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murraymcleod · 11-11-2022, 02:03 PM

Thanks for that diagram...that makes sense and is basically what I see except that I have no chassis batt disconnect (the ignition switch?) and the BIRD can also power the isolation relay, in addition to the AUX switch, right?

murraymcleod · 11-11-2022, 02:18 PM

OK...I finally got in there and disconnected everything from the isolation relay and pulled it out for testing. Previously (see above), when the resistance across large contacts was tested with the relay in place and with wires connected, it always showed zero ohms indicating contacts were always closed with no isolation (which I suspected was the problem).

Now on my bench those same contacts always shows infinite resistance indicating the relay is open!!! The relay stays open when 12v are applied to the small contacts as well, so the relay doesn't seem to be working (don't feel or hear any relay motion either)...but I can't explain why it appeared always closed in the coach, but now shows always open...??? Could I have some other "back-connection" between the batt banks unrelated to the iso relay?

I'll order a new relay to put in, but I'd really like to understand what's going on here...any suggestions?

murraymcleod · 11-11-2022, 03:00 PM

A similar problem thread:
https://www.irv2.com/forums/f103/coa...ml#post6356116

twinboat · 11-11-2022, 04:12 PM

Find the 2 wires that go to the small terminals and see if 12 volts is on them.

You can tie all of each large posts wires together for a test.

1, Pushing boost switch. Yes
2, Key on. Maybe
3, Engine running. Yes

OakHillFarm · 11-11-2022, 05:10 PM

The relay wasnt terribly difficult to replace on my Canyon Star. Make sure you take photos and pay close to all wires you disconnect so they get back where they belong.

I did change the way the converter (charger) connected to the house battery bank. Originally both + and - connections for the converter were on the inboard most house battery. Changed the - side to the outermost house battery.

Everything continues to work correctly with the new isolation solenoid installed.

murraymcleod · 11-11-2022, 08:43 PM

Quote:

Originally Posted by twinboat

Find the 2 wires that go to the small terminals and see if 12 volts is on them.

Actually there are more than just two wires on the small posts; looks like three wires on the negative post and two on the positive post (?). I might expect more than one on the positive post, if there is more than one source of power (BIRD and AUX button). But why so many on the negative post?? Isn't one ground enough? (see pic)

twinboat · 11-11-2022, 11:13 PM

The 3 grounds may be there as a junction point for other items, like the large terminals.
1 grounded wire and 2 wires off it to ground other things.

Brave Salmon · 11-18-2022, 11:07 AM

Bingo, if a standard Ford style starter solenoid was used, it will fail quickly because it is not a 100% duty cycle unit. If not sure, get the proper solenoid and pitch this one out the window. Nothing like two dead battery banks at the wrong time.

murraymcleod · 11-18-2022, 05:43 PM

OK, I ordered and received a new isolation relay, and bench tested it to make sure it was working. I could hear it click and close contacts when 12v were applied. and the large contacts seemed to open and close appropriately per ohm measurements.

I reinstalled (with some difficulty, as it's a hard area to access against the firewall on my coach). Hooked all batteries back up and....nothing has changed; it "worked" just as before. The contacts on the isolation relay are always in the closed position with no battery bank isolation.

I checked the small 12v contacts, and it seems there are always 12v across those terminals, even with no shore power and with the "salesman switch" off to kill all 12v power. I checked the battery boost switch on the dash, and disconnected wires from it hoping that the problem was simple and it was just stuck closed or something, but no such luck. Still 12v to the relay's small contacts.

Since my old iso relay was always in the closed position and wouldn't cycle when I took it out and tested it, its large contacts probably burned and fused together since that relay was always powered. How long until the new relay meets the same fate?!

So the only remaining suspect (?) is the BIRD. Can this thing fail so that it always provides 12v to the relay, even when the coach's 12v are off?? or could it be hooked up wrong or something? Thanks.

THenne1713 · 11-18-2022, 10:38 PM

Get the Brand/Model OF YOUR ird/bird, AND FIND/ DOWNLOAD THE paperwork and READ the Sequence of Operation. If not for Lithium, probably much simpler. BUT make sure Unplugged when trying to verify isolation condition? Ohmmeter probably not good, either, you need to test VOLTAGE. I know if you have no charging voltage above 13.x, it should disconnect, but it might do so immediately, =might require the surface charge voltage to fall off below 13.x before disconnecting? (guessing possibly x-minutes delay?)

THenne1713 · 11-18-2022, 10:43 PM

re: << its large contacts probably burned and fused together since that relay was always powered. How long until the new relay meets the same fate?!>> I do Recall reading ONE difference in solenoids is the SILVER CONTACTS in the more expensive solenoids, vs copper, and this make LIFE Rated # cycles MUCH higher, at much higher price.

murraymcleod · 11-19-2022, 08:33 PM

After installation of the new isolation relay I can't really figure out of it's working or not. If I bypass all charging methods (no generator, no converter, booster switch off, etc.), the iso relay does seem to eventually "open" to isolate the two batt banks (after a BIRD induced delay?), but then I test the boost switch and the relay closes but appears to stick closed! Is there a BIRD delay associated with that too?

While all of the above is going on, my "house/chassis" voltage monitor in the coach always shows the same reading for both, even after turning on the headlights for awhile and/or running the furnace to try to bring each set of batts to a different voltage level.

All this got me thinking about this whole process. It seems that, with my coach, it's either sitting in the driveway under shore power, on the road with alternator power, or at a campsite with shore power. All times when I don't want the batteries isolated. Rarely are we boon-docking with no power source.

So I'm thinking I'll bypass all this complicated automated battery isolation process by just installing a battery disconnect switch on the line from the chassis battery to the iso relay. That way I can manually isolate the chassis battery when needed (boon-docking) and just let the automated process do its half-a**ed job otherwise, since it always seems to NOT isolate anything anyway.

Does anyone see a problem with this approach? Thanks.

tomato · 11-20-2022, 10:30 AM

Quote:

Originally Posted by murraymcleod

After installation of the new isolation relay I can't really figure out of it's working or not. If I bypass all charging methods (no generator, no converter, booster switch off, etc.), the iso relay does seem to eventually "open" to isolate the two batt banks (after a BIRD induced delay?), but then I test the boost switch and the relay closes but appears to stick closed! Is there a BIRD delay associated with that too?

While all of the above is going on, my "house/chassis" voltage monitor in the coach always shows the same reading for both, even after turning on the headlights for awhile and/or running the furnace to try to bring each set of batts to a different voltage level.

All this got me thinking about this whole process. It seems that, with my coach, it's either sitting in the driveway under shore power, on the road with alternator power, or at a campsite with shore power. All times when I don't want the batteries isolated. Rarely are we boon-docking with no power source.

So I'm thinking I'll bypass all this complicated automated battery isolation process by just installing a battery disconnect switch on the line from the chassis battery to the iso relay. That way I can manually isolate the chassis battery when needed (boon-docking) and just let the automated process do its half-a**ed job otherwise, since it always seems to NOT isolate anything anyway.

Does anyone see a problem with this approach? Thanks.

I believe you are concerned about not having juice to start the engine. Rather than change things around for the rare occasion you are dry camping, why not just get one of these? This one is for a diesel, so a gas-sized one would be less expensive. Cheap insurance for us. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

THenne1713 · 11-20-2022, 10:16 PM

<< but then I test the boost switch and the relay closes but appears to stick closed! Is there a BIRD delay associated with that too?>>

(Some) IRD/BIRD are designed to charge the OTHER battery is TWO conditions exist: 1) OTHER battery showing LESS than 100% charge; 2) ONE source showing a CHARGE VOLTAGE (greater than 13.0?) AVAILABLE. Now when you charge a battery, even for short period, and then disconnect, it will show a FALSE HIGH Surface VOLTAGE from the charger voltage applied. Might be 13.6, 13.2, or 14.4.... and it will take 15-30-minutes for that voltage to fall back to an ACTUAL battery voltage (depends on how high CHARGER VOLTAGE was), (and maybe low battery condition and SOC?)...e.g. a battery was run down to 11.8v and was charged at 13.2 for 15-minutes vs 24-hrs charge.

If coach battery charged for two hours drive from ALT at floating 13.6-14.4v, BIRD might take 30-min to disconnect if IGN is left ON for some reason, with ENGINE OFF? I.e. the HIGH surface voltage on chassis battery could keep BIRD connected? If IGN=turned OFF, I would expect maybe designed to disconnect immediately? If BIRD IGN sensing wired wrong, maybe the issue? or maybe IRD failed? BUT would have to refer to literature for YOUR Model # BIRD? Good Luck.