48 to 12 volt conversion [RE-wrenches]

[Darryl Thayer]

Change as much as possible the 12 volt halogen lights
to 12 volt Compact Flourecent.  Which will greatly
reduce the 12 volt load.  

To maintain the L-16s in the 12 volt supply, is a 12
volt charge controller that has a float charge stage. 
I recovered another system about 2 yr ago where they
had two systems a 24 volt system and a 48 volt system.
 I used a MX60 supplied by the 48 volt system to
charge and float the 24 volt battery system.  I did
this with help from Outback in the set up of the MX60.
 I was warned that the MX could not necessarly handle
the very stiff 48 volt battery source, however so far
this works well.  The good point is the MX maintains
the 24 volt properly.  And it draws very little power
in doing so. Also if the load (24 volt) is high the
MX60 can supply a fair amount of power to support the
load and reduce the size of the lower voltage battery
set.  Of course I think this would work with 12 volt
as the lower voltage.  

The problem with the 12 volt charger is it does not
have a float charge, (it will over charge the
batteries).  The charger is low in efficiency
requireing 120 volt AC and inverter operation.  the
charger can not load follow.  

Good luck
Darryl   

--- Cvsolar2 at aol.com wrote:

> hi everybody;
>        dan brown here. seems we have a customer who
> just can't seem to give 
> up her old 12 volt system. she's had it forever, and
> now has a huge investment 
> in it, and although she's evolved through several
> system up grades,  she can't 
> seem to bring herself to give up her "12 volt back
> up lites". ( she still has 
> gas lites too). 
>        we just up graded her system from  24 volt to
> a 48 volt dual outback 
> system to connect with a 10k bergey. her old 12 volt
> system has a vanner 24 to 
> 12 volt converter paralleled  with 4 L16s that are
> about 13 years old. when i 
> took the old 24 volt system down, the 12 volt system
> promptly crashed. i 
> suspect the old L16s (buried in their own little
> cubby -way under the stairs). have 
> never seen much of a cycling. the care taker tells
> me he checks the fluid 
> level  monthly - but that they never use water.  i
> have a 12v -10A charger on 
> them now, and it seems to be  doing the job, but i
> don't see it as a permanent 
> solution.        
>         we've run down a bunch of possibilities, but
> john suggests i throw it 
> out to you folks. here's what we have so far. 
>        I got a clamp meter on her 12 volt system
> last night. We figured she's 
> pulling somewhere around 60 to 70 amps at 12 volt
> full use. which she says 
> she never does. 
>        She runs a lot of 12v halogen. I'd like to
> see her up grade from 
> halogen to LEDs, but i suspect the logistics alone
> would scare the pope, so I'm 
> kinda counting that one out. maybe a longer term
> solution
> so;
> option #1)  replace the spent L 16 batteries with
> gel cells, and up grade to 
> a real charger. $$
> option #2) replace the converter . ( with a 48v to
> 12v ). $$
> option #3) install a stand alone transformer 1k
> x-former (120v to 12v). $ 
>        any advice? am i  missing something?  thanks.
> dan
> 
> dan brown
> central vermont solar and wind
> rutland vermont
> (802)-747-0577
> 


	
		
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