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Questions (FAQ's) for IBS-DBS Dual Battery Systems

All the information listed below is correct when the batteries are in operational order this excludes damaged batteries (batteries with shortened cells, or even dry batteries).

In IBS Dual Battery System terms this means the low battery alarm on the IBS monitors shows no regular alarms.

Frequently asked questions (FAQ)

  1. Is during the running of the engine the charging of the batteries done automatically?

    Yes! The IBS Dual Battery System is controlling the link and the delink of the batteries automatically. No action is needed from the driver! 
  2. Is it possible to use the AUX battery for link start support?

    Yes! There is no need for “Jump Cables”, hit only the Link-button and both batteries are linked in parallel to support the start of the engine!
  3. Is it possible to use different sizes and types of batteries?

    Yes! Different types of batteries can be installed in this dual battery setup, as long this batteries are not any Li-Po or Li-Ion Batteries. While the engine is stopped both batteries are separated and cannot affect each other in a negative way.
  4. But what type of battery do I need?

    Different types of batteries: Liquid, Gel, Dry or AGM can be installed in such a battery system.
  5. Is the IBS-Dual-Battery-System supporting the use of an electrical Winch?

    Yes! The winch has to be connected to the starter battery. If you actuate the LINK button the auxiliary battery is linked in parallel with the main battery. During winch operation it is recommended to have the engine running to support the heavy load of the winch, which can draw up to 400Amp.
  6. Where the additional appliances should be connected?

    Additional user appliances must be connected to the auxiliary battery. Possible appliances are: Fridges, Refrigerators, GPS, lights for inside or outside, Radio devices, compressors, water-pump, etc. Even the car stereo and the cigarette lighter may be hooked to the auxiliary battery.
  7. Which cable size has to be used between the batteries?

    In campers cables of 16 mm² or 25 mm² should be used. For 4WD's 25 mm² and with winches 35 mm² should be used. In vehicles for rally competition a section to 50 mm² may be useful.
  8. How can a battery system be optimized?

    A direct connection of the minus pole of both batteries by a copper cable will improve the efficiency of the battery system. Use same wire section as used on plus cable connections. The chassis of the vehicle isn't good enough as conductor.
  9. Is the IBS Dual Battery System disturbed by electronic spikes or climate?

    No! The IBS Dual Battery Systems are used worldwide and withstand extreme conditions. Modern automatic manufacturing, allow us to guarantee best quality!

    The IBS Dual Battery Systems are delivered wit a 5 years warranty.

  10. Who is using the IBS-System?

    Police, Ambulance; emergency vehicles, Rally-sport and Rally-support, Fire brigade, 4WD, in Trucks, Military and many more.
  11. Why the IBS Dual Battery System has been developed?

    In the Great Victorian Desert of Australia I was stopped 20 years ago in the middle of the desert in my 60er LandCruiser because of 2 empty batteries. The cause was a broken alternator. My installed dual battery system had no charge and battery status indication. The system did also not offer a link start feature. The only solution was to gather all not used cables and make a primitive jump-cable, what finally also worked.
  12. Are the IBS Dual Battery Systems only available for 12V batteries?

    No! New IBS Dual Battery Systems are available in both 12V and 24V versions!


  1. I have replaced a battery and the Monitor is not properly working again!

    Behind the unit is a grey automotive Deutsch connector. Disconnect for 5 secs and then reconnect again. System does now a full restart and shows with the Main and Aux LEDs the software version (Main 6 and Aux 3 LEDs means version 6.3).
  2. The low battery alarm sometimes goes off at night while sleeping!

    It is possible to deactivate the alarm, contact your dealer or IBS for further instructions (only suitable for technical people with appropriate tools). There is another link failure alarm what cannot be disengaged at all as this is part of the safety feature. The low battery alarm (beeper) can be disengaged by pressing display once. If it happens the battery is still under strong discharge the Alarm starts again at 10V. Otherwise the system then stays quiet.
  3. I have been playing with the manual link function and system behaves now strangely!

    The system is equipped with delay functions to stabilize the battery system (mainly in combination needed with low amp solar charge), before an action starts the previous has to be expired. (if the system has linked wait for 5 mins until it delinks automatically). Wait for 10 mins and then the system works fine again. If you enter the car after a stop what was longer than 5 mins, the system links immediately. The link function (30 mins if pushed once and 120 mins if pushed twice) resets automatically. If you wish to return to full automatic operation again just push auto. Some diesel cars with extended glow procedure might take up to 5 mins to link.
  4. My aux battery failed, what can be done?

    The system allows to be configured in emergency situation as a single battery system (Just main battery being charged from alternator). Push link for 5 secs until beep, from now on system is not linking (neither automatically nor manually) anymore!!! You have to disengage this function manually again by pushing auto for 5 secs, or unplug monitor for 5 secs for a system reset. This feature allows returning safely with the starter battery setup to service place. Batteries can fail due to extreme heat, mechanical shock or age. Check batteries regularly. If Low battery alarm goes off regularly this is an indication to check the batterie(s).
  5. When is a RBM (Relay Booster Module) needed?

    The IBS-DBS and DBi-DBS can be equipped optionally with this module. The standard system as delivered has a safe operation range of down to 8.5V on starter battery, what in most cases more than needed. In case of severe main battery failure it still might happen, the main battery voltage drops below 8.5V what means the link function is not supported anymore (no link start possible anymore). RBM extends this safe working range virtually down to approx. 5V main battery voltage, what sounds low but it showed this can happen. RBM is an electronic MOSFET unit and is wired into the relay and monitor circuitry. The IBS-DBR product does not need this RBM as this feature is already integrated.
  6. My aux battery is in the back of the car and only needed while travelling!

    From IBS-DBS Software 6.4 and newer the system is equipped with the trailer battery recognition, what means the aux battery can be removed and the system disengages on the next link cycle the link mode. No power is now on the aux side of the relay until the aux battery is attached again. This feature is well useful when the aux battery is located in the trailer. While no aux battery is present the system switches back to single battery operation, only main shows display level and aux display stays off. IBS-DBR is also equipped with this function.
  7. My car is equipped with a voltage reducing alternator (sold currently only in Australia)

    Some 4WDs such as LandCruiser 150 and 200, LandCruiser 70 V8, accept in the fuse box for alternator circuitry a compensation ATO Mini diode instead the fuse what increases the charge voltage by 0.6V. This modification brings the IBS dual battery systems back to full performance and charges at the same time again the batteries properly. Contact your store or IBS for further instructions.

Rumors and the correct answer:

  1. A fully charged and an empty battery are linked in parallel, a massive current flows from the good battery into the discharged battery?

    First at all the charge voltage has to be above 13V that the battery starts taking charge. In both batteries there are inner resistances, cable resistance, terminal resistance what are in the sum at least 0.01 ohms (resistance of the good battery, the discharged battery and wiring). A voltage difference of 0.6V divided by 0.01 ohms creates a current of roughly 60 Amps; this is only during a very short time. If a battery is shortened, currents above 500Amps are possible.
  2. In the set-up of an IBS Dual Battery System a good and a discharged battery are linked in parallel for a “linked” start, the discharged battery immediately discharges also the good battery?

    This is correct that if a good and discharged battery are wired in parallel for a long time, the discharged battery starts to discharge the good battery, but this happens over hours or even days. In short term only the new system voltage will be somewhere between the voltage from the two batteries before they have been linked. The reserve capacity is still available and can be used for a proper link start. For this kind of situation it is recommended to have the optionally available RBM (Relay Booster Module) installed, that guaranties to have access to the auxiliary battery capacity if the starter battery has failed totally.
  3. The alternator only sees the well charged starter battery and does not properly charge the discharged auxiliary battery?

    The alternator is a constant voltage charging device with temperature compensation and delivers up to its maximum rating charge current. The IBS Dual Battery System links the batteries as soon the charge voltage exceeds 13.1V this happens within a few seconds up to 3 minutes depending on the car. When the batteries are linked, the current flows according to the internal resistance of the batteries. The starter battery, in most cases, only takes a little current and the rest of the alternator capacity is available to recharge the auxiliary battery and to run auxiliary electrics and electronics.
  4. A bad starter battery gets no support from a discharged auxiliary battery in a link start situation?

    To get an engine started it requires most of the time just the initial kick. If the starter battery won't be able to deliver the required cranking amps the linked in auxiliary battery is usually able to add the required additional energy to get the engine going. In these circumstances it is important the IBS Dual Battery System has been installed with recommended heavy duty wiring (25mm2) to avoid unwanted resistance between the batteries. In a cold winter weather it helps to start the car with the batteries linked.
  5. In link start the IBS relay is going to be destroyed?

    The IBS Dual Battery System is supplied with the new IBS200Amp high performance relay with dual bond technology. This offers a 200Amp continuous and 500Amp surge current. Alternator and starter motor are always wired to the starter battery, on this battery there is also the point of lowest resistance. In the case of a link start, the auxiliary battery only tops up what the starter battery can not supply. The cross current even under extreme conditions is not exceeding 250A.
  6. Sure the IBS relay is going to be destroyed in winch applications?

    The IBS Dual Battery System set up requires the installation of the electric winch on the starter battery (even if your best mate tells you different). The system follows the load sharing rules between the running alternator, the starter battery and the manually linked in auxiliary battery and the electric winch in operation, the relay is designed to handle this application without restrictions. In any case an electrical winch is the heaviest possible load and the car manufacturer has never designed the car electrics for this kind of load. If using the winch therefore it is always recommended to have the engine running and link the auxiliary battery in (two manual link modes are available: 30mins and 180mins, both with automatic reset). If not being in a competition or urgent situation stop the winch action from time to time to let the system recover or use a snatch block with a double line pull to half the stress on all components.
  7. It’s a new system and there is no experience if it handles my needs. Can I trust it?

    The IBS Dual Battery System is already for in different generations 18 years worldwide on the market. The IBS DBS has been continuously improved and developed. Thousands of applications are being used under extreme conditions such as in Siberia (Russia) or the Australian Outback. Military services, police forces and 4WDing industry use it around the globe. IBS offers 5 years warranty on the system. The system is simple to use and install but uses the latest microprocessor technology and specially developed high performance relay technology. The systems are manufactured in Switzerland with latest robot assembling machinery.
  8. DC-DC dual battery systems are much better than conventional systems such as IBS!

    Due to its simple design and the bidirectional architecture IBS offers great benefits not many offer. IBS supports full link start from aux battery and full winch support. With a classic DC-DC unit you can neither start the car with the reserve aux battery capacity nor use it for winch support. With an IBS installation a battery charger or solar system can be attached to the aux battery and the main battery automatically is charged also. The IBS systems stay operational in seriously extreme conditions such as -55°C to +100°C. Multi battery setups with IBS-DBS and IBS-DBR are well possible.

    Beat Wyss, IBS Intelligent Battery System GmbH

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