Batboard

OK, I want to hook up an isolated aux. battry on my 05 6 ltr silverado. Anyone have the wire diagram for the factory set up? I've seen a solonoid to isolate it but want to learn a little more about it before I try to set one up. Anyone know where to pick up the tray, cables, and solonoid without loosing my shirt?

I want the battery to run all my accessories with the vehicle off and help power the plow during snow season.

Thanks!

Your best bet is to use a battery isolator diode. This allows both batteries to be charged
while the engine is running. The diode isolator keeps one load from discharging the
other battery. The simple connections needed is to lift off the alternator output,
the heavy wire. This goes to the common of the diode isolator. One battery goes to
one connection and the other battery goes to the other connection.

Word of caution when using this dual battery set up. The diode isolator needs to
be sized to be larger than the rated current output of the alternator on the engine.
Second, the alternator needs to be larger than the stock vehicle alternator. You
now have 2 batteries to charge. If they are both down somewhat, the alternator
will try to charge both. If you don't have enough current available, you will probably
burn out the alternator and or never bring the batteries up to a full charge.

To answer the question of how the voltage is regulated, that will take care of
itself. Most of the vehicles today have a remote wire sense. This will take care
of the voltage drop of the diode isolator. Just remember that these are not
normal silicone diodes. The diode isolator uses a low voltage drop diode for
just this reason.

You could put in a solinoide fro emergency starting the vehicle. This way your
plow can run off of the second battery and you won't have to worry about killing
the normal vehicle battery.

Jim

rrfd43 wrote:OK, I want to hook up an isolated aux. battry on my 05 6 ltr silverado. Anyone have the wire diagram for the factory set up? I've seen a solonoid to isolate it but want to learn a little more about it before I try to set one up. Anyone know where to pick up the tray, cables, and solonoid without loosing my shirt?

I want the battery to run all my accessories with the vehicle off and help power the plow during snow season.

Thanks!

I see a number of isolation solonoids out there. My assumption is the batterys would sit isolated when the solonoid was open. On startup the batteries would then be in parallell with would increase the available current for starting and running devices........

On my old diesel they were in parallele all the time....

Diesels commonly need two batteries in parallel to provide adequate current to the starter (far more current than a gasser due to the high compression ratio) and enough reserve capacity to run the glow plugs.

I would go with an isolation solenoid. Less parts to fail, and you don't have the voltage drop issue to deal with.

I didn't say anything about starting solenoids. What I said was to look at using diode isolation for the 2 batteries.

One of the major no - no's is to hook 2 batteries directly together with a solenoid or a switch after they are
several years old. Batteries don't age the same and as such the internal resistance is different. When 2
batteries are connected with this method, you could get a tremendous flow of current from the higher
capacity to the lower capacity battery. This could cause damage to the plates internal to the battery.
Under the right condition, you could actually cause a battery to blow up. Many a jumper cable being
connected to a battery that has a high output of hydrogen gas has had the gas ignited by the spark
made from the jumper cable. This caused the gas to ignite and blow the battery up. Not a nice site
and generally inflicts eye damage to the person standing there from the acid burns.

If you look at Sears, most boat supply places and some of the towing supply houses, they all will carry
some diode isolators. Sure is one company that sells them.

When using the diode isolator, the batteries remain electrically isolated. When ever the engine is running,
they both will be charged. You don't have to do anything. A truck with a diesel engine and 2 batteries is not
the same thing we are talking about. The diesel requires much more current to turn the engine over and
thus has 2 batteries always tied together. When these batteries get about 3 years old, you need to replace
both at the same time.

Jim

rrfd43 wrote:I see a number of isolation solonoids out there. My assumption is the batterys would sit isolated when the solonoid was open. On startup the batteries would then be in parallell with would increase the available current for starting and running devices........

On my old diesel they were in parallele all the time....

go down to your local boat or marine supply shop, they will have everything you need that will do auto and manual switching and automatic charging of both batteries.