battery equalisation charge

[ColinR]

Looking at the advice on battery charging from some major manufacturers, (eg Trojan) a periodic equalisation charge is recommended at 15.5v. My Sterling pro digital regulator has an absorption charge of 14.8, and the Rutland wind gen is regulated to 14.4v. So this means the battery never gets an equalisation charge. I dont feel the domestic battery is ever fully charged, could this be why? Sorry this seems a bit nerdy but I am really trying to get to grips with my charging setup. Colin

 

[vyv_cox]

There has been a thread on this in the past couple of days. Is it a USA battery/advice? Apparently they take a higher charge, 15.5 was the figure quoted I think, whereas advice from Sterling was lower.

 

[ColinR]

There has been a thread on this in the past couple of days. Is it a USA battery/advice? Apparently they take a higher charge, 15.5 was the figure quoted I think, whereas advice from Sterling was lower.

yes that was me. Daily charge is recommended as 14.8v by eg Trojan, but 15.5 for occaisional equilisation. Presumably that means in a regulated setup the battery will never get an equalisation charge and I thought a smart regulator was the bees knees for keeping a battery fully charged and in good nick. US Batteries however recommend a charge rate of 15.5v and for equalising no voltage constraint (!) at 5 amps. I emailed their tech advice.
Sterling said other people have had problems with US Batteries, which are excellent quality but need a higher charge voltage. I'm trying to make sense of all this! Colin

 

[earlybird]

I'm puzzled. Why do American batteries need a higher charging voltage than European ones? I rather thought 15.5 volts would damage a battery in the longer run. Presumably they're all lead-acid.
Do US cars/ boats have different regulator setting for battery charging?

 

[macd]

Is it a USA battery/advice? Apparently they take a higher charge, 15.5 was the figure quoted I think, whereas advice from Sterling was lower.

Sterling themelves sell a battery desulphater unit, for around £50. It's permanently wired into the batteries (simple pos and neg) and periodically pulses a small current at around 15.5V the 'wrong way' through the batteries to 'blow off' any sulphates from the plates. That, at least, is what the bumf claims. I installed one last year and it seems to work, having given my batteries a new lease of life. I've no evidence of adverse effects on any other electrics on board.

I've been told, but haven't checked, that some of Sterling's latest battery chargers now incorporate a desulphation facility.

 

[ColinR]

I'm puzzled. Why do American batteries need a higher charging voltage than European ones? I rather thought 15.5 volts would damage a battery in the longer run. Presumably they're all lead-acid.
Do US cars/ boats have different regulator setting for battery charging?

'US Battery' is a brand and the advise was from their tech help. Trojan is also an American make but does not require increased voltage. I am only quoting info I have picked up from web sources in an attempt to understand my US Battery (I refer to the brand, not to an amercan battery) reluctance to come up to full charge using a pretty good charging setup. Colin

 

[vyv_cox]

Sterling themelves sell a battery desulphater unit, for around £50. It's permanently wired into the batteries (simple pos and neg) and periodically pulses a small current at around 15.5V the 'wrong way' through the batteries to 'blow off' any sulphates from the plates. That, at least, is what the bumf claims. I installed one last year and it seems to work, having given my batteries a new lease of life. I've no evidence of adverse effects on any other electrics on board.

I've been told, but haven't checked, that some of Sterling's latest battery chargers now incorporate a desulphation facility.

I have a desulphater but I believe it applies AC to the battery, no idea at what voltage. It does seem to make a difference to them, whereas the Sterling alternator controller would previously go to float at 14.2 volts it now goes to 14.4.

 

[rivonia]

The gassing point for ANY deep cycle battery IS 14.2... No need to discuss fact is fact

Some deep cycle batteries will register higher BUT the actual gassing point IS 14.2

Peter

 

[Stu Jackson]

I'm puzzled. Why do American batteries need a higher charging voltage than European ones? I rather thought 15.5 volts would damage a battery in the longer run. Presumably they're all lead-acid.
Do US cars/ boats have different regulator setting for battery charging?

No, they don't. See this, a respected source of basic boating information: http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Battery-Charging.htm

"Regular" equalization during every charge cycle appears to be incorrect. Equalization is special higher voltage sustained charging regiment that should be done monthly, periodically, yearly, pick your boat. It should also be monitored by opening up the battery boxes for ventilation, turning off lights and other voltage sensitive components, like stereos, and being present for the four to six hour process.

Regulators for alternators, unless they are constant voltage tapering chargers, should have the three stages of charge.

A good reference source for regulator charging regimens is in the Balmar instruction manual for their M612 regulator, here: http://www.balmar.net/PDF/2005-mc-612-manual.pdf The bottom of page 9 has the different cycles for different types of batteries. I have not checked, since I don't know their website URL (but could probably find it with your help) but would figure that Sterling would have pretty much the same information either on their website or in their instruction manuals.

Other than the types of different 12V batteries, battery charging technology should be the same on either side of the pond.

 

[ColinR]

No, they don't. See this, a respected source of basic boating information: http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Battery-Charging.htm

"Regular" equalization during every charge cycle appears to be incorrect. Equalization is special higher voltage sustained charging regiment that should be done monthly, periodically, yearly, pick your boat. It should also be monitored by opening up the battery boxes for ventilation, turning off lights and other voltage sensitive components, like stereos, and being present for the four to six hour process.

Regulators for alternators, unless they are constant voltage tapering chargers, should have the three stages of charge.

A good reference source for regulator charging regimens is in the Balmar instruction manual for their M612 regulator, here: http://www.balmar.net/PDF/2005-mc-612-manual.pdf The bottom of page 9 has the different cycles for different types of batteries. I have not checked, since I don't know their website URL (but could probably find it with your help) but would figure that Sterling would have pretty much the same information either on their website or in their instruction manuals.

Other than the types of different 12V batteries, battery charging technology should be the same on either side of the pond.

the Westmarine link gives a very good explanation. But this is what US Battery tech help said:

'Normal charging requires that the battery be brought up to 15.5 Volts (or the temperature corrected value) and held there for two to four hours. Mind you, this is not equalization.

In your case, ideally, the equalization should be done after a normal charge, at 5 Amperes, with no Voltage constraints, until three consecutive hourly Voltage readings are within 0.024 Volts of each other'

That is different to advise from other brands which is generally in line with the Westmarine explanation. US Bat. is saying that for their batteries normal charging is at 15.5v and equalisation is with no voltage constraint. Now my question is, does the US Battery brand have a different charging regime which renders my sterling charger unsuitable? Thats what it looks like to me and would expain why the thing never seems to be fully charged except when I take it home and leave it for days on a trickle charger. Colin

 

[Gumpy]

The gassing point for ANY deep cycle battery IS 14.2... No need to discuss fact is fact

Some deep cycle batteries will register higher BUT the actual gassing point IS 14.2

No its not
To be a pedant the gassing voltage changes with the state of charge so it cant be a fixed voltage!
As for equalisation its what it says
Its not charging as such but what it does is equalise the cells and stops stratification in the cells.
The voltage may be high but its at a very low current 3-4 amps so doesnt charge the batteries as such merly causes gassing which stirs the electrolyte.
Its normally run when the batteries are fully charged until the specific gravity of all the cells is equal
Some notes from my charger manual that might explain matters.

Stage 4 - Equalizing Charge This is the
only battery charger stage which is not
engaged automatically. It must be manually
initiated each time it is necessary to equalize
using a dip switch on the back of the Freedom
Remote Control or the front panel on the Link
Instrumentation. Applying an equalizing
charge is not possible without the use of a
Freedom Remote Panel or Link Instrument.
Periodic equalizing is recommended by
most wet cell deep-cycle battery manufacturers.
There are no firm rules for how
often an equalizing charge should be applied,
but once a month is a good rule of thumb for
batteries which are regularly cycled, less often
for systems in only occasional use.The equalizing charge is a timed, 8-hour
cycle. If desired, it can be ended by interrupting
the AC power to the charger at any
time during the cycle. Equalizing should only
be engaged after the batteries have been fully
charged by a normal battery charging cycle.
During this charge cycle, the battery
voltage will increase to the equalize voltage.
This will cause the battery bank to gas
profusely and will accomplish the following:
1. Removal of residual sulfate. Each time a
battery is cycled (discharged and recharged),
a small amount of sulfate is left on the plates.
Over time, this gradual build-up of sulfate will
compromise the performance of the battery.
By applying an equalizing charge, the sulfate
is returned back to the electrolyte, raising the
specific gravity and fully exposing the active
material of the plates.
2. Bring all cells to the same potential. All
lead-acid batteries are made up of individual
2 Volt cells. As the battery bank is cycled,
slight differences in the cells result in different
cell voltages, affecting the overall charge
effectiveness. Equalizing brings all cells up to
the same voltage and the electrolyte in each
cell to the same specific gravity.
3. Mixing up of the electrolyte. Electrolyte in
battery cells tend to separate into layers of
acid and water. The vigorous bubbling action
of the battery during equalizing serves to
physically mix the electrolyte.
Equalizing is not required on gel cell
batteries. For more information and precautions,
check the battery manufacturer specifications
and recommendations. Additional information
on equalizing is also available on our Web
site http://www.heartinterface.com.

 

[Stu Jackson]

the Westmarine link gives a very good explanation. But this is what US Battery tech help said:

'Normal charging requires that the battery be brought up to 15.5 Volts (or the temperature corrected value) and held there for two to four hours. Mind you, this is not equalization....US Bat. is saying that for their batteries normal charging is at 15.5v and equalisation is with no voltage constraint. Now my question is, does the US Battery brand have a different charging regime which renders my sterling charger unsuitable? Thats what it looks like to me and would expain why the thing never seems to be fully charged except when I take it home and leave it for days on a trickle charger. Colin

Something sounds very, very off. Do you have a link to the US Battery information? I understand that you agree that it is NOT equalization, but a bulk charge voltage of 15.5 V is simply "nuts" as we Amerikans sometimes say! One of the reasons for this is that on board electronics may not be designed for this high a voltage. More importantly, it goes completely against every single battery charging discussion I have seen in the past 35 years. Really...

 

[halcyon]

Something sounds very, very off. Do you have a link to the US Battery information? I understand that you agree that it is NOT equalization, but a bulk charge voltage of 15.5 V is simply "nuts" as we Amerikans sometimes say! One of the reasons for this is that on board electronics may not be designed for this high a voltage. More importantly, it goes completely against every single battery charging discussion I have seen in the past 35 years. Really...

Back in the 1980's AC Delco introduced the Freedom range of batteries, we had to make special a special charger setting for them, They charged to 15.4 volt and the float charge was 14.4 volt.

It all depends on the type, and make of battery you are charging, they all vary, there is no standard.

The other problem is, what is equalization charge ?

A lot like back in the 80's when I was making multi-stage chargers, I was told we were wrong it should be 13.6 volt, look all the other manufactures are using that voltage.

Three stage chargers may not be that good either?

There many ways to charge a battery, you can charge a battery to 98% capacity with a very simple charger, you pays your many, and takes your choice.

Brian

 

[ColinR]

Something sounds very, very off. Do you have a link to the US Battery information? I understand that you agree that it is NOT equalization, but a bulk charge voltage of 15.5 V is simply "nuts" as we Amerikans sometimes say! One of the reasons for this is that on board electronics may not be designed for this high a voltage. More importantly, it goes completely against every single battery charging discussion I have seen in the past 35 years. Really...

I quoted from an email from their tech help who I had asked about charging. Here is a link to their FAQ's: http://www.usbattery.com/usb_faqs.html
This also gives a charging voltage of 15.5 if my sums are right (2.583v x 6 = 15.5) and this is specified for charging not equalisation. Colin

 

[Stu Jackson]

1. Back in the 1980's AC Delco introduced the Freedom range of batteries, we had to make special a special charger setting for them, They charged to 15.4 volt and the float charge was 14.4 volt.

2. It all depends on the type, and make of battery you are charging, they all vary, there is no standard.

3. The other problem is, what is equalization charge ?

4. A lot like back in the 80's when I was making multi-stage chargers, I was told we were wrong it should be 13.6 volt, look all the other manufactures are using that voltage.

5. Three stage chargers may not be that good either?

6. There many ways to charge a battery, you can charge a battery to 98% capacity with a very simple charger, you pays your many, and takes your choice.

Thanks, Brian, interesting information from someone "who has really been there."

And for Colin, thanks, too for the link.

1. That's a new one on me. I'll ask around and next weekend am gong to see a friend who is in your line of work and will ask him. Thanks again for the input.

2. I was mistakenly under the impression that 12V batteries had the same regimens for charging. Live and learn.

3. By "definition" as expressed in the linked West Marine Advisor I presented in Reply #9. Is there another?

4. That 13.6 V looks suspiciously like a float voltage. As long as we're talking about bulk, absorption and float, with equalisation a separate regimen, that's all I'm suggesting.

5. I agree. We have had our owners end up with catastrophic situations with "Pro Mariner Fly Back" chargers that actually burned up, both the charger and the boat. We have documented these and warned our owners against using them. Like this: http://c34.org/bbs/index.php/topic,5179.0.html and this http://c34.org/bbs/index.php/topic,3073.0.html. One skipper lost his to lightning, although he was on his third one, which should tell you something about all three of them! I've had a Freedom 15 combined inverter charger since 1998 with no troubles.

6. I agree, too. A simple single stage internal regulator on an alternator will work quite well in keep the bank between 50% and 85% charged before the battery acceptance will make a difference compared to a three stage charger. Many "successful" chargers are single stage, but not great for keeping the boat plugged in all the time with resultant overcharging and loss of acid. This, in itself, is a long, separate subject.

But to get back to the topic at hand, I look forward to learning more about why any manufacturer would recommend a 15+V charge for a 12V battery as part of a "normal" charging cycle.

Reason is that I'd also like to know where in the world one would find a three stage (or single) shorepower charger that would provide that voltage? Most all of the ones we're familiar with have the output voltages adjustable within the regimens I've noted at Balmar's instruction manual for their regulators, page 9, here: http://www.balmar.net/PDF/2005-mc-612-manual.pdf To avoid confusion between shorepower chargers and alternator regulators, these referenced voltage regimens are the same voltages that the manufacturers of smart shorepower chargers utilize for their shorepower chargers. One could adjust the alternator output voltage with the M612 regulator, but there's nowhere in that literature that suggests that high a voltage for 12V banks, whether for regulators or shorepower chargers.

That Balmar reference also discusses charging in pretty good detail.

Are yours in the U.K. different? Or is it just this battery vendor (and the older Delco you mentioned)?

Thanks, again,

Stu

 

[Gumpy]

Reason is that I'd also like to know where in the world one would find a three stage (or single) shorepower charger that would provide that voltage?

To name one
Victron. My Combi is quite capable of running a normal absorption cycle anywhere between 12v and 16v on the nominal 12v setting. All depends on what you do with the software.

 

[rivonia]

No its not
To be a pedant the gassing voltage changes with the state of charge so it cant be a fixed voltage!
As for equalisation its what it says
Its not charging as such but what it does is equalise the cells and stops stratification in the cells.
The voltage may be high but its at a very low current 3-4 amps so doesnt charge the batteries as such merly causes gassing which stirs the electrolyte.
Its normally run when the batteries are fully charged until the specific gravity of all the cells is equal
Some notes from my charger manual that might explain matters.

Stage 4 - Equalizing Charge This is the
only battery charger stage which is not
engaged automatically. It must be manually
initiated each time it is necessary to equalize
using a dip switch on the back of the Freedom
Remote Control or the front panel on the Link
Instrumentation. Applying an equalizing
charge is not possible without the use of a
Freedom Remote Panel or Link Instrument.
Periodic equalizing is recommended by
most wet cell deep-cycle battery manufacturers.
There are no firm rules for how
often an equalizing charge should be applied,
but once a month is a good rule of thumb for
batteries which are regularly cycled, less often
for systems in only occasional use.The equalizing charge is a timed, 8-hour
cycle. If desired, it can be ended by interrupting
the AC power to the charger at any
time during the cycle. Equalizing should only
be engaged after the batteries have been fully
charged by a normal battery charging cycle.
During this charge cycle, the battery
voltage will increase to the equalize voltage.
This will cause the battery bank to gas
profusely and will accomplish the following:
1. Removal of residual sulfate. Each time a
battery is cycled (discharged and recharged),
a small amount of sulfate is left on the plates.
Over time, this gradual build-up of sulfate will
compromise the performance of the battery.
By applying an equalizing charge, the sulfate
is returned back to the electrolyte, raising the
specific gravity and fully exposing the active
material of the plates.
2. Bring all cells to the same potential. All
lead-acid batteries are made up of individual
2 Volt cells. As the battery bank is cycled,
slight differences in the cells result in different
cell voltages, affecting the overall charge
effectiveness. Equalizing brings all cells up to
the same voltage and the electrolyte in each
cell to the same specific gravity.
3. Mixing up of the electrolyte. Electrolyte in
battery cells tend to separate into layers of
acid and water. The vigorous bubbling action
of the battery during equalizing serves to
physically mix the electrolyte.
Equalizing is not required on gel cell
batteries. For more information and precautions,
check the battery manufacturer specifications
and recommendations. Additional information
on equalizing is also available on our Web
site http://www.heartinterface.com.

Very informative and possibly useful to some people. However please be informed that the GASSING point IS 14.2V

Peter

 

[Gumpy]

Very informative and possibly useful to some people. However please be informed that the GASSING point IS 14.2V

Sorry I posted two points instead of restricting myself to one which I will do this time.

There is absolutely no doubt whatsoever that charging at the gassing voltage does indeed charge faster than charging below it or above it.

The difficulty arises in the fact that the gassing voltage isn't fixed. When we say "the gassing voltage is 14.4 volts" or "the gassing voltage is 14.2 volts" or some other figure it isn't strictly true. That's an average figure, usually throughout the range 50% to 100% SoC.

The reality is that the gassing voltage changes as a function of the DoD. The flatter the batery, the higher the gassing voltage.

With a totally flat wet cell battery the gassing voltage is very, very high. Probably in the region of 15 to 17 volts. Maybe even higher with some types. With a fully charged battery the gassing voltage is not much higher than the recommended float voltage.

So ideally we want to charge at a voltage that reduces throughout the charge cycle to match the gassing voltage. Charger manufacturers have been trying to come up with a workable solution to this dilema for many years. So far no one has succeeded but there are patents (that can never work in practice) for just this process.

 

[Conachair]

Very informative and possibly useful to some people. However please be informed that the GASSING point IS 14.2V

Peter

Are you sure? Found this here http://www.powerstream.com/SLA.htm
which states that the gassing voltage can vary due to temperature. (if you can see through the messed up formatting)

Voltage table for cyclic use charging. The higher voltages (above the gassing voltage) should only be used on flooded batteries that can have the water replaced:
Battery Temperature Charge Voltage per cell Charge Voltage for a 12 Volt battery Gassing Voltage per cell Gassing Voltage for a 12V battery
-20 °C * 2.67 to 2.76 16.02 to 16.56 2.97 17.82
-10 °C * 2.61 to 2.70 15.66 to 16.2 2.65 15.9
0 ° C * 2.55 to 2.65 15.3 to 15.9 2.54 15.24
10 °C 2.49 to 2.59 14.94 to 15.54 2.47 14.82
20 °C 2.43 to 2.53 14.58 to 15.18 2.415 14.49
25 °C 2.40 to 2.50 14.40 to 15.00 2.39 14.34
30 °C 2.37 to 2.47 14.22 to 14.82 2.365 14.19
40 °C 2.31 to 2.41 13.86 to 14.46 2.33 13.98
50 °C 2.25 to 2.35 13.5 to 14.10 2.30 13.8

 

[Gumpy]

I wasn't even going to mention temperature that's a whole other can of worms.........