What causes high voltage fault?

[Scott T-Bird]

Every once in a while I have returned to my boat after 5-days on the charger to find the battery monitor showing a high voltage fault. But, the current condition is always in "float" with voltage reading 13.4/13.5V (it fluctuates) for the House Bank, and 13.5/13.6V for the Aux. batt.

I have the Balmar SG200 monitor, Sterling PCU 60 charger. The message says !Bank 01! / "Fault Over Voltage Detected" , then "Voltage 15.0V Fault Limit 15.0V".

The batteries are 2-4D AGM for house bank and Grp 27 AGM deep cycle for aux. The house bank is in 8th season, the aux batt is new this season.
When at rest with no current for about 15 minutes, my house bank retreats to 12.8V and the aux retreats to 12.8/12.9V. One curious thing, I noted ... with the Aux resting overnight with no current, in the morning I found 13.1V (it seems to bounce back).

I don't get any over voltage faults when the alternator runs, it is only when on charger after I have left the boat. I leave the charger on so the fridge doesn't drain the batteries. The monitor is set to 15.0V fault per the recommendation for AGM batts.

One unusual circumstance that I created: I made charger connections to both the house bank and the aux battery. I figured that the ACR would not need to close when the charger is charging. But I soon realized that the light indicates the ACR is closed even when the charger is the only source. I know it is unusual and not necessary. The charger is so close to the battery, that the cable run was inconsequential. I've been intending to remove the Aux batt cable from the charger, but haven't done so yet. Is there any chance this could be leading to over-voltage fault?

 

[Ward H]

Sounds like you have the max bulk voltage setting in your external regulator set to 15v and your default on your SG200 for max volt alarm is also set at 15 or a little under.
You can raise the high voltage alarm setting on the SG200 or reduce max voltage on your regulator.

 

[Davidasailor26]

Does the Sterling charger ever go to absorption briefly after a period of float? I know my Xantrex charger does a very brief absorption period once per week if it’s not disconnected from shore power for a full 168 hours. Also, do you leave any loads on, like a fridge? I wonder if something like a fridge turning off at just the same time as the charger being in absorption could lead to a very brief spike above 15.0 V.

 

[Scott T-Bird]

Sounds like you have the max bulk voltage setting in your external regulator set to 15v and your default on your SG200 for max volt alarm is also set at 15 or a little under.
You can raise the high voltage alarm setting on the SG200 or reduce max voltage on your regulator.

No, never see high voltage when charging by alternator & the regulator is not set to 15.0v

 

[Scott T-Bird]

Does the Sterling charger ever go to absorption briefly after a period of float? I know my Xantrex charger does a very brief absorption period once per week if it’s not disconnected from shore power for a full 168 hours. Also, do you leave any loads on, like a fridge? I wonder if something like a fridge turning off at just the same time as the charger being in absorption could lead to a very brief spike above 15.0 V.

I don't know about a brief absorption charge ... I haven't gone 7 days off shore power, that's for sure. The fridge runs a lot in this weather, that's also for sure. I have turned it down when leaving from time to time (but not always) and perhaps the frequency of the fridge running coincides with a spike.

 

[Scott T-Bird]

I wonder if something like a fridge turning off at just the same time as the charger being in absorption could lead to a very brief spike above 15.0 V.

Now that you mention it, though, I've often been at the boat with the charger on and the fridge running on & off, but the fault has never occurred when I'm at the boat. It's only occurred after I've been away for more than a few days. That said, other loads would be on when I'm at the boat, except overnight, but I always turn the charger off when I'm staying on-board at the slip overnight .... just one of those habitual things, I guess, I don't really know why I am more comfortable sleeping with the fewest possible electrical devices energized!

 

[Scott T-Bird]

There is a history function that tells me when the faults occur, I think. I haven't thought to look at that yet ...

 

[JamesG161]

perhaps the frequency of the fridge running coincides with a spike.

That would be a good guess.

The Frig kicks on, triggering the charger on, then the charger tries to make up the Voltage very fast.

Typical for AGM , if I remember correctly.

Jim...

 

[walt]

maybe?

Automatic Desulphation mode: 7-10 days cycle with anti-stratification program to keep batteries rejuvenated.

http://www.sterling-power-usa.com/library/Sterling%20Power%20USA%20-%20ProCharge%20Ultra%20Battery%20Charger%20Product%20Sheet.pdf

 

[Davidasailor26]

There is a history function that tells me when the faults occur, I think. I haven't thought to look at that yet ...

If it tells you the duration of the alarm condition that would be interesting. If it’s just just a momentary spike from changing loads that’s no big deal. If it’s staying over 15V for hours on end that’s a bigger issue.

 

[Davidasailor26]

maybe?

Automatic Desulphation mode: 7-10 days cycle with anti-stratification program to keep batteries rejuvenated.

http://www.sterling-power-usa.com/library/Sterling%20Power%20USA%20-%20ProCharge%20Ultra%20Battery%20Charger%20Product%20Sheet.pdf

Sounds pretty interesting to me.

 

[Stu Jackson]

but I always turn the charger off when I'm staying on-board at the slip overnight ....

You are aware that you are unnecessarily cycling your house bank?

 

[Scott T-Bird]

Sounds pretty interesting to me.

Explanation?

 

[Scott T-Bird]

You are aware that you are unnecessarily cycling your house bank?

Is that a problem? What is consequence when overnight loads are next to nil? The fridge does run and a few cycles on the electric toilet ...

 

[Davidasailor26]

Explanation?

What I meant was that the automatic desulphation feature Walt cited does sound like the kind of periodic charger cycle that could cause the alarm. Sterling isn’t clear in their flier on what that cycle actually does, but I’d assume it’s some kind of periodic surge to above float voltage - either to absorption voltage or higher.

 

[Scott T-Bird]

What I meant was that the automatic desulphation feature Walt cited does sound like the kind of periodic charger cycle that could cause the alarm. Sterling isn’t clear in their flier on what that cycle actually does, but I’d assume it’s some kind of periodic surge to above float voltage - either to absorption voltage or higher.

Yes, it makes sense. It would have made more sense for me to ask @walt for explanation because it seems that he might have some specific knowledge about it.

 

[Stu Jackson]

Is that a problem? What is consequence when overnight loads are next to nil? The fridge does run and a few cycles on the electric toilet ...

Scotty, a fridge uses 60 ah per day. Overnight, and when first starting as it cools down the box & its contents, you could use up to 20 to 30 ah overnight. Why "use up cycles" of your batteries when it's not necessary? Turn your charger on, and it can carry the load(s).
You might even "learn" about those infamous spikes while you're there...
Good luck.

 

[jviss]

Scotty, a fridge uses 60 ah per day. Overnight, and when first starting as it cools down the box & its contents, you could use up to 20 to 30 ah overnight. Why "use up cycles" of your batteries when it's not necessary? Turn your charger on, and it can carry the load(s).
You might even "learn" about those infamous spikes while you're there...
Good luck.

If your fridge is already. cooled down, is reasonably insulated, and there's plenty of thermal mass inside (like lots of beer and frozen meat), then it probably won't use that much. But I hear. you, on my trips I assume 5A at 50% duty cycle, so 60Ah/day. But overnight, no one opening it, full of stuff - probably not so much power.

 

[walt]

Yes, it makes sense. It would have made more sense for me to ask @walt for explanation because it seems that he might have some specific knowledge about it

.

I dont have any specific info, just remember that some chargers do a periodic auto equalization and this could involve voltages in the range of 15V. I didnt try and dig up the manual to see if they describe the voltages in whatever that function is.

Equalizing is described here BU-404: What is Equalizing Charge?

They mention 2.5 volt per cell during equalization which would be 15 volt for 6 cells.