Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 15-10-2015, 10:17   #46
Registered User

Join Date: Mar 2012
Location: On board in Alanya, Turkey
Boat: Hunter Legend 420 Passage
Posts: 626
Re: Equalization

Quote:
Originally Posted by a64pilot View Post
.....I assume that an honest 100% SOC is nearly impossible without 24 hr charger power, but that maybe 98% SOC is acceptable to be consider fully charged?.....
That's the problem with most chargers that drop to Float well before 100%.

If you only ever reach 98% then eventually permanent sulfation sets in and it is impossible to remove with equalization. The next cycle you are charging to only 98% of the 98% of usable battery left. And so on and so on until the battery capacity is so low that it is useless. If you can get to 100% more often the battery will last much longer.

Quote:
Originally Posted by a64pilot View Post
But I've also noticed something that I cannot explain.
I have two banks, one 220 AH, one 440 AH, both identical batteries, identical age etc.
If I pull 50 AH out of the 220 bank it takes longer to recharge it than if I pull 50 AH out of the 440 AH bank. That is opposite of what I would have thought, why is that?

I've even considered combining them into one 660 AH bank with the combiner switch, I don't worry about killing my start bank.
I attempted to answer this back in post #30! But how do measure this? You can't just use SmartGauge to switch from one bank to another as it has to 'learn' the bank over as many cycles as possible - the more it learns the more accurate it becomes.
__________________

__________________
sailinglegend is offline   Reply With Quote
Old 15-10-2015, 10:24   #47
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 4,019
Re: Equalization

Quote:
Originally Posted by sailinglegend View Post
That's the problem with most chargers that drop to Float well before 100%.

If you only ever reach 98% then eventually permanent sulfation sets in and it is impossible to remove with equalization. The next cycle you are charging to only 98% of the 98% of usable battery left. And so on and so on until the battery capacity is so low that it is useless. If you can get to 100% more often the battery will last much longer.
The chargers that drop to float early usually do this based on a timer. Since the timer doesn't change eventually the battery capacity will come to match the charger's idea of 100% full and then it should get no worse. So I don't think it's accurate to say that the battery capacity will degrade to zero. It all depends on the size of the charger and the timeout set for dropping to float.

This is why some AGM vendors want a charge source of between 0.25 and 0.4C. They want to get most of the charge in before the charger drops back to absorption and float based on a time limit. If you know the size of your bank and the charger is programmable you should adjust the timeout for float charge to minimize the risk of this problem.
__________________

__________________
transmitterdan is offline   Reply With Quote
Old 15-10-2015, 12:02   #48
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,045
Re: Equalization

Quote:
Originally Posted by sailinglegend View Post
That's the problem with most chargers that drop to Float well before 100%.

If you only ever reach 98% then eventually permanent sulfation sets in and it is impossible to remove with equalization. The next cycle you are charging to only 98% of the 98% of usable battery left. And so on and so on until the battery capacity is so low that it is useless. If you can get to 100% more often the battery will last much longer.


I attempted to answer this back in post #30! But how do measure this? You can't just use SmartGauge to switch from one bank to another as it has to 'learn' the bank over as many cycles as possible - the more it learns the more accurate it becomes.

I don't use the smart gauge to determine SOC while charging, I read on Maine Sails article that it wasn't as accurate whilst charging, I use the amp draw while in equalization mode (14.3 V) to determine full charge.
I know my nightly amp draw to be about 55 AH and used that as a basis, batteries fully charged and sitting in float mode for a week before test, and it's not just a few minutes difference either, it's like a third faster to put the same amount of amps back into a larger bank than the smaller one.
Now this is not a real conformed test under controlled conditions, just a Jim-Bob sort of test so obviously I may have missed something, but I expected the larger bank to take longer to charge as acceptance rate would be so low starting with a bank at 88% charged to begin with as opposed to a 220 AH bank at 75% SOC.
I was trying to determine am I better off combining my banks to one 660 AH Bank or leaving separate and using the 440 AH bank as the house bank?
Better meaning which one will recharge the fastest, or if there is a difference and how much is it.
I'm not worried about having one bank and killing it so I can't start the motor

The other thing I have noticed is my alternator's charge controller kicks into float mode much earlier than my shore power charger does too, I don't know why, is the Alt controller just voltage driven so that when X volts are reached it trips into float, while the shore power charger takes voltage and a drop to X amps?

I'm learning all this, it's new to me, but I want to learn as much as I can to try to keep from failing once we leave, plus it fun.
__________________
a64pilot is offline   Reply With Quote
Old 15-10-2015, 12:13   #49
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,045
Re: Equalization

I think my charger has a min time in absorption, not a max, I believe but am not sure it's watching both voltage and amp draw to determine when it's drop into float?

Sterling Pro Charge Ultra, 60 amp
__________________
a64pilot is offline   Reply With Quote
Old 15-10-2015, 12:46   #50
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 3,060
Re: Equalization

Quote:
Originally Posted by a64pilot View Post

But I've also noticed something that I cannot explain.
I have two banks, one 220 AH, one 440 AH, both identical batteries, identical age etc.
If I pull 50 AH out of the 220 bank it takes longer to recharge it than if I pull 50 AH out of the 440 AH bank. That is opposite of what I would have thought, why is that?
How are you measuring this?????
How are you charging both banks?
What is the charge rate?
How have you determined SOC on the start bank?

You can not use the Smart Gauge to monitor two different banks for SOC.

Personally I find a 220Ah AGM start bank to be real waste of good lead when a small group 24 AGM would suffice. Combine it all into one contiguously wired bank...
__________________
Marine How To Articles
Maine Sail is offline   Reply With Quote
Old 15-10-2015, 13:28   #51
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,045
Re: Equalization

Quote:
Originally Posted by Maine Sail View Post
How are you measuring this?????
How are you charging both banks?
What is the charge rate?
How have you determined SOC on the start bank?

You can not use the Smart Gauge to monitor two different banks for SOC.

Personally I find a 220Ah AGM start bank to be real waste of good lead when a small group 24 AGM would suffice. Combine it all into one contiguously wired bank...

I'm not measuring, have to assume that the charger has done it's job, that and being on float for a week the bank is full, the charger has multiple outputs, I have one for each bank.

Charge rate is determined by the charger, up to a max of slightly more than 60 amps

SOC is determined solely on assuming charger has done it's job after sitting on for a week.

I'm not using the smart gauge for any of this, I believe I'd have to have two of them to do that, but identical loads for identical times on both "tests" should result in same discharge, then turn on charger, wait for it to enter float, recycle it to force back into absorption and watch amps to determine SOC.

I fully admit it's not any kind of real test, just something I tried out of curiosity.
Reason why was I had thought it best to combine both banks into one large bank, that splitting them was a waste of money, unless I rotated banks so to speak, using one one night, the other the other night.
Didn't know if a smaller bank would be more efficient than a larger one? but didn't want to set myself up for partial SOC cycling if I could help it, I wanted to find out if there was a difference in recharge time of different sized banks, assuming current drawn out was the same, if it took considerably longer to recharge one big bank, them maybe one big bank wasn't what I wanted.
__________________
a64pilot is offline   Reply With Quote
Old 15-10-2015, 14:17   #52
Registered User

Join Date: Mar 2012
Location: On board in Alanya, Turkey
Boat: Hunter Legend 420 Passage
Posts: 626
Re: Equalization

Quote:
Originally Posted by transmitterdan View Post
The chargers that drop to float early usually do this based on a timer...... So I don't think it's accurate to say that the battery capacity will degrade to zero......
Please read again exactly what I said!!!!

IF you only ever reach 98% - for example if you were using solar - then because there are not enough hours in the day to get to 100% then the capacity will eventually fall dramatically if you don't equalize regularly. 98% of 98% of 98% of 98% of 98% is about 90% of usuable capacity left!.........
__________________
sailinglegend is offline   Reply With Quote
Old 15-10-2015, 14:21   #53
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 3,060
Re: Equalization

You can't use a charger to determine time to full unless everything is equal and there is no way to make this equal with two unequally sized banks.

The Sterling PCU/ProMariner ProNautic P use an algorithm that looks at the time it takes in bulk to help determine time spent in absorption then % power supply being used and current drop off over time before going to float. It will likely never be the same twice because it is not just a simple egg-timer charger.

Re-cycling a charger like this only serves to shorten the next absorption cycle because time in bulk will be nil so the absorption will also be nil but it does not necessarily mean the battery hit 14.4V and 0.5% at the same time... It does not use an egg timer like cheaper chargers that can often be re-cycled to trick it into a longer absorption cycle.

Sadly the marine charger market has a LONG way to go before we get the controls we really need. The Balmar regulators are perhaps the best at giving us the control we really need over charging and only Outback, Magnum and a few others actually get close in Inverter/Chargers.

The only way to measure this is equally with the same charge rate per bank. You'd also need the ability to hold voltage to 14.4V as long as it takes to hit 0.5%. You can do a temporary custom program where float and absorption are both 14.4V but you can't shrink the size of the charger to get equal charge rates so there will still be discrepancies. Your basic marine charger is what it is and this is why I use lab grade power supplies in my shop, not "smart chargers".

Your 440Ah bank is being charged at a max rate of 13.4% of Ah capacity yet your 220Ah bank is being charged at a rate of 27.3% of Ah capacity. I think if you did this at equal charge rates you would see that both banks charge at similar speeds. Simply put a charge rate of 27.3% could certainly charge faster than a charge rate of 13.4%...
__________________
Marine How To Articles
Maine Sail is offline   Reply With Quote
Old 15-10-2015, 14:59   #54
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 4,019
Re: Equalization

Quote:
Originally Posted by sailinglegend View Post
Please read again exactly what I said!!!!

IF you only ever reach 98% - for example if you were using solar - then because there are not enough hours in the day to get to 100% then the capacity will eventually fall dramatically if you don't equalize regularly. 98% of 98% of 98% of 98% of 98% is about 90% of usuable capacity left!.........
Taken to the limit 98% raised to the power of 100 (100 cycles) says you would reach 13% of capacity after 100 cycles. Clearly that won't happen in real life.
__________________
transmitterdan is offline   Reply With Quote
Old 15-10-2015, 15:30   #55
Registered User

Join Date: Mar 2012
Location: On board in Alanya, Turkey
Boat: Hunter Legend 420 Passage
Posts: 626
Re: Equalization

Quote:
Originally Posted by transmitterdan View Post
Taken to the limit 98% raised to the power of 100 (100 cycles) says you would reach 13% of capacity after 100 cycles. Clearly that won't happen in real life.
But the battery won't achieve permanent sulfation after each cycle - only maybe every four weeks. It's not the cycles it's the time at 98% before being fully charged. You can't put exact figures on this, but in the end sulfation causes premature failure.
__________________
sailinglegend is offline   Reply With Quote
Old 15-10-2015, 15:39   #56
Registered User

Join Date: Mar 2007
Location: On the hook in Florida
Boat: Tayana V42 - Passages
Posts: 504
Re: Equalization

Quote:
Originally Posted by zboss View Post
So, when we are sitting at anchor somewhere in the Bahamas using our 30 amp max output solar, expensive AGM batteries have no advantage over cheaper flooded lead acid batteries.
In terms of charging with 30A of solar, no. But, you don't have to add water.
__________________
Trying to live on 20th century money in the 21st century.
jcapo is offline   Reply With Quote
Old 15-10-2015, 16:09   #57
Registered User
 
pacific_voyager's Avatar

Join Date: Sep 2007
Location: Aboard
Boat: Kelly Peterson 44 Cutter
Posts: 43
Re: Equalization

If I assume that the original poster meant having FIVE 105AH 12V batteries in parallel he will be lucky to get 2 years out of the bank. He will probably see less. Every parallel string in a battery bank degrades the lifetime of the battery bank. You should avoid, if possible, parallel strings and certainly never have more than three.
__________________
pacific_voyager is offline   Reply With Quote
Old 15-10-2015, 17:09   #58
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,045
Re: Equalization

Main sail,
So can I put back the amps faster into a larger bank if it's discharged to a lower SOC or faster into a smaller bank discharged to a higher SOC, or is there not really enough difference to matter?
Is there any logic to having two similar banks, but alternating their use every other night?
Should I just put the battery switch to ALL and just have one large bank? I'm not worried about killing one bank and not being able to start the motor.
Finally assuming I pull 100 AH out of a 660 AH bank nightly, is there an advantage to doubling up the chargers and being able to charge at 120 amps as long as the bank would accept that, would that significantly shorten charge time? Assuming a twice weekly use of the generator allowing shorepower chargers to be used.


Sent from my iPad using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 15-10-2015, 19:12   #59
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,712
Re: Equalization

Quote:
Originally Posted by pacific_voyager View Post
If I assume that the original poster meant having FIVE 105AH 12V batteries in parallel he will be lucky to get 2 years out of the bank. He will probably see less. Every parallel string in a battery bank degrades the lifetime of the battery bank. You should avoid, if possible, parallel strings and certainly never have more than three.
Do you have a reason for that assertion or even better, a reference?

I have 5 x 200AH AGMs in parallel and they have lasted a lot more than 2 years.
__________________
StuM is offline   Reply With Quote
Old 16-10-2015, 10:16   #60
Registered User
 
zboss's Avatar

Join Date: Sep 2011
Location: On a boat
Boat: Cabo Rico 38
Posts: 3,426
Re: Equalization

Quote:
Originally Posted by a64pilot View Post
I have never heard of any problems with Hydrogen accumulation and a hydrogen explosion,
But they are your kids, and with my kids I wouldn't take the chance no matter how minuscule it was, now I'd sleep on them any day
My smoke alarm goes off when the batteries are really off-gasing.
__________________

__________________
zboss is online now   Reply With Quote
Reply

Tags
equalization

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery Life and Equalization Charge Curtis Electrical: Batteries, Generators & Solar 22 18-03-2009 10:06
Equalization Necessary? SCCatSailor Electrical: Batteries, Generators & Solar 5 17-03-2009 15:20
Equalization Question Extemporaneous Electrical: Batteries, Generators & Solar 7 23-02-2009 21:06
Iota chargers and equalization witzgall Electrical: Batteries, Generators & Solar 11 21-07-2008 09:34
Lead-acid battery equalization phorvati Electrical: Batteries, Generators & Solar 22 01-01-2007 14:25



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:59.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.