looking into the hobby

I have heard this 180 amp thing for ever and yet the wire and LiPo battery will not supply that kind of power, scopes should write a disclaimer.
When a 550 can locks up it may draw 30 amps for a couple of seconds, burn out the connectors and wire (because you only used #14). OK so you used really good #12 silicone wire that brings the available current to about 30 amps, but then those pesky brushes turn red then white hot and fall to the bottom of the can in a molten slag pile. 550 motors are cheap and available and can be a really good option but they won't pull 180 amps, ever.

 

Stall current on the stock 550 is listed at 85A. Like Carl says, that's only for a second or so before something melts. FYI, the 555 motors, stall current at 12v is 9A and at 24v is 6A.

Here's empirical data on the 550: http://motors.vex.com/other-motors/bb-550

 

He did say in theory lol.

 

If you use :
--Lite speed /
--Anderson Power poles
For you battery connections
All of us ,in Michigan, use these so if you need to use one of our chargers or batteries
we can all swap batteries and/or charge.

 

for the Des Moines or Maryland, which would be harder to model the superstructure on?

also, I think what I'll have my esc in it's own batteries (my 2 lipos in parralel for run time), and the guns, reciever and rudder all on its own battery. This should help with available run time, as the 2 lipos would give me 8000mah, and only be used for driving the ship.

I have more lipos than just those 2, they are just paired together, when they were new they balanced and charged equally. I was thinking this way I would be able to just use what I have. I would only need to get a small charger to charge the third battery, and I should have enough power to not completely drain any of the batteries. If I went NIMH though for the guns, I do have a nice dual charger just for those, I just don't use it because I dont have any good nimh batteries. I could build 6v packs and not have to worry about Lipo on that side if the circuit.

I understand it would be neater wiring with the complete boars, but this way I'm squeezing out as much as I cam with what I have now.

also with the motor situation. I know I know I should probably use dual 550 brushed, but I do have a mamba max pro sct esc/ 2400kv 550 motor combo setup. with a gearbox reducer, could this work in place of the dual brushed motors?

I guess that idea also come down to how many shafts actually need? can 2 be dummies, or do all shafts have to be powered? each have 4 shafts and 1 rudder. I guess if I went dual brushed, I could have all 4 shafts turn, as there is that dual gear box reduction on BC.

 

When you have four shafts, the two outer props will be dummy's. We call these drag disks and they help with acceleration. Ignore the rudder design in this pic. They didn't work out well.

 

Rick at BC has a complete Des Moines he completed years back, used it at one Nats, and went back to Axis after that. You may want to email him and ask if his is for sale. He has it in a box up on the shelf in his workshop. last time he had it down around 3 years ago, everything was still working in it. Would save you a lot of time. Just a thought.

 

that would be nice, but probably out of my budget. I'm going to have to slowly buy everything separate just for budget reasons.

unless he has a layaway plan for it

 

Batteries -

You need batteries to get you through the entire day of battling, not just one sortie.

We typically have at least 4 sorties per day, arranged as two battles with two sorties each. A sortie typically lasts 10-15 min at a local battle

For the Maryland, I expect that you would discharge around 5000 mAh from a 2S battery set up per sortie. I have a Tennessee class that is similar in size, I would regularly discharge about 2500mAh from a 4S pack, so you can double the mAh for equivalent power from a 2S pack. So, for drive alone, you would want at least four pairs of your 4000mAh 2S LiPo's in order to make it through a normal day

Guns don't consume much power

The pump is the largest load, a normal pump going full bore will draw 30 A. On my Tennessee class I would typically discharge between 3 Ah and 10 Ah per sortie for the pump (at 2S), depending on the damage.

In regards to the drive system, it depends on how much you value having a working ship. If you want to spend the money to build the ship, and travel to the battles, just to spend the day in the pits trying to get your drive system to work, then you could stick with your 2400kV setup. I'd consider the $40 or so to get 550 motors and the hobbywing 60A ESC well worth the cost to greatly improve your chances of having the boat on the water.

The same can easily be applied to the integrated board. If you wanted to separate out the pump and the drive batteries you could still do it with the integrated board, you would just have the drive hooked up to its own battery, and have the other battery (or set of batteries) power the pump and guns via the board.

 

one thing I forgot, you could get a charger to charge batteries between battles via your car battery, a few battlers have done this with reasonable success rates. You would still probably want enough Ah for two sorties.

 

Just make sure your car battery is good so it doesn't die on you. [cough cough]

 

It may save you a lot of money to buy an already built boat,
also you would be on the water faster

 

I sometimes bring a small generator so I can charge but generally I need the weight so I use enough battery to last an entire day.

 

say I got 2 of those 20Ah batterues, and ran them together for the voltage, would that get me through a battle, 2 sorties? or would that be a days worth?

 

gotcha. I'm leaning more towards the Des Moines just to start out, Inthink something smaller and less complicate would be best to start.

 

i

Im not opposed to it. i just don't think I'd be able to swing the money, or get the fiancee to approve the purchase

 

ASK !

Also I ran my HMS Invincible with 20ah a whole battle (two sorties)
used about 1/3 of my power (with HOT bilge pump) 6 volts

 

Him? or her? I know she would say no. i'd def have to sell some things first. i'll probably still ask him, but i can't say for certain i could buy it. but it would be great to know a general ballpark figure of what one would cost to buy.

 

Dude, get the BC Suffren hull. Excellent first boat. One powered shaft, two guns, a full pump, minimal superstructure. Will get you on the water fast with a lower cash outlay.