Danger Warning ACR's

[FlyingCloud1937]

Well as of today I have a new reason to continue not installing Automatic Charge Relays.

This morning I went to a call for dead starter battery, an 8-D Dyno 12volt. As soon as I opened the ER hatch, I new what I was going to find. Just by the the smell of Sulfuric Acid.

A shorted cell in the battery caused the battery to explode. The battery was contained in a home made plywood box, that wasn't liquid tight, nor did it have a cover. So acid is everywhere.

Now about my warning.
The battery was being charged by an Automatic Charge Relay. I surmise that one cell in the battery began micro shorting causing undue current to flow, which generated excess heat, and caused further degradation until we now had an 11 volt nominal battery, which caused more current to flow, until the battery blew.

That's exactly why I have always installed the Balmar Due-Charge with temp sensing.

Lloyd

[ontherocks83]

Would an in-line fuse on the ACR going to the starter battery have prevented this? I would think that it would pop well before the battery got to that point but I could very well be wrong.

[FlyingCloud1937]

Originally Posted by ontherocks83

Would an in-line fuse on the ACR going to the starter battery have prevented this? I would think that it would pop well before the battery got to that point but I could very well be wrong.

There is an ANL sized to the ACR/Cable. The fuse will only help in the event of over current or dead short. The micro shorting didn't blow the fuse before the battery blew.

Lloyd

[JK n Smitty]

Did the charger have a temp sensor? Should that have caught the excessive heat?

[FlyingCloud1937]

Originally Posted by JK n Smitty

Did the charger have a temp sensor? Should that have caught the excessive heat?

This a twin engine, with an 8-D start battery, for each engine, and a house bank.

Each start bat has an ACR between the House Bank. The House is charged by an inverter/charger. While the inverter has an option for the temp sensor it is not installed. It would not have changed the circumstances, as it would be on the house bank.

Also another fault on this specific install is that while ANL fuses were installed at the house bank for each ACR, there was no fusing at either of the start batteries. This leaves the cables between the start bat and the house unprotected in a fault.

Lloyd

[Stu Jackson]

Was he plugged into shorepower when he was away from his boat?

[FlyingCloud1937]

Yep,

The boat sits at it's marina during the winter, he comes down once a month to start the engines, maybe a day cruise here and there.

The house sits on float charger through the inverter/charger. The current demand from the ACR to the start bats, boost the charger output needed to maintain the float of the house bank.

A recipe for disaster.

Now if there would have been a temp compensated Duo-Charge instead of the ACR. As the battery began to heat the Duo-Charge would of current limited the start battery.

Lloyd

Originally Posted by Stu Jackson

Was he plugged into shorepower when he was away from his boat?

[sabray]

That's a awful bunch of presumptions you make. It is a poor installation. The boat and charger are left with Ac current on. The fusing is not adequate. Now who to blame.
I have had great use from acr . I don't leave the charger on or the boat on Ac charge when I leave. My batts have the same charge profile . They are fused as are charge sources. Solar is fused etc...
Yes a poor install isn't good. You describe a bad install and compare it to a good install. It's like guppies and sharks. Acr works well if installed well. If your a dumb SSS and short out this stuff you will see things that make headline stories.

[FlyingCloud1937]

NO ASSUMPTIONS MADE BY ME.

I am a FULL TIME Marine Electrician. I make my Living Designing/Installing On-Board Power Systems. Over 30 Years Experience.

This was not my install. I was called by referral.

You, my friend have made some mighty assumptions.

What I reported is what I found.

My analysis, of the faults is not guess work.

lloyd

Originally Posted by sabray

That's a awful bunch of presumptions you make. It is a poor installation. The boat and charger are left with Ac current on. The fusing is not adequate. Now who to blame.
I have had great use from acr . I don't leave the charger on or the boat on Ac charge when I leave. My batts have the same charge profile . They are fused as are charge sources. Solar is fused etc...
Yes a poor install isn't good. You describe a bad install and compare it to a good install. It's like guppies and sharks. Acr works well if installed well. If your a dumb SSS and short out this stuff you will see things that make headline stories.

[sabray]

But you said it was a bad installation. Blamed the ACR. Did not explain how the ACR failed. Did not explain how the banks were set up. You represented assumptions that blamed the acr or represented it as a fault of acr. Something else failed. Not the acr but the system and owner perhaps.

[SVTatia]

Originally Posted by FlyingCloud1937

NO ASSUMPTIONS MADE BY ME.

I am a FULL TIME Marine Electrician. I make my Living Designing/Installing On-Board Power Systems. Over 30 Years Experience.

This was not my install. I was called by referral.

You, my friend have made some mighty assumptions.

What I reported is what I found.

My analysis, of the faults is not guess work.

lloyd

Yes, we understand and I am sure you are a good professional and have seen it all, but...

what Sabray is saying, and I second, is that you are blaming the ACR. This is a bad install to start with, and the owner has dangerous practices, so why is the ACR or all ACRs being designated as the equipment at fault?

[FlyingCloud1937]

Evidently you do not fully read, or either didn't understand. I, faulted the ACR circuit, bc it cant distinguish between a micro-short and current draw.

That is not part of the design, it has no temp compensation, so it can't know when the battery is getting warm, there-fore it can't current limit.

Neither in a fault, nor when 2 batteries are located in two separate compartments, with differing temps.

Lloyd

Originally Posted by FlyingCloud1937

Well as of today I have a new reason to continue not installing Automatic Charge Relays.

This morning I went to a call for dead starter battery, an 8-D Dyno 12volt. As soon as I opened the ER hatch, I new what I was going to find. Just by the the smell of Sulfuric Acid.

A shorted cell in the battery caused the battery to explode. The battery was contained in a home made plywood box, that wasn't liquid tight, nor did it have a cover. So acid is everywhere.

Now about my warning.
The battery was being charged by an Automatic Charge Relay. I surmise that one cell in the battery began micro shorting causing undue current to flow, which generated excess heat, and caused further degradation until we now had an 11 volt nominal battery, which caused more current to flow, until the battery blew.

That's exactly why I have always installed the Balmar Due-Charge with temp sensing.

Lloyd

Originally Posted by sabray

But you said it was a bad installation. Blamed the ACR. Did not explain how the ACR failed. Did not explain how the banks were set up. You represented assumptions that blamed the acr or represented it as a fault of acr. Something else failed. Not the acr but the system and owner perhaps.

[sabray]

I did no presumption please read the post I didn't attack or presume . The system you describe lacks proper fusing. The failure cannot be related to the acr alone. No description of how the banks are set up .
You must be right oh master certified poster it surely is the acr that failed given that the install was botched and you say so.

[FlyingCloud1937]

Proper fusing would not have changed the outcome.

The failure is a result of the battery micro-shorting, and the lack of fault tolerance of an ACR circuit.

Every install of an ACR is subject to the same fault that happened in this instance.

The ACR didn't fail, it did what it was designed to do. =Pass current to the 2nd battery to maintain voltage.

When the second battery fails, current will pass up-to the limits of the ACR/Fusing.

The ACR lacks any knowledge of how hot the 2nd battery is, or the voltage. So it does it's job of passing current, to maintain voltage of the system design. Until there is an open circuit.

Lloyd

Originally Posted by sabray

I did no presumption please read the post I didn't attack or presume . The system you describe lacks proper fusing. The failure cannot be related to the acr alone. No description of how the banks are set up .
You must be right oh master certified poster it surely is the acr that failed given that the install was botched and you say so.

[sabray]

In this system where is the failure.
1 the owner left the boat with the charge system on. 2 the system was built with inadequate fuse and install was poor. 3 acr circuits caused the failure.