"Gabriel Latrémouille" wrote in
ble.rogers.com:

Looking for suggestions on isolating the motor cranking battery from the
house deep cycle batteries both being charged by one alternator & wind
generator.


Gabriel



Before we go off to amazingly complex, amazingly expensive charging system
Lalaland, I'd like to show you how I automated the process of flipping the
ON-OFF switch located between starting battery + and house battery + on my
battery system. (Pardon me for being so simple...(c

http://commerce1.cera.net/tacbuspart...g.asp?cat_id=7
0
Sorry if the 0 wrapped. It belongs after the 7 at the end of the URL.

At the top of this page is a 200A, CONTINUOUS DUTY (this is the important
part) solenoid relay similar to the one I'm using. Your auto parts places
will have similar parts from 50A to 200A or more you can get CHEAP!! I see
this 200A beast you can leave on 24/7/365 is only $42. You can crank your
diesel through it from the house batteries! Very handy.

The simplest connection is to simply hook the coil of the solenoid to the
engine's power switch so it closes every time you turn on the key. This
will parallel every battery in the place to crank the engine, even the dead
ones. Some won't like that, but it really works just fine this way. The
hot battery (starting) cranks the engine just fine with dead house
batteries at 50% charge, really!

The contact terminals, the monster terminals at 200A, are simply connected
to each battery's positive terminals so they'll be in parallel when the
engine is on and, when you shut off the engine key, separate them when the
engine is off so you don't discharge the starting battery through the
house. The negative side of both batteries is, probably, already
connected. IF YOU DON'T SEE A REAL HEAVY CABLE BETWEEN NEGATIVE BATTERY
TERMINALS, ADD ONE OF YOUR OWN! I know someone who "thought" they were
connected, but, in reality, it was some of the equipment grounds connecting
them that caught fire when heavy current (starting?) happened. Make them a
nice #2 jumper with the appropriate battery connectors (Autozone?).

Now, every time you crank the stinker, all the batteries get charged off
the one alternator. The batteries with the lowest voltage gets the most
current whichever way it needs to go through the solenoid we added.

For the windcharger, I'd simply parallel this 200A monster with a much
smaller solenoid (look down the webpage at the bottom), perhaps the 85A one
which will use about 1/2A of coil current while it's "on". This smaller
solenoid would operate from a manual switch to the starting battery so I
can turn it "on" with totally dead house batteries. Put a red light
indicator somewhere everyone can see it, but not at the helm where it will
blind you at night, so you don't forget to turn it off. I'm a kinda
smartass, so I like to use a tiny miniature switch to control all this
power (just the relay's coil current, 1/2A?) next to the indicator wherever
you like. Over the DC power panel is a great place.

Sorry it doesn't have a 32-bit microprocessor, gigabytes of ROM and RAM
running some amazing microcode written by a genius that radiates half a
kilowatt of RF noise to trash EVERY radio/stereo/TV like these damned fancy
charger/inverters while you're charging. Listen close when it "clicks" on
or off and you'll hear the only little pop in the radios it
makes....Otherwise it is dead quiet while the engine or windcharger does
their things.

PS - I have this system also in my mobile electronics shop in an old Air
Force stepvan. The starting batteries are the red AGMs the Air Force
installed a couple of years ago before selling the truck. My house
batteries are 330AH golf cart batteries from batteriesplus.com.
Paralleling them with the engine running has no ill effects on either.
They both charge just fine. The 80A alternator on the truck charges both
through a 100A CONTINUOUS DUTY 12V solenoid I described. Look at ES-18-3
for $27 on this webpage I quoted. That's the relay. The same one also is
a master primary power switch that switches the entire electronics suite on
Lionheart on and off with a simple push-pull switch, except for the
emergency VHF radio on another circuit. The big red light next to that
switch keeps my captain from leaving all our electronics (including the
autopilot by the way) on for weeks when he's off his boat....(c; I don't
like dead batteries, either...

Larry