Intermittent issue with the house battery

[2100V]

Hey everyone,

I have a strange issue that's happened to me the last few trips out. A little background, I have 2 batteries with a 1/2/combine switch, and an ACR charging isolator. I have a starter battery and a deep cycle house battery, both of which are new. The house battery circuit, which I have the ballast pumps, radio, and dash switches connected to has intermittently stopped working on me. It's been when I've had all 3 pumps and a few other things running. Everything coming from the house battery goes completely dead. If I combine batteries it all works fine. The strange part is if I wait a while, the house battery circuit comes back to life. So clearly it is not a blown fuse, and I know for a fact that the pumps are wired directly to the house battery side of the switch because I wired it, so it's obviously not a relay either. The dash switches and radio are all on their original wiring but also wired directly to the house battery through their own wire separate from the pumps. But when the issue happens, everything loses power together and then randomly it comes back. So whatever's going on is happening somewhere between the house battery and the switch, and the only things there are an 80 amp block fuse which is not blown and the wires themselves.

What on earth could cause intermittent loss of power from one battery, at times when I'm putting a heavy load on the battery? Bad ground crossed my mind, but it possible for a ground to be "just bad enough" to only cause a problem when the battery is heavily loaded?

[chpthril]

but it possible for a ground to be "just bad enough" to only cause a problem when the battery is heavily loaded?

Thats exactly when a cable issue will show its ugly head.

Safe to assume this boat originally had a single battery, prior to the switch and ACR? If so, this leaves the original main starter cable from the battery now on the switch and the original ground cable. All other battery cables would be new at the time of the install. Are they off the shelf automotive battery cables or where these custom made form bulk? With the age of the boat, you can easily have an issue with the old cables or a corrosion or poor termination with one of the new cables.

You stated the pumps are wired to the house side of the switch, implying the battery POS. What about the pumps' negative leads, where are they connected?

Have you measured alternator voltage on both sides of the ACR with the engine running? Does the combine light ever come on?

[2100V]

Thats exactly when a cable issue will show its ugly head.

Safe to assume this boat originally had a single battery, prior to the switch and ACR? If so, this leaves the original main starter cable from the battery now on the switch and the original ground cable. All other battery cables would be new at the time of the install. Are they off the shelf automotive battery cables or where these custom made form bulk? With the age of the boat, you can easily have an issue with the old cables or a corrosion or poor termination with one of the new cables.

You stated the pumps are wired to the house side of the switch, implying the battery POS. What about the pumps' negative leads, where are they connected?

Have you measured alternator voltage on both sides of the ACR with the engine running? Does the combine light ever come on?

The cables were all replaced when I set up the dual batteries, with marine cables each sized for their purpose. I don't believe any of them are original at this point, except possibly the POS starter cable which I've never had issues with. The pumps are grounded through a bus/block, with one wire that terminates at the house battery. The house battery then terminates at the engine block, on a separate post from the starter battery.

I have measured alternator voltage with the engine running at both batteries. Starter battery is 13 +/-, and the house battery would not get above 11.8 even when I combined batteries at the switch. For some reason I never connected the combine light, although I probably will now.

[chpthril]

Starter battery is 13 +/-, and the house battery would not get above 11.8 even when I combined batteries at the switch. For some reason I never connected the combine light, although I probably will now.

Something is not wired correctly. Im certain if this. Sounds like the ACR has never worked form the beginning and even bypassing the ACR still doesnt send alternator charge to the house battery.

The light is part of the ACR's operation. Nothing "extra" to wire up to make the light work. It tells you that the ACR is closed/combined if the ACR is wired correctly and working. Just note, not referring to the remote light, but the light right on the ACR.

Can you post up your wiring schematic you used? Might be able to spot something.

[2100V]

Something is not wired correctly. Im certain if this. Sounds like the ACR has never worked form the beginning and even bypassing the ACR still doesnt send alternator charge to the house battery.

The light is part of the ACR's operation. Nothing "extra" to wire up to make the light work. It tells you that the ACR is closed/combined if the ACR is wired correctly and working. Just note, not referring to the remote light, but the light right on the ACR.

Can you post up your wiring schematic you used? Might be able to spot something.

I've never had an issue in 5 years until a couple of weeks ago. It's always kept both batteries charged. Even now the battery doesn't discharge, I just lose all power immediately. I've discharged a (previous) house battery and it took a long time and you could hear the pumps running slowly. This is instantaneous, and it comes back to full life moments later. I've only checked voltage at the batteries once during this, so I guess it's possible I checked the house battery while the starter battery was getting all the alternator current. That might explain the steady 11.8V.

Ok I think there is a green light on the ACR. IT's mounted on the back side of the rear panel though so I'll have to use a mirror to look at it next time I go out.

It's wired exactly like the ACR instructions showed, except the NEG battery cables each go straight to the engine block:

http://assets.bluesea.com/files/reso.../990170140.pdf

[2100V]

Actually scratch that comment about the starter battery getting the charging current; they charge simultaneously. So they might have been in a discharge state at that point, which would explain different voltage readings at the battery. I guess I need to check voltages while the charge light is on. And next time I lose power from the house battery, check voltage at the house battery.

I wonder if the battery 1/2/combine switch is the problem... that's where the POS connections for everything are, and that's where the leads for the pumps, radio, and dash lights are combined.

[chpthril]

Even now the battery doesn't discharge, I just lose all power immediately

Just a heads up, but 11.8 is about 90% dead and if this was measured with the engine running, somethings amis with the ACR. Knowing now that the system has been in place for 5 seasons, changes things a little. Barring a cable thats gotten left off some how recently, youve got a failed cable, failed ACR or switch. A bad switch could prevent the alternator output from reaching battery through the ACR as well as through the switch in the combine position.

[2100V]

A bad switch could prevent the alternator output from reaching battery through the ACR as well as through the switch in the combine position.

When I combine batteries, everything comes back to life and then later when I switch back to isolated batteries it all continues to work fine. The ACR feeds each battery exclusively of the battery switch, which means it should charge them both regardless of whether the switch is combined or isolated. But if I combine them, the house and starter battery receive a charge in parallel, correct? Which could mean I do have a problem with the ACR and the only time the house battery gets charged is when I combine batteries.

[chpthril]

The ACR feeds each battery exclusively of the battery switch, which means it should charge them both regardless of whether the switch is combined or isolated.

Actually, it doesnt, The main bank ALWAYS sees the alternator. ACR has not bearing on it. You can take out the ACR and the main still charges.

Starter battery is 13 +/-, and the house battery would not get above 11.8 even when I combined batteries at the switch.

This is why I made the comment about the combine position. Combine bypasses the ACR, so you should have instantly had alternator input on the house bank, when switch to combine.

So you really need to get at it with a volt meter and confirm the ACR operation first. Look for the green light as well as alternator voltage on both sides of the ACR. do the same by putting the switch in combine. Should have alternator voltage on all 4 post. Do this test with the ACR disabled. For an suspect cables, do a voltage drop test on them.

[2100V]

Actually, it doesnt, The main bank ALWAYS sees the alternator. ACR has not bearing on it. You can take out the ACR and the main still charges.



This is why I made the comment about the combine position. Combine bypasses the ACR, so you should have instantly had alternator input on the house bank, when switch to combine.

So you really need to get at it with a volt meter and confirm the ACR operation first. Look for the green light as well as alternator voltage on both sides of the ACR. do the same by putting the switch in combine. Should have alternator voltage on all 4 post. Do this test with the ACR disabled. For an suspect cables, do a voltage drop test on them.

Best way to disable the ACR is pull the ground wire from it?

[chpthril]

yes

[2100V]

Ok thanks. Will report back later this week.

[2100V]

So I didn't get to do much diagnostics yesterday b/c I had a boat full of people, but did figure some things out. The house battery is getting charged because it had plenty of juice to run everything when I went out. But I ran the pumps and had the stereo loud yesterday, blower running, etc. so I put it under a pretty heavy load. It died while we were underway - the amp started clipping and the pumps were running weak and then nothing. I combined batteries for about 30 seconds, and then isolated them again. When I isolated them, the house battery was weak but holding it's own and it took a charge during the ride back to the dock.

I read the ACR has a lockout that will refuse to combine batteries during charging if the voltage on one of them drops below a certain point, so if that's what's happening then I guess the ACR is working right. And when I combine batteries the house draws off the starter battery charge long enough to get above critical voltage, at which point the ACR allows it to continue charging. The question now is why is my brand new house battery draining so fast, even with the engine running, that it drops below the ACR cutoff point? For what it's worth, the dash voltmeter rarely gets above 13 now and in years past I remember it would climb almost to 14 for a few minutes and then drop off (regulator cutout) and it doesn't seem to do that anymore.

[JTs-rz2]

I would start by getting a charger on your house battery. Maybe discharged too low for too long of a time and not getting caught up. If it is a new battery under warranty try to get it swapped.

Otherwise missing a cable somewhere. Or the acr is having an issue. You will have to check the voltage on the house when in operation. It does not seem like it is too low for the acr to shut off.

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