DMCGONAGIL said:
I understand the relays and the fuse block/distribution block, but is it always necessary to use a solenoid, or when you have more equipment?
Great drawing for anything Halogen, Pretty over the top for anything LED. And I am not trying to derate the drawing by any means but there are some redundancies that only complicate the system, and are not needed.
Realistically, The solenoid is huge overkill for an LED up fit. Many Solenoids are generally rated for 85 - 100 amps, We carry them that can handle 200, and there are some that are bigger. Off the shelf relays are commonly rated at 30/40 amps NO/NC. Granted there are others of those as well, but they are not as common. So if your entire LED load is 7.5 amps, you could replace the $35 solenoid with a standard $5 relay, and be just fine. I would have 2 fuse blocks though, 1 ign hot and 1 batt hot.
I want to point out to; solenoids have 2 different ratings, Intermittent, and Continuous. I have heard so many people say "Go get a ford starter solenoid" for this type of system, which is wrong. The starter solenoid is intermittent duty and will not last. It is better to head to your local RV dealer and get what they will probably call a "Battery shut off" solenoid. What you really need is a “continuous duty” solenoid.
Relay triggers only take around 250 mA. So you could use a much smaller gauge wire from the switch to the relay. 18 is fine, but you could go down to 22 if you wanted with no problems. 18 is a lot easier to work with and will save you a few bucks.
The 10 gauge to the relays is great for high powered lights, but for LED, 14 gauge would be more than plenty and still meet
NFPA requirements, even on very long runs.
The Wigwag modules generally have a power lead, and a trigger wire. The power lead could go straight to the fuse panel, and the trigger lead to the switch, eliminating another Relay. They do not have any parasitic draw when they are off, so you don’t have to worry about killing your battery.
I also am not entirely sure why you have a relay on the siren?? I would run the siren straight to the fuse block and eliminate a failure point.
The inline fuses after the relays are redundant and not needed since you have a fuse block in place. If you had multiple lines coming off the relay going to separate areas of the vehicle, then those fuses could be usefull, but still pretty redundant.
I see why you would run each switch to an individual fuse, but again, redundant and not needed. It will add a spaghetti mess to your switch panel when really you only need 1 “switch power” lead that will branch off to each switch. If you were not using relays, YOU WOULD fuse each individually.
I would also add a diode across the coil of the solenoid, to help suppress the high voltage Coil inductance that can kill LEDS.
And not that this is on the drawing, but I feel I should point it out because there always seems to be confusion on this. All the grounds should go to a chassis ground, NOT to the battery. IF you want to go to the battery, you SHOULD fuse the grounds AT the battery. I know, seems weird, BUT say you hook your grounds to the battery lug that goes to the ground post, then the ground cable that attaches to the body, or to the engine block starts to fail or become disconnected, the only way the vehicle is going to get a ground to turn the starter, is to try and complete the circuit through the auxillary grounds you attached to the battery lug. This can do some serious damage to equipment. If you fuse those grounds, then the fuse should blow preventing bigger problems with your equipment, but to be safe, I would just run them to the chassis.
For someone that is trying to put together a very safe system though, this is a decent diagram and will be way overkill for most applications.