Just a casual enquiry to whoever has the experience to answer. I intend to fit a dual battery controller into my UK spec Landcuiser 80 I am a bit wary of electronics when used in hostile environments hence the use of the all mechanical 80. I have researched the marine versions of various controllers which I like for their ability to be manually overridden at the press of a button on the actual unit but also want the display of battery condition. I had considered mixing theNational Luna dual display (not controller) with the marine solenoids when I came across the IBS system, (I agree with whoever pointed out the name could have been better :elkgrin

anyway, the IBS appears to have it all untill I read up on the unit, it seems to have the 'best' system you now need three relays or two relays and a relay booster module which looks like a relay, why?
The RBM (Relay Booster Module) performs a Link Start from the auxiliary battery even if the starter battery has failed completely. RBM fits into the wiring of the IBS 200Amp relay. RBM improves the link start support to 100%, if sufficient charge is still available in the auxiliary battery.
In the case of a deep discharge of the starter battery (start up of engine from starter battery is no longer possible), the "Link" button on the IBS battery monitor (IBS-DBS/BM3 or DBi-DBS) is pressed. With the support from the RBM at starter battery voltage below 10V the start of the engine from the Auxiliary Battery (AUX) would be activated.
In very cold weather or when starting capacity is reduced the RBM supports the relay to make sure the contacts stay properly closed during link start, this extends the relay life.
We carry only the new IBS Battery Monitors (with uC Technology) in our kits. These monitors are equipped with a low battery alarm on both batteries. If this alarm starts to sound, then check your battery system before further traveling. If doing so the risk of having battery problems is very small and RBM is only there if things go totally wrong.
I like the KISS principal and it seems that the additions are simply making up for the weakness of the original solenoid, perhaps a heavier relay would make the other units redundant?
The RBM module is simply an add-on for those with too much wiring on the main battery. If you think of it like a capacitor to trigger the relay, it might make more sense. The relay (solenoid as your calling it) is capable of 500amps.
Also, does the IBS LED display stay on whilst you are driving so you can monitor the batteries or do you have to press a button to see what is happening with the individual batteries?
On the IBS Battery Monitor there is a display button, this button will adjust the brightness of the LED's and also enable the battery voltage lights to illuminate for a preset time (I think 60 seconds). The charge and status LED's are the only ones that stay illuminated while driving, these are also dimmable by the display button. I found that you get a good grasp simply by the status LED's, and the alarm will trigger if anything goes wrong.
Hope that helps you out Dave.... let me know if you have any other questions, or feel free to give us a call and we can discuss the IBS vs. National Luna vs Ironman, etc...