ProIsoCharge Isolators..........again

echandler1971

'05 360 FV - ProIsoCharge 130a 2 alt in 4 banks out.

I know I'm beating a dead horse with these things and generally, these Promariner isolators are more trouble than helpful, but I'm at a loss for what's going on.
I have both engines out at the moment (new TAs getting installed). Both alternator cables (going to the isolator) are live with 12-14vdc.
1. Is this normal in that if a battery is hooked up, it will be live in the reverse when the engine is off (no diode stopping it)?
2. I thought the battery switch handled breaking the battery connection to this thing?

Thanks

YYZRC

I believe there is +12v DC to the ignition switch that breaks the battery connection, no?

echandler1971

YYZRC said:

I believe there is +12v DC to the ignition switch that breaks the battery connection, no?

Indeed and I have it connected to the helm key switches. I’m thinking that the house bank is back feeding, since there are several always on things that turn on as the batteries are first connected but with helm and cabin switches off. I’ve since added a master shutoff during the reworking of cabling I did with the engines out. I may see if shutting them off does the trick? 

Still, I’m wondering if the unit is supposed to stop back feed via diodes or something, but they’d have to be massive diodes to handle 130a. 

YYZRC

Interesting. I'm sure @LaRea will have some insights.

echandler1971

I’ve already illuminated the Larea signal on the clouds

LaRea

  There should be some circuits that always have power regardless of battery switches or isolator ... bilge pumps, MerCathode, I forget what else.  Is that what you're talking about?  

echandler1971

No, my issue is that when the alternator leads were pulled, they were live and make sparks when hitting a grounded part of the boat. I’m wondering if that should or shouldn’t happen. 

LaRea

This was when you were pulling the engines and you disconnected the alternator wires?  Unless I'm mistaken, the batteries shouldn't be able to feed current back up through the isolator into the charging sources (charger and alternators).  

On a side note, if the wire from the alternator to the isolator is longer than 40 inches, it should be protected by a fuse or breaker that would have popped when the circuit got grounded.  

echandler1971

From the horse’s mouth 

Yes, this is normal behavior. The prosio automatically latches to the engine start battery when it powers down so the alternator sees a voltage and will output when the engine is started. We strongly recommend disconnecting the batteries at the battery terminals before performing maintenance on your vessel. This behavior is normal and does not damage the alternator and allows the alternator to work properly.

 

Kind regards,

 

Zachariah | Technical Support Representative | NAVICO GROUP | POWER SYSTEMS

LaRea

Ahh -- that makes perfect sense.  Good addition to the forum knowledge base.