CMB16D voltage

[Robert Burton]

I am playing with the idea to use a 25amp power supply for my board. It has a 13.8v output. Will the CMB16D do ok with this voltage. May not have seen in the manual...but do not see what is the max voltage. I can probably get into this power supply and turn it down...but I am sure since it was built to operate at voltages close to 13.8v....it would be happy close to that instead of 12v.

????
Robert

[JBullard]

The CMB-16 can handle up to 60 volts.

[Guest guest]

I assume whatever devices you are trying to power will also be happy with 13.8V?

[Robert Burton]

That is a very good question on the voltages. I will be running 2 Rainbow Floods and 6 Rainbow Spots with this board. I may use it to switch a relay for something...but no worries on that one.

[huskernut]

So I am pretty sure pond-dude (Greg) stated the rainbow products shouldnt be run that high? Close isnt close enough if I remember correctly.

[rmturner54]

The RBF's were designed for 12VDC. You will need to recalculate for different size resistors if your using anything other than 12VDC.

I havent actually done the math to see what the tolerances are + or -, but typically most calculations for LED's are done with 20ma standard. That seems to be there happy place. And with resistor values calculated using 20ma you can get away with some variances in supply voltage.

[JonB256]

That power supply sounds like a battery charger. They don't usually have a very "clean" output and the noise could interfere with the controller.

[Robert Burton]

JonB256 wrote:

That power supply sounds like a battery charger. They don't usually have a very "clean" output and the noise could interfere with the controller.

Noooo. It's a "Radio Power Supply". I am a ham radio op. who builds repeaters that we use in conjunction with the NWS in the state of GA. I use to use this very one on one of my UHF repeaters. Pretty clean. Not to say that you can get a "dirty" supply. Honestly the switching supplies I keep seeing people use (and I still may consider using) are notoriously dirty. Granted they have gotten better on the filtering of those. This has a LARGE transformer in both of the ones I am considering. Probably weighs 20 or so pounds (the unit itself). That is food for thought though. I will put it on my spectrum analyzer before hooking it up to the board. Thanks for the suggestion :-)
Robert
KD4YDC
www.georgiaskywarn.com

[Steven]

I should have posted it here, but I started a new thread with info on the light-weight power supply I used.

[TJ Hvasta]

Hey Robert,

I'm going to use my Astron RM30A supply.. 'had been using it for my TS430, TM221 and -421 at home but sold them couple years ago, so the Astron has just been collecting dust. I also have a Motorola bench supply that used to power Micors during testing in a radio shop, so as they're pretty clean, and stable I figure it'll be good enough for the LOR board..

TJ, NS2E

[JonB256]

If your 13.8V power supply is not adjustable, you could do something simple like put a few Power Diodes in line. Silicon diodes will drop 0.5V (pretty much independent of the amount of current they are carrying). You could use 3 of them in series, and the amount of load you put on it would depend on the diode ratings. (for example, if the diodes are 5amp diodes, then don't load them over 4amps continuous). It is cheap voltage regulation!

[Robert Burton]

Just be careful what you are going to use with the LOR DC Board. Don't want you to fry any LEDs :-) I *Think* those things can either be "dioded" (good English...) to drop the voltage or you may be able to turn it down. Brain fried right now...still at school tonight! I THINK it is a shotkey (how do you spell that diode) diode that is sometimes used for charging up batteries in line with a repeater???? I know there is some voltage drop with that. Mmmm. Wonder what a couple in line would do? Might have to heat sink that bugger too. Just an idea. I know a few people have take the voltage higher to charge up batteries with that inline...and keep the repeater at a decent operating output. I know there are some ways to move those Astrons. You just might have to play with it...if you are needing to take it down to a 12v state.

I hit gold. Have some 5v supplies that we turned down and used 3 inline for a repeater power supply. (Many moons ago before I became power supply strong ;-) I think that thing would hold up 50amp pull great. Just have to be sure they will be stable and generate noise when dropping it. Switchers :-(

Robert

[Robert Burton]

Hey JonB526
Saw your post after posting the before this one.
That sure will work. Think I will check my stash of diodes and see what I can find. Might have to make a Rat Shack run ;-)
Great suggestion. Thanks!
Robert

[Robert Burton]

Yeah!
I had one ham radio power supply that was built out of 3 5v switching power supplies. (switching - lightweight but sometimes real dirty rf wise. Linear - BIG transformers most times...heavy. Cleaner rf wise) This supply had already been tested years back when it was in 24/7 use and would carry about a 50amp load. Much bigger than I needed, but found out each one is adjustable and each is fused :-) Real tricky to get it on 12v (turn this, turn that) but finally got it to 12.03v...steady. Looks like it is pretty clean on the specturm analyzer. Did find A LOT OF HASH right in the middle of the FM "Car Stereo" range! Guess if I ever change from 88.7mhz....will have to find out where that non-sense is coming from!

Still will play around with the other radio power supply (13.8v) later with some diodes in line...just to have a backup.

Thanks everyone for all the suggestions.
Robert