[Elecraft] Battery back-up system for multiple rigs

[N2TK, Tony]

Tnx Don for the advice. The batteries are all identical marine type
batteries.  But still like the idea of isolating them.
They will have solar and a generator too.  
73,
N2TK, Tony

-----Original Message-----
From: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
Sent: Thursday, January 22, 2015 7:21 PM
To: N2TK, Tony; elecraft at mailman.qth.net
Subject: Re: [Elecraft] Battery back-up system for multiple rigs

Tony,

There is no problem connecting batteries in parallel *if* (and only if) they
are the same capacity, manufacturer and age.

If the batteries are not identical, isolate them with diodes so one does not
draw current from another battery.  You will suffer the diode voltage drop
in the output voltage.  The diodes must be capable of carrying the full
maximum current load for all the rigs that will be operating at the same
time.

73,
Don W3FPR

On 1/22/2015 2:47 PM, N2TK, Tony wrote:
> Looking for some advice. Trying to help out a friend who is setting up an
> emergency communications system for the Hams in their condo group.
>
> They have several marine batteries they want to tie in parallel so they
can
> run multiple rigs,  K3's plus UHF/VHF for extended periods. They have a
> charger for the batteries. They use the 12V off the batteries to a
> distribution box for the 12V equipment.
>
>   
>
> Questions:
>
> -          What is the best way to isolate the equipment from the
batteries
> if something happened to the battery (ies).
>
> -          Is there a way to isolate the batteries from each other if
> something happened to one battery so it didn't draw down the other
> batteries?
>
> -          Am I missing anything else that should be done for safety of
the
> equipment, batteries and the operators?
>
>   
>
> Tnx
>
> N2TK, Tony
>
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