Overvoltage Error

[Eddie]

This year I rewired the charging system, has worked well during the last year. I then added solar and a Blue sky controller. Charger is a Freedom 2500. I have been running on the solar most of the time. Last week though I left the boat with the Freedom and the solar running. When I returned to the the boat the Charger had shut down, giving me an error code that shows overvoltaqe. I think this is the first time the two sources have been run simultaneously. Anyone have this problem before? I have One bank AGM batteries of 420 amps. Solar putting out 14.2 amps at most on display. Thanks Ed

[cfarrar]

Ed,

FWIW, our Blue Sky controller has never conflicted with our Xantrex charger. Do you know what acceptance and float voltages you have programmed for the Blue Sky and the Freedom Charger? Any chance they are significantly different?

[SV Demeter]

Do I understand yo uto say you left the boat with the freedom battery charger on and plugged into shore power and also had your solar panels charging the batteries at the same time? I'm still learning about solar charging systems but my understanding was that you were supposed to shut down the solar panels when charging from shore power or the alternator. Maybe I missed something?

[colemj]

There is no problem running the two simultaneously - the regulators will take care of everything. I think cfarrar is onto the problem - check to make sure both of your charging sources are set to the same charging values. If the solar is set to acceptance or float voltages higher than the charger, then the charger will see an "overvoltage".

Do they both have temperature compensation? If one does and the other doesn't, then this could also cause an apparent voltage differential.

Mark

[cfarrar]

Come to think of it, I would also look at the conditions required to shift from acceptance to float, in addition to the voltage settings. I don't have the #s in front of me, but I think that my Blue Sky shifts into float mode after both a set time period (two hours?), and after the charge rate falls below a certain value (a couple of amps?). If the Freedom charger has no minimum time period in acceptance mode (I have no idea whether this is true), then it might be transitioning to float first.

[SV Demeter]

This is why I was thinking you would turn off the solar panels when charging from shore power or the alternator. Im thinking that unless the two regulators have EXACTLY the same algorithm/parameters they are likely to bump into eachother at some point. There are a lot of control points too: Temperature, voltage, amperage, timing, etc. Seems to me sort like it would be pretty tough to get both regualtors doing precisly the same thing. Also seems sort of pointless? I mean if you are plugged in to shore power why not just use that?

Until someone shows me a single charge controller that can handle inputs from: Shorepower charger,engine alt , Solar, Wind, towable etc. I see the easiest solution is to simply shut one source down.

Ive been told the reason for needing 2 charge controllers has to do with the input source. In that Shorepower charger and Alternators are both AC current where as solar and wind and towable are DC. But like I said I am still learning about this stuff and am no expert.

Ears and Eyes Open

[senormechanico]

Does your BlueSky controller have the automatic equalization function?
If it does, once a month it will go into that function and raise the battery voltage to 16.2 for a few hours. If that happened, your charger would sense this.

The charger won't be damaged, just turn it off for a few seconds and turn it back on.
If the battery voltage is over a certain amount, the charger might not go to float.
My Xantrex will give me a yellow light during the day if I turn it on when the solar is on. All it's saying is "I don't need to do anything right now".

I don't even plug in my boat unless it's winter when I need to add an electric heater to keep things from freezing.

[colemj]

Why shut one off? Yes, they will conflict when the voltage reaches a preset level and the "weaker" regulator will throttle back its charging source. But until that point is reached, both will fully contribute to their abilities. When that point is reached, the regulators discuss it among themselves and take care of things automatically.

The reason for multiple charge controllers isn't because of the input source (all are DC input regardless of how the DC is generated). It is because the devices requiring regulation have different needs and modalities. For instance, your alternator needs voltage feedback to its excitation circuit while your solar simply needs to be shut off for a portion of the time and your windgen needs its excess current to be dumped somewhere. It is also better to not put all your eggs in one basket - particularly the weakest basket.

Mark

[Eddie]

I need to check the settings this weekend. The solar controller starts charging at about 13.5 volts in the morning when the batteries are down about 100 amps. Later when batteries down only down about 20 amps the amps to the batteries from the Blue Sky will drop down but the voltage will increase to about 14.2 volts. I would think (without more reading} that as the batteries come close to full charge the voltage to them would be less rather than more.I have the 3012 Blue Sky, and will check on the equalization mode. THANKS FOR THE SUGGESTIONS

[Maine Sail]

Originally Posted by Eddie

I need to check the settings this weekend. The solar controller starts charging at about 13.5 volts in the morning when the batteries are down about 100 amps. Later when batteries down only down about 20 amps the amps to the batteries from the Blue Sky will drop down but the voltage will increase to about 14.2 volts. I would think (without more reading} that as the batteries come close to full charge the voltage to them would be less rather than more.I have the 3012 Blue Sky, and will check on the equalization mode. THANKS FOR THE SUGGESTIONS

As batteries charge the internal voltage rises. When down 100 amps they will not actually be at 14.2 or they would then be near full. It takes a while for the internal voltage to get to 14.2. The voltage does not necessarily "rise" in terms of the what you thought you saw on teh regulator regulator panel as it has always been striving for a "target" absorption voltage which in your case sounds like 14.2 volts.

The regulator has always been trying to get to 14.2 and finally gets there when you approach near full. Once the batteries are pretty much 98% full or generally accepting less than 2% of bank capacity, or there about, the charger, controller or alternator may then revert to a float mode and actually reduce target/output voltage.

Most chargers, regulators and solar controllers are constant voltage driven meaning they are always trying to get to a voltage set point, usually between 14.2 - 14.6 but depends upon battery type. Once they get to the target voltage they may apply a time+ or % acceptance algorithm to decide how long to stay at 14.2-14.6 before reverting to float mode.

A "dumb" regulator only tries to get to a single voltage set point of what ever it is set to. On most new single stage chargers or alternator regulators this is usually between 14.2 & 14.6 volts. Some older alts were set to 13.8 which chronically undercharged banks. Once at the voltage set point they just continue to put out 14.2 - 14.6 and don't revert to float. Amps follow battery acceptance. Amps out are driven by either battery acceptance or limited by the max cold or hot output rating of the device if you are not pushing up against acceptance. AGM's can accept a lot of amps when drawn down.

[cfarrar]

My Blue Sky (2512ix) controller follows this schedule:

Bulk Mode: max current until batt. voltage rise to 14.2
Acceptance Mode: 14.2 volts & gradually decreasing current
Float: (> 2 hours in acceptance or current drops below threshold) 13.2 volts

These values are adjustable in your user settings, but probably right for your AGMs (you can check with your battery manufacturer).

Steve B. makes a great point. Make sure you aren't equalizing. That will trash your AGMs!

[osirissail]

Originally Posted by Eddie

. . .Charger is a Freedom 2500. I have been running on the solar most of the time. Last week though I left the boat with the Freedom and the solar running. When I returned to the the boat the Charger had shut down, giving me an error code that shows overvoltaqe. . . .Thanks Ed

Huh? What exactly do you mean by "overvoltage"? I cannot find any reference to "overvoltage" fault in the on-line Freedom 2500 manual. Assuming the unit was operating at a battery charger - you might have an overvoltage if the AC power in-supply exceeded the charger limits. If the battery voltages exceed 15.5 volts there is a fault lite on. Do you have regulators on your solar - is it set for the correct "max voltage?"