[aprssig] Re: OT - DC Auto Charger with auto cutoff

Robert Bruninga bruninga at usna.edu
Tue Jul 20 10:04:54 EDT 2004

>>> "KC2MMi" <kc2mmi at verizon.net> 7/19/04 10:06:23 PM >>>
>>When considering operating mobile/portable do not 
>>overlook the DIRT CHEAP uninterruptible power supplies 
>>that are showing up in junk piles and at hamfests. >
> Um. Except many.most of the cheap ones are designed to 
>run off gel cells, which run at a significantly lower voltage 
>than wet lead or AGM batteries.

Hummh..  All the ones I have found, are using either 
12 volt or two 12 volt batteries and the battery chemestry
is similar and so they will  work just fine from a car battery.

> They will not optimally charge "vehicle" batteries, and 
>although they make great cheap inverter/chargers...
>they're also designed to recharge ... at something like a 
>20-hour rate, a very slow charge.

Yes, true, I agree..  But in many HAM mobile applications, 
re-charge time is not an issue, the UPS and availability of 
battery generated AC is either to fill in emergency power 
interruptions or short term sourcing of power.  The requirement 
for -high-amp rapid charging is unusual in the typical "field
day" style of ham radio operating...

Anyway, they are cheap and very useful...

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