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Has anyone installed a painless kit in a convertible? The kit is complete except that they move the horn relay to the fuse panel. Problem is the feed wire for the convertible top switch comes off of the horn relay. I talked with Painless and they said I need 2 relays and they would fax me a wiring diagram to make it work. Another friend suggested tapping off the battery to the existing 30 amp breaker on the firewall.

Any thoughts or suggestions?

Bob
 

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wire it straight to the battery- that is alays better than any junction block.

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
 

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i agree wire it straight to the battery, i am against drilling holes in the fire-wall but am for using ones that already exist.

BE SURE TO PUT THAT IN LINE FUSE, AT LEAST A 30 AMP for your conv.. take care God Bless

p.s all that relay crap is for the birds wire it to the batt, i have a painless complete set as well, on my 67 it does the job with the new style fusses....
 

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Knightmoose......I couldn't help seeing your comments on relays. I would like to explain why auxillary relaying works and is safer and more reliable than "direct connection technology" since you are questioning it without comment. BTW, I designed relay circuits for nuclear power plants (including backup DC systems) as my first job out of college as an EE, and participated in redesigning a couple of popular manufacturers automotive kits as of late, so I know just enough to be dangerous to comment. I thought you would enjoy some info.

The idea of taking a 15+ amp circuit (for example) from the battery thru the fuse thru a switch/sensor then to the appropriate appliance has several inherent flaws or inefficiencies. First, most switches will not handle the amperage for automotive applications and especially in the space given. Yes, there are large bulky high-current switches, but they are very short lived and very unreliable compared to modern qualitative relays. Lower amperage switches are far more reliable and have multiple times the cycle life than much larger ones. It's hard to find a 10 amp switch these days that will take the continous and instantaneous loads and last any viable time. Secondly, rather than pipe the main feed, for example in a high current cooling fan, from the battery to the switch in the interior to the fan on the raditor is faily long routed by today's standards. Length is resistive and loses power over the length of the run. By simply running a signal circuit to a relay mounted on the fire wall (like the horn is set up)for operation, reduces the length of run, which reduces the size of wire needed and reducess the number of junctions and connections in the primary circuits, which reduces the voltage drops in the entire circuit meaning that the motor/fan/device will operate properly or at even higher efficiency with less battery capacity. Third, the availability of the main battery buss under the hood is most convenient with all the signal circuits coming from the interior or peripheral devices. Forth, because these long wires that are directly wired can carry in excess of 20 amps, there is need for cooling of the wires and run in their own bundles and that is hard to do under the dash. This is why ALL OEM car makers do NOT use an amp gauge any longer. This is much easier achieved under the hood and in case of a problem with that wire their is much less risk under the hood of a major burn down. Fifth, high quality, automotive relays are designed to take the cycles (most in the hundreds of thousands of cycles), operate in higher temperature environments, have innert or sealed contacts, have higher contact areas per amp, and have built-in timing mechanisms to help them quench high voltage spikes when circuits are switched open or closed whith can kill computers and other electronics. In terms of MTBF (Mean Time Between Failure)of a circuit, relayed circuits when designed correctly will have a three to five fold MTBF over direct switched circuits for all of the reasons mentioned above and a few more.

As a final testimony to relay technology, just open the hood of any OEM automobile and look at the relays they have incorporated there. It's state of the art, reliable, safe technology.

As another comment on high capacity fuses for inductive circuits (motors). For proper protection, most inductive high current circuits should be protected by themal breaker technology rather than fuses. This is because high inductive inrush currents, especially in motors, can blow fuses easily and usually to offset this normal condition most people "overfuse" the application. In other words, they just put a larger fuse in. Sometimes this works, but is not ideal and offers compromised circuit protection. Most,if not all automotive breakers will not trip on these short inrush currents and can be designed to more closely match the motor circuit and have the advantage of automatically resetting should a problem arise.

NOw, this may seem a bit too long...but I just wrote a big dissertation in Northern Rodder Magazine and Southern Rodder Magazine on this very subject. I hope you will reconsider your view.

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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by HOTRODSRJ:
In terms of MTBF (Mean Time Between Failure)of a circuit, relayed circuits when designed correctly will have a three to five fold MTBF over direct switched circuits for all of the reasons mentioned above and a few more.
Most,if not all automotive breakers will not trip on these short inrush currents and can be designed to more closely match the motor circuit and have the advantage of automatically resetting should a problem arise.

NOw, this may seem a bit too long...but I just wrote a big dissertation in Northern Rodder Magazine and Southern Rodder Magazine on this very subject. I hope you will reconsider your view.
<HR></BLOCKQUOTE>

Now really Jack, is there an answer to the initial question? We both know that MTBUR is a more important factor to the user than MTBF.
I found that the best way to limit in-rush current was to design ahead of the load. But that's just me.
"but I just wrote a big dissertation in Northern Rodder Magazine and Southern Rodder Magazine on this very subject."
Yeah, but you guys always leave out the California views.
 

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Hey John,....I am not familiar with the "California view" other than ocean and mountains. What is the view? Can I look it up in my circuits book? LOL!

I am not sure what you are after here? Are you saying that relays are not effective technology and design sufficient? What about OPMTP of circuits? This should be taken into account as well.

You and I both now that DC Buss Sequencial Relaying is solid technology for specific reasons regardless of MTBF or your liking.



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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm
 

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Steve
Sorry. I should have included more in my response. Quick responses, on my part, always come out sounding wrong.
While your idea is one way of doing the job, it is does have flaws. The mechanical relay has always had inherit flaws. The one that comes to mind, at the moment, is the "sticktion" of the contact pivot. This occurs if the relay has sat for a while. The coil, run at it's rated voltage, can not overcome the mechanical pivot resistance. This is seen more at temperatures below ambient but does occur at ambient.
While I can't say relay cycle testing is flawed, it is written in such a way that this effect won't be seen. It allows the manufacturer to exercise or warm up the relay prior to test start. Otherwise, relay MTBF would be far lower than the published figures on any given lot.
Commercial manufactures rely on the old military specifications for the basis of their testing. I don't have access today to more information. If you care to do some additional reading, I'll dig up a site tomorrow where you can download basic specifications such as MIL-R-39016. In there one can see that the testing gives the advantage to the manufacturer. I would expect a circuit to work first time -every time, but a mechanical relay doesn't have to.
 

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Hey John....no offence taken at ALL as well as none meant.

Usually wide temperature performing automotive relays are pretty good at performing the tasks that they are designed and applied to. Some of the newer automotive relays do not have pivots as designed by Volvo aircraft. They have only floating busses spung by high grade stainless with copper contacts and held in operational range by a window restictor. Pretty cool stuff, and omits any mechanical issues with friction points. Have you seen these? They have average lifecycles in the millions of operation! Of course this is somewhat current related as you would know just due to contact issues, not mechanical operation issues!

Any information, eps MIL specs, that I can learn from I always have an open door to. If you have time fine...if not no big deal. Thanks for the offer.

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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm
 

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Discussion Starter #9
Steve, John...

Thanks for all of the technical info. I must admit it is above my head. Could you please give me an idea of what to use in laymans terms?

Thanks

Bob
 

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My opinion for what it's worth. I agree with Steve that it is foolish to run an auxiliary fan circuit to a switch in the cabin. The power source (battery) and the load (fan) are two feet away from each other under the hood.
Not so on a folding top. The battery is still up front while the motor is in the back. You will still have large lines front to back no matter how it is switched.
The example, of the aux fan circuit, uses only one relay. The bi-directional folding top will need two, along with a bi-directional switch.
Chevy uses a single pole, double throw, center off switch on cars of this vintage. Perhaps a relay would be a good improvement but haven't heard a lot about extensive failures of the factory folding top switch. My opinion is to hook it up with a switch just like Chevy did.

Steve
This should get you to a lot of Mil specs. Try clicking on this link. This is not a complete list but as good as I can find for a free access site. No chance to read through this stuff searching for the proper paragraph. Maybe in MIL-STD-202 but that document is huge.
In the DODISS ID number block, enter the number you need. Should be able to print it out through Adobe. http://stinet.dtic.mil/str/dodiss4_fields.html

EDIT
Oops. The original question. I'd hook up the switch feed line to the fuse block. Chevy used an "always hot" or BAT terminal to run the switch. Their was not fused but adding a fuse or a breaker in that line is always a good thing to do. Shouldn't have a problem operating the motor unless the car is running, lights are on, heater on full, and trying to light a cigarette all at the same time.



[This message has been edited by John_Muha (edited 09-03-2002).]
 
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