SI-ACR Aux battery setup - alternator light issues

[lwillis]

[crazyvwvanman]

I don't think that voltage reading is itself a problem. The battery is only providing 12.5v or so to the wire leading to the dash and it drops all along the way as a fact of physics in any wire that has current flow.

Mark

[lwillis]

[Nitramrebrab72]

As Blue Sea state themselves the ACR does not direct the charge to the lowest voltage battery.
Its a relay type isolater so as such will have a parallel type charging circuit. They are more efficient but less independent as charging goes.
As I said earlier your batteries have become so unbalanced its effecting your alternator.
Disconnect the 110AH and if you haven't damaged your alternator everything should go back to normal.

[lwillis]

Thanks for the reply.

Actually, both batteries are new and both are kept fully charged, either by the alternator or the battery charger when connected to shore power.

I initially thought that the alternator was behaving correctly when disconnecting the ACR, but I was wrong; it does not kick in, either with one or two batteries.

This alternator has been connected to a fairly used and problematic main battery up until recently, and there was also an unwanted ground along the blue alternator field wire’s path. I’m guessing one of these situations lead to the alternator prematurely going bad...

Hopefully it will all work out with the new alternator. I am getting the van back by the end of the day...
_________________
LP Willis
1989 2.1L Vanagon

[SyncroButter]

[crazyvwvanman]

Could be the reason you don't follow it is that it doesn't make sense going by what the OP reported was happening. The ACR doesn't activate until AFTER a charging voltage is applied to one side and so the aux battery wouldn't be connected until after the alternator began charging. The OP says his alternator doesn't begin charging anymore, so disconnecting the aux battery wouldn't change this since it is never connecting in the first place. Of course that is the fundamental purpose of the ACR, to separate the aux battery unless charging is already happening.

Connecting 2 different size/type batteries to the same alternator isn't in itself a problem for the alternator. Connecting a bad battery could damage the alternator. Even connecting an excessively large battery with too heavy of wire could damage the alternator if the battery is deeply drained but this would more likely be over time and show up as shorter than expected alternator life. The devil is in the details.

OP, the blue wire does connect to ground through a working fridge relay but the relay coil acts as a resistor that will limit the amount of amps that pass through. This is normal operation so merely unhooking the blue wire from the relay doesn't indicate a true "short to ground" just because the light then turns off with the relay unhooked.


(I hope people realize that it is critical to measure right at the alternator to get the most meaningful reading of what the alternator is doing)

Mark

[Nitramrebrab72]

[fxr]

[shagginwagon83]

[Paulbeard]

[shagginwagon83]

[fxr]

[crazyvwvanman]

You are misunderstanding how batteries work and how the alternators in our vans work.

A battery only takes much charge current when it needs it. The closer it gets to full the less it takes. Connecting a thirsty battery next to a full one doesn't make the full one thirsty too. Only a thirsty battery will drink very much.

The alternator puts out a constant voltage. If anything draws on that voltage the alternator senses the flow and increases the amps to as much as the draw takes. The voltage stays the same, only the amps increase or decrease as needed. Connecting a thirsty battery to a full one increases the amp draw and the alternator makes whatever extra amps the thirsty battery takes. None of the extra amps go to the full battery because it is full. As the thirsty battery gets filled the amps gradually decrease. The alternator voltage stays the same the whole time.

The ACR doesn't direct the charging current flow, the laws of physics and chemistry do that.

Mark

[Nitramrebrab72]

Okay so here it is I got onto the main Bosch /Varta battery supplier and they finally replied, they categorically stated that any parallel charging of un matched batteries not only in AH (which is the case 110Ah deep cycle type lead maze vs 60ah starter type lead maze) but also un similar internal lead maze layout but with same size AH in parallel charging will preference one of the two batteries leading to premature failure seriously reducing the batteries life. He went on to say that identical batteries in type and AH should be both fully charged before connecting in parallel to avoid unbalancing of the batteries and the longest life possible for the batteries.

[Nitramrebrab72]

The answer is NO!
That's stated by Deep Sea themselves the ACR does not manage battery charge as they state Deep Sea not moi "an ACR does not direct the charge to the battery that most needs it" . So if it doesn't direct to the battery that most needs it then to which battery does it direct to? Well by simple elementry deduction the one that needs it the least derrr.
Eventually making the batteries so unbalanced (especially with such a miss match 110ah/60Ah deep cycle /starting types) damaging the weaker batter causing over heating in both the battery and alternator which also can be damaged in severe cases.
Deep Sea were designed as a safety device for boat users to avoid a flat battery while anchored out at sea and that is how they are marketed on their official youtube promotional video they are not Ideal
but a bit of stop gap between that and a expensive fully fledged battery management system . The batteries need manual battery management either by a pos 1&2 battery switch to manually top up and rebalance
the batteries.
I have a great simple setup up in my t25 hi top westfalia I live in it all year round in France when I have 5 mins I will put it out there.

[crazyvwvanman]

You are mistaken about what happens when the alternator is doing the charging. Charging done with our style of alternator is different than charging done by a multi stage battery charger. With alternator charging the output voltage stays nearly the same at all times, as I said above. All the ACR does in that case is decide if there is enough charging capacity available at one battery to share it with the other. Each battery itself then decides how much current it accepts. Full batteries don't accept much. In our vans the alternator is ALWAYS connected to the starting battery. All the ACR does during alternator charging is decide if and when the aux battery will also be connected to the alternator. It doesn't "steer" any extra to the starting battery when that happens. It only shares what could otherwise go the starting battery but that the starting battery doesn't need.

Mark

[fxr]

[Steve M.]

Pull the voltage regulator as others have said.
I put in a rebuilt Bosch alt. from Manny,More & Hack last year.
I was having a problem with charging voltage at the battery so I pulled the regulator.
The was only about 1/8th inch left on the brushes...rebuilt my a#*
I always carry a spare voltage regulator so I put it in and that definitely made a difference
I still have a resistance problem in the long cable from the starter to the battery as the alt output measured at the alt. is 14.3 and at the battery it is 14.15v whereas before it was showing 13.28 at the alt. output. (Even with only 1/8" on the brushes it still should be outputting a full Output. It will be stamped on the VR what that Output is. The VR I pulled had 14v stamped on it.)

Now I just have to find out why my Aux. Batteries charging rate is lower then my start battery going through the SI-ACR to the Aux. Batt.
The way I read the SI-ACR literature is that the ACR does not regulate the charging rate it just opens the charging circuit so that both Start & Aux battery's are charging.

A voltage regulator is a small size item so it is an easy spare to carry.
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