AC recharging at 14.6 volts over wintertime.

[sibaroni]

40A-12V Intelligent 7 Stage Mains Battery Charger
I have been using this charger since November to compensate for zero solar this winter.
The bank is 5 X 100ah in parallel sealed lead acid, calcium.
I have noticed that this charger is doing its job for the 6 hours nighttime at my Economy 7 grid rate to bring the bank up to 100%.
The slight issue is that the charger reports 14.7volts but the Victron Smartshunt says the bank is ONLY 14.5 or 14.6 volts.
The charger only stays in bulk or boost, never float as it is designed to do after a full charge.
Are the batteries in danger of degradation due to this protocol?
There is not a lot I can do, without, say purchasing a very expensive Victron charger where I can manually set the voltages... This charger has set parameters and is currently set to the Wet battery config.
Cheers all.

 

[gotbeans]

Might have a potentiometer inside of it if you open the case up to adjust it's readings. It really can't adjust the voltage in that digital display?
Aren't lead acid supposed to be floated at like 13.8?
You don't even have to boost/bulk it can just sit at float. The purpose of boost/bulk is to give it some extra but this can be achieved by floating for way longer periods.. we don't have that with the sun though since it goes down at a certain time thus the boost/bulk etc

Most multimeters have 1-4 potentiometers to adjust their readings.
You can get calibration chips for like $10 to make sure your stuff reads correctly too

 

[sibaroni]

Might have a potentiometer inside of it if you open the case up to adjust it's readings. It really can't adjust the voltage in that digital display?
Aren't lead acid supposed to be floated at like 13.8?
You don't even have to boost/bulk it can just sit at float. The purpose of boost/bulk is to give it some extra but this can be achieved by floating for way longer periods.. we don't have that with the sun though since it goes down at a certain time thus the boost/bulk etc

Most multimeters have 1-4 potentiometers to adjust their readings.
You can get calibration chips for like $10 to make sure your stuff reads correctly too

My setup at home , the loads are refrigeration, TV, IT stuff...averages out at about 120 Ah usage..and my cheap rate electricity runs from 1am to 7am..so it has proved invaluable this winter season.
I'll just see how it all pans out until the sun returns in February... I'm not one for opening up cases btw!
The alternative is the Victron 30amp Blue Smart....there I can configure the voltages manually...but it is a last resort.

 

[hugemoth]

If the charger has a temperature sensor it may be optimizing charging voltage for a cold lead acid battery which is higher than a warm battery.

 

[sibaroni]

If the charger has a temperature sensor it may be optimizing charging voltage for a cold lead acid battery which is higher than a warm battery.

Batteries are in warm environment...

 

[mikefitz]

40A-12V Intelligent 7 Stage Mains Battery Charger

This type of charger is not that intelligent. Termination of the absorbtion period is determined on a 'test' where charging is paused and the battery voltage evaluated. If the 'test' is sucessful the charge volts drops to float, if not, remains in absorption and adds a 'conditioning cycle'.

Sealed lead acid calcium batteries don't have a long service life, it's possible they are past their best. Since the smart shunt is recording current and SOC, this may help determining the success or not of the charging process. One method of determining full charge for a battery in good condition is to monitor current and regard 'full' when the charge current at absorbtion volts drops below 1 amp per 100Ah of battery.
I would not be concerned with a slightly low charge voltage, 14.5 is enough at room temperature. Remaining in absorbtion at 14.5volts for the long period, 6 hours, may cause issues, but considering the fact that the calcium batteries are starter batteries, that may have to tollerate continual high charge volts in an automotive application, its perhaps no great worry.

 

[sibaroni]

This type of charger is not that intelligent. Termination of the absorbtion period is determined on a 'test' where charging is paused and the battery voltage evaluated. If the 'test' is sucessful the charge volts drops to float, if not, remains in absorption and adds a 'conditioning cycle'.

Sealed lead acid calcium batteries don't have a long service life, it's possible they are past their best. Since the smart shunt is recording current and SOC, this may help determining the success or not of the charging process. One method of determining full charge for a battery in good condition is to monitor current and regard 'full' when the charge current at absorbtion volts drops below 1 amp per 100Ah of battery.
I would not be concerned with a slightly low charge voltage, 14.5 is enough at room temperature. Remaining in absorbtion at 14.5volts for the long period, 6 hours, may cause issues, but considering the fact that the calcium batteries are starter batteries, that may have to tollerate continual high charge volts in an automotive application, its perhaps no great worry.

Yes, beginning to think on same lines.
I might save up for the Victron 30amp.
The batteries, well they are supposed to be deep discharge , leisure but then again, everything can disappoint.
The Victron Smartshunt does report 100%SOC...but the issue being , after SOC gets to 100%, the voltage does not drop.until the charger stops at the end of cheap overnight electric.

 

[mikefitz]

save up for the Victron 30amp

Might not be needed.
The graph shows an almost ideal absorbtion period with the current becoming almost constant at just over 6 amps at 06.00.
This is exactly what I would expect from batteries in good condition.

The 'text book' condition for a full charge is when, at absorbtion volts, the current falls below 1% of capacity or remains constant at a low value.
I doubt the Victron charger could improve the situation.
Because you have, in effect, a time limited 6 hour charge period, there is no danger of overcharging even without a float charge.

The smart shunt will sync to 100% before the battery is fully absorbed. It's relying on a absorbtion period of at least 2 hours after sync and/or a long period at float, 12 hours to 24 hours, to complete the charge.

Having seen the graph I think you have no worries about a safe sucessful charge or about battery condition.

 

[sibaroni]

Might not be needed.
The graph shows an almost ideal absorbtion period with the current becoming almost constant at just over 6 amps at 06.00.
This is exactly what I would expect from batteries in good condition.

The 'text book' condition for a full charge is when, at absorbtion volts, the current falls below 1% of capacity or remains constant at a low value.
I doubt the Victron charger could improve the situation.
Because you have, in effect, a time limited 6 hour charge period, there is no danger of overcharging even without a float charge.

The smart shunt will sync to 100% before the battery is fully absorbed. It's relying on a absorbtion period of at least 2 hours after sync and/or a long period at float, 12 hours to 24 hours, to complete the charge.

Having seen the graph I think you have no worries about a safe sucessful charge or about battery condition.

Thank you! Under MPPT conditions, bulk,abs,float cycle just works... February should see an improvement!