Dual Battery System Issues - IBS & Victron (3 Viewers)

[troopysahara]

Hello,


i have been having some issues with my dual battery system that i hope someone can help with.

I have a standard lead acid 90 Ah as a starter battery in my 78 series troopy. connected via the IBS dual battery system, to an AUX 80 Ah lead acid battery. the system works fine and connects the two batteries when i have the engine running and the relay feels the 13.5V charge from the alternator.

I then added a cheap standard PWM solar controller connected to a 150W solar panel on the roof. The solar controller was connected to the AUX battery.

When i turn off the engine the IBS system isolates both batteries, however when i have enough charge coming in from the solar system the IBS links both batteries and charges the starting battery as well, displaying that both batteries are fully charged. yes this all sounds great till now haha.



However once i replaced the the PWM controller with a VIctron 100/20 Mppt controller the system has begun to act a little funky. in addition, I run all my loads off the load output of the MPPT controller, just to have an idea of how much power im consuming (just have a fridge and one led light running of this)



once I plug in my 150W solar panel, connected to my Victron mppt 100/20 solar controller to my aux battery,The IBS begins to feel a charge (indicated on the left bottom led 13-13.5V) but no linked led on. Then the charge drops and the relay kicks in and the linked led comes on but no charge. And it repeats this cycle every 30 seconds or so. I checked all my battery settings on the Victron app and the data seems to be correct to those set for a lead acid battery.


Now my start battery has died for some reason after not starting the car for 2 days! using an avo meter, the start battery reads around 11.5V and the aux battery is reading 13.5V, which is basically the same figure my Victron app is showing for my aux battery which is 13.7V at a float state of charge.


I even tried the link function off my IBS system and it is not able to jump start the starter battery. I have even used jumper cables between both batteries and still nothing, even tried hooking up to another car's battery, still no hope. I am starting to feel like it could be a faulty start motor on the 1HZ.

I dont understand why my IBS system is acting this way once i connected the mppt controller, and now i dont get why my start battery would die.

any help or recommendations would be greatly appreciated!

 

[e9999]

The oddest part of this is that you could not jump the starter battery. Have you tried disconnecting all the 2nd battery stuff from the starter battery, and then tried to charge it or jump it?

 

[troopysahara]

i mean when i disconnect the IBS monitor that is basically disconnecting the 2nd battery, however i can try to remove the terminals off the aux battery and give it a go.

 

[e9999]

I would first want to know if the starter battery is OK. So I would physically disconnect everything -including the IBS- from the starter battery to test it.

 

[troopysahara]

these are the two pictures of what my IBS is reading when my engine is turned off and solar is charging the aux battery.
usually the charge and link light stay on together, but here they keep alternating every 30 seconds.

and as you can see, when they are not linked my start battery seems low, but in reality i have been using the car all day before these images.
so something is draining my starter battery and i cant seem to figure it out.

 

[e9999]

are the battery voltages measured with dedicated leads to the batteries or is it just at the IBS device?
And what is that "charge" voltage, exactly, if not at the batteries?

 

[troopysahara]

So the relay of the dual battery system is connected each battery and then connected to the IBS display.
the charge voltage shows you how much charge is going to the batteries.
when the relay detects a voltage of 13.0V or higher the relay kicks in and connects both batteries together.
it works both ways, so if it feels the charge from the alternator it will 'link' the batteries and same goes with the solar input.

the strange thing is that it either shows charge but not linked, or linked but no charge, usually both LED's should be on the same time

 

[troopysahara]

Hey just an update:

So i ran a short circuit test, and found out that the center lock i had installed may be pulling current.
disconnected the center lock and couldnt find any current being drawn.

It is also not the start motor, as i moved the aux battery to the starter battery position and the car fired up straight away.

I also went back and installed by old cheap PWM solar charger and the link and delink on my IBS continued, it never used to do that before.

this was the response from the IBS team:

"This behavour is correct. If the charge from the solar kit / Victron is not high enough the IBS is doing this cicles. With solar the Aux battery is charged. Then Aux battery reaches the Link voltage of 13.3V then the system voltage of Aux and Main drops below the delink Value as the solar power delivers not enough power to bring up quick enough the Main and Aux voltage. Therefore the system seperates the batteries again. This cycle goes on until the Solar panel braught up the main battery voltage to the level the batteries are not seperated anymore.

So all is good, this is just how the physics works between the batteries."


But even if a drive for a full day and the batteries are both fully charged, once i turn off the car, the IBS still does the same behaviour.

if i leave it connected for a while and check the batteries again, i realize that the start battery has gone down from 12.8 to 12.4V

i am starting to think it could be a faulty relay in the IBS system. but what could be causing it, it is supposed to be a two way relay and would open if it feels a 13V charge from either battery.

 

[troopysahara]

After re looking at this diagram, I actually have the negative wire from the solar charger/regulator connected to the negative terminal on the auxiliary battery, would removing that connection and hooking it up to a ground on the chassis fix this solution?

 

[TreadingLight]

That doesn't sound like a factor. In fact it might make things worse if your grounds are less than perfect as the solar controlar might not get an accurate voltage reading.

It sounds to me like you have a parasitic draw on the starter battery. It doesn't sound like there is anything wrong with the IBS or the Victron.

I would put the solar/dual battery stuff out of mind and diagnose for a draw. You can disconnect that stuff while you diagnose or leave it in place - shouldn't matter.

 

[peesalot]

The aux batt neg should be tied to chassis ground so no matter where the solar controller picks it up as long as connections are good. FWIW for me picking up ground at a battery terminal is bad just cause of corrosion unless you have agm or Lipo then that isnt such a concern. I have my solar controller grounded to chassis very close to controller.

 

[TreadingLight]

The only thing I connect to the neg terminal on a battery are the engine/chassis grounds, so I agree with you, but in this case I would make no changes until the root problem is solved because:

1) we don't know the state of the vehicles grounds. if bad they could make troubleshooting more complicated

2) it is unrelated to the problem the OP is having

I'd look at battery recabling after determining what is draining the starting battery.

 

[peesalot]

I'd fix the ground

 

[TreadingLight]

I would too but ... one thing at a time. This stuff about grounds is a distraction from troubleshooting the issue the OP is having.

OP needs to figure out why the starter battery is discharged. Bad battery, parasitic draw, or alternator not charging.

would removing that connection and hooking it up to a ground on the chassis fix this solution?

No it won't. But you should do it anyway. Personally I'd avoid getting distracted optimizing things unrelated to your problem until you have your problem diagnosed, but that's just me.

 

[peesalot]

I re read the original post and it does appear his starter battery is crap. Grounds would not fix that.

 

[Hugh Heifer]

I have had a few issues with my IBS system. The most recent is I frequently need to unplug the monitor and plug it back in to get it to turn on. I detailed the other which was the failing of the link module (or whatever they call it - the RBM.) I detailed that in another thread.

 

[TreadingLight]

Unrelated to the OP's issues, which are all in the vehicle charging system/battery, not the IBS.

If you happened to buy it from Extreme Outback in Vacaville gave them a ring. They are very helpful.

 

[Hugh Heifer]

Unrelated to the OP's issues, which are all in the vehicle charging system/battery, not the IBS.

I agree the OPs issue is probably a battery one but I wanted to bring up there have been a few gremlins in the same IBS-DBS and that is what he suspected initially. He also never posted his solution.

If you happened to buy it from Extreme Outback in Vacaville gave them a ring. They are very helpful.

I did not. I got it about 12 years ago from Will at Sierra Outfitters and a replacement RBM from Slee when that burned out.