1. The Air Shield comes with one battery that lasts for 4 hours. You
can plug another battery into the unit with the first battery and
increase your run time to 8 hours. At first glance this arrangement
might seem okay.

2. The battery charger is a wimpy little plug in charger similar to an
entry level cell phone. This charger takes 14 hours to charge one
battery to full capacity. It would take 28 hours to charge both
batteries to full capacity so I could use them for 8 hours. I've now
used up the better part of two days to get one short day of use out of
this thing. So I thought that I would purchase another charger. The
price range for this charger is 75 to 120 dollars for a charger that
probably cost $1.50 to make. I am not about to spend that kind of
money on a cheap charger.


http://www.batteryspace.com/

I can't find exactly what kind of battery pack the Trend uses. But
the above place sells welded together battery packs in whatever
voltage and type of battery cell you want. Also check NiCad Lady for
battery packs. NiCad Lady uses name brand quality battery cells
instead of no name ones. The above link does have battery chargers
for any and all kinds of batteries. Smart chargers that have various
protection circuits built in and sense the amount of charge necessary,
etc. $30 or so. I have one and it charges 4000mAh 6 volt NiMH packs
just fine at a 1Ah or 2Ah (selectable based upone mHh of pack) rate
until it senses the battery is charged. There is no law in this
country that requires you to use the official brand name accessories
on a product. No one questions whether you can use a Freud or
Forresst sawblade on a Unisaw. Or use a Milwaukee bi-metal
reciprocating saw blade in a Makita reciprocating saw. Why would
someone think they are required to buy Trend brand batteries and
chargers for their Airshield?