Hey All,
First I want to say I am a big fan of Trend's products and have the Air Pro Shield, and use it daily. Customer service at Trend is the best and has always given me more than I asked for. I have found though, that the replacement battery packs to be very expensive from $65-$80 at most places, and my last two Battery Packs didn't last much over a year. I decided to find an alternative to the price and found batteries with the same voltage and have approx the same rating for ah. The case of the 8 hours pack opens easily with tabs and after cutting away the hot glue on the battery pack I was able to see the wiring configuration. I duplicated that with a few soldering connections on the new Batteries found here. http://www.batteryjunction.com/tpeh-t43a3600p.html I used the existing leads and bought the new batteries with soldering tabs on them. It made it much easier to solder to the new batteries. It took about 30 minutes to replace batteries in two battery packs. I used flux on the tabs which made soldering a breeze. I just finished them yesterday and charged them for 12 hours so far. The new batteries fit perfectly in the existing pack, so there is need to change anything other than the batteries. Note: The replacement battery is not AA. It is a 4/3A and bigger than AA, so keep that in mind when searching for replacement batteries. This morning I tried both re-built packs in my Trend Air Pro and found that they seem to work very well. The true test will be after a long day of turning. I will post a tutorial later, if there is any interest. I bought 6 batteries with tabs and paid a total of $27 with shipping. That is enough to do two battery packs, which would have cost an average of $145. Disclaimer: This procedure is not approved by anyone and I don't assume any responsibility for those wishing to duplicate it. It was a personal test to find an alternative and so I don't endorse the process or even recommend it to anyone.