On Oct 24, 3:53 pm, Bruce Gordon wrote:
In article ,

John Davis wrote:









On 10/10/2011 4:14 PM, Bruce Gordon wrote:

I use a pair of L16HDs in series to power my shacks 12Vdc Buss. They

are feed by a Numar 35Amp Regulated Power Supply, that is set for

13.4Vdc. The Power Supply floats the batteries at 13.4 Vdc

If you are floating batteries you should consider a proper 3-stage
converter/charger..http://www.bestconverters.comis a good source of
those.. he specializes in RV converters. (By the way I have no
connection with him)

My Motor home has a Progressive Dynamics 9180 with optional charge
wizard. This is on the large size for a pair of GC-2 Golf car type
batteries in series... but man does it do a good job. a 8260 would b
e a
better choice for these batteries (one pair)

It has 3 charge voltages depending on teh battery voltage it either
limits current, limits voltage, or limits both.

If you are just floating the Batteries across a Regulated Powers Supply,

there is NO Need to go to the expense of a Three State Charger. 99%

of the time you will not be using the Battery for anything but a buffer.

The 1% of the time, where you have actually USED some of the Battery

Capacity, and are in Recharge Mode, the amount of current supplied to

the Battery, as opposed to the attached Load, only depends on the

battery Voltage, to Regulated Voltage Ratio, and that will just slow

charge the battery back to 100% Charge, and the Set Float Voltage.

What does a Three State Charger, give you, that isn't inherent in the

Regulated Power Supply Setup? Just wondering?

--

Bruce in Alaska add path before the @ for email

Bruce

A three stage charger, with the input supply voltage set to the
correct level, will quickly recharge the battery while the source
current is available by applying a higher voltage to the battery than
it's float voltage. That feature was very important in the aftermath
of severe weather when I need to minimize generator run time in order
to conserve fuel. It then holds the charging voltage to that level
until the current tapers off to a preset level or until a set time has
passed. It then drops the voltage to the float level and allows the
maximum current available from the power supply to pass through the
charger to the loads connected to the battery. The Chargers thermal
sensor adjust the charging voltage to compensate for the battery's
temperature so as to minimize charging time in cold weather and limit
the heat stress on the battery in hot weather. By sensing both
battery temperature and current flow it will prevent battery runaway
and overheating if the battery fails internally thus avoiding battery
rupture, explosion, and / or fire. If my 100 Ah battery were to short
a cell, while directly connected to the Astron RS-50A power supply, it
would continue to take up the fifty amps of current available from the
Astron RS-50A until it ruptured or exploded. The only protection
against that occurrence would be the fold back circuit on the power
supply that would only come into play when the current exceeded it's
fifty ampere capacity. The controller also pulses the battery every
several seconds with a pulse width modulated charging voltage to
retard the formation of sulfur crystals on the plates that would
increase the internal resistance of the battery and reduce it's
capacity. It is those conditioning pulses that are causing the QRN in
my radios.

--
Tom Horne, W3TDH