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Which Isolator

June 20, 2014, 10:44:59 am

I'm replacing the Powerline battery isolator with the Cole-Hersee  #48160 due to a wider availability...and cost.  I noticed however that it said that it wasn't to be used with an alternator with an internal regulator.  It recommended that the #48162 but from what I've read the smaller post for the exciter wire is not used anyway. So, do I go ahead with the 48160? 

 Thanks, Bruce

Battery-Related Products | Battery Isolators | Cole Hersee - Littelfuse

Thanks John, just now figured that out

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Re: Which Isolator

Reply #1 – June 20, 2014, 10:49:00 am

 Bruce, just a note on the link you posted as it does not come up as a "clickable one" Do not put links in brackets as the program does not recognize it as a link then!! I am right I think-Michelle?
JohnH

A person can still copy and paste of course, but nice to just "click"

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Re: Which Isolator

Reply #2 – June 20, 2014, 12:27:28 pm

Bruce,

You need to determine how your alternator is set up.  Some alternators are externally excited - some are self-excited.  If your alternator is "self-excited" it doesn't need a separate "excite" wire connected to a ignition-switched source, so the way I read it you won't need the 4th post.  You DO still need a small gauge wire from the alternator to the "engine start battery" post on the isolator.  This is called a "sense" wire.  It gets kinda confusing, I know.  I also went through learning about this subject a while back:

Brain Teaser (Electrical)

If there isn't a big difference in price between the two isolators, and the specs are otherwise equal, you could just go ahead and buy the 48162.  That way you are set no matter what kind of alternator you have now, or may have in the future.  Call it "future proofing"!

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Re: Which Isolator

Reply #3 – June 20, 2014, 12:37:05 pm

Just checked Amazon.  The 48162 is actually 43 cents cheaper than the 48160.  What a deal!

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Re: Which Isolator

Reply #4 – June 21, 2014, 01:01:41 pm

I'm going to impose on you good folks one more time. I was reading and it says that the Cole-Hersee splits the amps between both legs. So in other words on a 200 amp isolator one leg gets 100 and the other 100. But in reality the alternator is 160 amp so each gets 80.  I read about a "Charles" isolator and it delivers the full amount to both legs. It's quite a bit higher but if thats what it need then so be it. I don't want to be out with yellow lights and slow windshield wipers at slow idle due to voltage drop. Is anyone familiar with the "Charles" isolator?

Marine: Battery Isolators

Thank you for your time and knowledge,
Bruce

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Re: Which Isolator

Reply #5 – June 22, 2014, 12:17:13 am

I was not aware that a 200 amp isolator only has 100 amp diodes and will limit alternator amps going to each battery bank.

Batteries determine how many amps they will accept. And if one bank only wants 10 amps and the other wants 150 amps, I assumed the isolator will pass what is needed to each bank.

Marine isolators may be more expensive due to their more harsh environment and the need to prevent explosions, not because of capability.

Isolators are dumb devices that have diodes between center and side terminals, and the ratings are based upon how much heat they can disperse and how many amps the diodes can handle without self-destruction.

All isolators 'split' the amps, as that is their job, to flow current to the two banks with the banks being "isolated" from each other. I don't think 'split' means equal split or 50-50%.

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