> would pull way too much current and seemed like a waste of current.
POWER!!
The relay shown is 12V 41.7mA or 0.500 WATTS.
That is about the power needed to pull a clapper with that many contacts that big. Reed relays can work on less power, with fewer smaller contacts. Automobile starter relays have one BIG contact, need 10-20 Watts to pull that sucker up (and against the spring needed to bust it loose after 200-Amp load arc-welds the contact).
You can buy those Omron G5v in 5V or 48V, maybe custom in 1V or 100V. But the WATTS is what pulls the clapper(*). So you could get 1V 500mA or 100V 5mA.... it is still 0.5 Watts per relay.
> Your problem is a 6 of one half dozen of another
Or maybe: 12 of one and two half-dozens of the other.
> series? If I had a parallel setup, the current draw would add per component draw, right?
Yes, but the voltages don't add in parallel!
The real thing is: how you gonna turn them off? Unless all relays are on all the time (why?), it is usually much easier to run the relays in parallel so the switch or transistor return may be common to all.
> use a current limiting setup. ....to keep current down.
This works like putting an orifice in the shower head. If large, it has no effect; if small, it doesn't work right.
Eight relays at 0.5 Watts each is 4 Watts. You need a 4W power supply.
Relays do NOT need regulated power. The Omron G5v will work at 80%-200% of rated voltgae.
On a clean-sheet design, you could use "any" power voltage. But these are AC relays, we live in an AC world, we need a rectifier. Rectifiers have 1V-2V loss, We want to keep the system voltage well above 2V so we get more power on the relays than in the rectifier. That suggests going past 100V, but the fine wire needed to wind the relays raises the cost, also 2-cent transistors are rated 40V so even a 48V system costs more.
Use a 12VAC or a 24VAC winding with ample Power as determined by summing the loads. Rectify and filter slightly.
> 24V transformer that is used to double up for phantom
1) "Phantom" is usually about a Watt total. If you "add" a 4W burden to a 1W supply, it gets unhappy. You need to design for ALL the loads, and the relays are not negligible compared to Phantom.
2) most "doublers" will not happily give large output at half the double-voltage. 600V at 300mA with a 300V 30mA tap makes sense. 48V 20mA with a 24V 333mA tap does not make sense.
3) you can get 48V Omrons. If you do your switching with transistors, you must pay the 0.5-cent extra for 60V transistors. If you do it with switches, you are right AT the 50V rating of most cheap switches. And since relays are clacky, and Phantom should be clean, and Phantom should be regulated while relays don't care, it is wasteful to hang more than 1 or 2 relays on a Phantom line.
> what calculation do you use to get 7V
> I'll need some time to digest the math.
You are very weak in Ohms Law. I tell you, you MUST understand basic battery and resistor problems before you will be comfortable at any electric design or modification. If I tell you my battery is 12V and my O2 heater is 3 ohms, what is the Current? What is the Power? If I say I need this heater to give 20 Watts, what battery should I buy? Do a hundred of these pointless exercises every morning for a week, you can do them FAST which is the only way to move ahead to real problems.
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(*) Yes, in a single turn, the pull is proportional to current. But we always use a many-turn coil. 100 turns at 10mA pulls the same as 200 turns at 5mA. The total coil size is limited by relay frame. When you figure out the smaller gauge to fit 200 turns, you find the resistance has quadrupled. So double turns needs double voltage and half current to give the same pull. It comes to the same Watts.