Motor for 24" hydro on 2s/3s parallel?

[Mxkid261]

Just finished this 24" delta force hydro recently and love it. Looking to try a parallel setup for a little longer run times though, what would be a good motor/KV for 2s and 3s parallel? Also what would be a good size prop to start with? The few props I have are atleast 40mm or larger in diameter. Boat has a T-180 speedo in it. It does around 50 right now on 4s thanks

[NativePaul]

2s2p wont get you any more run time than you have now unless you slow down, it has the same energy available as 4s1p you would just be doubling your amp draw for no benefit.

3s2p does have 50% more energy so you could get longer run times at the same speed, but 6 cells is a very heavy load for a 24" hydro to carry, 4 cells is already more than usual. Can you fit enough flotation inside, along with all the cells to stop it sinking should it fill with water? I would have a serious think about whether you really want to do it, but if you do and are happy with the way the boat runs now, take your KV and multiply it by the nominal voltage of your pack (14.8v) to get your rpm, then divide that rpm by the voltage of your new pack (11.1) to get a motor that will spin the same speed on 3s and if you choose a motor of that KV the same size you can spin the same prop that is working for you on 4s and get roughly the same speed from it but with 50% extra run time.

[Mxkid261]

2s2p wont get you any more run time than you have now unless you slow down, it has the same energy available as 4s1p you would just be doubling your amp draw for no benefit.

3s2p does have 50% more energy so you could get longer run times at the same speed, but 6 cells is a very heavy load for a 24" hydro to carry, 4 cells is already more than usual. Can you fit enough flotation inside, along with all the cells to stop it sinking should it fill with water? I would have a serious think about whether you really want to do it, but if you do and are happy with the way the boat runs now, take your KV and multiply it by the nominal voltage of your pack (14.8v) to get your rpm, then divide that rpm by the voltage of your new pack (11.1) to get a motor that will spin the same speed on 3s and if you choose a motor of that KV the same size you can spin the same prop that is working for you on 4s and get roughly the same speed from it but with 50% extra run time.

Cool thanks for the info, I wasnt aware of that I thought a parallel system basically doubled the mah. I have ran two 3s packs in it for 6s and the boat was a rocket and handled great. Im running an 1800kv right now, if I wanted to go to say a leo 3674 what would be a good kv for 4s/5s? Thanks

[NativePaul]

It does double the mAh, but if you halve the voltage at the same time, you have to run double the amps to get the same power so you burn through your mAh twice as quick.