I don't understand batteries

[Jim Cate]

if you have access to regular 100% recharging , you have little need for batteries at all.

This only works if you have a VERY long shore power cord.

What a silly statement!

Jim

[goboatingnow]

Originally Posted by Jim Cate

This only works if you have a VERY long shore power cord.

What a silly statement!

Jim

I was being facetious. The point being that day boats etc as mentioned gain no benefit from AGMs over simply fitting VRLA wet cells. If you have sporadic use or access to regular recharging , your demands on your battery are not intensive.

Only in very rare occasions have I seen AGMs exploited properly on a Boat

[rslifkin]

Other than a little faster bulk charging and a bit less voltage sag under heavy load my AGMs probably don't gain me a lot compared to flooded cells. But the reduced ventilation and containment requirements plus not needing quick access for watering does mean I have more flexibility in where to mount them, etc. That part is most of the advantage for me.

It also helps that I have enough solar, etc. that it's fairly rare to go more than 1 day without making it to float (based on absorb end amps) and spending a few hours in float. So my system is pretty good at not trashing the AGMs.

Good quality VRLA wet cells just aren't really available in the US, so they're basically not an option. And by good quality I mean heavy plate 6v deep cycles, not the mediocre "marine" batteries commonly seen. My current AGMs are heavy duty L16 6 volts so they should hold up much better than the cheap dual purpose ones.

[Rumrace]

AGM is serious tech. Solved two huge problems which caused failures for less than perfect treatment. They are human tolerant.
It’s not unlike many things with progressive technology. Some of the old stuff is pretty good at its peak.
Early LED lighting was poor then poor became a standard making it harder for quality builders to survive. The quality guys couldn’t stop the public from buying LEDs harmful to them.
I see that happening in lithium and hope the new Windsor, Ontario battery factory has some honest salvation rather than liars and crooks.

[Mike OReilly]

I've always though AGMs were more finicky than good old standard wet cells. Less tolerant of deep discharges, and less able to live with poor charging regimes. They also cost twice as much (or more).

Seems to me the only advantage they have is being able to live on their sides, and not needing as much ventilation. Unless you value these factors, I don't get the desire for them on a boat.

The other advantage of AGMs is they are "maintenance-free", but so are my current batteries. And as the premise of this thread states, these batteries appear to be performing very well.

[ranger58sb]

Originally Posted by goboatingnow

I stand by my opinion based on years of sorting out boat electrics, and my professional expertise, the categories of boats you mention gain nothing by deploying AGMs...

In our case, and especially in many smaller boats I think, I suspect the most used advantages are about off-gassing and physical maintenance. Often batteries are installed in such a way that access is difficult and/or something else needs to be moved out of the way to service wet batteries and/or excessive gassing causes damage to other nearby stuff.

And then some old people (ahem) don't bend too well any more...

And then some old people would rather go boating than yutzing around with batteries (even though yutzing doesn't usually need to happen often)...

As I said earlier, I'm mostly reacting to dogmatic blanket statements that don't leave much room for "it depends" factors...

Originally Posted by goboatingnow

I often see people buying AGMs conflating them with getting a superior wet cell, when in fact if they want good quality cells they should simply buy good quality wet cells.

Agree.

-Chris

[rslifkin]

Originally Posted by Mike OReilly

I've always though AGMs were more finicky than good old standard wet cells. Less tolerant of deep discharges, and less able to live with poor charging regimes. They also cost twice as much (or more).

Seems to me the only advantage they have is being able to live on their sides, and not needing as much ventilation. Unless you value these factors, I don't get the desire for them on a boat.

The other advantage of AGMs is they are "maintenance-free", but so are my current batteries. And as the premise of this thread states, these batteries appear to be performing very well.

That's more or less correct. A good AGM will tolerate deep discharges fine, but they're less tolerant of PSOC cycling without being topped off regularly.



Beyond ventilation, no watering, and mounting, the other advantage is higher charge acceptance in bulk (it still slows down like any lead-acid, but it'll take more at first). And the lower internal resistance that allows high charge acceptance also means they handle short term high loads a bit better than FLA and show a bit less voltage sag. So if you're up-sizing a bank to handle higher momentary draw (but don't really need more capacity), AGMs will require a little less up-size than FLA.



Of course, they do cost more. I keep debating whether I should figure out a good way to mount, vent, and water flooded batteries for my house bank for cost reasons. But I know I'd need a bigger bank than I have now (already considering that anyway) for charge rate and discharge rate decisions. And that assumes I don't decide to go LiFePO4 by the next time I need to buy batteries.

[Rumrace]

It’s just evolving technologies. I just read about a hemp battery showing more promise than lithium. I’m still laughing but who knows. I’ve had so many boats and batteries than I can count.
Years ago I bought the coil batteries from Canadian tire. Had a power boat with twins a 90 and a 130 alt. Top of the line for 96 charger which had a new solar port.
The factory Mercury set up cooked 4 “Marine “ batteries made by Exide labelled CTC. The tire did not honour the warranty. Blamed my alternators running at 14v which were not connected to batteries. Seems battery manufactures like to dodge by pointing fingers elsewhere. I never made it to small claims court. Canadian Tire gave me a refund plus damages out of court.
Don’t shop there. The dealers just sell the company line.
I bought drop in lipos made in Quebec. Don’t care if they fail early. They work great and are perfect 3rd season. They claim it will peak at 200 amps but they are 6x 100, bow bank and two house banks. The little crank for the motors crapped out and a pair of lipos boosted it no worries. It’s just a piece of junk from westmarine.
I had huge German made Gel cells in a SeaRay. Was no roi on them at all over liquid acid but I loved the massive power bank they provided.
I owed several tow motors. We always had one having a battery repaired a charger rebuilt. I scrapped one rather than replace its batteries and bought a new one. Tow motors need the extra battery weight my shipper told me.
My advise is pretty lame because I don’t want to pass on Marine Battery Marketing lies. I just know by practice I avoid all things Chinese. And the guys putting 3.2’s in boxes calling them domestic batteries can bite me. We have this cool 25% tax on Chinese appliances and TVs coming from US that’s making garbage non competitive. And good old Canada Customs stops many smaller equipment batteries from entering the country so it’s certainly looking up. Lots of false UL CSA ULC SAE CE and ETL labelled products out there. We tried to buy an extended battery for a drone and Canada Customs said it was not a legitimate approved product. Got an immediate refund from Amazon.

[Tetepare]

Originally Posted by rslifkin

If it's got openable caps and you can get electrolyte out of it to use a hydrometer then it's definitely not an AGM. Just a plain old wet cell.

Not to beat a dead horse, but NAPA says it's AGM https://www.napaonline.com/en/p/BAT8270

"Thanks to the AGM (Absorbent Glass Mat) engineering, you don’t have to worry about dangerous battery acid spills or corrosion of the terminals, an important feature on a marine battery."

Huh? No spills? But it has caps, I know I lifted them and added distilled water.

According to NAPA the manufacturer is East Penn, so I called them. They said it's flooded, not AGM. So NAPA is lying. Arschlochs.

[rslifkin]

Originally Posted by Tetepare

Not to beat a dead horse, but NAPA says it's AGM https://www.napaonline.com/en/p/BAT8270

"Thanks to the AGM (Absorbent Glass Mat) engineering, you don’t have to worry about dangerous battery acid spills or corrosion of the terminals, an important feature on a marine battery."

Huh? No spills? But it has caps, I know I lifted them and added distilled water.

According to NAPA the manufacturer is East Penn, so I called them. They said it's flooded, not AGM. So NAPA is lying. Arschlochs.

Yup, NAPA's info is definitely wrong. Just looking at the picture screams that it's a standard flooded battery.

[goboatingnow]

Originally Posted by Mike OReilly

I've always though AGMs were more finicky than good old standard wet cells. Less tolerant of deep discharges, and less able to live with poor charging regimes. They also cost twice as much (or more).

Seems to me the only advantage they have is being able to live on their sides, and not needing as much ventilation. Unless you value these factors, I don't get the desire for them on a boat.

The other advantage of AGMs is they are "maintenance-free", but so are my current batteries. And as the premise of this thread states, these batteries appear to be performing very well.

Correct. You make the same case I do. Most people buying AGMs are not in a position to exploit their advantages but are affected by their disadvantages

[Mike OReilly]

Originally Posted by goboatingnow

Correct. You make the same case I do. Most people buying AGMs are not in a position to exploit their advantages but are affected by their disadvantages

Agreed. But I suppose the other benefit mentioned by rslifkin is around batteries placed in poorly accessible locations. I can see the benefit of having an AGM battery in a place that is hard to reach. Especially if this space requires the battery to be on its side.

[CarlF]

As mentioned, AGM's are a poor choice for a house bank for a boat that will not plug into a dock every few nights. PSOC is very hard to avoid at anchor - I've tried.

Flooded are better for most people in this situation.

For the same price as AGM's, Gels are an overlooked option - they accept high charge rates, don't suffer from PSOC and are long long lived. You just have to have enough basic skills to set your chargers to 14.1v

And finally, if I was the OP I'd look at making the transition to FLP. There's a learning curve and you need a professional installer but they have many, many advantages for the cruising sailor and are now much cheaper on an annual cost basis.

[Rumrace]

Thank CarlF I totally agree. Dive in I say. The worst FLP system is better than the others.
I learned the fridges are set to high at some valve preset. My Fridges use to hum off and on a lot. Tricks like keeping them full of cold water bottles help. I was surprised to find out the amperage consumed by plotters or autohelm dang!
The solar panels keep everything up pretty well. I noticed the Gels worked ok with a couple small panels. The panels would never fully charge one battery but the controller was primitive. Solar panel and FLP are like mates. Ultraviolet photovoltaic tech captures that powerful circadian light and even moon light.

[GrowleyMonster]

Originally Posted by Mike OReilly

Yes, I know all this. Which is all the more reason to ask: why are they still alive, and so far, performing fine?

Sometimes you get the alligator, sometimes the alligator gets you.