Why upgrade to 5.5mm Bullet connectors?

[IRON-PAWW]

Ok so some embarassing new guy questions

I read that the common consensus is to upgrade all the connectors in the Impulse 31 to 5.5mm bullets. What exactly is the benefit in doing that?

I assume this means pulling out the deans connectors the Lipo's plug into as well as replacing the smaller bullets the motor plugs into the ESC with? Are the Deans really that bad?

If I'm just going to run stock for a while on 5000Mah 40C Lipo's then will I be ok without doing the upgrade?

I assume that if I do a prop upgragde (definitely on the cards) and the motor starts drawing more amps - then this is when I'd really need to upgrage all the connectors? What happens if I don't upgrade? Leads get hot??

Cheers all!

[Darin Jordan]

First off... the system will draw around 58amps continuous (average) with the stock prop... Those Dean's are only rated at 60A, and those 3.5's are better fitted to a Micro plane than a Hi Performance boat. While they will hold up to the amps, the solder joints will NOT. As the 3.5s build heat, the small mass concentrates the heat and will melt out the solder. Experience has shown that upping them to 5.5's or 6... or 6.5's, will prevent this from happening. I up mine to 5.5's and NEVER have an issue with this.

Unfortuneately, getting the 4mm or larger contacts from the factory thus far has proven difficult, especially in these times of penny pinching tight budgets...

Up them to 5.5's, minimum. You will be much happier. I'll promise that! ;)

[lenny]

Yes, And you lose power to your setup that could be more speed.
Instead you end up with heat and more amp draw.
Not good for your setup, 5.5 good !

[IRON-PAWW]

Thanks for the Replys Darin & Lenny!

Ok makes sense now you've explained it. Sourced some good 5.5 bullets and they just seemed too large for the wiring in the Impulse 31. But melting out the soldering I can definitely understand. So really, the guage of the wiring has nothing to do with it - it's the soldered weak points we're trying to eliminate by doing this upgrade. The larger connectors deal with the heat build up better and shouldn't melt the soldering.

Extremely nice boat by the way Darin. Some really good design right there.

[petej]

On the stock 1800 Kv PB motor, so that I can use one of my other ESCs, I replaced the male banana connectors with larger, 4mm connectors. Running with a pair of 2S, 40C 5000mAh batteries, 120A ESC and an Octura x645 prop, I'm having the problem, where the solder at the motor connections melt, a motor lead disconnects, ...
Question: It seems the motor leads are the smallest component/gauge in the system (batteries, ESC, connectors are large) how can I improve the solder connections on the motor leads or, what am I doing wrong?

[lectriglide]

On the stock 1800 Kv PB motor, so that I can use one of my other ESCs, I replaced the male banana connectors with larger, 4mm connectors. Running with a pair of 2S, 40C 5000mAh batteries, 120A ESC and an Octura x645 prop, I'm having the problem, where the solder at the motor connections melt, a motor lead disconnects, ...
Question: It seems the motor leads are the smallest component/gauge in the system (batteries, ESC, connectors are large) how can I improve the solder connections on the motor leads or, what am I doing wrong?

REREAD post number 2 by the boats designer. Stock 3.5mm vs 4mm "upgrade" doesn't really accomplish anything. Also the x645 with the 120a esc is pushing it IMO. What are your temps? Gotta be :flammes-09:

[IRON-PAWW]

So that is another question i've got. If I plug a 120amp + esc into the stock motor with decent batteries aren't I going to be pushing that stock motor waaaaay beyond it's design parameters. Like - how can I tell how much curry I can give any particular motor? The leads on the stock engine seem way too small to push much further at all. From where I sit - it's prop up until things get warmish with the stock parts and then that's about as far as you can push it??? Can you benefit from going higher amperage on the ESC? Like - you can't cool the leads right? So you need a better spec motor after that?

With the amperage of the ESC's (another complete new guy Q). Does that limit the total amperage the system can process at any one time? Like the only load available to the engine will be 60 amps with a 60amp ESC in the system? Or - what I guess - does the amperage spec of the ESC really mean?

The Impulse 31 has a 60amp stock ESC is it?

Please feel free to shake your heads at what I don't know...... :)

[petej]

OK, While the wire gauge/ampere calculators indicate the motor wires to be too small for these current capacities, I will try 5.5mm bullets between the motor and ESC.

Thanks.

[JT13031]

The esc rating means thats how many amps you can push through the esc before you risk blowing it. It will not push that many amps to your motor unless the motor is drawing that much.

[lectriglide]

Iron - time to do some reading and studying. Do some "searches". The amp rating of an esc is intended to represent the maximum constant amp draw it will handle safely. They also usually give a temp/surge/burst current. It does not mean it "forces" that current into the motor. Many factors effect the amp draw of the motor such as type of hull, wet or loose setup, prop size, battery voltage, motor rpm etc etc.

[ClintIII]

Darin, I am running the Impulse 31 stock with an Octura X445 with 2 Dynamite 2s 5200 mah 50c Batteries . The boat runs GREAT except for the small bullets coming from the motor heating up alot. The Deans are warm but the shrink tubing on the small bullets melted basically.

The bullets on from the motor fused together and the solder popped on one just like you said. Can I use the 5.5 mm on those wires on the stock motor? or are they smaller?
I am going to upgrade them first and then possibly upgrade the Deans connecters to bullets.

What would you recommend? This is a great boat!

Best!

[IRON-PAWW]

Well - went up to 5.5mm bullet connectors.

Then I've put in a Leopard 4074 2150Kv with a Seaking 180 ESC.

Then I installed the upgraded flex shaft and whacked on an Octura X 445.

Installed larger diameter water tubing just to make sure. Got really good water flow though this system

Boat flew like an absolute rocket for about 3 minutes until it spat the flex cable out the back! :cursing: Had to go for a swim to get the Impulse :cursing:

Motor was barely warm and the ESC basically cold - so that was good. Wiring not heated at all.

First question: I assume the OSE flex coupler will solve this issue?

Second question: Can anyone tell me what size / Dimension the hex head screws are that (1) hold the motor to the to the mounting bracket and (2) bolt the bracket to the hull?


Thanks for your help!!