Castle Chart

[Steven Vaccaro]

Have you guys surfed this page?

http://www.castlecreations.com/support/documents/neumotors-castle_boat_apps.pdf

[Meniscus]

Good info!

[Flying Scotsman]

Very good info and it was prepared by Brian Buass "The Snowman" and he knows how to destroy an ESC

Douggie

[AntronX]

Looks like large boats are not covered under warranty at all. I like that they recommend running 2P regardless of hull size, to make sure voltage drop will not destroy an ESC. That's what took out one of Hydra 120 HVs i ran with KB45 motor in my big hydro. I have been asking Castle for a while, to start releasing articles and tutorials how to set up a boat properly. They need to release an article written by their engineer about how and why ESC's fail.

[Flying Scotsman]

What is wrong with 1P. The voltage drop will be the same regardless of 1,2,3,4P. The difference is available amps

[Darin Jordan]

The voltage drop will be the same regardless of 1,2,3,4P. The difference is available amps

This isn't accurate... The V will drop less with 2P over 1P... and 3P over 2P... up to a limit, of course...

The difference between 1P and 2P is noticable for the power systems we run...

[Flying Scotsman]

Darin, this makes no sense. Each cell will deplete it's own voltage to what it was charged at. If the cells are not balanced ...problems...and this will increase with multiple cells and you do not have a device on board that will measure each cell's voltage.

Douggie

[Doby]

My Fellow Canadian;

What I think Darin is saying ( I could be wrong) is that with 2 packs in parallel, the controller will see less voltage drop because its sucking power from 2 packs and they will be able to "balance the load" better than a single pack. You would be sucking power from 8 cells vs 4 cells and the 8 would provide a more stable voltage source.

The more cells (packs in parallel), the more stable the overall voltage will be, even if you have some weaker individual cells.

I think ...................................It sounds logical in my little mind But I have been wrong before.......................

[ghostofpf1]

Unless I missed it they don't say 1p or 2p.They only suggest that the packs total ampacity be large enough to supply sufficient voltage at anticipated loads.

HTH
Ghost

[TRUCKPULL]

Douggie

You are a little lost here.
If you look at a discharge graph for any cells be it lipo or Sub C.

Example
4S 4500 – 25C
At 32A you would average 14.4 V
At 64A you would average 14 V
At 90A you would average 13.7 V
At 96A you would average 13.3 V

As you can see the voltage under load drops with the amp draw.

If you run a 2P setup the amp draw that each pack sees is cut in half.
Resulting in a higher voltage under load that is put to your motor.

Also only half the stress put on your cells.
If I run a 4S2P set up in my Wip and draw 100Amps each pack only has to deliver 50A
They run a lot cooler and will last a lot longer (more cycles)
If I run it on 4S1P the pack has to deliver 100A to the motor, resulting in a
- Lower motor Voltage,
- Higher battery temperature which turns into higher internal resistance
- Less Voltage under load output.

The biggest loss is in speed of the boat, even with the extra weight.
At 1850KV-- 0.7V = 1295 RPM on the motor = about 3 MPH
Even with my bad driving I will still beat you in a 1 mile race with a 3 MPH advantage
And my cells will still like me.

Larry

[Flying Scotsman]

Looks like large boats are not covered under warranty at all. I like that they recommend running 2P regardless of hull size, to make sure voltage drop will not destroy an ESC. That's what took out one of Hydra 120 HVs i ran with KB45 motor in my big hydro. I have been asking Castle for a while, to start releasing articles and tutorials how to set up a boat properly. They need to release an article written by their engineer about how and why ESC's fail.

This is what I am referring to. A voltage drop should never destroy an ESC.

Douggie

[AntronX]

This is what I am referring to. A voltage drop should never destroy an ESC. Douggie

Yes, too much voltage drop will destroy an ESC. First the capacitors will overheat from too much voltage ripple, then they will leak the electrolite. Once that happens, they can no longer smooth out current ripple spikes. Then FETs short out and you get fireworks. Voltage ripple is more dangerous at controller's maximum continuous current rating.

[Flying Scotsman]

Thank you Antron. What is voltage ripple in regards to capacitors, in a simplistic sense at low voltage?

Douggie

[Darin Jordan]

Douggie,

There is some decent information here on that topic, including a picture of before and after the application of a capacitor: http://en.wikipedia.org/wiki/Ripple_(electrical)

[Flying Scotsman]

Douggie,

There is some decent information here on that topic, including a picture of before and after the application of a capacitor: http://en.wikipedia.org/wiki/Ripple_(electrical)

Thanks Darin and Antron and others for the knowledge. We are always learning, but some old farts need a knock on the head from time to time