[aprssig] Prius Power for Field Day

Ray Wells vk2tv at exemail.com.au
Sat Oct 13 00:58:19 CDT 2007

Steve Noskowicz wrote:

>>>Oh and I load tested it at 120VAC input and at 21
>>amps it was down to under 10 volts.  So it does not
>produce the 23 amps at 13.8 that the nameplate
>I noticed that most Ham switchers are *advertised*
>with the  peak current rating rather than the
>continuous rating (mentioned elsewhere in fine print).
> So perhaps you wound measure somewhere around 18-20
>A. continuous.
>73, Steve, K9DDCI
I use a switchmode supply that comes from a Chinese manufacturer that is 
rated at 40A continuously. It delivers 44A before it goes into foldback. 
At some point thereafter (that I haven't bothered to measure) it trips 
on overload until the load is removed. The supply is also very RF 
friendly with S0 being the standing background noise on HF in my rural 

It flies under the brand of Powertech in Australia. That even sounds 
impressive, hi.

The circuit shows no provision for operation outside the range 207 - 
254V so I don't know if a 110V version exists. The test results indicate 
the P/S was intended for the ham radio market because it was tested for 
the effects of RF at 437MHz and 144MHz with a 5W tx. (Given that the 
Australian ham market isn't large enough to attract manufacturers I 
suspect the US market may have been in their mind.) The current figures 
I see align well with the production specifications of 40A continuous, 
with protection current starting point being 43A (min), 43.5A (typ) and 
44.5A (max). Other specs include over-voltage protection (16/16.5/17V), 
load regulation 200mV from 0 - 100% load, line regulation 50mV from 
207-254V. Efficiency 80% for 13.8V/40A and 82% for 15V/40A. The 3 digit 
panel meters are +/-1% accuracy. The manufacturer's identification is 
SPS-9400 but none of the documentation carries a manufacturer's name. 
The name Powertech is one used by a local supplier for a range of power 
supply products.

These power supplies are an excellent choice for a ham shack.

I have no association with the manufacturer or the supplier, I just 
happen to own one.

Ray vk2tv

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