[SMCARA] Used Power Supply

Tue Nov 4 12:20:35 EST 2014

Quite right about the chargers, Gene.

Those little "Battery Minder/Battery Tender" type devices work great for keeping your boat battery or the one in the convertible that only comes out when the sun shines and it is short sleeve weather, from going dead!  A couple of things to watch out for; they will not charge/work if the battery voltage falls below 11 volts or so, and some are awful noise (aka RFI) generators. Additionally if you try to charge a couple hundred Amp/Hour battery with one, it will take forever, as they only put out an amp or so.

 I recently purchased a computerized, 15 amp  charger that has charge mode, float mode, and restoration/pulse mode, which helps reduce sulfadation on the plates.  It also will not start charging if the voltage is below 11 volts.  It takes a couple of amps from a "dumb" charger or a hefty power supply to get it above 11 and allow the charger to do its thing.

On the positive side, they monitor the voltage of the battery and do "shift gears" from a charging mode to a  float mode.  The float mode keeps the battery from outgassing, which is deadly to a cell.  The old lead acid cells could be "topped" up with electrolyte, but the SLAs and Gel cells just let the gas escape and there is no way to replenish the electrolyte, thus transforming it into a doorstop.

Every once in a while you will hear someone on the repeater or on HF with horrible hum on their signal.  If you use your HT with the "wall wart" charger plugged in, that will do it.  Same effect on HF if you have a charger on the deep cycle battery powering your rig.

73 Tom/W4OKW

-----Original Message-----
From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Eugene Guazzo
Sent: Tuesday, November 04, 2014 6:04 AM
To: Tom Clarke
Cc: smcara at mailman.qth.net
Subject: Re: [SMCARA] Used Power Supply

Change/Shift in subject ---  Don't know whether Tom is just using the "old"
word (trickle charger) but the circuitry in these mini-chargers has been changed so that they don't keep on mini-charging after the battery is fully charged.  "float charger" (the newer circuitry) apparently "shuts down"
when the battery is fully charged, preventing overcharging/damaging the battery (?) We use float chargers here on the farm to keep our stand-by, battery-start gas generators ready to go (power outages are not uncommon in downtown Maddox, Maryland, pop. 60)  --- 73  gene KA3ZZF

On Mon, Nov 3, 2014 at 11:13 PM, Tom Clarke <w4okw at md.metrocast.net> wrote:

> A 12 volt battery will work for a while,  but most HF rigs go a bit
> daffy as the voltage sags.  You may get an hour or so out of a fully
> charged battery.
>
> If you operate the rig with the trickle charger on the battery, you
> will windup with hum on your transmitted signal.  A trickle charger
> will also take forever to recharge a depleted battery.
>
> Look for an Astron 20 or similar.  Some surplus houses sell switch
> mode 25 amp supplies that will do the trick.
>
> I have an old Bullet 25 amp linear type power supply that probably
> qualifies as the ugliest PS in the county (possibly on the East Coast!).
> It is yours for the asking!. You could even fashion a cabinet and it
> won't be ugly anymore!  If you would like something nicer, I do have a
> Heathkit
> HP-1144 22 amp 12VDC supply for $50.
>
> 73 Tom/W4OKW
> 301-904-2053
>
>
> On 11/2/2014 4:26 PM, amajni wrote:
>
>> Hi Folks, I am looking for a used power supply for my IC7000.
>> Or, do you think I could use a 12v deep cycle battery with a trickle
>> charge.
>>
>> I was borrowing a power supply and my friend needed it back, so i'm
>> stuck without a way to power my radio.
>>
>> Thanks,
>>
>>
>> *April Holkok3alm*
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