What count as a cycle (battery life)

[Exile]

Originally Posted by a64pilot

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.

* * *

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.

OK, I was under the erroneous impression that overcharging from "dumb" alternators was the issue, but it is in fact undercharging if alt output is closer to 14v. I assumed 14.4v based on readings off my analog meters, so the first thing I need to do is take readings off the alt & batts themselves with my digital meter. Either way my batts spend much more time charging off my 3-stage charger than from running the engine so I'm probably not doing much if any harm.

Thanks for the helpful info. I should probably pay better attention but my batteries are kinda like refrig for me . . . as you've said if the beer stays cold & the ice cream frozen then I tend to move on to more pressing issues. Not always the best policy but that seems to be the way things often go.

[john61ct]

2 setpoints is normal, means three stages. The timing of the first CC-CV transition is not controlled by the regulation but by the bank.

The second is to Float.

A stock dino juice or mains source keeping Absorb going forever **would** overcharge, not a good idea for expensive House banks.

But the actual damage depends on the batt.

[Exile]

Originally Posted by john61ct

2 setpoints is normal, means three stages. The timing of the first CC-CV transition is not controlled by the regulation but by the bank.

The second is to Float.

A stock dino juice or mains source keeping Absorb going forever **would** overcharge, not a good idea for expensive House banks.

But the actual damage depends on the batt.

In plain English, what is the "CC-CV" transition?

When you say "not controlled by the regulation but by the bank," I take that to mean that the amount of amps is determined by the batts' acceptance rate? So in the case of a "dumb" alternator, it simply puts out the same voltage throughout the charging cycle and the amount of amps going into the battery is controlled strictly at the battery end and not at the alternator/regulator?

In contrast, my charger (set for AGM) seems to use 14.3v or 14.4v (can't remember) for bulk & absorption, and 13.3v for float. I assume this is what you mean by only two set points but three stages?

[a64pilot]

CC is constant current. You have an 80 amp charge source, your bank is low and even though it’s set to maintain say 14V the bank is so low it can’t get to 14 V, it’s clipped at 80 amps, hence constant current.

However there are some chargers that can be set to maintain a constant current and let voltage fluctuate, but they are not all that common. Either voltage or current has to change for the other to remain stable.

Voltage is often referred to as pressure, the higher the voltage, the higher the pressure, the more power you can stuff into a battery. However a battery is to some effect a monsterous resistor, try stuffing in to much too fast due to its internal resistance, it will overheat, and heat is what damages a battery from overcharging, in my opinion.

Now once you have been charging for awhile your charger has increased in voltage until it’s set point, it now has to slowly back off of the amps to keep from having the voltage go too high and overheat the battery.


A regular “dumb” alternator really isn’t meant to be a charge source, it’s meant to return the tiny amount of current that was used to start the engine and to run the electrical accessories when the engine is running. Automobile is a good example. To use one to recharge a flat battery bank, is going to take a loooong time.

However for those of us that use our big battery banks overnight and want to recharge them during the day, we want to increase the pressure so we can refill that battery faster, but then reduce the pressure when they get full so we don’t bust them.

[a64pilot]

Originally Posted by Exile

When you say "not controlled by the regulation but by the bank," I take that to mean that the amount of amps is determined by the batts' acceptance rate? So in the case of a "dumb" alternator, it simply puts out the same voltage throughout the charging cycle and the amount of amps going into the battery is controlled strictly at the battery end and not at the alternator/regulator?



In contrast, my charger (set for AGM) seems to use 14.3v or 14.4v (can't remember) for bulk & absorption, and 13.3v for float. I assume this is what you mean by only two set points but three stages?

You have it, your correct [emoji1303]

[Exile]

Originally Posted by a64pilot

You have it, your correct [emoji1303]

So btwn bulk & absorption the charger is maintaining CV but backing off on amps to avoid overheating the batts? A bit confusing since I thought this was controlled on the battery end. I also think I got confused when Maine Sail posted awhile back about there needing to be a 0.1v difference bwtn bulk & absorption. That may be true, but I'm assuming that's how the charger accomplishes the reduction in amps?

Sorry for the noob questions. I thought I had this down awhile ago when I started reading Maine Sail's website, but apparently not. Could just be a problem with the lingo.

[john61ct]

Originally Posted by Exile

In plain English, what is the "CC-CV" transition?

When Bulk (so-called Constant Current) stops, V setpoint has been reached so regulator caps it, Absorb is Constant Voltage.

What point in time and SoC that transition occurs is up to the batt chemistry and current available. Not the charger controls.

The alt only makes Amps available. The regulator usually only determines Voltage, actual amps accepted is set by the batt.

Stock alts rarely do stages as per what the batt needs. These days fuel efficiency is often the goal.

Smart VRs like Balmar MC-614 can reduce amps available in order to protect the alt.

And allow you to vary the setpoints.

> In contrast, my charger (set for AGM) seems to use 14.3v or 14.4v (can't remember) for bulk & absorption, and 13.3v for float. I assume this is what you mean by only two set points but three stages

Exactly. My point was only the Float transition is determined by the charge source, not the one from Bulk to Absorb.

[john61ct]

Originally Posted by Exile

So btwn bulk & absorption the charger is maintaining CV but backing off on amps to avoid overheating the batts?

No, CV is Absorb. CC is Bulk.

Very few charge sources allow for derating current, Balmar MC-614 is one.

The alt overheating is the usual reason.

Temp compensation varies voltage.


> I also think I got confused when Maine Sail posted awhile back about there needing to be a 0.1v difference bwtn bulk & absorption.

That is only under Balmar's misuse of the terminology and triple setpoint idiosyncracies.

[john61ct]

All this is further confused by the fact that (some) VRs, although actually only regulating voltage as perceived from the outside, are in fact doing so by varying current internally, thousands of times per second.

Best to just ignore that fact, treat the VR as a black box, that 99.99% of the time only regulates output voltage.

[a64pilot]

Forget all the terminology and technology for a minute.
Low battery bank first thing in the morning, you crank the engine and the alternator puts out all that it can make, battery could absorb more cause it’s low in charge, but the alternator just can’t make more.
This continues with the voltage slowly rising until the amount of power that the alternator can make exceeds the ability of the bank to absorb the power, from this point on the voltage set point has been reached and is maintained and as the bank gets fuller and fuller, the current continues to decrease, until reaching usually a timer and then the regulator goes into float, whether the bank is full or not.
A “dumb” regulator keeps on chugging along, it has only one set voltage.

The time that the alternator isn’t big enough to reach voltage set point is called Bulk.
The time that the alternator can make more power than the bank can take and voltage is controlled to prevent overcharging is called absorption.
Once the regulator times out and drops to a lower maintenance voltage, this is called float. Float is not meant to charge, it is meant to power accessories off of the alternator and to not discharge the battery.

[a64pilot]

If you had an infinitely large alternator, there would never be any bulk

[Exile]

OK, this all makes a lot more sense. Thanks.

[john61ct]

Originally Posted by a64pilot

Forget all the terminology and technology for a minute.

hmm

> Low battery bank first thing in the morning, you crank the engine and the alternator puts out all that it can make, battery could absorb more cause it’s low in charge, but the alternator just can’t make more.

Rephrase, either the bank is accepting all that the alt puts out, or the batts acceptance is the limiting factor.

> This continues with the voltage slowly rising until the amount of power that the alternator can make exceeds the ability of the bank to absorb the power,

Almost, the voltage rises, maybe very fast with high current, until the VR setpoint is reached, at which point you've gone from CC/Bulk into CV/Absorb, and as you say, the VR is preventing voltage from climbing.

> and as the bank gets fuller and fuller, the current continues to decrease, until reaching usually a timer and then the regulator goes into float, whether the bank is full or not.

Yes, but with a good (adjustable) VR that should be adjusted by the owner to ensure that only happens after Full endAmps has bee reached.

> A “dumb” regulator keeps on chugging along, it has only one set voltage.

Very dumb.

> The time that the alternator isn’t big enough to reach voltage set point is called Bulk.

Not "isn't big enough", relates to other factors as well. Yes time is shorter with higher current available. LFP may be considered Full as soon as setpoint is reached, usually well over an hour of charging.

> The time that the alternator can make more power than the bank can take and voltage is controlled to prevent overcharging is called absorption.

The time between the Absorb setpoint V being reached and dropping to Float.

> Once the regulator times out and drops to a lower maintenance voltage, this is called float.

Whatever causes the VR to drop to the Float setpoint V or below, is Float

> Float is not meant to charge, it is meant to power accessories off of the alternator and to not discharge the battery

Many people think there is still charging going on, but that is because the drop to Float happened way too early.

Done properly, current into the bank is insignificant, also outbound, until Loads amps are higher than the source is delivering.

A regulator bringing volts back up to Absorb setpoint more quickly when that happens, would be better for the bank longevity than one that waits longer to do so.

Ideally preventing another cycle from occuring.

[john61ct]

Originally Posted by a64pilot

If you had an infinitely large alternator, there would never be any bulk

No, it would just be very short.

Low acceptance chemistries like FLA make it that bit longer than say AGM.

Of course that high you'd need such high gauge connection you'd sink the boat 8-)

[Standbly]

To stirr things up and at the same time be very serious... My advice would be: Buy 65 amp car (automotive) batteries. Put them in parallel to ad up to your desired amperage. Do not pay more than 1,20 per AMP!

These automotive cheap ass batteries are produced by the millions, so their price is low. They last about two to three years. If you get a good deal from the automotive dealer, they are in warranty for at least 2 or 3 years.

What-could-possible-go-wrong is what I asked myself before I actually bought them. Well. Nothing! Don't heel with them above 70 degrees and you're fine.

reminder 1,20 or less per amp... beat that.