samlex voltage-sag is causing an undervoltage-reset issue
 

I have an HT that draws 1.9 amps when transmitting, and the voltage can't
sag more than 2v or the HT does an undervoltage reset. I just bought a
samlex 12v, 4amp power supply to run my HT but there's a problem. The
samlex 12v output voltage begins to sag as soon as the mic is keyed and the
amount of sag increases steadily until 3-4 seconds into the transmission the
HT does an undervolt-caused reset because it's input voltage has sagged 2v.
I might not be able to return the samlex to the shop and replace it, and I'm
wondering if there's something that can be done to enable me to use it some
way, somehow to power my HT. The HT will work fine on a reduced
transmission power setting but then I can't reach repeaters. I have another
wall -wart plug in adaptor that puts out 1700mA at 12v.
-Is there some way I can combine the two power supplies together?
-In parallel maybe? Parallel would probably work if they were batteries
because I know in series the voltage would exceed the max of 16v.
-How about some kind of arrangement with a transformer?
-If I get a lead-acid, 12v, 10amp/hour battery, how complicated acircuit
would I need to charge the battery from the samlex? is this a possibility?

Thanks for all the help. The problem has been solved. You were all very
helpfull.