of issues, I'm just trying to warn you because I've seen my friends try it and it's always wound up with something blowing up. Like I said before other people may have different opinions but I have seen it short out two proboat 60 esc's

[stadiumyamaha]

The problem isn't your batteries, it's the motor your using.
The kv is too low to run fast on 3s and too high for 4s.

[704Authentic]

I think you maybe on to something: What kv would you suggest on 3s?
On 4s?

Wildcat EP

[stadiumyamaha]

I think if it was me I'd put a ul1 motor in it and run on a single 4s battery much like diegoboy did with his mini impulse. It's a 2030kv.
You could try the motor you have but I'd run a small prop.

[stadiumyamaha]

You would need something like a 3000kv motor to go good on 3s.

[704Authentic]

What do you consider "small"?
Is the Stilleto 1.6x2.6 prop small? ...why small, anyways?

You do know it's not the mini - it's around 26.

Thanks,

[siberianhusky]

As long as everything about the batteries is EXACTLY the same with the exception of cell count there is no problem what so ever.
Pile of bunk claiming that the esc will draw more from one battery than the other, unless they are different C, capacity or brand that may have different internal resistance.
The esc would see a 2s and 3s pack in series just the same as if the cells were assembled into a 5s pack for example.
I'd go as far as to make sure the batteries are the same age with the same number of cycles. As we know lipos do age, running a 2 year old battery with many cycles with a brand new pack can cause issues as with age the internal chemistry undergoes some changes. Thats why eventually they die.

[stadiumyamaha]

http://forums.offshoreelectrics.com/...ad.php?t=38783

Check out this thread. Not the same boat but the set up should work for your boat. Runs nice.