For you power experts out there!

[Hoghappy]

I plan to add a shorting plug to my UL-1. One deans will be a shorting plug under my easily assessable cockpit area. Another plug will be to add a way to unhook/remove the entire cowl.

Anyone know if adding two more deans plugs, in line, from the battery packs to the ESC, will add a noticeable amount of resistance causing a reduction in power/revs to my prop?

I will also be adding about a 1-2 ft of the standard battery 12 ga. or 14 ga. wire to the equation too.

All this to be able unhook the battery power to my boat without having to de-tape and open it each time. :rolleyes:

[Shaun Hendricks]

The deans plugs resistance would be negligable. If you want you can use a conductive 'grease' on the plugs and even improve their conductivity (I understand it also makes them easier to plug/unplug).

Tamiya plugs on the other hand would definitely drop your performance.

[nick_75au]

Using the thicker 12 Ga wire will help to an extent, as it has lower resistance. keep all wire lengths as short as reasonable. some guys I've seen use the bullet connectors used in brush-less motors as an alternative to the Deans. Then you only have a single contact(each contact increases resistance). Lower voltage systems are more vulnerable to the effects of parasitic resistances.


Nick

[boater_dave]

Shaun, if you are refering to dialectric grease it's actually non conductive. It's non gelling silicone. You use it to limit corosion. It may help with sticky or tight plugs, but there must be some drag on the plug in order to get positive contact between the blade and socket. Conductive materials used in and around power plugs is always something to avoid.
And I agree with the other posts, if you use quality plugs and wires you won't notice a difference.

Dave

[Hoghappy]

I looked at the wires last night and the factory battery pack wires are 12 ga., the wire harnesses going from the batteries to the ESC in the UL-1 are 14 ga. I have some 12 ga. same silicone type as battery wire. I may try the modification after this weekends testing. This will give me more base line information to base my future testing on.

Thanks guys....I appreciate the input...there are not a lot of responses to this question here and no response at all over at another site. ;)

[retoabcr]

Hoghappy; reading about 14 ga wire; were these wires coming from the lipos or nimh? Now as far as changing to 12 ga on either lipos or nimh should be a piece of cake as long as extreme care is taken especialy with the lipos. Make sure on the lipos you tape one wire while working on the other wire. Just take your time. Now if you know this already, disregard. If memory serves me right Paul 785 of Australia did rewiring of lipos and he mention caution is the word.-------888888 nick 75au made a good post on resistance.=-=-=-=-=-=-=-=-Adding 1-2 ' of 12 ga wire to an already setup will make a difference. You could go 10 ga but added weight of 1-2' would gain nothing but added wiring and probably turnout to be a headache.

[Shaun Hendricks]

Shaun, if you are refering to dialectric grease it's actually non conductive. It's non gelling silicone. You use it to limit corosion. It may help with sticky or tight plugs, but there must be some drag on the plug in order to get positive contact between the blade and socket. Conductive materials used in and around power plugs is always something to avoid.
And I agree with the other posts, if you use quality plugs and wires you won't notice a difference.

Dave

I wasn't referring to a dialectric grease, which I have and have used but not on Dean's plugs.

I don't know what the guy I watched using it was using, it was a very small white tube, reminded me of a thermal grease tube, but he used a Q-tip and put it on the male side of the plug and it made a difference to how easy the plugs worked and on top of that, the resistance actually dropped noticeably on an autoranging meter from a virgin pair of plugs. He said the stuff had to be renewed every so many plug and unplug cycles. I'm guessing you would have to clean the plugs before each renewal but I didn't ask him that. He was using the stuff on a road car that could pull up to 80amps peak so the stuff seemed to work.

I ran across a similar stuff in an electronics catalog about a year ago and was going to order some but never did. I'll see if I can find the stuff again.

[nick_75au]

I think this is what Shaun might be referring to

http://www.mgchemicals.com/products/8463.html

It appears that in the US Digikey stocks it.
I just searched Silver Grease in google.
Nick

[Rex R]

the esc uses 14ga. wire...since the esc is only rated to 60amps 14ga. should be sufficent(plus they are fairly short runs). for your 'safety loop' I'd use 12ga.

[Shaun Hendricks]

The tube didn't look like that but it might do the same job if used very thin. You don't want too much and the opposite terminals to make 'contact' via the 'grease'. That is what boater_dave was warning against and I agree with him. You need to be careful with anything of this nature.

Nice find Nick, I may have to get some of that stuff for other purposes but maybe test it out on my deans.

[785boats]

Let me tell you what I know about conductivity grease.
As an electrician we sometimes connect the consumers mains to the LV side of the supply authorities transformers. These can be anything up to 2,500kva transformers. The last one we connected had 5 x 300 sq mm cables per phase as the consumers mains.
We have to use conductivity grease between the lugs & the copper plates on the transformer connections to help the flow of that 2,500 amps/phase.
As it was described to me, the actual metal to metal contact between the lug & the copper bar (both of which are nice & shiny to look at) is only about 45%. This is due to the valleys & mountains in the metal created by the linishing/polishing process during manufacture.
The conductivity grease fills these voids under pressure when the termination bolts are tightened.
This effectively makes a 100% surface contact termination.
In model boats the resistance of connections will measurably drop, as Shaun has witnessed, because I would say there is a similar metal to metal contact area as in the "full size" transformer terminations.
The problem that I can see with Deans plugs is that if any squelches out when they are plugged together & tracks across between the pins there will be a dead short across the battery.
Bullet connectors will be fine & I've often thought of trying it on my FE bullet connectors. Don't know why I haven't. It's such a logical thing to do.
Anyway, Just thought I'd share.
All the best.
Paul.

[boater_dave]

Back when I used to race R/C cars, there was a guy who hot soldered his battery pack in place before (and after) each race. We asked him why and he said it was to avoid the voltage drop and plug problems. To me this is extreme, but if you are looking for that last bit of speed it might be worth it. Unless this application is an extreme racing boat, I would think an extra Deans plug and a short bit of wire would not make that much difference.

Dave

[Martin Irvine]

What kind of current are you pulling? I use 12 gauge over 35A.

Martin