Batt question

[bwells]

re post #1 Nicads will deliver less voltage as they are used, a slow spiral down ( a slide) whereas a NiMh will run virtually the same voltage for a time and drop off real quick ( a cliff). With the setup you have, I would try a 3s lippo with the largest MaH you can afford. You would still be under the 12 volt limit of the motor and hopefully the ESC and have way more punch for a lot less money and hassle than switching to brushless. Disclaimer: IMO!

[bwells]

One more thought, well two. If you are happy with the speed of the 8.4 fully charged NiCd, I find that a 7.4 Lippo is better, not sure why, maybe less weight or just the voltage dump you get. It's a cabin cruiser and a big one at that and you don't want to dump the sunbathing babes of the bow! If you have enough room between the motor and floor, some cooling coils would be nice as well as brush cooling with a transom mounted Traxxas water pickup and it looks as though the prop is submerged and will help circulation. Who makes this boat? I like it!

[785boats]

Hi Tony.
Here's one from HiModel. No BEC & no water cooling .

http://www.himodel.com/electric/HiModel_FLY_Seires_70A_Brushless_Speed_Control_for_boats_W_Reverse_function_Type_NAVY_FLY-70-OPTO.html

But I Agree with bwells. A 7.4 Lipo in this situation will be better than the existing NiCd. Two in parallel would hold up the voltage better & give a good run time. Watch the heat.
Scale models that I used to run on 12 cells also run better on 3s Lipo.
As bwells suggests a 3s pack will give good performance in this boat.

The only thing is that a lipo cutout is going to be required & the usual suspects from Dimension Engineering will not work on a reversing brushed ESC.
Novak however make one that does. I use one but I can't find the model number to give you. If You don't get one just keep an eye on the voltage of the pack & if it gets down to say 3.7V -3.8V per cell unloaded, call it quits.

All the best.
Paul.

[Tony]

One more thought, well two. If you are happy with the speed of the 8.4 fully charged NiCd, I find that a 7.4 Lippo is better, not sure why, maybe less weight or just the voltage dump you get. It's a cabin cruiser and a big one at that and you don't want to dump the sunbathing babes of the bow! If you have enough room between the motor and floor, some cooling coils would be nice as well as brush cooling with a transom mounted Traxxas water pickup and it looks as though the prop is submerged and will help circulation. Who makes this boat? I like it!

I'm happy with the scale speed, i just want to run it a bit longer than 5 min. One of the thing i like about the boat is it has plenty of room for upgrades. This boat is a product of Graupner. Hobby Engine bought it, and continue making it.

[Tony]

Hi Tony.
Here's one from HiModel. No BEC & no water cooling .

http://www.himodel.com/electric/HiModel_FLY_Seires_70A_Brushless_Speed_Control_for_boats_W_Reverse_function_Type_NAVY_FLY-70-OPTO.html

But I Agree with bwells. A 7.4 Lipo in this situation will be better than the existing NiCd. Two in parallel would hold up the voltage better & give a good run time. Watch the heat.
Scale models that I used to run on 12 cells also run better on 3s Lipo.
As bwells suggests a 3s pack will give good performance in this boat.

The only thing is that a lipo cutout is going to be required & the usual suspects from Dimension Engineering will not work on a reversing brushed ESC.
Novak however make one that does. I use one but I can't find the model number to give you. If You don't get one just keep an eye on the voltage of the pack & if it gets down to say 3.7V -3.8V per cell unloaded, call it quits.

All the best.
Paul.

Paul,
I have 2s, and 3s lipos i can use. I also have a LipoShield LV cutoff. I think it would work like the Novak right?

[Tony]

re post #1 Nicads will deliver less voltage as they are used, a slow spiral down ( a slide) whereas a NiMh will run virtually the same voltage for a time and drop off real quick ( a cliff). With the setup you have, I would try a 3s lippo with the largest MaH you can afford. You would still be under the 12 volt limit of the motor and hopefully the ESC and have way more punch for a lot less money and hassle than switching to brushless. Disclaimer: IMO!

I have a 3s1p 5000mAh which i could use with the brushed setup. What do you mean hopefully the esc?

[Flying Scotsman]

If, you are happy with the scale speed just put in LIPO 2S batteries with a higher mah than your current 8.4v 1300mah NiCd batteries and use a Graupner brushed motor with an ESC designed for scale boats. Which can be run at low speed/voltages with brushed motors. You may wish to get on a site or hobby shop that has scale boat experience

Douggie

[785boats]

Paul,
I have 2s, and 3s lipos i can use. I also have a LipoShield LV cutoff. I think it would work like the Novak right?

I'm afraid not Tony.
Both the LipoShield & the CellShield from Dimension Engineering are for 'Forward only' ESCs. With reversing ESCs they can lock them into full revs forward when you hit reverse. Not good on any day ending in the letter Y.
Here's a link to the Novak one. A lot of scale boaters use them. Me included.

http://www.teamnovak.com/products/lipo_cutoff_module/index.html

As Douggie & others have suggested, run the boat on a 2s pack. You should get at least 20mins run time from a 5000mah pack with such a small load. But check the voltage regularly .
This will be your cheapest upgrade. Then try a 3s pack for comparison, but I think it may be well above scale speed.

All the best.
Paul

[Tony]

Guys, thank you all for your advices. Like i said, i'll be happy with run time of 10 min or more. I'll use 2s-3s lipo with the current setup. Money saved for the NUE 1521 1.5Y motor.

Paul,
Thanks for the Novak links.