Batteries

We have used lifeline batteries for our powerboats and sailboat couldn't be happier maintaince free.little more exepensive than other brands but well worth the investment

I was told my charger should have a switch for AGM or standard lead acid, and not to use the wrong setting. That implies to me I can't just switch to AGM without the proper AGM charger...?

Hard to add anything very useful without that further info from Scott...

-Chris

Depend on your charger. Some older charges may have only two "settings" (charging profiles), for example, one for lead acid/AGM and one for gel cells. Newer charges often offer several profiles so you can better select one that comes closest to the recommendations your specific battery maker suggests.

Are your charger and battery manuals not helpful? If not, or if you don't have those, you can sometimes get info about your specific products direct from each of those maker's websites.

-Chris

New boat, lots of manuals to read, lots of minor issues to tend, so I haven't read that manual. I don't even know yet how healthy my batteries are, they look good visually and have held charge well so far. I'm not interested in switching from regular lead-acid, so haven't worried about a switch for AGM or gel. I'm pretty sure if I flipped such a switch, I'd have to commit to switching all my battery banks over, which is not going to happen. The online manual for the current version of my charger indicates it does have a switch.

With AGM once you get sulfation of plates it's pretty much done because they can't handle the high voltages needed for desulfation that is typically needed when doing an equalization charge. I use good old lead acid batteries and once a year or so put them through an equalization charge (16.5v) while monitoring the electrolyte. You can get 8-10 years out of them if properly maintained by not discharging below 50%.

Lifeline recommends periodic equalization for their AGM batteries.

-Chris

If you've been satisfied with Lifeline AGMs, I'd suggest you consider staying with them. That (being satisfied) should indicate your system (batteries, plus charger, plus inverter, plus everything else connected) is probably well-matched. That should mean your charger is likely already sized to be able to take advantage of AGM's faster charge acceptance rate, etc.... whereas if you switched battery brands it might not be.

(Lifeline recommends a minimum of C/20 charging capacity (20% of a bank's capacity), but Odyssey, for example recommends a minimum of C/40 charging capacity. If your charger is well-matched to your two-8D bank, that suggests it's a 100-amp charger or larger.)

You are likely also already aware of the maintenance-free and reduced off-gassing advantages of AGMs. And assuming you've gotten good service life from your current batteries, that suggests you've properly re-charged you banks to 100% as quickly and as often as possible after cycling.

The only new technology that would bring more advantages is LiFePO4... but I've read that is absolutely not a drop-in solution, and requires much more in the way of well-matched battery management system (BMS), etc.... and it's all at great cost (relatively) so far.

Practical Sailor Magazine published some testing, 2015 Ithink, May and June issues I think -- Lifeline and Odyssey were the two "regular AGM" brands they recommended. Firefly Carbon Foam AGMs (only available in Group 31 size) gave impressive results relative to partial state of charge (PSOC) operations.

IOW, my guess is that you're already where you want to be.

Ref "We all understand..." -- fair enough, in your case, but apparently many do NOT understand that batteries and chargers perform best when all system components are well matched.... and it was not obvious to me in your first post that you're one of those who do understand.

-Chris

Some chargers just can't.

-Chris

Not stupid, no worries, we are all learning one thing or another.

Equalization is when you basically overcharge the batteries once they are fully charged in an effort to re-establish the capacity of the battery back to what it was when or close to new. This can only be done to lead acid batteries and it's normally at a voltage of 15.5-15.75 volts for a period of time while monitoring the specific gravity and temperature of the electrolyte in the cells. Each manufacture will have an equalization procedure for their batteries.

The purpose is to remove the build up of chemicals that occurs on the plates each time the batteries are discharged by literally boiling them off the plates. They call this build up sulfation because the plates actually get coated with sulfates.

With time if a lead acid battery is not equalized it'll start to loose capacity. So say you had a 100 amp battery that you typically pulled 50 amps from (50% discharge) and when that was done the voltage of the battery was 12.2 volts. What will eventually happen is that it will get to 12.2 volts when less amps are pulled. For example, if only 25 amps are pulled from the battery and you're at 12.2 volts you now have lost capacity. If you continue to pull current from the batteries past 50% discharge (typically 12.2 volts for most batteries) you're now shortening the life of the battery dramatically. In this example you lost 25 amps usable capacity from the battery...

Equalization doesn't always work on older batteries because the longer the sulfates stay on the plates the harder they are to boil off. Normally it's a process that is done at a some time interval depending on usage and some higher end chargers have this feature built in to the charger.

Just survey a boat with 10 8D Lifeline AGM's which were new in 2012. After reviewing the maintenance records the 4 house batteries were replaced in 2015 got my attention. Hard to justify to more than double the cost for AGM's vs wet cell with no increase in longevity. Several years ago a large battery store in Lauderdale told me they have not seen any better performance with AGM's in marine applications than their inexpensive brand of wet cell 8D's. Maybe good in hard to get to areas or where acid spillage could be more likely?