What count as a cycle (battery life)

[sailinglegend]

Originally Posted by geoffschultz

Based upon what I read in the LifeLine Manual: "The charging current during the Bulk state should be set as high as practical; higher current means faster charging and less time for the plates to become sulfated......"

....higher current means faster charging and less time for the plates to become sulfated....

Nowhere in the manual do Lifeline say this about sulfation!!!!!

They do say ".. if the output current is less than 0.2C the cycle life may be negatively affected..."

I should add that I have never been able to charge my 1050Ah Lifeline bank at 0.2C - and my bank is in it's 13th year as a liveaboard - with only 120 amp shore power charger and 140 watts of solar charging.

[john61ct]

All it takes is money

[Exile]

Re: the 0.2C recommendation, namely that the charger capacity should approximate 20% of battery AH. My house bank consists of two 8D's, each with a 255AH rating so 510AH total. My charger (Xantrex XC5012) is only 50A but senses which of the two batteries requires charging and applies that charge to each one at a time. So I've always assumed I am approximating the 0.2C recommendation since I'm essentially using a 50A charger on a 255AH battery at any given time.

Is this correct? Do most modern batt. chargers operate this way?

[a64pilot]

I think your charger has the capacity to charge two banks which means if one is low then it will charge the one that needs it and not the one that doesn’t.
However if both are low, then it charges both, of course it has to split the capacity to do so, in your case most likely 25 amps into each.
I have two banks, but leave them interconnected with the switch set to both, so my charger that also has the capacity to charge independent banks charges both, but as they are interconnected, it’s really one bank.
I suspect you really have one bank also so the effect is the same as if your charger only could charge one bank.
We haven’t realized any advantage of separate bank charging.

[Exile]

A FYI for those with Lifeline AGM's:

My older Xantrex charger is not set up for equalizing AGM's, probably because Lifeline is the only AGM mfg. (that I'm aware of) which allows & encourages equalizing. My charger has an equalization function for FLA, but it has no sensing ability and so does it with a one-hour timer function, relying on use of a hydrometer (sp?). This is not possible, of course, with sealed AGM's.

So I contacted Lifeline for advice and they recommended I purchase a 25A portable charger made by CTEK for equalizing/conditioning. It automatically senses when the batts. have completed their equalizing/conditioning cycle and then reverts to float. I make sure the batts. are topped off with my main charger and then use the CTEK on each battery individually every few months. It doesn't seem to take very long when the batts. are otherwise healthy, and there's no real need for monitoring (although I stay onboard & periodically check on them anyway). I don't recall the CTEK being all that expensive and it also serves as a backup.

[Exile]

Originally Posted by a64pilot

I think your charger has the capacity to charge two banks which means if one is low then it will charge the one that needs it and not the one that doesn’t.
However if both are low, then it charges both, of course it has to split the capacity to do so, in your case most likely 25 amps into each.
I have two banks, but leave them interconnected with the switch set to both, so my charger that also has the capacity to charge independent banks charges both, but as they are interconnected, it’s really one bank.
I suspect you really have one bank also so the effect is the same as if your charger only could charge one bank.
We haven’t realized any advantage of separate bank charging.

My two house batts. are also paralled via a switch that I always leave set to both, but are not wired in parallel together. So my understanding (could be wrong) is that the switch only affects batt consumption/distribution but not the charging side. IOW, the charger decides which batt to charge regardless of where the switch is set. Does this make any sense?

My charger has the usual 3 ports with separate wires (and temp sensors) going to each battery (the 3rd going to my eng start batt). According to the manual and the readout on the charger itself, it definitely only charges one battery at a time and doesn't split the charge, although I'm not exactly sure how & when it decides which battery to charge when more than one are low. As far as I can tell from reading the manual and observing the readout, I think it's a combo of sensing and a timed cycle.

[john61ct]

Originally Posted by Exile

Re: the 0.2C recommendation, namely that the charger capacity should approximate 20% of battery AH. My house bank consists of two 8D's, each with a 255AH rating so 510AH total. My charger (Xantrex XC5012) is only 50A but senses which of the two batteries requires charging and applies that charge to each one at a time. So I've always assumed I am approximating the 0.2C recommendation since I'm essentially using a 50A charger on a 255AH battery at any given time.

Is this correct? Do most modern batt. chargers operate this way?

No, that's very rare afaik

Good article here

https://www.practical-sailor.com/iss...ry/5245-1.html

Not intended to accommodate the C rate issue, designed to handle separate banks with different chemistries, not sure I'd try charging paralleled same-bank members separately?

[john61ct]

For a single bank best to just buy a big enough charger, or stack multiple ones in parallel.

[Pete7]

Originally Posted by geoffschultz

Anyhow, almost all of my charging of my 2 Lifeline 8D AGMs is done via solar and wind at a relatively low charge rate (10-20A). Most mornings the batteries start out at 12.8 and by noon are at 13.2 via just solar. If the wind is blowing, my Morningstar Tristar controller brings them up to 14.2 (average temp 85F). -- Geoff

Geoff, how long have you been using this charging regime? does everything appear okay? I would be tempted to leave it alone and just go sailing because to achieve a 0.2c charge rate for a pair of 8Ds is going to take some solar.

[Exile]

Originally Posted by john61ct

No, that's very rare afaik

Good article here

https://www.practical-sailor.com/iss...ry/5245-1.html

Not intended to accommodate the C rate issue, designed to handle separate banks with different chemistries, not sure I'd try charging paralleled same-bank members separately?

Both the XC5012 and the Lifelines were professionally installed about 8 years ago, and the boat has been mostly plugged into shore power with the charger running 24/7. The charger is still going strong but I recently had to replace the batts.

But you're right that the charger appears more designed for different batt chemistries which I don't have. It has now been supplanted by the Xantrex TrueCharge2. I'd be curious if this newer model also has this "multiplex" feature.

[a64pilot]

When your battery switch is set to both, the batteries are connected together electrically, very much as they would be if wired in parallel.
It’s not possible to charge a battery independently with them connected by the battery switch.
Of course any other selection other than both and you could.

[geoffschultz]

The image below is from the Lifeline AGM manual, page 21. Based upon this, I'm thinking that perhaps I should equalize my AGMs on perhaps a monthly basis.

[a64pilot]

Every 30 days or less.
Less if you never get to 100% SOC.
I equalize monthly for about three hours, if not in a Marina, little Honda is good for this cause it doesn’t take much power and I’d rather put hours on the little Honda as it’s a whole lot easier to replace and cheaper too.

[geoffschultz]

Ok, 1 more question. My solar controllers never seem to go into Bulk charging mode. I assume that it's because the DoD never goes very low. Should they go into Bulk mode or is it OK for them to stay in Float mode?

[a64pilot]

If you never see bulk, something is wrong.
Reason I say that is all bulk is, is that the charge source isn’t big enough to bring the bank up to absorption voltage, and in the morning, early, your only dribbling in a few amps and that can’t be enough to get to absorption voltage, so your in bulk.
If your not seeing that, then something is wrong.

Bulk, as I understand it is not really a different phase, charger is set to absorption voltage, just can’t get there, when it can, no settings change (usually) just now your in absorption and most chargers start a timer, cause now your supplying all that a bank can accept.

Now for some odd reason Balmar with the 614, you can set a different voltage for bulk, I don’t understand the need, and at least what I read in the Lifeline Manual doesn’t support this, so I set bulk voltage to absorption voltage.