The 2500 charger does not like my power source!

I tested the 2500 Smart Charger in my car using cig. lighter and it worked without flashing red. The place it fails is in my house using a 12V DC 500ma and/or 1500ma output... this is an AC adapter from Radio Shack... I use it with another charger I have from ParkZone and works fine. So the Smart Charger does not like something about my 12V output... any ideas? Is there an adapter that works with the Smart Charger?

From : Don Stackhouse

I'm surprised your other charger works on that adaptor. Most of those simple converters have a lot of ripple in their output voltage, and that confuses the computer in the charger. I use a battery to power the Smart Charger. A car battery works great, although it's a bit heavy and bulky. Motorcycle batteries are much better in that regard, although there is still the problem of possible spillage. My favorite is a 17 amp-hour gel cell I bought at a surplus company (Mendelson's Electronic Surplus in Dayton, OH) for $20. It's small and light enough to carry around conveniently, so I can use it both at home and at the field. I've had it about 5 years now and it's still going strong. A cheap car battery charger keeps it charged, and then I can run several chargers for a variety of batteries from it simultaneously. I've had as many as three small NiMH chargers and two Li-poly chargers running from it all at the same time. I also have a large sealed-type deep-cycle car battery I bought at Sam's Club some years ago for powering a winch for sailplanes, and it does a great job as well. The only drawback with it, of course is the weight.

You may be able to find a power supply with a smooth enough output to run the charger. There are some laboratory power supplies that you can get fairly cheaply from places like Radio Shack or Jameco that will work. It may also be possible to add some large capacitors across the output of your present adaptor to smooth its output sufficiently to make it work. However, that still leaves you with something that only works where you have a 110 volt socket to plug into. I've also heard of folks using an old power supply from a PC as a voltage source. Those have a 12 volt output as well as a 5 volt output, and from what I've heard you need to put a resistor across the 5 volt output to give that portion of the power supply something to do, in order to get the 12 volt side of the power supply to regulate properly. It takes a little tinkering, but properly done it works.

However, the car or motorcycle battery and a cheap car battery charger from the automotive section at your local discount store is the safest bet.

Don Stackhouse
DJ Aerotech