Do AGMs have more usable capacity than regular Flooded?

[dmkkeng]

Originally Posted by newhaul

Side note for everyone in this situation or considering it in the near future .
Lfp prices are falling rapidly
Mind you these numbers are from the ev market but will apply to us similarly
That figure now stands at roughly $137 per kilowatt-hour, and likely to plunge to about $100 per kilowatt-hour in the next couple of years,
It was well over $1100 per kwh 10 years ago.

Other than the cost of the actual batteries, you may also need to include the cost of upgrading your various charging systems.

[newhaul]

Originally Posted by dmkkeng

Other than the cost of the actual batteries, you may also need to include the cost of upgrading your various charging systems.

And what upgrades are needed aside from resetting your solar controller to a new ( in my case 13.8v) charge stop setting?
And possibly adding a b2b to protect your alternator ? Or a programmable external regulator for same ? Most have these items already on board.

[newhaul]

Originally Posted by dmkkeng

Other than the cost of the actual batteries, you may also need to include the cost of upgrading your various charging systems.

Question what is your current lfp installation?

[dmkkeng]

Originally Posted by newhaul

And what upgrades are needed aside from resetting your solar controller to a new ( in my case 13.8v) charge stop setting?
And possibly adding a b2b to protect your alternator ? Or a programmable external regulator for same ? Most have these items already on board.

Its more than just voltage, the charging profile for lithium batteries is different. There is a good chance the only profile choices that you have with your existing charging systems are Flooded, AGM or Gel.

[newhaul]

Originally Posted by dmkkeng

Its more than just voltage, the charging profile for lithium batteries is different. There is a good chance the only profile choices that you have with your existing charging systems are Flooded, AGM or Gel.

Full disclosure. Retired shipwright service provider.
I used to install these setups for specific customers and yes they are still happy and friends.

My own system is as follows
250ah lfp cells in a 1p4s with a 200 amp Daly bms with active top balancing.
200 watts rigid solar 200 watts flex running via a 30 amp pwm solar controller set to 13.8v
Soon to have a westerbeke 10 two with a 55 amp alternator, small fla start battery and a 40 amp b2b set to 14.1v to charge lfp when needed/ motoring anyway. With a manual shutoff of sense wire to alternator that will also power the renogy 40 amp b2b . ( this is to protect my alternator from melting .
Also I have a 10 amp charger just to keep the start battery charged if I am ever on shore power.
So no I don't just have the options you stated and I am willing to put good money on most people with solar having similar charge controller adjustments available.
If not they need to upgrade solar controller anyway to set for agm specific charge profile

[merrydolphin]

If you really want to see a difference, go Lithium. More money but probably worth it in the long run. Thats’ the way I’m going next time.

[Adelie]

How would it be worth it?
I can see it if you are very weight limited.
I can see if you needed really high output currents.
I can see if you have limited solar and nothing else so you can’t afford to waste any watts at all.
In terms of bang for the buck, FLAs are almost twice as good. More if you count ancillary costs for new regulator and maybe a new plug in charger.

[newhaul]

Originally Posted by merrydolphin

If you really want to see a difference, go Lithium. More money but probably worth it in the long run. Thats’ the way I’m going next time.

Actually not that much more expensive than good quality fla in upfront costs .
Where you really begin to see the $ advantage of lfp is at the 4 to 5 year mark when your fla have died for whatever reason ( lack of maintenance, chronic PSOC, or just plain old use.)

Leaves you buying new fla batteries again . The lfp are at this point just really getting broke in and hitting their stride.
As to the ancillary items well resetting your solar charge controller to stop charging at 13.8 or so instead of 14.5v ( which is a bit higher than I want to charge my lfp but still within specs ) and possibly a new shore power charger . ( many that have been available for the last decade have an lfp setting)
Also something that will regulate the amp output of your alternator to protect it .
In my case it required a 40 amp b2b that is on sale now for $149.00 USD. ( it will regulate the output to the house to 14.0v and 40 amps ) protecting my alternator .

[T1 Terry]

This nonsense about having to replace all the lead acid battery charging equipment if you change to LFP batteries was spread by the lead acid battery resellers .... and for good reason, they would loose that constant repeat sale and eventually shut up shop. That will happen anyway, only a few lead acid battery sellers who look after a specialist market will remain. I guess the buggy whip makers went through the same changes in the market pace, but denial didn't help them so I doubt it will help the 19th century technology battery makers either.
If the gear you are using is quality stuff, the charging parameters are adjustable and they will handle the constant high current a lithium battery will accept until it is fully charged. If your equipment is not quality stuff and they are claiming outputs they can't really maintain, the lithium battery will kill them.

If you look back across the yrs, lead acid batteries have never been cheaper than they are now .... but they lasted a lot longer back then so ..... could it be they are cheaper for a very good reason?

The original question was, "Do AGM batteries have more capacity than regular flooded" Genuine capacity matched, no, weight matched, no ... well maybe 1 or 2 kg but the electrolyte is that heavy. It takes 30kg min of lead to make a 100Ah (@ C20 rating) 12v deep cycle battery ... they don't and never have made light weight lead. If the 100Ah 12v battery weights 32kg (70lb) then it is a 100Ah 12v lead acid battery, if it weighs less than 30kg, it is not a deep cycle 100Ah (@ C20 rating) 12v battery no matter what the sticker says .....
Start batteries are not deep cycle batteries, even if the man at the battery shop said they were the same thing, they are not. Try to use a start battery as a deep cycle battery and it will get a short cycle life. Try to use a deep cycle battery as a start battery and it will not get the cycle life it would have achieved as a well maintained deep cycle battery. Yes, they can do both jobs, but that was not what they were designed to do and the cycle life will suffer as a result.

T1 Terry

[sailinglegend]

Originally Posted by T1 Terry

This nonsense about having to replace all the lead acid battery charging equipment if you change to LFP batteries was spread by the lead acid battery resellers ....

If the gear you are using is quality stuff, the charging parameters are adjustable and they will handle the constant high current a lithium battery will accept until it is fully charged....

And by another...

Originally Posted by dmkkeng

Other than the cost of the actual batteries, you may also need to include the cost of upgrading your various charging systems.

This is an AGM thread - and if you change from FLAs to AGMs you WILL have to 'upgrade your various charging systems' because of the much higher charging currents demanded by AGMs. So a higher amperage charger will be needed and probably a new hot-rated alternator with an external regulator. A standard automotive alternator is not designed to deliver high charging currents for extended periods - it will overheat.

Originally Posted by dmkkeng

Its more than just voltage, the charging profile for lithium batteries is different.

It's all about voltage!!!!!

Both AGM - and Lithium chargers - must be multi-stage devices that start by offering a set voltage delivering a constant maximum current that the charger can deliver. When the set voltage is reached the charger changes to a constant voltage device and the current the battery can draw will fall. After a pre-determined time, or a 'Smart' choice by the charger, it changes to a lower voltage in 'float mode'. Lithium batteries don't need this 'float mode' setting.

Never buy a charger for a cruising boat with only dip switches for FLA, AGM, and GEL as modern batteries all have different voltage requirements, a new AGM charger must have custom profiles for changing these settings.

[Sailing4Jesus]

Shipmates,

I am wondering if any of you know anything about the New Batteries such as Telsa uses, if there is hope for us yachtsmen that sometime in the near future we will see a complete New Type of these batteries be offered in a type suitable for the Marine Industry? Certainly there ought to be hope for us also. Because that I will be Seventy-Seven day after tomorrow I probably will not be here to see that, but I can at least Hope for you younger yachtsmen.

One great advantage of living aboard one's own yacht is that if you are so unlucky as to have a neighbor who is a jerk, you only need to weigh anchor and move. Houses are not so easily moved.

Chauncey M. "BUDDY" Freeman
Senior Chief, U.S.NAVY, RETIRED

[newhaul]

Originally Posted by Sailing4Jesus

Shipmates,

I am wondering if any of you know anything about the New Batteries such as Telsa uses, if there is hope for us yachtsmen that sometime in the near future we will see a complete New Type of these batteries be offered in a type suitable for the Marine Industry? Certainly there ought to be hope for us also. Because that I will be Seventy-Seven day after tomorrow I probably will not be here to see that, but I can at least Hope for you younger yachtsmen.

One great advantage of living aboard one's own yacht is that if you are so unlucky as to have a neighbor who is a jerk, you only need to weigh anchor and move. Houses are not so easily moved.

Chauncey M. "BUDDY" Freeman
Senior Chief, U.S.NAVY, RETIRED

Actually there are many of using rhe tech now personally i am running 250ah lifepo4 as my house bank charged off solar and wind .
Rob HTCS Retired