battery selection

[dogg]

Hi there everyone, I have some good advice from members here but am after extra advice as to battery selection for the following setup...

Supervee 27 with a Turnigy 3665 b 2300kv motor (14.8v max, 76a current draw), turnigy 120a esp, I was thinking of running 2 x Turnigy 5000ma, 2s, 40c packs in series for the 14.8v output, (I worked out appx 4 mins run time).
I am trying to keep weight down so that it doesnt run wet and gets up on plane easier.
Does anyone have a better idea regarding pack sizes/cell counts?
Is it worth going 2 x 5000ma, 4s, 40c packs in parallel for better run times at the expense of extra weight?

Anyone able to give info regarding the difference in run time would be appreciated.

Thanks.

[siberianhusky]

Never tried it but the SV might actually run better with more weight, not the best hull design out there.
The thing that would worry me is heat build up with longer runtimes.

[ENCORE MAN]

I have tried 2x 4s many times on rough water days and I would not recommend it. The boat will not handle well with THAT much extra weight. Many people would agree the best option for rough water running is to put a few ounces of ballast (1 or 2 expired D cell batteries, attached with velcro works well) about 1.5 inches in front of the motor and regulate the throttle accordingly. An ugly rollover lid will save you a lot of rowing time. Goodluck. BG

[dogg]

Thanks Siberianhusky, I am very aware of both of these issues, thanks for the input...

Encore man, thankyou. I suspected that this may be the case and hence my querie. Please advise as to your idea of a lid that assists in correcting rollover as I have seen some (in other style of boats) filled with expanding foam but am unsure whether there is a better way - also the lid doesn't have much volume so your input is welcome. PS thanks fro the D size battery idea...

[TheShaughnessy]

for a super vee i would say stick with 4s1p if you wanna run 5000 mah packs. It is a fairly small boat to run 4s2p and it would be a tight squeeze of course this is assuming we are talking about 5000 mah packs. You could try running 2 4s 3300 mah is a 4s2p configuration and that might be better then having the dead weight of lead. I personally have a thing for 4s2p as opposed to just 1p.

[dogg]

for a super vee i would say stick with 4s1p if you wanna run 5000 mah packs. It is a fairly small boat to run 4s2p and it would be a tight squeeze of course this is assuming we are talking about 5000 mah packs. You could try running 2 4s 3300 mah is a 4s2p configuration and that might be better then having the dead weight of lead. I personally have a thing for 4s2p as opposed to just 1p.

Does the use of parallel cells (4s2p per cell) somehow extend the run time or what is the benefit? Sorry for my ignorance...

[TheShaughnessy]

just seems like you get less voltage sag and its easier on the packs. More cells to pull from I guess. I'm no engineer.