Twin drive cats.....a discussion.

[ED66677]

In the case you run batts in //, if one esc burns and drain all the current both batt will smoke!
I would go for two separate system 1 batt 1 ESC 1 motor, if one of them dies you can always drive the boat back to the shore!

[ozzie-crawl]

iam going to run each side with its own batterie pack. have read this is the better setup

[lomdel]

iam going to run each side with its own batterie pack. have read this is the better setup

with the parallel set-up. Great to have some kind of back-up. Ozzie, why is your motor-mounts so far forward? I know you said something about COG, but I would reckon shorten the drive-shafts and put the batts in the front . (You remember about my mounts?)

[ozzie-crawl]

yes i put the mounts up front to get my c.o.g rite, if i done it the other way around c.o.g would have been to far forward here is some pics show what i intend (hopeing to get your brackets done this week have to make them at work)

[Gerwin Brommer]

Depends on how much amps you'r drawing.
If you wanna save the lipo's you better run 2S per motor.

[bonewar]

Here is another one for the twin users.
If I am using two packs is it better to go for completely independant systems, being Battery-->Esc-->Motor.
Or to go for a Paralell on the power side, being Pack+pack(2P)-->Esc's--> motors.

Paralell power or independant setups??

Simon , I would run the paks parallel, then you don't run the chance of drawing to many amps from 1 side of the boat. The lipos will stay balanced because both motors are seeing both packs. I ran the MARITIMO with the paks independent 2- 5 cell lipos , After the run 1 pak read 18V, the other pak read 17V. the pak that read the least v was the inside turning motor. SO that pak was under what i like to stop at 3.6V per cell. It was 3.4V per cell, now this was for about 5 Min run. I have changed to parallel now the lipos are staying balanced. MUCH SAFER!!!!! BONEWAR

[lomdel]

This may sound stupid, but how would a wiring diagram look for a parallel set-up to two ESC's? Say I use 2x 4S packs parallel to two separate ESC's(?)

[ED66677]

both batt have the positive pole together as well as the negative one it is the same for the ESC's, so basically for 2 packs and 2 ESC'S you have 4 red wires together and same for the black ones.

[Gerwin Brommer]

Simon :

Which lipos are we talking about ? ( capp. )

[crrcboatz]

If you run them parallel, doesn't that remove the possibility of the batt. being placed in the sponsons? I thought that was a very important requirement to a twin cat running well.

Curt

[Simon.O.]

Gerwin
At the moment this is a theorey session, so hull, motor, esc and packs sizes are not decided on yet. I'm working on it

Curt
Wiring the packs in paralell does not determine thier placement.
I would see packs and motors in the sponsons and esc's on the tunnel top.
There would be very little more wire than in an independant setup.

I see the case for separation based on esc smoke leak
Given that I am now prone to over spec a whole power system to keep the strain off I can see the chance of esc failure as being reduced.

Bonewar pointed out the reality of running twins and has tried it both ways.

[crrcboatz]

It just seemed that running wires from both sides of the boat to a central site and the escs compounded the resistance with the extra wires necessary. Can someone post a drawing for the parallel battery setup leaving the batteries in the sponsons? How do you avoid extra wires? I almost have all I need to start the 36"Team Believer project using stingers on the sponsons, and my motor, esc and batteries in each sponson. Help appreciated.

[bonewar]

OK GUYS, This is how i got around this problem, 2 different ways to go about it . Hope this helps. BONEWAR

[peells]

Problem "No Problem"

Look at all that wire, here is a little device I cooked up last night,
WE have been discussing this same thing on "yes another Catamaran build"
Ok I had these connectors in my box they plug right into a Dean's so I used them.

Pete

[crrcboatz]

I like the KISS rule will stay with one batt. one esc, one motor in each sponson.

Curt