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**a64pilot** · 30-04-2017, 13:58

Got it

belizesailor · 30-04-2017, 14:07

Quote:

Originally Posted by a64pilot

...
It may help to know that there is really no such thing as bulk, bulk is nothing more than absorption, but due to limited Charger size, absorption voltage is unachievable. Also "full" is of course the end of absorption, so it could be said that there really is only one stage of charging, absorption.
...

Yes, thats one way to look at it...which maybe fits LifeLine's equation better, but both Ample Power (NS2) and BlueSky (3000i) use the bulk/ absorption/float terminology consistently.

**a64pilot** · 30-04-2017, 14:12

Marketing makes them all call it three stage charging.
If everybody else is selling three stage chargers, and you sell a two stage, how well do you think your sales will do?
I think maybe my Balmar 614 may even have three voltages? However I've just recently installed the thing and have not even programmed it yet

**Adelie** · 30-04-2017, 14:13

Quote:

Originally Posted by belizesailor

As stated, I have, and my reading comprehension is quite good. The LifeLine manual does indeed give a formula for "time to reach full charge", but this formula is for total time, not just ABT. . . .

Top of page 20 - 3hr for batteries consistently recharged from 30-50% DoD.

belizesailor · 30-04-2017, 14:21

Quote:

Originally Posted by Adelie

Top of page 20 - 3hr for batteries consistently recharged from 30-50% DoD.

Aha, Im not going senile after all ! We have different versions of the LifeLine docs. Mine does not have that table.

Sorry for the confusion.

**Adelie** · 30-04-2017, 14:23

Quote:

Originally Posted by belizesailor

Aha, Im not going senile after all ! We have different versions of the LifeLine docs. Mine does not have that table.

Sorry for the confusion.

I was starting to wonder if you were looking at a different document.

The one I linked to is the general one on the Lifeline website.

Maine Sail · 30-04-2017, 14:47

Quote:

Originally Posted by a64pilot

It may help to know that there is really no such thing as bulk, bulk is nothing more than absorption, but due to limited Charger size, absorption voltage is unachievable.

There is such a thing as "bulk charging". Bulk is constant current or the max current potential of the current source before the constant voltage set point has been achieved.

**a64pilot** · 30-04-2017, 14:59

Quote:

Originally Posted by Maine Sail

There is such a thing as "bulk charging". Bulk is constant current or the max current potential of the current source before the constant voltage set point has been achieved.

You were the one I believe that pointed out that bulk was just a charger trying to get to absorption voltage but could not due to it was current limited, and in fact nothing happens, no difference In programming etc occurs when the charger hits voltage set point and current begins to drop, just it hit its voltage set point was all.
That in fact a three stage charger was actually two stage?
Float is a maintainer voltage, very little charging occurs in float, that the bank should be ideally 100% charged prior to float?
Did I not understand?

On edit, I guess a time will start once absorption voltage is reached if termination is to be done by time

sailingharry · 30-04-2017, 15:04

Bulk and absorption are marketing terms. In both cases, the regulator maintains a desired set point -- or at least tries to.

It's like the cruise control in your car having an "acelleration" phase and a "setpoint" phase. Nothing changes, at least from a programming or design standpoint. With a sufficiently large charge source, there is no "bulk" phase.

Now, I guess in a perfect world, the battery mfgr would like you to limit charge to 20% of capacity. A regulator that is aware of amps (few are) could then control amps and then control volts, creating a true bulk phase .

**a64pilot** · 30-04-2017, 15:14

In this case though as we are talking about Lifeline AGM's, it would be one truly monsterous charger. I think a Lifeline can initially accept up to 5C charge rate, for my 660 amp hr bank, that would be well in excess of 3000 amps

john61ct · 30-04-2017, 19:13

The charger should ideally be .4C -.6C, 5C may be theoretically OK but boy you'd need some amazing wiring, switches, fuses etc, and you'd likely be impacting bank lifespan.

The real Absorb termination point should be current dropping to .005C

Setting an absorption TIME parameter will vary enormously depending on the DoD and charge rate, and will be a trial & error guesstimate to get to the end Current, and of course assumes some consistency.

So really, why not just try to get a controller that can be set to terminate Absorb based on current?

If solar alone rarely gets you to full (float), then you should IMO be burning some fuel at least a few mornings per week, past hitting Absorb, or else your very expensive bank won't last as long as it could.

boatbod · 01-05-2017, 04:02

In my experience with Lifeline, 14.3 is too low and risks premature sulfation. You are better off charging a little harder around 14.6.

boatbod · 01-05-2017, 04:13

In my experience with Lifeline, 14.3 is too low and risks premature sulfation. You are better off charging a little harder around 14.6.

ranger58sb · 01-05-2017, 04:24

Quote:

Originally Posted by Maine Sail

There is such a thing as "bulk charging". Bulk is constant current or the max current potential of the current source before the constant voltage set point has been achieved.

Quote:

Originally Posted by a64pilot

You were the one I believe that pointed out that bulk was just a charger trying to get to absorption voltage but could not due to it was current limited, and in fact nothing happens, no difference In programming etc occurs when the charger hits voltage set point and current begins to drop, just it hit its voltage set point was all.
That in fact a three stage charger was actually two stage?
Did I not understand?

FWIW... and everyone has probably seen these already...

In Nigel Calder's "Boatowner's Mechanical and Electrical Manual" I've found Figure 6-7 ("Three-Stage Charge Curve") helpful to conceptualize the difference between bulk and absorption.

Also, Maine Sail's Compass Marine site and his short description of bulk and absorption charges -- scroll about halfway down the page -- here: Compass Marine How To's Photo Galleries at pbase.com

-Chris