What size bullet connectors to use

[rumrunner]

What size bullet conectors should be used on Qtunnel 6.5 say up to 200amps and 8.0 say 300 amps

I'am using a swordfish 240 esc and a 1521 motor . I have 6.5 already should I change to 8.0?

Thanks

 

[moparbarn]

i know VIRTUALLY NADA 'bout fe boats, but in any other electrical stuff i've dealt with bigger is always better on connectors. too small equals resistance which equals heat, bad juju. error on the safe side, shane.

 

[Mark Prins]

well, 5.5 does ok with 4s-6s with a 180 amp. 6.5 has been used for this also by some racers. not sure if you should/have go to 8.0. I would think the above advice is good. I would ask your question on as many forums as you can and see if you can find the someone who KNOWS why or why-not. At my hobbyshop the guys know a lot, but rc boat racing is another beast, rc boats are sealed, and not the many have done it, let alone with large FE's, so you get what will be their best guess. You could go with your 6.5 bullets and down the road you'll be the guy who knows why or why-not.

Mark

 

[Jim Caldwell]

Definatly go with the 8mm bullets, They run at 120F. 6mm run at 170F, heat equalls resistance like an electric heater.

 

[HTV Boats]

Shane,

I use 6.5mm on my batteries. 8mm can get difficult to disconnect As to a performance advantage not sure you could measure any in an outboard heat race setup.

Mic

 

[lohring]

The 6.5 mm bullets should be fine. The 8 mm bullets are hard to disconnect. I only run them in one boat, my 1/8 scale. There I run 2 - 4S 5000 mah batteries in parallel connected into a harness with 5.5 mm bullets. The harness connects the 4S packs in series into the ESC with 8 mm connectors. The ESC to motor connectors are also 8 mm. Even so, we didn't draw 200 amps when setting the NAMBA 2 lap record.

Lohring Miller

 

[ken turmon]

I,m surprised you find the 8mm harder to disconnect. Maybe the brand. I run them in all my boats and started using a small piece of silicone tube inside the male plug for a snugger fit.

 

[longballlumber]

I,m surprised you find the 8mm harder to disconnect. Maybe the brand. I run them in all my boats and started using a small piece of silicone tube inside the male plug for a snugger fit.

I would argue the need to have tubing for a "snugger" fit means your not getting a proper connection with the connector. That would be worse than a 6.5 with the proper fit IMO

Later,

Mike Ball

 

[rumrunner]

Thanks guys , think i'am going to use my castle 6.5 connectors.

 

[Don Ferrette]

Be more concerned with the QUALITY of the connectors as opposed to size. I've seen some 8mm ones that were downright awful and 6mm that were excellent. Personally I've run 6mm on everything from heat racers to 10S record trial boats with great success.

 

[RaceMechaniX]

I mirror Don's comments. It's not about the size, but the fit and consistency between connectors. You also want to select a connector that has sufficient "meat" on both sides of the connectors. I have seen some 8mm's recently that had extremely thin cross-sections. 6's or 6.5's are likely fine for your set-up, but try to pick a single brand which has decent stock. Check the fit before soldering any of the connectors and weed out and undersize connectors. I run 8mm's on most of my motors and 6mm's on almost all my battery connections.

A fun fact, my 10S SAW rigger ran parallel sets of 3.5mm connectors when it set the record. Just goes to prove it is about the fit and consistency.

TG

 

[Dick Loeb]

I run 6.5 Castle on all my stuff saw and heat race,( good solder joints and good contact at plug ins ).

 

[Grimracer]

we just did a bunch of testing.. I would opt for 8mm (knowing whats on the market now) if you can.

having said this fit is important but more for cycle life then current capabilities.

If I posted the results of our testing. Which I cant.. you would not believe the results.. enlightening for sure.

Truth is regarding current bullets. larger is better (blanket statement) with whats on the market now.

Grim

 

[Jim Caldwell]

It is very enlighting Grim! Jorge the world record hold from mid 2000's to last fall at 140 mph, ran the tests back then. Fit is very important but they don't have to be so tight you can hardly get the apart. The fit is easly adjusted.

I use only Steve Nue's ( Nue motor mfg) bullets MUCH better than anything else.

 

[Don Ferrette]

It is very enlighting Grim! Jorge the world record hold from mid 2000's to last fall at 140 mph, ran the tests back then. Fit is very important but they don't have to be so tight you can hardly get the apart. The fit is easly adjusted.

I use only Steve Nue's ( Nue motor mfg) bullets MUCH better than anything else.

+1 on the Neu connectors, I've had excellent results with them.