Question on Diodes

[RLC]

I’m doing a circuit on a motorcycle where I need a diode to block the 12vdc from bleeding back and powering up other components. My question is if I twist the cathode leads together then the anode leads together on 4 50v 1amp diodes will this give me a diode that would handle more than 1 amp? Hope this makes sense to the EE’s on here. I cant’ find a diode rated over 1 amp locally and was wonder if this would work. Thanks in advance.

[Al_The_Man]

That should work OK, what is the current when it is forward biased?
Leave the leads full length as the copper leads constitute the heat sink on a diode.
Al.

[RLC]

Al,
thanks for the reply,the current draw is 1.5 amps. What I am doing is this, its a custom bike with 3" monitors mounted behind mirror tint glass(they look like the mirrors for the bike), their is a mini camera in the tail of the bike. this all works fine now but when it is on display at shows we are running them off of a power supply, the diodes are there so we dont power the motorcycle do to the fact they are wired to come on with the key as well.

[Al_The_Man]

Four should handle that OK. Is the power supply isolated and grounded for safety?
Al.

[ViperTX]

Well....you would be better off with a switch....with the diodes you will have reverse leakage....not sure what other components you may have that are affected by that....probably none if the key switch is off, but you apparently see something otherwise you would be asking for a solution....what is it that you see??

Also adding the diodes is going to introduce a diode drop in voltage....don't know if that will affect whatever circuitry is in your monitors.

[RLC]

Al,
The ps is actually just another 12v battery that can be easily unplugged at night. Most all of the custom shows require that the battery be disconnected and the fuel drained. A lot of show bikes are just that “Show”, some don’t even run. This one gets ridden as often as possible. Disconnecting the battery is no big deal, just a pain. I have mounted a terminal strip with in the tail and ran 2 positive leads one going to the m/c battery which has a switch (open when on display) and the other to a connector for the outside power source. Not the best diagram, but this is what I’m going to do below “>” and “^” being the diodes. The diode on the “Bike” side is so I don’t back feed the harness of the motorcycle. It has a digital ignition that has an auto power off but I have still seen them smoke if the bike isn’t running and there is power to them, the old CDI’s (capacitor discharge ignition) where real bad about that, key on, bike not running = big bucks in repair parts


Aux power + --------->----:----- load
|
Bike power + ---------------^

[RLC]

This might make things a little clearer, not sure if I use the correct terms or not

[Al_The_Man]

That seems a bit of a design flaw if the Digital ignition can't take power if the bike is not running.
But if the diodes are on the Bike side, it should be OK.
Al.

[RLC]

Al
the new ignitions can, both the cdi and tci ignitions have timers to kill the power if the are not doing anything. I have seen 2 tci ignitions fail because the key was left on..just not taking any chances, I tried to up load a pic..but it didnt work. its in my photo gallery

[RLC]

viper,
switch would be the easiest, just not much room to hide things any more, 2 monitors in the mirrors, cam in the tail section, dvd player, NOS, neon lighting led strobe, XM radio, remote starter, and i'm sure ive missed something, the only saving grace is that it is a sport bike (full fairing and plastic body parts) so it use to easy to hide things, Some of my Harley customers are want some of the same stuff on theirs, I just cant find the hiding place on the custom HD's

side note: I have tried several times to insert a pic in a post like see all over the zone, but never can seem to get it to work, whats the trick?

[Al_The_Man]

The drawing seems OK, are you paralleling four up?
Al.

[RLC]

yes there will be actually 8 total, 4 per symbol on the drawing. I havent wired anything yet, I will do it in the morning, was wanting some imput before I spent time on something that wouldnt work