T&T: 24 volt charger replacement...

[2elnav at netbistro.com]

Back in 2000  I equiped a Queenship 70+ footer with  twelve  TC40+   wired 
series parallel.  I don't recall the  specific as to why  Statpower units 
were chosen;   but they wanted  200 amp plus of charging capacity to a 24V 
bank.  We wired  two  TC40 in series to get 24V then paralled  six banks  to 
give 240 amps total capacity.
To be sure it woudl work reliably, we ran the concept past engineering who 
gave their approval.
Last I heard  the boat was still running this  system.  The only  mishap 
developed  when somebody left the aft  hatch from E/R to swim deck  open and 
a following wave  entered the electrical compartment.   Several of the 
chargers got soaked with salt water.  After replacing the damaged units the 
system continued in service.
I lost track of the boat  after five years.

Arild


----- Original Message ----- 
From: "Dave Legrow" <dlegrow at yahoo.com>
To: <trawlers-and-trawlering at lists.samurai.com>
Sent: Sunday, May 03, 2009 11:50 AM
Subject: T&T: 24 volt charger replacement...


>>> Yes, I know that combining two 12 volt chargers in series will create
>>> 24 volts but my understanding is that it isn't a safe way to charge
>>> the 24 volt bank.  A better way to combine them for charging is to
>>> split the bank
>
>>Jeff is quite right.
>
>
>>Where does anyone get the idea that running two chargers in series is
>>safe, effective, or practical?
>
> However, Jeff's document does not indicate that there is any switch or 
> relay
> to break the batteries apart when charging.  A fully isolated charger 
> cares
> only about the potential between the output leads as long as the float 
> above
> ground does not exceed the design limits.  I trust Arild on this one. 
> (but I
> probably would have spent the money on a 24v charger)
>
> Dave
>
>
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