Friday, November 21, 2008

Battery testing and a good inexpensive charger

I have been testing a good number of batteries lately that have been coming out of UPS units where I work. I had 2 dozen sitting in my area last week. I am down now to half of that, but I have quite a few at home still that I need to check out (and a large pile that needs to be taken to the recyclers too).

In order to do this, I needed to be able to charge the batteries up in order to run them down with my tester (a CBA II). I found a really nice charger for a really good price - a Tempest BC-1250. I ordered 2 of them and so far, I really like them. They are well built (metal cases, sturdy cords) and the voltages they use are just right for the SLA batteries I use. If you have batteries sitting around going dead, don't wait - this charger is worth the $32.50 - you need to charge them up periodically so they don't sulfate and kill themselves. If you charge them up separately first, one of these chargers should be able to maintain several small/medium batteries connected in parallel.

Since I go through at least 2 charge/discharge cycles on most batteries, it has been nice to have a couple of extra chargers (I can drain them a lot faster than I can charge them). They have been perfect for the relatively small batteries I've been working with (mostly 7 & 12 Ah, but a few 18's also). For larger ones, I still have my other bigger charger.

For something that can maintain (or very slowly charge) a battery at the proper voltage, get one (or several) of these Float Chargers from Harbor Freight.

Tuesday, November 18, 2008

Getting APRS running again

I'm going to try to get my digipeater running again. I swapped the dual port TNC I was using for a single port that has APRS capable firmware. I won't be running an I-gate anymore, but there seem to be enough around here already. I just want it to provide extra coverage for the area.

This site in Finland is doing some really cool things with APRS. It's best to use your callsign as your username, but make something up if you don't have one, or don't want to give it.

So, the first thing I've got to do is get a USB to serial adapter to connect to the computer so I can program the settings in the TNC. Once I set it up, it can be disconnected from the computer (a major source of problems in the past) and run on its own.

The radio is a Phoenix SX 16 channel and puts out somewhere around 30 watts. The antenna is an 8 foot Diamond X200 clone installed on my roof about 30 feet up. Power is supplied by a home built power supply that float charges a 75 AH battery.