Duracell AGM not holding solid charge

4x4junkie

Explorer
That doesn't sound right... If lets say there is 80 amps flowing through it, that means you're consuming 40 watts inside of the unit, which would burn up it's contacts in very short order.

Just for s#!ts & giggles, try measuring directly across the ACR's connections (your meter's + lead on the input hot terminal, - lead on the output hot terminal). Should be 0 volts or something real close if it's energized to pass current through it. If you actually do get 0.5V, I would say that it's defective.
 

wrcsixeight

Adventurer
Spoke with BlueSea today, they indicated it didn't seem unusual that there was a 0.5v difference between the input and output voltage on the ACR. I asked why? And he didn't have a good answer. He said he would check on it and call me later this week. Any thoughts?

If a 0.5v drop is acceptable to Blueseas on their ACR, then I am no longer using any BlueSeas products and redacting all previous praise of their products.

That much voltage drop is huge and will increase charging times drastically.
 

ebg18t

Adventurer
That doesn't sound right... If lets say there is 80 amps flowing through it, that means you're consuming 40 watts inside of the unit, which would burn up it's contacts in very short order.

Just for s#!ts & giggles, try measuring directly across the ACR's connections (your meter's + lead on the input hot terminal, - lead on the output hot terminal). Should be 0 volts or something real close if it's energized to pass current through it. If you actually do get 0.5V, I would say that it's defective.


If a 0.5v drop is acceptable to Blueseas on their ACR, then I am no longer using any BlueSeas products and redacting all previous praise of their products.

That much voltage drop is huge and will increase charging times drastically.

I was a little surprised by the comment. I have all BlueSea products on the boat and everything has been flawless. Hopefully they redact the statement later this week when they call me back.

I haven't had a chance to measure at the ACR, hopefully can accomplish that this weekend as I have to pull the battery to get to the ACR.
 

dwh

Tail-End Charlie
Well, there should be NO voltage drop through a set of contact points.

To check it, disconnect the batteries from the big terminals of the solenoid. Switch the meter to read resistance and read both sides of the solenoid (across the big terminals). Should be infinite ohms with the solenoid disengaged (which is what your meter will read when set to ohms and the probes aren't touching anything), and damned near 0 ohms with the solenoid engaged.

If there is a high ohm reading then the internal contacts are mostly likely burnt, though a weak electromagnet could also cause it by not pulling the contacts into a nice tight connection. (Also, the electromagnet would act weak if there was inadequate voltage to energize it, but I think that's unlikely with the Blue Sea units since they get their power directly from the battery connections.)




Here's a decent vid of a guy testing some solenoids:







Blue Sea has diagnostics flowcharts for their ACRs. One for SI series:

http://assets.bluesea.com/files/resources/technical_briefs/Technical_Brief_7610_FAQ_Matrix.pdf


One for ML series:

http://assets.bluesea.com/files/resources/technical_briefs/Technical_Brief_ML-Series_FAQ_Matrix.pdf
 

dwh

Tail-End Charlie
Hrmm. Crap.

If the Blue Sea is getting power to energize the electromagnet from the big battery terminals, then disconnecting the batteries from the solenoid would also make it impossible to energize the electromagnet.

So I guess you'll have to check that thing with the batteries still connected.

Still, there should be almost no resistance measuring across the contacts.
 

ebg18t

Adventurer
I am going to pick up a new battery this weekend. It doesn't seem to hold a charge more than a few hours. Within 1-1.5 days it drops from resting charge of 12.79v to resting of 12.58v with no load and still getting charge thru the ACR when running 2hrs a day.
 

dwh

Tail-End Charlie
There it is.

But if you're running a load like a fridge off that battery 24/7, you might not be driving enough to get the battery fully recharged. You might consider either disconnecting the fridge when you don't need it, or getting a decent multistage charger and topping that new battery up at least once a week.
 

ebg18t

Adventurer
There it is.

But if you're running a load like a fridge off that battery 24/7, you might not be driving enough to get the battery fully recharged. You might consider either disconnecting the fridge when you don't need it, or getting a decent multistage charger and topping that new battery up at least once a week.

Nothing is connected to the battery, I have it for the sole purpose of the fridge. I have a separate plug (8 or 10ga from battery to plug) in the back for the fridge and it is only plugged in during use. I have been checking it every morning with the multi meter and it can't hold the charge fully. I am assuming that it shouldn't drop 0.3v without any load over a day or two?
 

comptiger5000

Adventurer
It's possible that at 12.8v it's just showing a bit of surface charge. The Duracell AGM (group 34) in my Jeep usually settles to ~12.6 volts after sitting for a few hours to bleed off surface charge, but stays there for several days (even with the slight parasitic draw of the vehicle electronics).
 

ebg18t

Adventurer
It's possible that at 12.8v it's just showing a bit of surface charge. The Duracell AGM (group 34) in my Jeep usually settles to ~12.6 volts after sitting for a few hours to bleed off surface charge, but stays there for several days (even with the slight parasitic draw of the vehicle electronics).

It's possible, but My other Duracell AGM holds at 12.8-12.9v no problem during the same time. I think it's just a bad cell after being over depleted multiple times.
 

ebg18t

Adventurer
You're right, with no load it shouldn't drop that much that quick.
If a 0.5v drop is acceptable to Blueseas on their ACR, then I am no longer using any BlueSeas products and redacting all previous praise of their products.

That much voltage drop is huge and will increase charging times drastically.


Finally took the old battery out and tested the ACR. ACR was reading 13.79v which is good.

Old Battery dropped with no load over the past week to 11.59v with daily drive of 2hrs (1hr each way).

Unfortunately all the new batteries at Sams club (100% free replacement) were all at 12.1-12.2v. So now I need to get the replacement on the charger
 

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