# 6-cell or 7-cell?



## Kirk (Aug 10, 2006)

I recently got a new r/c boat which I haven't run yet. The motor and esc are water cooled, have Dean Ultra connectors, and are rated at 18V, 45 amps. The basic setup is that it is powered by dual 6-cell battery packs. Just for some extra "gusto" I was thinking of running dual 7-cell packs in it instead. From the little that I know, and from asking others, I feel fairly confident that the hardware could handle it ((2) 7-cell packs = 16.8 volts). Is there anything in the "amp" equation that I am missing? Or, is there something else that I might be missing altogether? 

The same idea from a couple other angles: Do you think that dual 7-cell packs, instead of 6-cell, is really going to give me enough added performance that it makes it worth "experimenting"? Or, given that this boat is supposedly twice as fast as my last boat, should I just take "baby steps" and try 6-cell packs first and then move up later if I want? That attitude makes perfect sense but there is the cost issue (more battery packs).

Any thoughts?


----------



## IndyRC_Racer (Oct 11, 2004)

Please post what type of speed control is in the boat. Someone may experience with the model in your boat.


----------



## Kirk (Aug 10, 2006)

AquaCraft Marine Brushless 45 Amp ESC


----------



## briano_72 (Jan 21, 2006)

brings back memorys of my good old miss budwiser !! it had 2 6 cells and 2 plane jain 540's and would not get out of its own way. the little ripples in the water that it tryed to make would pass the boat up. no matter what i did, it would never get on up on plane. then i saw a little 1/4 page ad in r/c car action, now this is back in about 1991-1992. was a whole new gearbox set up, 2 19 turn motors, a flex shaft and a bigger prop. i got a astrocraft speedo and did the 14 cell thing on my own. i also filled up all the empty spots in the boat with the home use spray foam insulation to help protect my new investment. the boat now flew, up on plane in about 3-4 seconds. first time i ran it was in a local lake, not too big, 3/4's of the way threw the batts, i hit a log i never saw the whole time i was out, boat flipped over on its lid and ran full speed till the batts died. took that sucker about 45 minutes with the light breeze to come back to shore. only ran it one more time, in the ocean about a year after the mishap, and sold her about a year ago. WOW !! sorry for the flashback, but do the 14 cells now and get it over with and go to funrcboats or offshore electric and get your self a prop kit too, props make all the diferance in a boat !! almost as much as the 2 extra batts your gonna add !!


----------



## Slider (Dec 7, 2003)

The added cells will help. But as Briano 72 stated. Put a bigger prop on it or a prop with more pitch. If it has a metal prop.Search out info on how to work a prop.you can gain so much from just working on a prop in the right areas.I would personaly work with props first. IMHO.


----------



## Kirk (Aug 10, 2006)

LOL....That's a great story Briano72!!! Yes Slider, I'm learning about props, seems like they can make a HUGE difference!


----------



## trackman (Aug 5, 2006)

If you have'nt ran the boat yet , try the reccommended 6 cell's as with the factory set up...

I really don't know much about the prop's , but my understanding is works under the same principle as pinion and spur gears do in an electric off road R/C...

You either modify touqe or top end by different pitches on the prop , number of blades on the prop, and probably length and or width of blades on the prop ...

So really I would run it with the factory setup and the 6 cell version to see which way you need to go with the torqe and or top end... It will probably depend on the area and type and size of the area you have to speed around on for running purposes...

6 cell packs will be easier to find for purchase ,and a lot of times cheaper count wise...

Also when you insert 2 seven cell packs you will probably have to find a better balance point for the boat to compensate for drag due to the extra weight of the 2 extra cells... When we added an extra cell to our electric airplane we had to readjust placement of the battery pack to balance it for a smoother flight...


----------



## briano_72 (Jan 21, 2006)

oh yea, and get the newer carbon props, dont have to balance or polish em and they do not flex, just like the metal ones !!!


----------

