|
|
|
|
|||||
|
||||||
From: C. Marin Faure (no email)
Date: Sun Nov 30 2003 - 00:02:49 EST
From: "Bob Austin" <>
Subject: TWL: Re: RE: Re: Battery charging question
>There has been form of "combiner" around for at least 40 years on
RV's--basically when you turn on the ignition switch, a relay connects the
house and engine start batteries.
This is the way the batteries in our boat are set up. The stock electrical
system, which is still on our boat, uses a relay to connect the "house" and
"start" batteries together when an engine start button is pressed
regardless of how the battery selector switch is set. I put house and
start in quotes because either battery can perform either function. It
just depends on how you choose to manipulate the selector switch.
We have an inverter hooked to the port battery, so that has become our
"house" battery, although if we don't use the inverter there's no reason we
can't designate the port battery to be the "start" battery and run the DC
appliances off the starboard battery while on a mooring.
The alternator outputs run through the battery selector switch, so prior to
starting engines we put the selector switch to "Both," which combines the
output of the alternators and sends it to both batteries. We do this so
that both alternators will pick up the load when we use the inverter rather
than just the port alternator. We do have to remember to switch the
selector switch to the "house" battery after the engines are shut down, but
since both actions are on our "Before Start" and "After Shutdown"
checklists, they're not something we're likely to forget.
As discussed in a previous thread, we don't have a problem with the
alternators "fighting" each other in "Both" (if they even would) as one
alternator has a slightly smaller drive pulley than the other one. The
speculation is that this was done deliberately at some point to make the
alternator with the smaller diameter the "dominant" one in "Both" when the
engines are at the same rpm, since this alternator will be turning faster.
This seems to be evidenced by the readings on the ammeters.
I don't know much about electrical systems, which I'm about to prove with
this question: I've tried to follow the discussion on combiners, and what
I've gleaned from it is that it's just a way of automating the same
functions we can accomplish with the battery selector switch and the
standard-equipment battery "combiner" relay connected to our engine start
buttons. Am I basically correct?
_______________
C. Marin Faure
GB36-403 "La Perouse"
Bellingham, WA
_______________________________________________
http://lists.samurai.com/mailman/listinfo/trawler-world-list
To Unsubscribe send email to
Include the word "Unsubscribe" (and nothing else) in the subject or body of the message.
|