Jim,
I found that even with several batteries in parallel, the operating
voltage would drop below the 12.5 volts that my rigs like rather quickly. I
went a different route. With 3 batteries in series, I get about 38 volts
DC. By running that 38 volts through a Series Pass Regulator ( just like
the Power Supplies use. ) I can keep the voltage at a useable level for
Many more hours. Also, in an Emergency, the usable life of the Battery
Backup is Greatly extended. The batteries can be run through their complete
discharge cycle and still be useable. There are many UPS Backup supplies
that use 2 or even 3 batteries in series.
Building the Beast for 38 to 13.6 is not a real problem. The Schematic
from any quality power supply can be copied. As an alternative. Just
replace the Main Voltage in a 35 Amp Power Supply from what is produced by
the Transformer and Rectifiers/Capacitor, with your Battery Voltage. Make
sure to Fuse the Input from the Batteries at 35 Amps! You then have
Over Current Protection ( Crowbar) and if the Supply is adjustable. Those
features still work also. Note..... A small battery to run the Regulator
and Aux circuits may be needed according to the PSU Design for Power
Outages. I just used several Series Pass Transistors on a Big Heat Sink and
an LM7815 3 terminal regulator. ..... 15 volts minus the .6 voltage drop of
the Pass Transistors equals 14.4 volts .... Now add another .6 volt drop
using a Silicon Diode and you have the perfect target voltage of 13.6
volts. A Crowbar or Over Voltage Circuit is very easy to build.
As to the Lithium Ion Batteries, It is my belief and only my opinion
that the life span and cost of Lead Acid batteries, would be more
economical. Have a Great Day Jim and 73!
Wade/KJ4WS
On Tue, Sep 10, 2013 at 1:18 PM, Jim Hicks <n7ino@yahoo.com> wrote:
> I use 6 deep cycle batts charged from solar or can use wall charger. I
> feed a inverter to power supply so the shack always has 13.8 volts. Deep
> cycle batts hold up well and about $ 85.00. My ups for computer has been
> changed over to out board deep cycle batt. and will keep me up and running
> for about 8 hours. Run time is great and I think its the only way to go. 73
>
>
> Jim and the Girls
>
>
> ________________________________
> From: denton sprague <denton@oregontrail.net>
> To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
> Sent: Monday, September 9, 2013 1:23 PM
> Subject: [TenTec] lithium ion batteries or ups?
>
>
> the other day I was at a battery and light shop to get a couple of
> replacement batteries for one of my ups units.
> I noticed they had rechargable lithium batteries presumable for cars…very
> light, small but pricey and had comparable ratings to full sized lead acid
> batteries…
>
> Wonder if anyone has used these in a ups(uninterruptible power supply)
> before?
>
> My station 3kw ups uses a 48 vdc, 76 amp hr vdc battery pack that will be
> due for replacement one of these days.
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