NextStep2 regulator bulk charge issue

[belizesailor]

Originally Posted by jackt

Thanks. I think it's sinking in. Have you a link to that post?

Three meter related articles here...and much more.

http://www.pbase.com/mainecruising/boat_projects

[jackt]

Originally Posted by Neptune's Gear

Get the make and model from the batteries, and then the spec sheet from the manufacturer. Use the voltages they specify. Don't take anyone's word for it, look it up.
The load for a 20 hour test to check battery capacity depends on bank size. That should be in the battery spec sheet as well.

I just called the supplier and they said 14.4 was "what they like"...but here is the spec sheet...??...

US Battery model: US 2200 XC
C20 232 Ah, 3 cell battery (x 4 = 464 Ah bank)

U.S. Battery | Leader in Deep Cycle Batteries | US 2200 XC2 - U.S. Battery | Leader in Deep Cycle Batteries
http://usbattery.com/wp-content/uplo...eet_2017HR.pdf

From spec pdf (link):
[my system in brackets]
---------------
Following is the charging recommendation and charging profile using 2 stage chargers for US Battery deep cycle products.
*Equalization and float charge modes are not considered to be one of the stages in a charging profile.


1.Bulk Charge
Constant current @~10% of C/20 Ah in amps to 2.45+/-0.05 volts per cell
(e.g. 7.35 volts +/-0.15 volts per 6 volt battery)
[So for my x4 batt bank of 464 Ah:
Constant current 46.4 A (10% of 464) to 14.7 V (7.35 x 2)
]


2. Absorption Charge
Constant voltage (2.45+/-0.05 vpc) to 3% of C/20 Ah in amps then hold for 2-3 hours and terminate charge
[Constant voltage 2.45 x 3 x 2 = 14.7 V to 13.9 A (3% of 464) for 2-3 hrs.
]


(Optional Float Charge
Constant voltage 2.17 vpc (6.51 volts per 6 volt battery) for unlimited time
[13.02 V (2 x 6.51)
]


Equalization Charge
Constant voltage (2.55+/-0.05 vpc) extended for 1-3 hours after normal charge cycle (repeat every 30 days)
[15.3 V +/-0.3 V
]

-----------

My thoughts:

Bulk is quite a low amps but comparable to my situation whereby my 90 A alternator happily puts out about 65-60 A at start of a deepish re-charge (about 1700 rpm i think).

This seems like a very high absorption voltage! No? As the sales rep and a marine electrician said to me - 14.4 is okay. But these specs say 14.7V! Really?? Is that what others here would recommend to? I don't want to boil etc. Even though I'm not in the tropics here (New Zealand), and a temp sensor is used.

Their absorption phase terminates at a current of 3% of bat capacity - 13.9 A - which seems quite high. Others here said "fully charged" is when current is 1% or less - 4.6 A or less, and I concur.

Their float charge seems very low - 13.02 V instead of about 13.4 V.

Comments??

[Neptune's Gear]

Use what the manufacturers say. They know their batteries specific requirements best. Most here talk about general rule of thumb values.

[jackt]

From your old post...

Originally Posted by Maine Sail

Your symptoms still point to a voltage sensing & voltage drop issue. We can't forget that voltage sensing needs to be a complete circuit, not just a positive side sense wire. My suspicion is that your regulator B- is not wired to the house bank neg terminal (the Ample manual is incorrect on Reg B- placement as is Balmar's) and therefore can't compensate for the volt drop in the negative wire between the alt B- and house bank negative terminal. Also remember that the reg B- may be asked to carry 2-8A +/- so the reg B- should really be sized for little to no voltage drop at all.

The real question is why you are charging, what I gather from your OP, ppis a bank of 6V golf cart batteries at such a low absorption voltage and for such a short absorption duration?

I need to check the B- issue.

As to your second paragraph, I am realizing I may simply need to increase the abs voltage and increase the time. Please see my last post on the specs for these "new" batts (around 4 years old but lightly used - no longer liveaboard!). The specs show abs of 14.7 V!! Is this plausible?!
Thanks Maine Sail

[jackt]

see edit - I SHOULD HAVE INCLUDED THE +/- 0.3 V...

Originally Posted by jackt

I just called the supplier and they said 14.4 was "what they like"...


1.Bulk Charge
Constant current @~10% of C/20 Ah in amps to 2.45+/-0.05 volts per cell
(e.g. 7.35 volts +/-0.15 volts per 6 volt battery)
[So for my x4 batt bank of 464 Ah:
Constant current 46.4 A (10% of 464) to 14.7 V +/- 0.3 V (7.35 x 2)
]


2. Absorption Charge
Constant voltage (2.45+/-0.05 vpc) to 3% of C/20 Ah in amps then hold for 2-3 hours and terminate charge
[Constant voltage 2.45 x 3 x 2 = 14.7 V +/- 0.3 V to 13.9 A (3% of 464) for 2-3 hrs.
]


(Optional Float Charge
Constant voltage 2.17 vpc (6.51 volts per 6 volt battery) for unlimited time
[13.02 V (2 x 6.51)
]


Equalization Charge
Constant voltage (2.55+/-0.05 vpc) extended for 1-3 hours after normal charge cycle (repeat every 30 days)
[15.3 V +/-0.3 V
]

Okay, it does say +/- 0.3 V so -0.3 V is 14.4 V.

Why would I go to 14.4 instead of 14.7?? And why not 14.7 + 0.3 = 15.0 V?! Now that sounds high! But could the batts take it for extended hours? I guess that's the "equalization" ability.

So why not 14.7 instead of 14.4? I am not in tropics so heat doesn't seem an issue.

[jackt]

ps. I am surprisingly not totally new to all this. Having spent several years cruising liveaboard in the tropics, I have had to try to deal with, fix, and understand these issues. I have Calder's1996 (2nd Ed)
Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair and Improve Your Boat's Essential Systems

- an excellent book on boat maintenance and I've read the section on batts and regulators many times. It's great. But obviously it is not enough. Hence, please bear with me with my quest to understand boat electrics better through this excellent forum!

[StuM]

Originally Posted by Neptune's Gear

Think of volts like pressure in a water pipe, going to a tank. Amps is like volume. Once the tank is full (the battery) it wont accept any more, unless the pressure (voltage) is increased.... and even then not much without distorting or destroying the tank!

Actually Amp hours is like volume. Amps is a flow rate like gallons per minute.

A better (but still imperfect) way to think about it is pumping water into a sealed tank which is initially full of air. As you pump more water (Amp hours) in, the air is compressed in the top of the tank, the pressure of the compressed air (battery resistance) opposes the pump pressure (Volts) so the rate of flow decreases (Amps). Once their is sufficient water in the tank (Amp hours) to compress the air so that it's pressure (resistance) is the same as the pump pressure (Volts), you can't put any more water (Amp hours) into the tank. If you increase the pressure (Volts) to try to squeeze a bit more water (Amp hours) into the tank the pressure can damage the tank.

[Neptune's Gear]

Yep, Stu, that's better!

[Maine Sail]

Originally Posted by jackt

see edit - I SHOULD HAVE INCLUDED THE +/- 0.3 V...




Okay, it does say +/- 0.3 V so -0.3 V is 14.4 V.

Why would I go to 14.4 instead of 14.7?? And why not 14.7 + 0.3 = 15.0 V?! Now that sounds high! But could the batts take it for extended hours? I guess that's the "equalization" ability.

So why not 14.7 instead of 14.4? I am not in tropics so heat doesn't seem an issue.

The US 2200 is a good quality GC2 battery. I can get an average life out of these, with proper charging, in a good installation, of approx 8-12 years.

For PSOC use (partial state of charge) as we do in boats, or in off grid, charge at 14.7V - 14.8V and this will yield a significantly healthier battery and one that will last considerably longer. Trojan recommends 14.8V for absorption.

A few things folks miss with the US Battery charge guidance..

Originally Posted by US Battery

Absorption Charge
Constant voltage (2.45+/-0.05 vpc) to 3% of C/20 Ah in amps then hold for 2-3 hours and terminate charge.

For a 464 Ah bank you charge at 14.7V +/- to 3% of Ah capacity in accepted current THEN HOLDfor an additional 2-3 HOURS. 3% is 14A for a 464 Ah bank. So when your bank attains 14A at 14.7V you then start the 2-3 hour time clock. Most chargers start a timer at the transition from bulk/CC to absorption/CV so it can be critical to to have equipment that allows custom programming.

In total time at 14.7V you will be looking at 4 +/- hours (depends upon charge current). Most folks assume you drop to float at a tail-current of 2% to 3% but this is not necessarily true.. From 14A at 14.7V + 3-4 hours you will wind up at about 0.3% to 0.5% acceptance or lower before you should drop to float. In other words US Battery wants you to charge to 100% SOC before you drop to float. Now you can see why your 1 hour of absorption at 14.4V was far too short. Higher absorption voltages, 14.7V to 14.8V also shorten the charging time while 14.4V takes longer.

Most every charge controller, regulator or charger in the marine market drops to float FAR TO EARLY. I call this premature floatulation. This is why the vast majority of the batteries in the marine environment die from sulfation and chronic under absorbing and under voltage charging and very, very rarely from over absorbing/over voltage charging.

The only failures I see from over-charging are failures of either charge equipment or the use of single stage automotive chargers.

I have a Xantrex charger in my shop right now that has no voltage limit, this was the chargers failure mode. D'oh... The other failures, due to over charging, have been from controller-less solar charging pushing the batteries daily over 15.5V even when already full. While the batteries are eventually destroyed this does not happen over-night.

As for max bulk current these batteries can be charged at up to .25C. They are sold for golf courses so the general industry practice is .1C. Fred W. or any of the guys at USB can confirm this.


The other things folks miss is this:

Originally Posted by US Battery

Actively used batteries should be equalized once per month.

On top of 14.7V +/- and 2-3 hours, once you are at 14A & 14.7V, still warrants an EQ once per month.

The problem in the industry is that we have all been scared to death of over-charging our batteries, and the end result is we murder them in very short order by chronically under charging them. I tested a 130Ah G15 date code (May 2015) Trojan SCS-225 battery just last night, the re-charge cycle just started about 15 minutes ago, which is about 6-7+/- hours earlier than it should have. This battery had only approx 45 +/- deep cycles on it. It tested at 81.77 Ah or 63% of its rated Ah capacity in less than 2 years.

This battery has been murdered, in in less than two years from it's installed date of June 2015. Stock Yanmar alternator and a solar array with a cheap Flex Charge ON/OFF or shunting solar controller, both conspired to murdered this "deep cycle" battery in just 45 +/- deep cycles. It is testing at 63% of rated capacity or "failed" in just 24 months from date code, 23 months from installation and 6 months of actual in-service use. Winters the owner kept the batteries in his basement on a Deltran Battery Tender. Solar is wonderful, and generally helps greatly for mooring sailed boats, but that ON/OFF controller was not really helping to compensate for the factory alternator.. This owner could care less and is happy with 2 years or less service life, but many are not. I can easily get this particular battery to a service life of 3-5 years + with correct charging practices.

[Neptune's Gear]

Great Post MS, totally agree!

[Maine Sail]

Originally Posted by Maine Sail

I tested a 130Ah G15 date code (May 2015) Trojan SCS-225 battery just last night, the re-charge cycle just started about 15 minutes ago, which is about 6-7+/- hours earlier than it should have. This battery had only approx 45 +/- deep cycles on it. It tested at 81.77 Ah or 63% of its rated Ah capacity in less than 2 years.

This battery has been murdered, in in less than two years from it's installed date of June 2015.

For those wondering how long it takes to recharge a used & sulfated battery......

I started this charge this morning before I left and about 15 minutes before the quoted post.. I set the charger at 16A or .2C based on the tested capacity. The battery is still accepting 2.6A at 14.8V and it has been approx 9.5 hours. 9.5H X 16A = 152Ah. The charger has the potential to deliver 152Ah's over 9 hours but most of this has been lost as wasted energy due to charge efficiency declines from a poor state of health.. This battery now has a horrible Coulombic efficiency and takes a horribly long time to reach full charge. Not uncommon for batteries as they age and sulfate.

At this rate the battery won't be fully charged for another few hours. The battery only delivered 81.77 Ah's and charge current was set to 16A & 14.8V and it has been 9.5 hours and it is still not full..

[lateral]

I have same setup as you Jackt, except for NS2.
(464Ahr- 6v x4)

For shore charging I have a Pronautic 60A.(same as Stirling)
Absorbtion is 14.8V, float is 13.6V@<4A diminishing to 0.5A.
Never boiled since I have been using it. Only mild gassing.
My alt is factory to be swapped out to a 115A bosch shortly with a MG Smartcharge one. Temp sensored & externally forced air to alt.

Brilliant thread-Thanks to all....

[jackt]

Originally Posted by StuM

Actually Amp hours is like volume. Amps is a flow rate like gallons per minute.

A better (but still imperfect) way to think about it is pumping water into a sealed tank which is initially full of air. As you pump more water (Amp hours) in, the air is compressed in the top of the tank, the pressure of the compressed air (battery resistance) opposes the pump pressure (Volts) so the rate of flow decreases (Amps). Once their is sufficient water in the tank (Amp hours) to compress the air so that it's pressure (resistance) is the same as the pump pressure (Volts), you can't put any more water (Amp hours) into the tank. If you increase the pressure (Volts) to try to squeeze a bit more water (Amp hours) into the tank the pressure can damage the tank.

Excellent...Tanks!

[jackt]

Originally Posted by Maine Sail

For a 464 Ah bank you charge at 14.7V +/- to 3% of Ah capacity in accepted current THEN HOLDfor an additional 2-3 HOURS. 3% is 14A for a 464 Ah bank. So when your bank attains 14A at 14.7V you then start the 2-3 hour time clock. Most chargers start a timer at the transition from bulk/CC to absorption/CV so it can be critical to to have equipment that allows custom programming.

In total time at 14.7V you will be looking at 4 +/- hours (depends upon charge current). Most folks assume you drop to float at a tail-current of 2% to 3% but this is not necessarily true.. From 14A at 14.7V + 3-4 hours you will wind up at about 0.3% to 0.5% acceptance or lower before you should drop to float. In other words US Battery wants you to charge to 100% SOC before you drop to float. Now you can see why your 1 hour of absorption at 14.4V was far too short. Higher absorption voltages, 14.7V to 14.8V also shorten the charging time while 14.4V takes longer.

Most every charge controller, regulator or charger in the marine market drops to float FAR TO EARLY. I call this premature floatulation. This is why the vast majority of the batteries in the marine environment die from sulfation and chronic under absorbing and under voltage charging and very, very rarely from over absorbing/over voltage charging.

Thanks, most helpful Maine Sail.

My NS2 (which is a typical and common multistep regulator is it not?) does not allow one to separately set a hold for further time in abs once 14A (3%) is reached. So why would US Batts recommend something that few can do?! But you are saying, I think, that effectively, using my NS2, I can achieve this and would need to extend the abs time well beyond the time it usually takes to get to around 14A. So if it takes 2 hours of absorption to get to 3% or 14A (from a typical 24 hr drain of -40 Ah used), then I need to adjust the NS2 to say 2 hrs of abs time PLUS their "extra 2-3 hrs at 3%" for a total of 4-5 hours(!!). Yes, no wonder indeed MS!...
While cruising for a few years I was charging at anchor the old set of 4 (440 Ah) for only about 1 hour, because the batt monitor was counting back Ah to zero and I thought all was okay with that time. And I didn't want the noise! And I read in Calder he charges for about that time (but I now see his 130 amp alternator is bigger so at around .25C his amps were probably around 100 A).

Sure enough, after 4-5 yrs my batts would not hold a charge too good! and dropped within a day to 12.0 V or less - with little load; they were done!! So with this "new" set (that don't get heavy discharge) I am trying to do it right. My Bosch 90 A alternator can put out 70 A but is happy putting out about 60 A at the revs I choose (don't really want to run it at higher RPM) so that's about .13C - not great, not .15C or .2C but do I need admonished?!

I do have a shore charger - 50A smart charger with bulk/abs 14.7V (float 13.7V triggered at 7.5A). Maybe I should use that to charge them properly and then re-test with the engine charge system after adjusting abs to 14.7 and abs time to 3 hrs...for a start.

Premature floatulation!!

Thanks.

[jackt]

Originally Posted by Maine Sail

On top of 14.7V +/- and 2-3 hours, once you are at 14A & 14.7V, still warrants an EQ once per month.

Are you agreeing that one should do an equalization once a month - if being "used regularly"? What of not being used much?

They say: Constant voltage (2.55+/-0.05 vpc) extended for 1-3 hours after normal charge cycle (repeat every 30 days)
so, 15.3 V +/-0.3 V.

But what amps? Would one use the normal NS2 regulator so after bulk is adjusted and set to 15.3 (using the screw pot), just let the NS2 system run...to 15.3...then to abs at 15.3 for set time of say 2 hours at current of its choosing (depending on charge acceptance so I assume quite low)...then to float after 2 hrs etc?

The shore charger has this fixed equalization schedule:
"Constant current (2.0 - 7.5 A) up to 16 V then held for 1 hour or 12 hr timeout".

Thanks.

ps. writing this all out is really helping (me) with understanding!