Copasetic
1/2 ton status
Good deal. How would I go about checking to see which alt I have? I've looked all over it for some kind of model number or something and all I've seen is "Delco-Remy" on the back. 


Copasetic said:Good deal. How would I go about checking to see which alt I have? I've looked all over it for some kind of model number or something and all I've seen is "Delco-Remy" on the back.![]()


chevyin said:Why did you chose an isolator, rather than just a relay? Relay's are simpler, cheaper, offer less voltage loss and imo I like the functionality of the relay setup better than an isolator. Something to consider if you decide to redo or have problems later, as it sounds liek you have it working now.

imiceman44 said:An isolator does much more than a relay does, and cleaner![]()
chevyin said:Im not sure what you mean by isolators are 'cleaner'. Isolators present more resistance to the circuit (more voltage loss) than do standard mechanical contacting relays. For this reason, if anything relays could be considered cleaner... assuming you mean a straight voltage/resistance comparison.
Isolators isolate the batteries 100% of the time. Relays isolate the batteries only when the ignition is off (assuming its wired that way). This means while the ignition is on (and hence, the engine/alternator), the two batteries work as one larger battery. Greater capacity for theentire circuit.
An isolator means you either draw from one batt, or the other. For a large current draw situation (large stereo, winch, etc) Id prefer the capacity storage of both batts combined. But if the second batt is mainly for many small add-ons (lights etc), then it doesn't matter nearly so much.
Lastly, relays are cheaper than isolators, by 1/2 generally. To me, this is the icing on the cake to chose a relay... under most circumstances.
Cheers.
4X4HIGH said:When running a relay both batteries are being charged but you DO NOT get any extra power. They would have to be wired in parallel.
Correct, when wired with a relay, when the relay's contacts are engaged, the batteries are in parallel.. they react as one large battery. If cable sizing between your batts prevents this, you need larger cable.imiceman44 said:Hey Scott
When they are wired with a relay, they are connected in parallel through the alternator with usually adequate cable for charging, but not for use.
You are right that you can not get more power because of the cable restriction, I do know the dead battery would discharge the good one and possibly kill the alternator if it had a short.
I don't think the alternator diodes will prevent the batteries from feeding thru the alt will they?
chevyin said:Correct, when wired with a relay, when the relay's contacts are engaged, the batteries are in parallel.. they react as one large battery. If cable sizing between your batts prevents this, you need larger cable.
The dead battery thing does remind me I forgot to mentionone drawback to running a relay, both batts needs to be of the approx same age. Just like when wiring two batts directly in parallel, if one exhibits much greater internal resistance than the other, they will not charge/discharge at an even rate. In other words, you will not be reaching the full potential gain of running multiple batts. For this reason I generally recommend putting in two new batts when going with a relay. An isolator, because it isolates 100% of the time, does not warrant concern over battery condition.
One nifty thing I like about relays is, if you have a big stereo (or winch) that you connect to the secondary batt, and use it with the engine off till that batt dies, the primary batt is still fully charged and ready to start the engine. Also, if you happen to forget and leave your lights on, draining your primary (starting)batt and cannot start your rig, having a short jumper wire to jump the relay allows you to drain from the secondary batt into the primary, and (hopefully) start the engine.
Im sorry, I guess I didn't realize we were even debating here. I just wanted to present the differences between isolators and relays and allow the reader to make the best choice, given his situation. Like I said above, in most situations Id chose a relay over an isolator, but there are exceptions where Id chose the isolator.imiceman44 said:Well if you drain the main battery, and then jump the relay and connect the 2, you will split the power going to the starter, it's like jumping the truck with an external battery, and i do the same with the isolator, did that one time when I forgot the lights on, it worked ok, gave enough thru the Guage 4 cable that I had the isolator wired with tio start the truck then the alt kicked in and charged both batteries.
We can debate this to death, there is definitely advantages to each way anyone can think of hooking up 2 batteries, I think one of the most versatile though are the marine switches.
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2 batteries, 1st battery, 2nd battery, or no batteries.
chevyin said:Im sorry, I guess I didn't realize we were even debating here. I just wanted to present the differences between isolators and relays and allow the reader to make the best choice, given his situation. Like I said above, in most situations Id chose a relay over an isolator, but there are exceptions where Id chose the isolator.
Yes, jumping a relay or isolator is just like jumping from an extra batt. BTW, if it doesn't turn the starter over right away, give it a min for the second batt to give the front one a decent little charge before trying to turn it over again.
Marine switches, from what Ive read, has a nasty tendency to bleed off voltage, depending on the exact design used. Ive never used one to try it myself however.
Its all good man.imiceman44 said:I am not debating![]()
Just throwing what I know out there, since the talk started about different types of connecting batteries.

ryoken said:One day I'll have the truck world converted over to ACR's...Old habits die hard...
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