# dual battery isolator



## hfdbuck09 (Oct 22, 2010)

After reading that i can fry my charging system the way ive got my batteries in-line with each other (though ive never had a problem on anything runnin 2 batteries like this) i broke down and bought a isolator. Now ive searched with no luck and the directions it came with are massively confusing so my question is if somebody has one could you point me in the right direction to hook it up to run both my batteries. I dont know if it makes a diff but its got 2 big (main) poles and 2 little poles. All i can think of is ea side of the possitive will go to one of the main poles and grounds to the little ones?


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## FABMAN (Dec 18, 2008)

I've worked with isolators before. but I'm not too sure exactly what you're up to or trying to accomplish.


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## hfdbuck09 (Oct 22, 2010)

Hook my 2 atv batteries together. Right now there inline with each other. Im trying to get the extra battery off my charging system battery. I run HIDs, fan, stereo, strobes, and whatever else on my second battery and just my charging system on the original battery. Both are tru gel batteries there already mounted and hooked up and havent had a problem yet but ive read that that was bad on the charging system to have them inline.


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## NMKawierider (Apr 11, 2009)

As is understand it...and I think I do...its not the fact that you are running two batteries, its the actual total amp load on the charging system. Its only rated for so many amps/watts at max output and with all the extras people put on it can become too much. If you want the second battery off the charging system, just don't tie the two batteries together at all and run your extras to the isolated battery. It will drain and you will have to charge it somehow when you get home but at least it won't take out the rectifyer.

OK, electronic isolators. These link two batteries together when the alternator or charging system is putting out power as in when the engine is running.. which is sensed by one of those small terminals and when there is nothing sensed, it opens the circuit unlinking the two batteries. Yes, the two larger terminals are for the positive cables. But this won't help you at all as it is the charging system you are trying to protect...so scrap that idea...imo 

Better to understand how much extra draw your extras are putting on the system and if it is actualy too much for it. It might not be. There are aftermarket kits to increase power output for these if necessary.


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## FABMAN (Dec 18, 2008)

nmkawierider said:


> As is understand it...and I think I do...its not the fact that you are running two batteries, its the actual total amp load on the charging system. Its only rated for so many amps/watts at max output and with all the extras people put on it can become too much. If you want the second battery off the charging system, just don't tie the two batteries together at all and run your extras to the isolated battery. It will drain and you will have to charge it somehow when you get home but at least it won't take out the rectifyer.
> 
> OK, electronic isolators. These link two batteries together when the alternator or charging system is putting out power as in when the engine is running.. which is sensed by one of those small terminals and when there is nothing sensed, it opens the circuit unlinking the two batteries. Yes, the two larger terminals are for the positive cables. But this won't help you at all as it is the charging system you are trying to protect...so scrap that idea...imo
> 
> Better to understand how much extra draw your extras are putting on the system and if it is actualy too much for it. It might not be. There are aftermarket kits to increase power output for these if necessary.


I concur. 
we used to use them in the diesel industry to isolate 1 out of the 3 batteries, the isolated battery to power the ecm but the alternator would charge all 3 on our air starter trucks . this way if the driver accidentally left the lights on over the weekend, the truck will still start even though the other 2 batteries are completely dead.


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## lilbigtonka (Dec 30, 2008)

I would like to accomplish 2 batt on my brute but can't find how or where to mount it and you said you have them mounted already and I would love to see pics of your setup please


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## hfdbuck09 (Oct 22, 2010)

If youll go the the quad of the month thread and find me on the first page midway youll see a pic or 2 of the back of the brute look just above where the tow tits are and theres a black box lookin thing there thats the second battery. All i did was take 2 pieces of aluminum angle, u-bolt them to the lower part of the back rack support, then a piece to go on the back of the battery, then just run another piece of flat aluminum bar from the back piece to the upper bar of the back rack support. If its to confusing ill try to take more pics later as im outta town and under liquid courage right now. But its not hard. Took me 30 min to make.

As for the isolator i coulda swore if i was to hook both batteries between the isolator that they wouldnt be in-line thus leaving the cranking battery alone when running the acc off the second battery and some how it is supposed to detect the currency and charge of each battery and and shutting off charge to the strongest battery? Meaning that i wouldnt have to charge either battery when i got home nor worry about if my charging system was ok or not. I dont know like i said ive hooked up dual batteries on multiple things and run the batteries inline and never had a prob but read a thread that said it wasnt good and to get an isolator so i did. Just dont know how to hook it up.


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## byrd (Jul 14, 2009)

ur right hfdbuck u can isolate which battery u want to run what but the charging system is still under strain cuz it has to keep a steady supply to the acc batt. what ull accomplish by using the isolator is making sure ur cranking battery is not dead cuz it has nothing drawing from it but the starter.


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## FABMAN (Dec 18, 2008)

I'd like to see the article you were reading. 

A isolator is like a large diode it will only allow electricity flow in 1 direction. The only benefit I can possibly see is by using a isolator you may reduce voltage spikes on the charging system assuming the isolator reacts quicker then the voltage regulator on the charging system. I would have to test it to be sure. If that is what your were trying to accomplish a compacitor is a better direction to go.

If you could send me or us a picture of the isolator and the diagram/ instructions 4 it I'm sure we can help you out. It appears just with the people that have commented on this thread alone there is enough knowledge here to figure this out.


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## hfdbuck09 (Oct 22, 2010)

10/4 ill get some pics of all of it fri when i get home. Im outta town til ton and work tom so itll be fri before i can. Im sure its a simple opperation but i dont understand electronics at all all i know how to do is hook up certain things and throw fuses on stuff. Lol! But basically im getting so far from this is that i kinda wasted money getting an isolator cause its NOT? gonna serve my purpose? Ill try to find the thread i saw this on i coulda mis read it also but i know its on mimb im just on my phone not my comp so i cant copy and paste. I think all i did was search dual batteries and it came up though.


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## jrfonte (Mar 9, 2010)

I may have missed it but what exact isolator are you trying to use some work some don't. I used a surepower isolator on my rhino's second battery to isolate it from the starting battery and run all my accessories off the second batt.


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## hfdbuck09 (Oct 22, 2010)

Its a efx pmbc100.

Oh and the thread i read was on HL i searched duak battery and it ms a thread named bualbatteries on rzr


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## IBBruin (Feb 10, 2009)

Check this out. 

http://www.colehersee.com/pdf/hot_feed/D-617_SmartBatteryIso.pdf


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## whoolieshop (Mar 22, 2011)

Okay I think some terms are being used a little interchangeably here that is causing some confusion.

The efx pmbc100 you purchased is not a "dual battery isolator", it is a heavy duty solenoid that is being used to mechanically connect / disconnect your batteries. You didn't buy the wrong thing, this will work fine although it's not completely automatic.
The two large terminals on the top should be connected to your first and second batteries positive (+) terminals. 

The smaller terminals activate the solenoid, one needs to be grounded the other ran to a switch. This way YOU pick when the batteries are connected, don't hook it to your ignition switch because you only want to switch it on with the bike running to avoid slowly discharging your starting battery. Once you crank up and are going for an extended ride flip the switch and you'll put some charge back on it. Just remember to flip the switch back off to separate the batteries.

As for the ground on the second battery it should be connected to the ground of your primary battery, NOT TO THE SOLENOID!

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A true "isolator" will have 3 large posts/lugs. It contains diodes that are like a one way valves for electricity. You connect your stator/alternator output to the CENTER terminal, then hook one battery to each of the other two terminals. The batteries are both fed whenever the bike is running but electrically separate. The 3 pole isolator has no way of knowing WHICH battery needs charge and doesen't care, it just prevents battery #2 from draining battery #1. 
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There's a third option called a "smart relay" or "voltage sensing relay" this is hooked up similar to an isolator however it's a solenoid / relay that only closes the connection between batteries when the voltage going into the relay is above 13 volts or so, ie when the engine is running.. Blue sea systems makes a version or two of these current sensitive relays.


All three options have purposes and advantages / dis-advantages, but they will all three do the job if hooked up properly. The particular option you have is the first one, a manual solenoid. The same thing can be found in a junkyard, it's in essence the exact same thing as a starter solenoid.


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## whoolieshop (Mar 22, 2011)

IBBruin said:


> Check this out.
> 
> http://www.colehersee.com/pdf/hot_feed/D-617_SmartBatteryIso.pdf



This is another one, designed to not connect the batteries until the primary battery is fully charged. It does the same thing as your manual solenoid just automatic. This looks to be much smaller than the blue sea system setup too.

It also has an optional manual override that allows you to wire in a push button to connect the batteries in case your primary gets drawn down somehow, if your starting battery is dead but aux has some juice you can hit the override and boost the cranking battery.

There are so many things called "isolators" now that behave very differently from a traditional isolator that it causes a lot of confusion when someone buys one.


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## IBBruin (Feb 10, 2009)

Although the one I posted is automatic, I think that is what he is trying to accomplish. Like you said, it can be done manually with just a switch.


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## hfdbuck09 (Oct 22, 2010)

ok after reading pondtunes instructions and reading the link from ibbruin i get it now. just one more thing and im gonna tackle this tom and while i do it im gonna do a how to to show where to put a second battery and to hook it up with the solenoid that i have. but on the switch do i hook up the wire from the little terminal on the solenoid to the on or off position of the switch? also do i just ground the other side of the switch of run it to the battery?


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## whoolieshop (Mar 22, 2011)

The switch will need a 12 volt feed into the switch on one terminal then out to one of the small posts on the solenoid. The other post should then be connected to ground the switch won't need a ground unless it's illuminated


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