Smartgauge w/ 3 batterys

[Exile]

Originally Posted by Exile

On my boat, every time my charger goes into float I get amp readings that are within the 0.5%C that Lifeline specs for 100% SoC, so it appears to be transitioning from absorption to float correctly.

Originally Posted by john61ct

That is only the case if that low current is at Absorb voltage, before the transition to Float.

Think of voltage as "pressure", higher V forcing higher A flow.

Ah Ha! A little late, sorry, but I finally got it. I would really need to flip the charger on & off to force it back to absorption, and then look at the amp reading. Thanks.

[sailinglegend]

Originally Posted by Exile

.....Btw, I'm impressed with the 13-year life span on your Lifelines, especially since I believe you wrote that you were on the hook full-time. How do you manage getting them charged back up to 100% every couple of weeks?

One secret is that my bank is 1050AH but with no regular large current drains, so the Peukert effect with an average draw of 10 amps means my bank can really deliver about 1500Ah. This means I only discharge to maybe 75% before motoring.

We only have 140 watts of solar and a 400W DuoGen Wind/Towing generator so we could last a week at anchor before running the DC genset which charges at 280 amps.

We always find shore power every two weeks to get back to 100% overnight, but make sure we are up to 85% from the genset before we go on shore power to guarantee that we get to 100%. No point in going to a marina or a town quay at 2000hrs with a flat battery and expect it to be fully charged by 0800hrs.

Originally Posted by john61ct

Note that industry standard is to scrap a bank when AH capacity has fallen to 80% of rated. Many owners keep it working way past that.

Lifetime is much longer if 100% Full is achieved nearly every cycle.

Lifeline say replace at 50% of rated capacity- my bank was down to 55% at the start of the season.

Lifeline, or any AGMs, don't need to be fully charged each cycle. That is a common misconception on here. As Lifeline says they are like ANY other lead acid battery and should be charged to 100% regularly. Every cycle is good, but every 1-2 weeks is ok before the salvation starts to permanently harden. I also equalise my AGMs twice a year.

[john61ct]

Sulphation 8-)

Yes Lifeline's really a class act, great stuff.

I'd love to see data on only getting to Full twice a week as opposed to every cycle.

With high amps on demand, I'd personally set up a routine to shoot for the latter, combining the morning charging with water or ice making, hor water, laundry, holding plate fridge. . .

But hard to argue with 13 years 8-)

[sailinglegend]

Originally Posted by john61ct

.....I'd love to see data on only getting to Full twice a week as opposed to every cycle.....

But hard to argue with 13 years.

A well setup cruising boat should have enough capacity to last a week with two cycles of 100-50%. Charging everyday is madness!!!!!

Bigger is better and more cost effective over the life of the bank, especially after 13 years.

[Exile]

Originally Posted by sailinglegend

One secret is that my bank is 1050AH but with no regular large current drains, so the Peukert effect with an average draw of 10 amps means my bank can really deliver about 1500Ah. This means I only discharge to maybe 75% before motoring.

Very interesting to me and my house bank of two Lifeline 8D's at 510 rated ah. I gather your house bank is 4 8D's with perhaps no separate eng/gen start battery? By "no regular large current drains," do you mean no 12v fridge and/or a wind vane vs. AP? Don't understand how the Peukert effect increases capacity over rated ah but you guys are way ahead of me on the techy stuff.

We only have 140 watts of solar and a 400W DuoGen Wind/Towing generator so we could last a week at anchor before running the DC genset which charges at 280 amps.

I have yet to figure how to get more than 100-150w of solar fitted onto my boat so I'm also not likely to avail myself of the otherwise good advice to let solar get the batts. from 85-100% after a morning charge with engine or genset. How's the DuoGen held up? Seemed like a great idea but when I looked into it awhile back there were reported problems with failed bearings, crummy customer service, etc.

We always find shore power every two weeks to get back to 100% overnight, but make sure we are up to 85% from the genset before we go on shore power to guarantee that we get to 100%. No point in going to a marina or a town quay at 2000hrs with a flat battery and expect it to be fully charged by 0800hrs.

DC gensets always seemed to make a lot of sense to me, at least in concept.

Lifeline say replace at 50% of rated capacity- my bank was down to 55% at the start of the season.

Glad you mentioned this since I had assumed 80%. Mine are now 7 years old and seemingly in good shape (need to test), but it was recently recommended I just replace before any significant passage. If I do a capacity test and they have a reasonable margin above 50%, are they subject to sudden/total failure or will they wind down at a more measured pace?

Lifeline, or any AGMs, don't need to be fully charged each cycle. That is a common misconception on here. As Lifeline says they are like ANY other lead acid battery and should be charged to 100% regularly. Every cycle is good, but every 1-2 weeks is ok before the salvation starts to permanently harden. I also equalise my AGMs twice a year.

Interesting, and contrary to what I've read -- mainly from the lengthy series on care & feeding on Lifelines from the Morgan's Cloud/Attainable Cruising site. Those folks do a lot of high latitude cruising and are mostly genset & engine dependent for charge sources I believe. They have high load demands so work their batteries hard, and make up for not getting back to 100% regularly by equalizing more frequently. They're happy if they get about 4 years out of their Lifelines.

[Exile]

Originally Posted by sailinglegend

A well setup cruising boat should have enough capacity to last a week with two cycles of 100-50%. Charging everyday is madness!!!!!

Bigger is better and more cost effective over the life of the bank, especially after 13 years.

For these reasons, I have long wanted to move my 3rd Lifeline 8D that I think is inefficiently devoted to engine starting over to my house bank, for a combined rated ah of 765. Some complexities involved, but perhaps only in my own mind. A topic for a different thread . . . .

[john61ct]

The last X% for 3-4 hours is low amps, very doable with just a couple panels.

AH ratings are at the 20-hr discharge rate. Peukert means lower rate is many more AH, higher rate a lot less.

Bigger the bank shallower the draw, lot linear but exponential.

[Exile]

Originally Posted by john61ct

The last X% for 3-4 hours is low amps, very doable with just a couple panels.

AH ratings are at the 20-hr discharge rate. Peukert means lower rate is many more AH, higher rate a lot less.

Bigger the bank shallower the draw, lot linear but exponential.

Probably only doable on my boat at anchor. I'm typically burning ~12ah while underway (under sail), btwn. AP, electronics, nav. lts. at night, incidentals. Which is why hydro looks attractive to me.

For anchor, have you looked at Power Film? PowerFilm - lightweight, thin, flexible solar panels. Hugely expensive for their larger panels, but high quality mil-spec. As usual there are cheapos but nothing seemingly in btwn. The idea would be a rollable or foldable that can easily be stored below but draped over the boom with grommets & lines at anchor. More durable I believe than traditional flexibles but at a cost.

[daletournier]

Originally Posted by Exile

For these reasons, I have long wanted to move my 3rd Lifeline 8D that I think is inefficiently devoted to engine starting over to my house bank, for a combined rated ah of 765. Some complexities involved, but perhaps only in my own mind. A topic for a different thread . . . .

For exactly the reasons stated above I now combine my three and keep a lithium jump battery in charged, and also have generator that can be used to get a flat bank going if I screw up.

[sailinglegend]

Originally Posted by Exile

[COLOR="navy"]Interesting, and contrary to what I've read -- mainly from the lengthy series on care & feeding on Lifelines from the Morgan's Cloud/Attainable Cruising site....

I have been a regular contributor to that site - subscription only - and that is where I got my quote form Lifeline's Justin Godber who said that AGMs are just like any lead acid battery regarding cycling and charging.

Even with a big house bank I still have a very small Red Flash AGM (35Ah) for the starter - which is also 13 years old - starting a 56 HP Yanmar engine.

[Exile]

Originally Posted by daletournier

For exactly the reasons stated above I now combine my three and keep a lithium jump battery in charged, and also have generator that can be used to get a flat bank going if I screw up.

I've also had one of those lith jump batts onboard for awhile now. Excellent piece of kit. Can start the engine in a pinch, USB's for devices, and holds its charge for a long time. I just keep it plugged in all the time. Wasn't even very expensive (for a change).

[Exile]

Originally Posted by sailinglegend

I have been a regular contributor to that site - subscription only - and that is where I got my quote form Lifeline's Justin Godber who said that AGMs are just like any lead acid battery regarding cycling and charging.

Even with a big house bank I still have a very small Red Flash AGM (35Ah) for the starter - which is also 13 years old - starting a 56 HP Yanmar engine.

Well, I've been more of a lurker on that site for years - since pre-subscription days - and at $10/year it was a no-brainer to stay subscribed. A lot of very smart & knowledgeable long-distance sailors make valuable contributions, and John runs a tight ship! I need to go back & review -- seems like I might be confusing conventional wisdom re: AGM's generally vs. Lifelines which, as you know, have some distinct features & parameters. I am encouraged by the longevity you have enjoyed.

In addition to my three 8D's (one for start; two for house), I also have a G24 Lifeline for genset starting which I could also theoretically use for engine starting as well. The listed CCA actually exceeds what my Westerbeke manual specs for my 82B engine, but then there's age, cable run, possible corrosion, etc., so I think probably a G31 would be a safer bet but no room in the box. Certainly an 8D seems like overkill for doing nothing but starting an 80hp engine but that's what I inherited. Along with my lithium jump batt, I also have relays where I can bring in the house bank to supplement engine or genset starting, so the G24 might be OK. I've also noticed from their website that Lifeline is offering G24, 27 & 31 AGM "start batts" which list higher CCA's than their identically sized "deep cycle" AGM's.

Marine Batteries - Lifeline Batteries

[transmitterdan]

Originally Posted by sailinglegend

I have been a regular contributor to that site - subscription only - and that is where I got my quote form Lifeline's Justin Godber who said that AGMs are just like any lead acid battery regarding cycling and charging.

Even with a big house bank I still have a very small Red Flash AGM (35Ah) for the starter - which is also 13 years old - starting a 56 HP Yanmar engine.

I think Justin is talking about lifeline batteries. He is not talking about all other AGM batteries. AGM batteries suffer from the same woes as regular flooded batteries if not charged to full on a frequent basis. But as far as I know lifeline says their batteries can be equalized. Other AGM manufacturers say not to do it. So for those other brands cycling to full frequently is the only sanctioned way to extend AGM battery life.

I had some lifeline batteries that came with our boat. Charger got into equalize mode and the battery cases bulged something terrible. Equalizing batteries must be done with the right care and attention.

[john61ct]

Yes AGM requires **more** diligence than flooded getting to 100% Full as often and quickly as possible to maximize lifespan.

Firefly Oasis is the only exception in the lead world, very tolerant of PSOC abuse but $500+/AH.

High charge rates (.4C and up) also help when available, true for all four quality makes.

And yes Lifeline is the only one left encouraging equalization.

Odyssey and Northstar are the other two good ones.

[sailinglegend]

Originally Posted by john61ct

Yes AGM requires **more** diligence than flooded getting to 100% Full as often and quickly as possible to maximize lifespan....

What is your source of this comment - references please.