Laurence,
The run time depends entirely on the current draw of the motor(s) and the speed at which they are run. For example, if the maximum current draw of one motor is 20 amps (2 motors = 40 amps total) then with 4.5ampHours of battery to draw from, they should run for about 5 minutes. If that 20 amps is the motor's maximum draw, then you should never see that unless something stalls the motor, bad news! If the 'average' current draw is something like 5 amps per motor (10 amps total) then you could expect something like 20 minutes run time from a 4.5 aHr battery. Probably about what you'd expect from an average boat not being run particularly hard/fast, maybe.
Where did I come up with those time numbers? Divide the aHr rating of the battery(s) by the current draw of the motor(s), then take a few minutes away from that because it allows for a safety margin. All of this is supposition, not facts (except for how to figure run time). Because the current draw can have a wide range depending on lots of things (the 'biggy' being how hard you press on that gas pedal!).
There are only two ways to get longer run times, less current draw, or a larger supply of current (bigger battery(s)). Batteries make excellent ballast, by the way!! If there's room for them.
- 'Doc

Shot dud! I will take that in to mind.

id install this one http://www.horizonhobby.com/Products...ProdID=PRB2314 to be sure

50A forwards 20A reverse, waterproof, 4.8-12v, BEC enabled, no fiddling around with a set up button either, plug and play.

I run one of these in a Najade on 9.6v feeding a Robbe 710/12, no issues what so ever! only reason it was replaced was water got in the boat and rusted the switch, so I replaced with another one, (the only difference was the box was purple not blue).

Hi

My only problem I have is connecting tree of them together. Got any tips?

I have done just that with my sydney Star, as the battery requires 3 feeds, one to the main drive, one to each of the thrusters.

the solution is a strip connector take the feed from the battery and join it with the red and black wires from esc input, (RED TO RED, BLACK TO BLACK) and put them inside the terminals on one side of the block, then take the esc's that are left and join red wires to red wires, and black wires to black wires.

the input leads will have a tamiya or deans connector on them,
output leads be blue/yellow or black/red with a gold plug on each wire.

all I did was remove the Tamiya type connectors to the Viper 15's used in the Sydney Star

also on the esc's if they have a BEC system which means the esc also powers the reciever, remove all but one of the red wires out of the tri-wire servo leads, so only one of the esc's is feeding power to the reciever, it is also important that you remeber to turn off all 3 esc's afterwards, easiest way to do this, unplug the spider loom (pictured) from the battery.

see enclosed image

That battery. If its a lead acid, sealed, gel, whatever, and it hasn't been charged, check it urgently and get it charged. They do tend to self discharge over time, and when fully discharged, tend to stay that way.
If the motors were bought with the kit, I would consider buying nice new ones at the same time as the controller. Reliability and up to date efficiency.

I made the mistake of leaving two esc's turned on in Celestia once, took a 6v battery down to 1v! and there it stayed, costing me a new battery!.

one thing that I did notice with my Najade, using an electronise esc capable of swallowing 24 volts and giving 40 amps, running it with two lead-acid gel cells in tandem to give 12v 4.5AH I gound that they would both get very hot, which for a gel cell, probably isnt doing it any good, so the move was made to Ni-CD/Ni-MH cells, dropping a couple of volts to 9.6, I found that these batteries wired in parrallel, the Najade was riding better and planing, where as with the gel cells she was getting the RPM but their extra weight was offsetting that.

even with 12v ni-cd cells, performance was only marginally faster than with the 9.6v. you may find she runs better on 9.6v and sub-C cells are comming now in somewhere around 3700mah - 5000mah, they can also be fast-charged where as lead gels can take offence to high power charging and rapid discharging.

result, Try the lead gels but you MAY find performance is improved with a paired set of 9.6v batteries