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Power supply and battery connected together?

remember that when you turn up a 12v supply to 14v, you de-rate the current capacity a bit.
also, these supplies aren't made to be run right at their max for very long.
they are intended to be run at a lower output then they advertise.

i think you are just pulling too much current for what you have available, and the cheapest solution is to just buy a 600w (50 amps at 12v) switching supply.
I see them for under 40 bucks on ebay from the US with free shipping.

im surprised you were able to get your supply up to 14v without changing a resistor, as in my experience, they rarely get much above 13 volts without a modification.
LC
 
loosecannon said:
remember that when you turn up a 12v supply to 14v, you de-rate the current capacity a bit.
also, these supplies aren't made to be run right at their max for very long.
they are intended to be run at a lower output then they advertise.

i think you are just pulling too much current for what you have available, and the cheapest solution is to just buy a 600w (50 amps at 12v) switching supply.
I see them for under 40 bucks on ebay from the US with free shipping.

im surprised you were able to get your supply up to 14v without changing a resistor, as in my experience, they rarely get much above 13 volts without a modification.
LC
Click to expand...
The Megawatt power supplies are tough designs and will deliver as advertised.
I never had any problems turning up the voltage to 14.5 volts.The following is directly from Megawatt Power supplies website:
We at MegaWatt Sell High Quality Power Supplies for Ham Radio, CB Radio, Linear Amplifiers, Shortwave Radio, HF and Audio Amplifies.

Great RV and Car Battery Chargers too. They also work with RC Battery Chargers, Car Stereos or for the use or testing of any 12 volt electrical devices in your home or business.
 
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i've used a couple of the megawatt power supplies to replace the stock ones in 2995's.

i liked them but could not see any difference between them and the cheapos.
(that doesn't mean there aren't any)

cant remember whether or not i found the resistor already changed in them.
LC
 
loosecannon said:
i've used a couple of the megawatt power supplies to replace the stock ones in 2995's.

i liked them but could not see any difference between them and the cheapos.
(that doesn't mean there aren't any)

cant remember whether or not i found the resistor already changed in them.
LC
Click to expand...
There is a posting on this website that shows a major difference in radiated "Birdies" and shows up on the spectrum analyzer. Here is the video of a proper test.
https://www.youtube.com/embed/pLIbzICKqaA
 
Last edited:
well im sold.

the video is pretty telling, but it's this pic that i think really illustrates his point:

two-power-supplies-jpg.15455



thanks for that Tallman!
LC
 
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That's funny, as that brand clone is the exact one I have. It doesn't have that turbine winding down in it though, but then again, it is always on and doesn't have to warm up.

OK, now here's another question. How big of an amp plus Galaxy 88HL would a 50A run? I have a shooting star 225 on it now, and that on sideband is my big issue, and I have considered an upgrade some day, like a RM Italy 7505 with fan. Would the 50A be sufficient? If I have to go bigger, I want to do it only once.
 
Cutlass327 said:
That's funny, as that brand clone is the exact one I have. It doesn't have that turbine winding down in it though, but then again, it is always on and doesn't have to warm up.

OK, now here's another question. How big of an amp plus Galaxy 88HL would a 50A run? I have a shooting star 225 on it now, and that on sideband is my big issue, and I have considered an upgrade some day, like a RM Italy 7505 with fan. Would the 50A be sufficient? If I have to go bigger, I want to do it only once.
Click to expand...
Do you have a ham radio? I can duplicate those result with the El Cheapo I bought before I got smart and started buying Megawatt.
 
Tallman said:
Do you have a ham radio? I can duplicate those result with the El Cheapo I bought before I got smart and started buying Megawatt.
Click to expand...

No, I'm using it on a Galaxy 88HL and Galaxy 939. Someday I'll step up my game to licenses, but for now, CB does me fine.

I imagine the difference in radios makes a big difference.
 
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Well, got my 100A p/s today, 2 days early!

Hooked it up in place of the battery, unplugged the 30A, and have tried the amp and radios. AM still drops on the RMS scale, the fan has kicked on once now while just the 2 radios on. I thought maybe the 30A is pulling power in some way, so I disconnected the output wires from it. 100A still gets warm. I didn't think 2 radios just "on" with no TX or other loads would pull that much - I figured 10A(?) that the pull at idle would be something it could handle without heat.

Ordered some terminal studs to rework my connections better. Also plan to eliminate the 3 Farad capacitor, this thing should not need the help.

One note, it arrived in a USPS shipping box, 2 pieces of cardboard in the box from being a spacer somewhere, but it failed because the one outside corner of the fan is broken off. I will have to replace it. I am just hoping nothing inside is bad. It was listed as a scratch/dent model, tested out as 100% working order. I messaged the seller (ebay seller) to see what they say...
 

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