Just a few beginner questions.
 

I am purchasing a proboat recoil 17 as my first rc boat. A 20c 1300mah battery is included wih the boat. I would like to get a second battery so that i can get more run time. Should i get another 20c 1300mah battery or should i go for a 20c 4000mah battery. Im not sure if that will be ok. I understand that mah is milli amp hour and that more will give greater run times. Also, can i get a 30c or 40c 4000mah battery? Im dont really understand the difference but i would assume that it would lead to extra performance. Thats all for now... thanks.

The stock battery for all rtr's is gunna be dooky so be ready to ditch that. The C rating is about constant discharge levels so yes it can give extra performance at a price (That's about the simplest explanation, there is a TON more to it but i would be worn out if i typed that much, also there is a lot of theory about the subject) Be warned that too much discharge or not enough can be a bad thing. I would go for the high MAH battery to give some nice long run times. If you were racing then worry about the crazy batteries, but just for fun the 20c 4000mah should make you pretty happy. Read up on that boats electric system and see what it's limits are. Keep in mind that the limits listed are the highest you can run for a few min with out catastrophic failure. If a vehicle says 6s lipo limit then i would run a 4s to make sure my hardware lasted but was still fun and fast. Stay in the middle of the stated limits and you should have a good running boat. If anyone wants to chime in feel free, i'm sure i missed things.

A small boat like that will be sensitive to the CG (balance point) and left-to-right trim. Substituting a larger heavier pack may upset the CG degrading performance, and it will allow the boat to run with the left side lower than the right. A pack with too high of a discharge rate (40C or 60C) might damage the motor by supplying too many amps, although the risk is low.

I suggest getting another of the stock packs, then you can bring the boat is, let it cool for a few minutes, then put in the other pack and go run.


.

Your other option would be to get THREE more stock packs. By getting three, you double your run time by wiring them in parallel and keep the boat balanced by running one on each side. That would give you one set in the boat while the other set is either charging or waiting to be used. The down side to this is that you would need to have someone(if you don't want to or know what's needed) solder you up a "Y" harness so that the two packs both feed the speed controller and, indirectly, the motor

Thanks for all the info. First of all, my boat came in the mail yesterday when i realized that the battery was "mini" sized. It is only about 3.5in long. Also, there are very few websites where i can find it. The weirdest thing is that on probots website, it says that a 30c 1400mah "speedpack" battery is invluded. My battery is a 20c 1300mah "reaction" battery. Anyway, ive been looking all over for a battery with about 4000mah. I found a Venom battery with a universal plug that would be pushing the limit of the size of battery that will fit. I have measured and it will have just enough room. Now Im thinking that it will weigh too much. Would adjusting the trim tab(s) help with that? Or should i put a small weight or something on the inside of the boat on the opposite side? I only got like 10 mins of run time so i definetly dont want another stock pack if possible. And the last thing, Hydro Junkie, if i did that, wouldnt i be giving 6s 2600mah into the esc? I know for a fact that it can only handle 2s or 3s. Thanks again

No, you wouldn't. If the packs are wired in series, like batteries in a flashlight, you would increase the voltage being supplied by the voltage rating of the packs times the number of packs but at the same mah level as a single pack. When you wire in parallel, you increase the mah since you're connecting the positive to positive and negative to negative between the packs and then taking the combined packs mah output, at the same voltage as a single pack, and supplying it to the ESC. The result would be double the mah and double the run time