Introduction and Dual Battery Question

[RC5280]

Hi, I have been lurking for a while now. I had a 81 CJ7 but the ride was too rough and I couldn't bring enough stuff for my camping trips with my wife, son and dog...so it had to go. After months of searching for a replacement, I decided on an 80 or 100. Last fall this 80 came up on crags list. (it was posted on here too). I don't know if I would have done all the upgrades, but it was built out and not too much $$. I have all the service records and most of the work was done at Slee, so it seemed like a good buy. 6 months later it is still running like a champ. I am planing on changing the radiator hoses and rebuilding the birfs, but that might be all it needs for now (famous last words).

Now my question. It has an IBS dual battery system which seems to be working. The cruiser is not my daily driver, so it does not get started every day. After setting for 10 days to 2 weeks, I noticed the low battery alarm was going off on the IBS system. Seems to me it should be able to set longer than that before running down? From what I can tell, the batteries are only 1.5 years old. I checked the voltage from the alternator and it is 14.6 volts. Both batteries were around 14.4 volts (truck running). I am thinking of rebuilding the alternator?? Anything else I should be looking at? Can't think of were the parasitic draw could be from if there is one.

Thanks,
Rob

Two photos. One of rig and one of volt meter while driving.

 

[LandCruiserPhil]

With a running alternator output of 14.6 volts I cant understand why you would consider doing anything to the charging system.

As for your dual battery set up, if you do not have a 100% understanding on how it works you should consider removing it IMO.

 

[Otamiway]

When the alarm goes off, did you measure the volt of each battery? I would first check for system drain.. I do not have a IBS but my system completely isolates the 2nd battery. Try running a check on the system?? Consult Slee??

FWIW I do not have anything connected to my 2nd battery.

PS Very nive rig...

GL
Stu

 

[BirfMark]

With a running alternator output of 14.6 volts I cant understand why you would consider doing anything to the charging system.

As for your dual battery set up, if you do not have a 100% understanding on how it works you should consider removing it IMO.

Why would you remove it just because you don't understand how it works? Do you pull your automatic transmission just because you don't know how to rebuild it?

Rob,
It sounds like there's a parasitic draw somewhere in your system. My rig only has a single battery, and it easily starts after two weeks of no driving without any problems. You can search out a parasitic draw by putting an ammeter on the positive lead of the battery, and then pulling fuses in the fuse box to see which one cancels out any draw measured.

 

[98 SNAKE EATER]

If you're charging @ 14.6v, then the alternator is fine.

I'd start by checking if the IBS system is connecting both batteries while the engine is off.

2 batteries connected will eventually self discharge each other and if the IBS system uses relays (I'm not familiar with that system), then keeping them connected will further drain them because they're constantly energizing a coil

If you're sure that the secondary battery is completely isolated when the engine is off, then check for parasitic drains on the primary battery.

 

[LandCruiserPhil]

Why would you remove it just because you don't understand how it works? Do you pull your automatic transmission just because you don't know how to rebuild it?

<snip>.

Simply you cant trouble shoot if you don't know how it works = you are stranded. I have seen it several times out on trail.

As for the automatic transmission, if it stops working 99% of the time you are screw even if you are an expert.

 

[Rwhat]

I have to partially agree with LandcruiserPhil. It's best to understand how the system works. I too have seen this problem in person.

Camping trip last summer my buddy had his newly purchased LC which had a dual battery setup that left him stranded for 4 hours on a one lane dirt road at night. We finally found him and he had no power. Not even parking lights. We jumped it enought to get it off the road.

Eventually the next morning a couple of us looked at his dual battery set up and couldn't figure it out. We finally found a broken lug on one optima and the other had the main ground detached.

Both battery's were dead. I had to take one of my battery's out and put it in his. Eventually he bought a IBS system and installed it.

What would the OP do if his main battery died and IBS solenoid died. Without moving the batteries. Theoretically.

Not trying to do a thread hijack, but maybe we should come up with a dual battery trouble shooting guide...

 

[RC5280]

I agree that there are always things to learn. I believe I have a handle on the two battery system. I was just thinking there might be some experience in the group on the battery drain. I will start pulling fuses and see if I can find anything. A trouble shooting guide would be great for the faq.

 

[sleeoffroad]

The IBS is a remarkably simple system. You have sense wires for each battery and then it connects the batteries with solenoid when the main battery sees a charge. The 14.7v sounds really high. It might be right after start, but our experience is that it does not maintain. The system is working and telling you your battery is getting low.

I don't know if we installed it or not, but if it is one we installed I can assure you we go to great pains to make sure it is safe, properly installed, tested and have no areas that could cause future failures in terms of wiring etc. So I would not rip it out. It would be very simple to just compare the suppliers wiring diagrams with your actual install and actually document it so you know what is going on. I agree that on a bought truck, it is a good idea to spend the time to understand what was done, but the system is so simple and non-invasive on the trucks wiring that it should be a simple process.

You need to isolate the draw if any. You also might have bad batteries. If they are bad, that might explain the high charging.

Here is their website ibs-tech.ch: Dual Battery System

You just need to check if you have just the IBS or the IBS with remote boost module installed. Then check the wiring make sure it works.

 

[Offroad80]

Ibs soleniod/relay

Hey Slee have you ever had any problems with the soleniod/relay on this system? I trying to find a problem with my system. The linked alarm comes on after the engine has been running for about ten minutes, i've checked all connections twice now and can't seem to find the problem.