help on mono setup

[zattan22]

hi,

i got a 65cm mono
current set up:
125A esc
540 size B3660 KV2726 with water cooler
D48mm prop
6S A123

after running 6mins of around 70-80km/h non-stop one cell of the battery blowed..

is my set up wrong??
thanks for any information.

[Mel279]

Its no suprise your battery blows up, your setup is pretty hot

with that motor u should use smaller prop max 40mm and 4s lipo

hope it help

[Adrianli]

Wow, urs is a hot setup meant for SAW runs only, one or two passes only.

For sport running, run it at 3S or 4S lipo and prop it to max 40-42mm.


I also have a 25" DF mono and using Feigao 9L 2700kv motor. Running her on two parallel packs of 3S1P 2200mah lipo and X637 prop. She clock ard 30mph(ard 48km/h) and can run for 5-6mins non-stop. Max amp draw is only 60amps. I am using a HXT 80amp ESC only.

[Adrianli]

Lets do the maths :

6S A123 : 6 x 3.3v = 19.8v

2726kv x 19.8v = 53,974.8rpm !!!

For sport running boats, keep rpm within 25,000 - 30,000rpm. For SAW running, rpm is within 45,000 - 50,000rpm with one or two passes only.


Also do note that A123 cells max continuous discharge is only 70A. In boating, most of the time its full throttle down the straights.

Nominal voltage: 3.3V
Nominal capacity: 2.3Ah
Core cell weight: 70 grams
Internal impedance: (1kHz AC) 8 mΩ typical
Typical fast charge current: 10A to 3.6V CCCV
70A continuous discharge
120A, 10 sec pulse discharge
Cycle life at 10C discharge, 100% DOD: over 1,000 cycles

http://www.a123systems.com/products

[zattan22]

i should use a lower KV motor??
but will i hit 70-80km/h?

[zattan22]

or how about using 2 * 3S 4400mah 25C lipo in series?

[Adrianli]

i should use a lower KV motor??
but will i hit 70-80km/h?

U can do a reverse calculation and get the required kv.

U want race running, sport running or SAW running boat???

[Adrianli]

or how about using 2 * 3S 4400mah 25C lipo in series?

Using tis for the current setup u have = smoking boat.

[zattan22]

For SAW running, rpm is within 45,000 - 50,000rpm with one or two passes only.

what is passes????

[zattan22]

and what is SAW???

[Adrianli]

For SAW running, rpm is within 45,000 - 50,000rpm with one or two passes only.

what is passes????

Pass is boat travelling from either left to right. One time = one pass.

Tis type of running is to clock fastest speed only. So ppl setup is extremely hot.

[Adrianli]

and what is SAW???

SAW is StraightAWay

U need to read more in other forums. Over here, not much of such info.

[Adrianli]

Look here for an example of SAW runs : http://www.youtube.com/watch?v=fNCpW0z62y4

[zattan22]

Lets do the maths :

6S A123 : 6 x 3.3v = 19.8v

2726kv x 19.8v = 53,974.8rpm !!!

For sport running boats, keep rpm within 25,000 - 30,000rpm. For SAW running, rpm is within 45,000 - 50,000rpm with one or two passes only.


Also do note that A123 cells max continuous discharge is only 70A. In boating, most of the time its full throttle down the straights.

Nominal voltage: 3.3V
Nominal capacity: 2.3Ah
Core cell weight: 70 grams
Internal impedance: (1kHz AC) 8 mΩ typical
Typical fast charge current: 10A to 3.6V CCCV
70A continuous discharge
120A, 10 sec pulse discharge
Cycle life at 10C discharge, 100% DOD: over 1,000 cycles

http://www.a123systems.com/products

so i use 2 *11.1v 4400mah 25 c in series
will be :
2726kv x 22.2v = 60517.2 rpm
will over 50,000rpm

but the A will be 110A which is lower then 120A esc

but if i use 2*6S A123 in parallel
will be

6S A123 : 6 x 3.3v = 19.8v

2726kv x 19.8v = 53,974.8rpm slightly over 50,000

but the A will be 140A

am i right?

[Adrianli]

so i use 2 *11.1v 4400mah 25 c in series
will be :
2726kv x 22.2v = 60517.2 rpm
will over 50,000rpm

but the A will be 110A which is lower then 120A esc

but if i use 2*6S A123 in parallel
will be

6S A123 : 6 x 3.3v = 19.8v

2726kv x 19.8v = 53,974.8rpm slightly over 50,000

but the A will be 140A

am i right?

From my calculation, u will see smoke. Most boaters in US will go for HV esc if they run on 6S to be on the safe side.

Are you sure ur motor and esc able to handle 6S???


My advise is to keep ur rpm within 30,000rpm. Urs is a mono, run it that way.