I've had this set up for some time now. Was working fine until the past few months the IBS monitor is unlinking the batteries while the engine is running due to it sensing 12.8 or lower voltage on the auxiliary battery. Upon starting, the first few minutes show 14.7 to 13.9 volts across both batteries. Shortly thereafter, voltage starts to drop to 12.8 or less at the aux battery and the system unlinks, as it's designed to do. I measured voltage at the input side of the relay (from the main battery) at 13.9v and across the relay it shows 12.8v. The aux battery also shows 12.8v. Now, if I bypass the relay, I get 13.9v on both batteries and the IBS system links up due to the higher voltage. I have a new relay, so that's ruled out. Why am I losing 1 volt across the relay? I'm stumped. Could the aux battery be bad? It's a die hard and I had to exchange it once already.
IBS Dual Battery System voltage problem
- Thread starter gsdog2
- Start date
I wonder if your battery is dying. Remove it and have it tested overnight at a place with a fancy dancy battery testing machine. AGM's 12.8 is 100% charged, though often you get more.
How old is the battery?
While I'm not running IBS, I found that when my Optima was going bad, my charging voltage while running gradually went higher and higher, until finally it hit 14.9 then 15.0 so I pulled it out, and had it tested, it was bad. The good news, I was 2 years into the 3 year replacement warranty.
How old is the battery?
While I'm not running IBS, I found that when my Optima was going bad, my charging voltage while running gradually went higher and higher, until finally it hit 14.9 then 15.0 so I pulled it out, and had it tested, it was bad. The good news, I was 2 years into the 3 year replacement warranty.
Of coarse I can't stop tinkering until I figure it out. So far I removed the Relay Booster Module from the circuit and I'm now getting 14.01 a 14.02 across the relay and at both batts while idling for about 15 mins. The alternator is putting out the same. So I'll watch it on a long drive and see what happens. I'll also go test the batts. Wonder if somehow the RBM was sucking voltage? My rig is a 95 80 series, btw.
LifeOverland
Adventurer
I did have the RBM go bad while in Baja. Went to Sierra Exp on the way home and spent all morning diagnosing the issue. Mine just wouldn't link the two batts together at all while charging. I had to manually connect the terminals to charge my AUX battery. Only thing that solved it was a new RBM. Was on the phone with the importer for hours trying to diagnose the issue.
One common fix was to unplug the meter for a bit to reset the system. The tech said that's the most common IBS issue.
I had my RBM mounted upside down, terminals up. Once removed, water dripped out of it. When installing I figured it would operate just fine either way but it sucked up moisture somehow. It didn't rain nor did we do any water crossings. Dunno if this is your issue, but my bet would be on that RBM.
Good luck!
Oh mine was in a 97 80 as well!
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One common fix was to unplug the meter for a bit to reset the system. The tech said that's the most common IBS issue.
I had my RBM mounted upside down, terminals up. Once removed, water dripped out of it. When installing I figured it would operate just fine either way but it sucked up moisture somehow. It didn't rain nor did we do any water crossings. Dunno if this is your issue, but my bet would be on that RBM.
Good luck!
Oh mine was in a 97 80 as well!
Sent from my iPhone using Tapatalk
Martyn
Supporting Sponsor, Overland Certified OC0018
Call George at Extreme Outback for trouble shooting advice on the IBS System.
Our experience with most electronic systems in vehicles is that while it's human nature to start examining the last piece of equipment you added to your rig to find the problem, it's always best to examine your basic electrical system first and eliminate that from the equation.
With dual battery systems we normally start out by looking at the wiring on the units to make sure they are hooked up correctly, that terminals are clean and there are good grounds. We check the voltage on both sides of the relay. If nothing obvious is going on we check then alternator output, separating the batteries and checking voltage and then load testing them.
In your case the IBS has a second relay, this enables the system to use the auxiliary battery to power the system should the main battery be dead, allowing starting from the auxiliary battery. This set up is unique to the IBS brand, and this relay needs to be checked when you check the main switching relay.
Sounds like you have done the basic testing, which is wonderful, call George with the info on Monday and he'll get you sorted.
Our experience with most electronic systems in vehicles is that while it's human nature to start examining the last piece of equipment you added to your rig to find the problem, it's always best to examine your basic electrical system first and eliminate that from the equation.
With dual battery systems we normally start out by looking at the wiring on the units to make sure they are hooked up correctly, that terminals are clean and there are good grounds. We check the voltage on both sides of the relay. If nothing obvious is going on we check then alternator output, separating the batteries and checking voltage and then load testing them.
In your case the IBS has a second relay, this enables the system to use the auxiliary battery to power the system should the main battery be dead, allowing starting from the auxiliary battery. This set up is unique to the IBS brand, and this relay needs to be checked when you check the main switching relay.
Sounds like you have done the basic testing, which is wonderful, call George with the info on Monday and he'll get you sorted.
Drove from Temecula to Long Beach today and the system showed stable voltage the entire time and worked perfectly. I had removed the RBM and this was the problem. I guess it went bad. I don't know if I really even need it since it was an option to the system anyway. Dont even know where to source another one.
Less junk to fail, seems like the Achilles heal of the setup. Maybe a cheap meter would suffice to check it once in a while if you are curious. If you want one, it seems like Martyn was saying you can probably get it from Extreme Outback. The electronics in the meter are probably very basic, maybe you can repair it, or get someone to repair it.
The RBM is the Relay Booster Module and is a separate device from the monitor/meter. The RBM's purpose is to allow you to start your vehicle from the aux battery in the event your starting battery has failed. The RBM gives support to the relay when using the aux battery to start. It is sold independently from the rest of the kit and is not needed for the isolator/charger to operate properly. However, without it you run the risk of damaging the relay if you were to try to start from the aux battery. (You could always just use jumper cables instead.)
A replacement RBM can be purchased from Sierra Expeditions
or Extreme Outback
osidepunker
Adventurer
So glad I found this thread! I'm having the exact same issue! It happens pretty randomly, but when it starts it keeps causing problems for hours on the road. I can pull the plug in the back of the controller and that will reset it for a few minutes then it fails again. When its failed, the controller shows the batteries are linked, but they obviously aren't as they're reading different voltages. A meter on both sides of the relay shows different voltages as well, even though the controller shows linked. Once the aux batteries drop below a certain point, I get an alarm. That's usually how I know there's a problem. IBS says 5 year warranty so I guess I will start with Sierra Expeditions and go from there. I kinda feel like just removing the RBM, but it seems like a worthwhile addition. Plus I paid for it lol