Where's my isolator?

wackerb · 09-12-2020, 12:40 AM

Sorry if this is covered somewhere, but searches just return lots of good info about what they are and how to connect them. I just want to know where mine is located. I have 2006 6.0 diesel E-350 SMB. I've looked all over for the three posts in a row type shown in the wiring diagram, but can't find it.

The two starting batteries are under the floor on the passenger side and the solar battery is back by the differential.

eddyturn · 09-12-2020, 08:56 AM

It depends on your interior layout or plan as to where they put it. Include some photos or refer to your SMB build sheet documents for the layout plan - RB50, or EB30 or, or whatever it is.

Scalf77 · 09-12-2020, 10:16 AM

I would have expected a 2006 SMB to have a SurePower Separator.

not the diode based isolator.

-greg

boywonder · 09-12-2020, 12:17 PM

Earlier vans had isolators under the hood..typically a box with some cooling fins.....later vans have separators like Scalf77 shows above; these can be anywhere.

.....follow the battery cables....they will lead you to the separator/isolator....

**daveb** · 09-12-2020, 12:23 PM

You don't know what model the SMB is? If it's an SMB-50 with a rear bench seat that pulls out to make a bed, it will more than likely be under it on the driver side. The board Greg showed is under there on most 50 models. I've seen a few that the separator in mounted on the other side of that board but most can be accessed under the seat. Walk thru models may have it in a different location.

wackerb · 09-12-2020, 02:40 PM

Thanks all. It is an EB-50. The separator is under the bench, but on the passenger side. However, the coil that is visible in the photo is hot and the van has been sitting all night. There might be a little shaded solar, but that shouldn't affect the separator, should it? Also, what are the small black parts in the last picture?

What prompted all this is my starting batteries going dead after being parked a few days. The radio switch was wrong, which is a documented concern and has been corrected, but is it normal that the separator coil is hot? I'd planned to wire a battery switch across the separator leads as a quick way to use the house battery to boost the start if it happens again.

wackerb · 09-12-2020, 03:41 PM

So the plot thickens. The separator has start assist, but it is always activated via a green wire that I can't trace very far. However, near the ignition a bundle of add-on green, blue, and brown wires appear. The green one has a fuse on it that goes into the ignition connector, but stays "hot" with the fuse removed and there is a constant 1.2v potential across the fuse connectors when removed. Also, with the fuse removed the green lead at the start assist remains hot. Any ideas? Where would a start assist switch be if not wired directly to the ignition?

wackerb · 09-12-2020, 04:13 PM

Oops, I was wrong to assume the only potential to the start connectors came from the green wire, thinking they just went to a solenoid. The green wire does go to the ignition, but is always hot, just dipping in voltage during an actual start. Even with green disconnected at the start connector there is a small current going through the ground connector. I couldn't get amperage, but there's a small spark to the ground, for now I'm leaving the green wire disconnected to see if the coil cools off.

pjpvi · 09-12-2020, 04:36 PM

I think my '05 EB-50 came with the same separator and if I recall, it also was hot all the time. I replaced it a long time ago with a Blue Sea ML-ACR. I have been very happy with it and has provided a long time of trouble free operation. FWIW.

Good luck!

Scalf77 · 09-12-2020, 04:58 PM

Other then the two battery cables, you have the ground connection, start assist and start assist indicator. Leave the ground connection connected or unit won't work. The start assist will force the unit to connect, the indicator can wired to an led to show that start assist is active.

When the unit is closed it will get warm, as it is a constant duty solenoid. If solar brings your house battery above 13.2 volts it will also connect the solenoid as the 1315 is bidirectional.

It is hard to follow your train thought on the measurements you taking, but there would be a small amount of current to keep the Separator alive, remember it is actively monitoring voltages.

The start assist going to an always hot line would be wrong, it would either have to be manually switched or just be hot in the "start" position.

The best way would have a momentary switch that you could hook between always hot and start assist.

Also based on the age any lifespan of a 1315, it would be a good time to look for a upgrade.

-greg