HELP!- Boat Stalls in water

[toiletfreak]

Hello,

Seem to be having this problem with my RC Yamato, 1/350 converted from Tamiya static kit..

Boat stalled a number of times while in my swimming pool, esp when I rev up the speed to a much higher level gradually. The last time I had to personally retrieve the boat by swimming I have done a test out of water, seems to be working fine. Please Help! =)

My configuration is as follows:

-An E-Fly receiver from Art-Tech, 4 Channel Rx/Tx
-1 servo which came with it
-2 motors (Promax 400) Which Singahobby recommended to me
-2 ESC, 20A also from Singahobby
**ESC are connected in parallel, all controlled by a single channel**
-8 AA batteries -- 4 1700 mHa and 4 2300 mHa, connected in parallel, giving an emf of 6V
**PS I cut out the wires for the electronic stuff and extended them**

Thanks for helping!

[skyblueblue]

maybe there is a thermal cut from the esc

chk ur esc setting also, make sure u don't set to lipo voltage cutoff.

[Adrianli]

Amp draw too high??? ESC thermal cut???

Running w/o water = no load so = very low amp draw.

Try holding the boat in water n throttle up n check amp draw.

[toiletfreak]

Re

maybe there is a thermal cut from the esc

chk ur esc setting also, make sure u don't set to lipo voltage cutoff.

Is it due to added resistance from water? And the motors / ESC does not seem to get extremely hot, (well, out of water ). Sorry, but noob qn: whats a lipo voltage cutoff?

[toiletfreak]

Amp draw too high??? ESC thermal cut???

Running w/o water = no load so = very low amp draw.

Try holding the boat in water n throttle up n check amp draw.

Err, sry but what continuous load current for an ESC should I buy? For scale boats, not speed boats. Thanks!

[skyblueblue]

some esc comes with a pre setting eg. 2s lipo it'll cut off at about 6v. So when u throttle up the esc sense a drop below 6v so it cuts off. This is juz an example.

[temannis]

Btw, your battery 4 cells in series is about 5.5v. Typically, a fully charge battery is about 1.36v, very seldom it will hit 1.4v, and never reach 1.5v. As skyblueblue said, esc usually have cut off around 6v. So this is the reason it will cut since it is way below 6v even when fully charged. Unless u connect 6 cells in series, give u abt 8.16v.

[Adrianli]

Pls let us know the spec of ur esc.

[toiletfreak]

Btw, your battery 4 cells in series is about 5.5v. Typically, a fully charge battery is about 1.36v, very seldom it will hit 1.4v, and never reach 1.5v. As skyblueblue said, esc usually have cut off around 6v. So this is the reason it will cut since it is way below 6v even when fully charged. Unless u connect 6 cells in series, give u abt 8.16v.

err..will motor spoil cos it is a 6V motor..

[toiletfreak]

Re

Pls let us know the spec of ur esc.

No brand name here, but it can hold 20A, no reverse.

[temannis]

err..will motor spoil cos it is a 6V motor..

Ur is a Promax 400 motor, which rated at 7.2v. Which can take up to u to 2 cells LiPo which is around 8.3v - 8.4v at full charge.

[toiletfreak]

Qn

Ur is a Promax 400 motor, which rated at 7.2v. Which can take up to u to 2 cells LiPo which is around 8.3v - 8.4v at full charge.

ok...will 8 AA Ni-MH batteries be fine? 4 X 2300 mHa and 4 X 1700 mHa

[Adrianli]

2S lipo will be lighter.

I dont tink AA batts can take the discharge rate leh.

[toiletfreak]

Re

2S lipo will be lighter.

I dont tink AA batts can take the discharge rate leh.

Ok thx..btw will the ESC be able to take it?

[Adrianli]

Should be, do measure ur amp draw.