Just wondering if anybody has some recommendations on a dual battery
isolator for my 96 suburban. I have visited a few web sites and some sites
say I need a special isolator to work with my stock alternator and other
sites say the regular one will work just fine. Anybody done this and which
one did they use? Looking in my Haynes(piece of crap) manual, the diesel
version came with 2 batteries but there is no mention of an isolator from
the factory or were they just both hooked together which would be stupid
because they would both be drained if you left the lights on. Main reason is
for when it's -40 deg and just the assurance of having an extra battery just
in case. Any thoughts would be much appreciated.
Helroaring's products looks good.
I planning on doing the same modifcation, however, I've having a tough time
find a good location to mount the second battery.
Do you have any thoughts on this? Where are you mounting the 2nd battery?
I have a Chev Sub 97, 454.
Let me know if you have any insights.
The best way is with a heavy duty relay. They are available many places,
like golf cart shops. They look like a Ford starter relay but they are
different internally. If you need help with the circuit, let me know.
The Diesel batteries are hard wired together. If you leave the lights on
they both die. On the newer trucks the computer shuts the lights off if you
forget them on:)
We have a 100 car fleat at work with dual batteries. one under the hood, and
one in the truck for the radio and computer equipment. (can not start the
car with the second battery) They are set up with a heavy duty relay. and
since the cars are run 24/7 on and off all day and night, the relays wear
out ofter a while. the manufacturer changed the relay contacts from silver
to some other metal. Just by not having the silver contacts, the relays last
half as long as the older ones. so make sure and get a top end relay of you
go that route.
After running dual battery cars at work in a 24 hour operation, the
batteries have laster over six years, both in the trunck and under the hood
with a relay setup. I really dont think we have anything special, just a
deep cycle battery in the trunk for the Radio and computer.
Go to Pep Boys and get an isolator rated at the amperage your alternator
puts out, or higher.
Wire as indicated.
Get a Ford starter solenoid <the kind that mounts to the fender> and wire
the positives of both batteries so that each mains terminal goes to one of
This gives you ultimate flexibilty. If you need a jump start, just activate
the solenoid via a switch you installed in the cab, and you're able to
Have done it on every truck I've owned and several folks in the Jeep club's
vehicles. Works like a champ, for about $100 of materials including cable
<use 0 gauge welding lead>.
Battery isolators are just large diodes. The forward voltage drop changes
with current. A relay is better any way you look at it. Years ago I did this
for a living, we used RBM 375 relays. RBM is now owned by Gould if someone
didn't buy them out. The 375 could handle a lot of current and was dead
reliable. It's easy to wire in, just one wire from the ACC terminal of the
ignition switch, easily found in the fuse box, and some wire and it's done.
No need to cut or splice any of the original wiring. If you think an
isolator is better, tell me why.
my 96 k2500 w/5.7 has dual batteries and they are wired together. I would
get the second tray from a junkyard or dealer and a new positive cable from
NAPA. The ground is just a ten gauge wire screwed into the drivers side
fender. There is no isolator from the factory and my truck fires up fine in
the winter (Indiana)
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