Why are so many in Love with AGM's

[Adelie]

Originally Posted by EarlWer

I have a new/old boat with no batteries.
Installing 340W of Solar Panels and Victron MPPT.

I am getting very high prices for FLA ($450) and AGM ($595).

If I shop for FLA at the local battery shop, what am I looking for?
Deep discharge?
GolfCart (seems only available in 6v)
any specific manufacturer?

thanks

Golf cart. More likely to actually be a deep cycle battery rather than a hybrid or starter battery that somebody has slapped a new label on.
Trojan in my area is a good compromise between brand name and price.

[atoll]

any idea what to set the temperature compensation at on a epaver solar controller with a MT 50 remote,i have a bank of 3 odyssey extreme 31-pc2150 12v 100ah float 13.7 bulk 14.7 and it is reccomended that voltage never rises above 15 v,temp range here about 0C to 25C?

[rslifkin]

Originally Posted by atoll

any idea what to set the temperature compensation at on a epaver solar controller with a MT 50 remote,i have a bank of 3 odyssey extreme 31-pc2150 12v 100ah float 13.8 bulk 14.7 and it is reccomended that voltage never rises above 15 v,temp range here about 0C to 25C?

Odyssey specs 24mv per degree C for a 12v battery. So for every degree above 25C at the sensor, it'll drop by 24mv, every degree below will increase by 24mv.

[atoll]

Originally Posted by rslifkin

Odyssey specs 24mv per degree C for a 12v battery. So for every degree above 25C at the sensor, it'll drop by 24mv, every degree below will increase by 24mv.

thanks was not sure how it worked,i recently blew up an inverter with the T105's in equalization mode at 15v .
will change the settings for the new batteries

is 13.7 and 14.7 ok for float and bulk,could go to 13.8 and 14.8 looking at the specs on the battery casing?

[silkie]

Originally Posted by sailinglegend

He shows this diagram of the 0.2C and 0.4C charging rates which show getting to Absorption about 4 times faster at 0.4C.



50% SOC @ .4C For 1 Hour = 85% SOC – Exited Bulk @ 19 Minutes

50% SOC @ .2C For 2 Hours = 87% SOC – Exited Bulk @ 1:16

That means the change from Bulk to Absportption is not happing at the same SoC. It also means gettings to 85% SoC at a low 0.2C charge rate is about twice as slow as charging at 0.4C?????

FLAs would be at about 0.1C - so the difference compared with AGMs at a high charge rate is even more dramatic.

So in the real world when the charge current starts to fall it would make sense to stop the genset or engine running sometime after the Absorption stage has started, and then let the solar take over. That would happen about 4 times faster at 0.4C as against 0.2C. FLAs may be charged at 0.1C so the bottom line is AGMs can get to absorption much faster than FLAs.

I'm not saying they can fully charge a bank 4 times faster - I'm just interpreting Mainesail's findings. Lifeline AGMs say they can charge 20% faster than FLAs and I would agree with that. Any saving on genset or engines use surely has to be worth it?

What does C stand for? as in 0.2C

[mitiempo]

Originally Posted by silkie

What does C stand for? as in 0.2C

Capacity. If you are charging a 100 AH battery at .2C you are charging at 20 amps.

[Dockhead]

Originally Posted by Adelie

Golf cart. More likely to actually be a deep cycle battery rather than a hybrid or starter battery that somebody has slapped a new label on.
Trojan in my area is a good compromise between brand name and price.

I agree. I think there is a fairly broad consensus that golf cart batts are optimum lead-acid batteries for cruising boats from a price/performance point of view, fairly long lasting and quite resistant to abuse for moderate price. I like Trojans and am currently using T-105's.

I think however that LiFePo4 are greatly superior in operation and are actually cheaper, given their long life, at least if you don't count the cost of reconfiguration of your charging system as if it were part of the cost of the batteries. I was going to convert my boat to LiFePo4 last year but just couldn't make room in my spring refit schedule for it.

[geoleo]

My 2 200 amp Mastervolt AGMS were getting hot and swollen today . Been there Ok for a year . What could be up with this ? They were bulging 1/2 inch thicker and were about 1.06 degrees. i turned the battery charger off and will check tomorrow . First will check the Charger for correct settings . Is it overchargeing? the voltage was 13.3 volts.

[geoleo]

Originally Posted by georgetheleo

My 2 200 amp Mastervolt AGMS were getting hot and swollen today . Been there Ok for a year . What could be up with this ? They were bulging 1/2 inch thicker and were about 1.06 degrees. i turned the battery charger off and will check tomorrow . First will check the Charger for correct settings . Is it overchargeing? the voltage was 13.3 volts.

106F degrees

[hzcruiser]

Originally Posted by georgetheleo

My 2 200 amp Mastervolt AGMS were getting hot and swollen today . Been there Ok for a year . What could be up with this ? They were bulging 1/2 inch thicker and were about 1.06 degrees. i turned the battery charger off and will check tomorrow . First will check the Charger for correct settings . Is it overchargeing? the voltage was 13.3 volts.

Do you have a voltage monitor that shows you the full history? How high the voltage was in the last few days? That should give you an indication. Such a monitor could also notify you before bad things happen.

Swelling is usually severe overcharging or shorting of a cell. If more than one batt is swollen, I would guess the former.

[geoleo]

Originally Posted by georgetheleo

106F degrees

In the meantime of several days this is the situation. They cooled off to room temp with Charger off. They are still swollen: plastic case is bulged about 1/2 inch out on the sides. They charge up just as they did previously. I ordered a new Battery Charger a 15 amp one -instead of the 25 yo 40 amp one. I now leave boat with charger off . Im keeping my fingers crossed that they are not permanently damaged as the are pricy to replace . another day in boat puzzles.

[Cabo Jim]

A similar situation happened to me while plugged into shore power. The batteries got so hot I could barely touch them. I shutdown the charger immediately. We carried on with our cruising plans and finally gave up when the batteries got weaker and weaker. This was an obvious thermal runaway probably caused by a short in one of the cells.
Scary situation. I would not trust those batteries, time for new ones.

[geoleo]

PO says they are only 1 year old. They cost 950each=1900 and weigh 128lbs each.

[rslifkin]

Originally Posted by georgetheleo

PO says they are only 1 year old. They cost 950each=1900 and weigh 128lbs each.

If they're only a year old, they should be under warranty. Even more reason to consider them suspect (infant mortality happens) and get a known good set.

[Chudacko]

We’re all going to have to get used to the AMG batteries as flooded lead batteries are going to be phased out within 3 years as well as any lead terminal ends.
I have had problems with the early AMG batteries not holding a charge but I have them in other vehicles and those are working just fine. Maybe they improved the design over the last few years.