[450] battery backup project

[Bob]

Your input has already led me to the plan of putting them in a box outside 
the window and cabling into the shack.....it's only a few feet away....

----- Original Message ----- 
From: "George Andrews" <gandrews at ntplx.net>
To: "144.450 Mailing List" <450 at lists.vhfwiki.com>
Sent: Monday, December 14, 2009 10:30 PM
Subject: Re: [450] battery backup project


> Bob,
>
> Not a problem. I still push the envelope. Tried recharging a rechargeable
> Lithium Ion battery in the last year. Got a little over confident in my
> understanding of the rate of change of temperature. The AA battery went
> bang. I had to get out the full face gas mask to get in the room! Had to
> open the window and put a big fan in the window. It took three hours or so
> before the air was of breathing quality. It took several hours more to 
> clean
> up the debris. The AA battery was reduced to a large number of chunks, 
> none
> bigger than gnat size. Glad no one or the cats were in the room at the 
> time.
> It was enough to keep away from rechargeable LiIon batteries! I was 
> finding
> pieces of the battery for six months afterwards.
>
> George
>
> ----- Original Message ----- 
> From: <n1ujs at toast.net>
> To: <450 at lists.vhfwiki.com>
> Sent: Monday, December 14, 2009 6:34 PM
> Subject: Re: [450] battery backup project
>
>
>> Thanks for your input George.  Always good to hear
>> from a man of science.  I tend to be more reckless in
>> my "mad scientist" endeavors of course, but will take
>> your warnings under advisement!
>>
>>
>>
>> ------- Original Message -------
>> From    : George Andrews[mailto:gandrews at ntplx.net]
>> Sent    : 12/13/2009 12:25:30 PM
>> To      : 450 at lists.vhfwiki.com
>> Cc      :
>> Subject : RE: Re: [450] battery backup project
>>
>>
>> Bob,
>>
>> I would only trickle charge the batteries as a
>> routine (100 mA or less) once they are brought to
>> full charge. Much better is to
>> charge such batteries as needed. These do not appear
>> to be SLA's, so there will
>> be venting. What gets vented is Hydrogen gas
>> (flammable, can have an explosive
>> concentration issue and over time, years, will belch
>> a very tiny amount of
>> dilute sulfuric acid). Hydrogen flame is invisible
>> unless it is burning
>> something else. I would keep such a setup out in a
>> well ventillated
>> garage and consider the fact that car batteries can
>> explode. Hydrogen
>> builds up, there is an arc inside the battery or a
>> source of ignition external
>> to the battery. This will splatter the sulfuric acid
>> over an area and on people
>> if you happen to be nearby. Then there is the
>> shrapnel from the battery
>> case!
>>
>> I had a battery blow up in a 64 Chevy. It was a
>> Sears battery with a year or so to go on the
>> warranty. I thought I was the
>> victim of a car bomb (radical politics days-thought
>> the Birchers got me) and my
>> ears were ringing for hours afterwards. The only
>> idenfifiable part of the
>> battery case was th botton inch or so and some of the
>> lead plates. It was
>> terrible decontaminating everything under the hood!
>>
>> The inverter will be expensive and might generate
>> noise on HF.
>>
>> All my stuff is 12 V, including a CFL that lights
>> up the shack.
>>
>> The 130 A/hr telcom batteries at the hamfest are a
>> better idea.
>>
>> You could build a Schottky diode device to trickle
>> charge and automatically switch over to battery on
>> power failure.
>>
>> George
>>
>>  ----- Original Message ----- 
>>  From:
>>  Bob
>>  To: 144.450 Mailing List
>>  Sent: Sunday, December 13, 2009 11:44
>>  AM
>>  Subject: [450] battery backup
>>  project
>>
>>
>>  Successfully revived two Orbital batteries for
>>  backup purposes.
>>
>>
>>  Battery specs. are here:
>>
>> http://www.remybattery.com/Products/Exide-Orbital-ORB78DT-84-Starting-Battery__ORB78DT-84.aspx
>>
>>  The plan is to tie them together as a backup
>>  supply for the entire shack in conjunction with an
>> inverter (anyone got one
>>  cheap to trade or sell?).
>>  Total cash outlay so far, $18.00 ("core
>>  value" for the two batteries).  They were new, but
>> on the shelf at
>>  work since '05.
>>  They seem to be good as new after charging with
>>  my Samlex APS 1215 (shown below, 15A cont., 20A
>> surge) which will be devoted
>>  to keeping them charged.
>>
>>
>>
>>
>>
>>
>>
>>
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