Frying My Batteries?

[Poeme]

Long time reader, first time poster...I appeal to your collective genius!

In July this year I installed a new 125 amp Balmar alternator as well as converting to their serpentine belt system. I'm continuing to use my Balmar ARS-5 regulator, installed in 2018, which worked flawlessly with the previous 75 amp Balmar alternator and 2 Firefly G31 carbon foam batteries (considered AGMs)...combined to a West Marine AGM start battery with Blue Seas ACR. The regulator is programmed for AGM battery profile, 14.3 bulk, 13.3 float.

I thought this would be plug-and-play. Except on each start-up, battery voltage goes straight to 15.5. After 10-15 minutes the voltage then corrects to 14.3 and drop to 13.3 float, depending on SOC. During long motorings this summer though, the voltage would also sporadically and for no reason pop back up to 15.5, stay there for another 15-20 minutes then correct itself again. Up and down, many times, even when E-meter shows full batteries. I cringe for the health of the batteries (and electronics) every time it goes into the "fry-zone". Full disclosure, the wonderful people at Balmar sent a new ARS-5 ...but same result. At wit's end! Anybody?

[smac999]

My first guess is your alternator is connected to your house bank. And the regulator is connected to the start bank. And the voltage sense can not get correct readings until the acr engages.

Does that reg have a dedicated voltage sense wire? Or only a power wire? I’ve only used the 614s

Does that one show you bv and cv numbers on screen?

[Poeme]

Thanks so much for responding.
Alternator output is direct to house bank. The voltage sensing wire from regulator though also goes directly to house bank. So I don't THINK the regulator is "connected to the start bank". (Except through the ACR)
I've tried taking the start battery out of the loop, isolating all charging to the house...and still, I get 15.5 volts on start-up.
Adding to the mystery, and perhaps related to your thinking...with ACR and starter connected...as an experiment, I switched off the engine start circuit with the engine running, and the regulator read-out went black, dead. Even though the charging circuit was still intact...total question-mark.
On the old alternator...the voltage sensing wire from the regulator connected directly to the Positive Output Terminal along with the the large output cable.
I feel the problem may be staring me in the face and I just can't see it.

[GordMay]

Greetings and welcome aboard the CF, Poeme.

[CatNewBee]

Sounds like enabled equalization program. This should be only enabled for open wet FLA batteries.

[Stu Jackson]

>>>>I switched off the engine start circuit with the engine running, and the regulator read-out went black, dead. Even though the charging circuit was still intact...total question-mark.>>>>>>>>>>>>>>


What is an engine start circuit? Do you mean the power at the cockpit panel ignition switch? If so, that is usually what powers the regulator, so is not surprising.

[Poeme]

No not the ignition switch (which I agree would turn off the regulator)...rather, the cable direct from start battery to start motor. (I have a keyed switch to prevent unauthorized engine starting). The charging circuit is separate from it. But, let me think...may be some connection I'm unaware of...
Brain freezing trying to figure this out...

[Poeme]

Originally Posted by CatNewBee

Sounds like enabled equalization program. This should be only enabled for open wet FLA batteries.

Sounds like a reasonable possibility. Will check regulator programming. But wasn't an issue on previous alternator, and haven't gone into programming this regulator for equalization. Thanks for opening my mind to this idea...

[smac999]

Originally Posted by Poeme

No not the ignition switch (which I agree would turn off the regulator)...rather, the cable direct from start battery to start motor. (I have a keyed switch to prevent unauthorized engine starting). The charging circuit is separate from it. But, let me think...may be some connection I'm unaware of...
Brain freezing trying to figure this out...

The cockpit key switch normally comes from the starter post. So shutting off the battery switch will also kill the cockpit and key. Which would kill ignition. Power and reg.

So I wound say normal. But not something I would be doing.

[Dsanduril]

I would start to think an intermittent bad connection on the voltage sense wire. I'd grab a chunk of new wire, run it from battery to sense terminal (over the cushions, through the cabin, whatever is easy). If the problem goes away then you can either chase the existing wire or properly install a new one.

[Edit] or use a DVM to measure voltage at the sense terminal while the problem is occurring. Also, another place to look is bad connections on the main negative cable, this can also lead to bad voltage measurement -> improper regulation. With a new alternator you may need to run a negative cable from the alternator case to block/battery. If alternator ground is via mounting bolts that can lead to intermittent voltage problems. And since the alternator is new....

[Poeme]

Originally Posted by smac999

The cockpit key switch normally comes from the starter post. So shutting off the battery switch will also kill the cockpit and key. Which would kill ignition. Power and reg.

So I wound say normal. But not something I would be doing.

It was a pointless experiment, won't do that again.
The fact that this high voltage has happened often and sporadically got me thinking...today on startup I jiggled the wires connecting the harness to the regulator (through a Ford plug) and for the first time since the new alternator installation, got correct bulk charge voltage. Possibly the Field Output wire has a bad connection within the plug. Hoping that's all there is to it, will get going on a deeper inspection and repair soon.
Very grateful for your comments!

[Poeme]

Originally Posted by Dsanduril

I would start to think an intermittent bad connection on the voltage sense wire. I'd grab a chunk of new wire, run it from battery to sense terminal (over the cushions, through the cabin, whatever is easy). If the problem goes away then you can either chase the existing wire or properly install a new one.

[Edit] or use a DVM to measure voltage at the sense terminal while the problem is occurring. Also, another place to look is bad connections on the main negative cable, this can also lead to bad voltage measurement -> improper regulation. With a new alternator you may need to run a negative cable from the alternator case to block/battery. If alternator ground is via mounting bolts that can lead to intermittent voltage problems. And since the alternator is new....

Thanks for the advice! Today on startup finally got correct voltage...believe I found a bad connection on Field Output wire to the regulator. Hope that's it...otherwise will inspect everything you have suggested here!