What count as a cycle (battery life)

[ranger58sb]

Originally Posted by a64pilot

Why is there a separate bulk? What does that achieve? Should I set voltage above absorption voltage for bulk? I set as close as close as possible as I can’t understand the purpose of having a different setting for bulk, I think of bulk as just being current limited, and your out of bulk when absorption voltage is made and you go from current limited, to voltage limited.

I've read it described as bulk = max current and voltage rising to the set point, whereas absorption = steady voltage at the set point and current falling. All that within the limits of what the charger's max output is, and within the limits of what the batteries will accept at any given time.

-Chris

[a64pilot]

Originally Posted by ranger42c

I've read it described as bulk = max current and voltage rising to the set point, whereas absorption = steady voltage at the set point and current falling. All that within the limits of what the charger's max output is, and within the limits of what the batteries will accept at any given time.



-Chris

Way I understand it too.
However Balmar if I understand, has decided to have a real separate set point they call bulk.
Normally there are really only two set points in a regulator, absorption and float, but Balmar has a third, they call bulk.

I don’t understand the reasoning for this third set point.
Marketing?
Having now read the article, I understand to set the reg .1v above absorption max, and absorption at max.

[john61ct]

Pretty sure I've seen that - wrongly labelled "bulk" setpoint - in other charge regulators, maybe solar?

I think it's a holdover from earlier, less standardized understandings and terminology of charging deep cycle banks.

If you think about it, at lower SoC you are less likely to over-gass and/or damage a bank, and a higher voltage allows for faster charging at higher acceptance rates.

Then as you get past say 80-90% and resistance is higher, you want to bring the rate down to avoid overcharging.

I think it over-complicates things and probably saves relatively little run time overall, but set so close together does little harm even if the bank is already close to full.

The real challenge as you point out is - when you're running the engine 5+ hours anyway - making sure it holds Absorb until endAmps is reached.

[a64pilot]

Originally Posted by john61ct

If you think about it, at lower SoC you are less likely to over-gass and/or damage a bank, and a higher voltage allows for faster charging at higher acceptance rates.

Then as you get past say 80-90% and resistance is higher, you want to bring the rate down to avoid overcharging.

I had sort of the same thought, but then realized, your current limited in what I have always called bulk anyway, your not hitting a voltage limit, when you do, that’s called absorption
I’d use it and set it to a higher voltage than absorption, if my battery manual supported that, but it doesn’t, so I’m left with trying to make it the same as Absorption.

[Maine Sail]

Originally Posted by a64pilot

Way I understand it too.
However Balmar if I understand, has decided to have a real separate set point they call bulk.
Normally there are really only two set points in a regulator, absorption and float, but Balmar has a third, they call bulk.

I don’t understand the reasoning for this third set point.
Marketing?
Having now read the article, I understand to set the reg .1v above absorption max, and absorption at max.

The first CV stage (bv) is for when you don't run the engine very long so you can set a slightly higher voltage-setpoint to get to a higher SOC in a short duration then drop back to the standard absorption voltage when you run the engine longer. It's a nice feature & can pack a bit more energy in for short run times. It just gets very confusing when an owner is says;



"I'm in bulk and my 165A alternator is only putting out 90A." "But, you're not in "bulk", you're voltage limited and current can only decline when you are." "but it says "bulk????"....



The black line is voltage it rises during bulk (maximum alternator output) to the constant voltage limit starting at bv. What Balmar shows is on the left and what actually happens is on the right.

[john61ct]

Originally Posted by a64pilot

your current limited in what I have always called bulk anyway, your not hitting a voltage limit

Say you have a robust and cool 300A alt charging a 50% depleted 500AH Lifetime AGM bank.

The current that bank will accept in the first hour or two of charging will be much higher at 14.9V that it would be at 14.5V, once the Balmar-labelled "Bulk setpoint" is reached, likely after just a few minutes.

Just as an example to further explain the rational.

But I believe IRL, not actually reducing runtime to get to 100% Full endAmps by all that much overall.

[NotCook]

We installed our two Deka 5D Gels in 2007. We rarely see the voltage below 12.5 volts, and only accasionally below 12.7 volts in the morning. For the first 7 years the lived on their charger st the dock in the Cleveland summers, and on the charger on the hard all winter. Last three years they have just been on the solar charge controller. We recently added 300 W more solar when we converted from 110 V refrigeration to 12 V (SeaFrost). The fridge cycles on and off 24 hours a day. We regularly run a fan in the master cabin all night. We try to do most things with a heavy load only during the day. So far these Deka gel‘s are doing fine, though we’re assuming we will have to replace them one of these days. Personally, I attribute the long 72 routinely low levels of discharge. Maybe I’m wrong, but my experience with this set says otherwise.

[john61ct]

Yes great batts, correct charging and shallow cycled makes for a long lived bank.

[a64pilot]

Originally Posted by john61ct

Say you have a robust and cool 300A alt charging a 50% depleted 500AH Lifetime AGM bank.

The current that bank will accept in the first hour or two of charging will be much higher at 14.9V that it would be at 14.5V, once the Balmar-labelled "Bulk setpoint" is reached, likely after just a few minutes.

Just as an example to further explain the rational.

But I believe IRL, not actually reducing runtime to get to 100% Full endAmps by all that much overall.

I understand that theory, although it’s fraught with problems.
It’s fine if you always start out with a discharged bank, but if you pull away from the marina, maybe you shouldn’t push such a higher than absorption voltage into a 100% SOC bank.
Lifeline says 14.3 + or - .1 V, I looked yesterday, my bulk is 14.4 and my absorption is 14.3, both within Lifelines recommendations.
I ran a 12 ga voltage sense line direct to my bank, I had it on the alternator output and it was actually reading .2 or so higher than actual bank voltage, not a whole lot, but I’m bored so I decided to run a dedicated voltage sense line. Balmar 614 said calculated and bank were 14.4, fluke on positive side of the bank terminal said 14.38, so that worked.

I’m going to “play” with field current to see if I can’t make that work to be when I drop to float, if I can’t, then I guess I will set the absorption timer to 5 hours or so. I left bulk timer at factory setting.
I hope to not do all that much motoring from one day to the next, so the alternator is not a primary charge source for me, but since it’s there, why not set it as correct as I can?


Balmar’s “Bulk” setting is really another absorption setting as I see it, cause Bulk is current limited, not voltage, and Balmar assigning a voltage level to “Bulk” is non sensical.
Makes about as much sense to me as the cell phone providers “unlimited” plans, which have limits.

I think it well may cause confusion, and maybe they ought to call it Absorption 1 and Absorption 2 or something, just not Bulk.

[john61ct]

I was not advocating this, just an illustration explaining a possible "what were they thinking?"

Obviously the actual setpoints will vary with circumstances, if active cycling and the batt spec is 14.4-14.7V for Absorb then setting pseudo-Bulk at 14.8-9, dropping Absorb to 14.7 should be fine IMO for FLA.

Especially when getting to Full is the usual challenge.

IMO during cruising, concerns about overcharging would be rare even with AGM.

[a64pilot]

Originally Posted by john61ct

IMO during cruising, concerns about overcharging would be rare even with AGM.

Understood, It appears however that Lifeline has done considerable testing to have a manual like they do, and they only allow plus or minus .1 V for absorption, that’s a pretty tight tolerance, in fact I’d say it’s zero tolerance, allowing plus or minus one is the educated way in my opinion of saying we want 14.3. If you just said 14.3 and didn’t state a tolerance some would think plus or minus one volt is fine.

So I’m sticking with what Lifeline says in their manual. I don’t think “pushing” the limit is warrantied, just nothing to gain in my case.

On edit, reading between the lines of Maine Sails posts, it would seem that as long as you have good charging systems, and control them within the voltage limits, that overcharging just doesn’t happen.

[LeaseOnLife]

Originally Posted by a64pilot

... If you just said 14.3 and didn’t state a tolerance some would think plus or minus one volt is fine.
...

Whaaaaat? Once an engineer defines decimals, this means 14.3 not 14.4 or 14.2. You then can argue about an allowed range of 14.26 to 14.34 or 14.25 to 14.35



:-)

[Exile]

Originally Posted by a64pilot

On edit, reading between the lines of Maine Sails posts, it would seem that as long as you have good charging systems, and control them within the voltage limits, that overcharging just doesn’t happen.

Probably a dumb question, but what then is the advantage of the external "smart" regulator when it comes to alternator charging? I have two of the internally regulated "dumb" kind that charge at 14.4v all the time, when the engine's running that is. If there's no danger of overcharging, then what is the advantage to having a float function? For that matter, and maybe this is somewhat unique to the Lifelines, what's the advantage of having separate bulk & absorption modes?

[a64pilot]

No, all batteries should ideally be charged with a three stage charger.
I argue that it’s really two stages as there are only two voltage set points, but I guess that is semantics.
Idea is to charge at a higher voltage that cant be maintained indefinitely without damage to the bank so that you can get them charged in a reasonable time, and then back off on voltage to prevent overcharging.
You can charge at lower voltages of course as all cars do, but the total time to fully charge is much longer and we are trying to reduce that time. Without harming our batteries.

I believe regular flooded batteries can handle and require a much higher absorption voltage than a Lifeline battery, it’s just coincidence that your alternator output happens to coincide within a Lifelines limit for absorption.

However the Concorde AGM battery in my little airplane which is nearly identical to their Lifeline battery, lives for years happily being charged at 14.2V so that I’m not so sure that an hour or two at most, every now and again at 14.3 V is going to hurt my Lifeline batteries.
I’d bet that a Lifeline battery would likely live for years in your boat as well.
The standard for auto alternators used to be 14 plus or mins .2V. I believe that was a Delco standard anyway. I’m surprised yours is 14.4.

On edit, alternators with “dumb”regulators pick a voltage that will charge, although not nearly as fast as if it was a higher voltage, but also one that if maintained forever won’t overcharge a normal battery.
Different batteries, and especially different chemistries of batteries ideally require slightly different voltages, and some like maybe Gels will be damaged by a regular “dumb” regulator.
I don’t know that is true for a Gel battery, but do think that they don’t live as long with dumb charging.

See, my boat when I bought her had a ferro resonant 30 amp Charger, it had one voltage output and never changed, just like the dumb alternator, and yet for years that was the standard, and it apparently worked, just now with modern regulators we can adjust down to a knats arse, so we do, somewhat because we can, but hopefully also to make our banks charge faster and last longer.

[a64pilot]

Only Balmar as far as I know has a bulk mode, nobody else does.
Normally bulk is defined as the time spent when a charge source is trying to obtain absorption voltage setting, but can’t due to its limited output.
It is current limited, if it’s an 80 amp source, then it hold 80 amps while the voltage slowly increase, when it has increased to the absorption voltage setting it then will slowly decrease current to maintain stable voltage setting. Amps will continue to decrease in absorption, voltage remains the same.
In bulk, amps remain stable, voltage slowly increases until set point.