Rolls versus AGM Batteries

[goboatingnow]

I agree that Flooded LA has many advantages over AGMs, but many boats have the batteries located when watering them is difficult to impossible, furthering the likelihood that they will be allowed to run dry. Also, many boats are built assuming AGMs and the "compartments" are not suitable to flooded batteries, i.e. they offer no leak containment, inadequate ventilation, and are located in areas that are not ignition protected.

Also, many boats are built assuming AGMs and the "compartments" are not suitable to flooded batteries, i.e. they offer no leak containment, inadequate ventilation, and are located in areas that are not ignition protected.

Misleading statements this, AGMs have all the failure modes of LA,

Then buy VRLAs, AGMS can also vent , AGM has no beneficial advantages over sealed LA and some disadvantages. flooded accessible cells are better,

"venting requirements " are a bit over hyped anyway.

dave

[deckofficer]

Charge acceptance is much better with AGM over flooded. Also charge rate is better. A flooded shouldn't be charge higher than a 0.1 C rate, a good AGM like an Odyssey can be charged at 1.0 C.

[goboatingnow]

Originally Posted by deckofficer

Charge acceptance is much better with AGM over flooded. Also charge rate is better. A flooded shouldn't be charge higher than a 0.1 C rate, a good AGM like an Odyssey can be charged at 1.0 C.

Right and for an EV great

so in your boat with a say 500 AH battery bank , you have a 500A charge source!!


Im not denying that AGM have superior characteristics, just that those are not relevant in a typical cruising boat, whereas there disadvantageous characteristics are relevant ( partial charge sensitivity, overcharge sensitivity, Gas venting in extremes, etc)

dave

[deckofficer]

I'm agreeing with you Dave, that is why I said in EVs and remote home sites, but the latter is how we use them on boats. Maybe no one as used (6) 700 a-hr 2 volt AGM's in series for their house bank, but it would be a robust, long lived bank if treated right.

[sailinglegend]

Originally Posted by goboatingnow

AGMs have no place on a boat, they have good characteristics that cannot be typically exploited on a normal boat and bad characteristics that unfortunately do manifest themselves on a boat.....

An old thread but lots of good and bad advice like this quote!!!

Maybe goboatingnow has had bad experiences with AGMs or knows a friend who has.

Nobody has yet made the point that NOT ALL AGMs are the same, so the Q "Rolls versus AGM Batteries?" is not a fair question. "Rolls versus Lifeline AGM Batteries?" would be a better comparison.

Many AGMs are not designed for faster charging or high charge rates, and many are specifically designed as Solar or Telecom standby batteries so are not robust enough for regularly falling off a 3 metre wave in a big sea.

We are in our 9th year with Lifeline AGMs and the benefits of faster charging and higher rates of charge have worked very well for us. We have a 280 amps DC genny, large alternator and solar and wind power.

The right AGM does have a place on a boat, even on a normal boat, but get the charging regime right to get the maximum benefit for the high price that you are paying.

[ka4wja]

Okay, it's summer of 2018....and I realize this is a very old thread and a 7 year old post of mine, but since I've been a happy Rolls customer and have decided to change (due to cost), thought I'd come back and update...

Well, I took another lightning strike....but got very lucky, 'cuz I had most of my electronics disconnected (I was doing some renovations), except for my AT-140 tuner...(Icom checked my M-802, and it was good, but replaced the M-802 anyway, along with the fried AT-140....sorry I digress.)


But, mother nature took out a few things, including my shore power charger (IOTA-90) and actually damaged some battery cells!! (weird, but it does happen)
Good news is that I've got Rolls 2-volt cells (8 years old, but still okay)....so as I checked 'em, and did equalization, and since I couldn't get discounts on single 2-volt cells (had to pay list price, unless buying complete batteries) found a could make a working battery bank of 2/3's the original....good enough for now....but then over the past few months found even those were using more water and not showing the capacity they should...well, 8 year old batteries and a lightning strike, etc....figured it was time to buy new batteries...

Well, when I got the price (even with a sizeable discount off of "list") it was still > $3 per A/H (about $3500 for 1125 A/H)...and I had to drive 90min to pick 'em up, get 'em down the dock, etc...thought I'd look around for better deals...

After decades of supporting Rolls/Surettes (and never really having any problems), it felt weird, but what I actually found is great!

Since 20 years ago, the boat originally had 660 A/H, that I upgraded to 825 A/H and then to 1125 A/H, but I never needed/used even close to those capacities, I thought I could "downsize" a bit....(if I move a couple hoses and a cable, I could squeeze in 1100+ A/H (at 12vdc) of GC2's....but an easy and quick fit of 880+ A/H's (at 12vdc) of GC2's...so..

So, that's what I did...I decided to change out to eight 6-volt GC2's, in series-parallel...

None of the above is all that earth-shattering....but, what I write here, below is wonderful!

I found Crown CR-220's at $95 each, delivered to my boat!! ($99 minus 5% "website discount") That's eight times $95 = $760!! That's $0.86 per A/H!! Delivered! Well, I'm a Rolls/Surettes user, but I'm not paying more than FOUR times the price, just 'cuz they're good batteries!!

Now, the CR-220's aren't Crown's highest capacity Golf Cart batteries, but $ per A/H, they're the most band for the buck! And, Crown is a good company, makes good batteries....(got a call returned within 30 minutes, from their engineering dept, to confirm absorption and float voltages!!)

So, I ordered eight CR-220's, and while they had six on the shelf locally, they asked if I could wait a day 'til they got eight fresh ones in....and they did....and they delivered them right to my boat, and placed 'em right on the scrap rugs I laid out on my cabin sole...AND they carried off EIGHTEEN 375 A/H 2-volt cells!!! (this was around the house, down 28' of stairs and down 300' of dock, and onto the boat and into the cabin....I had already taken all the Rolls 2-volt cells out, and placed 'em on the dock, but they carried them up and took 'em!)

For those of you near-abouts Stuart, FL....this is Treasure Coast Battery and Alternator...ask for David....and tell 'em you want the 5% off website discount.

https://www.treasurecoastbatteryfl.com/

772-324-9820


Here they are, before I secured them down:



It's been a few weeks and I couldn't be happier....we'll see how things go over the coming years!


Fair winds to all.
John

~~~~

Originally Posted by ka4wja

Don,
As I have Rolls batteries on-board, and my previos batteries were also Rolls / Surrettes batteries, and I've used both Rolls and other batteries over the years.....and since I'm pretty good at electrics/electronics (been in the electronics business for almost 30 years now), and have taught seminars on alternative energy, batteries, etc..... perhaps I can add a few tidbits that may help????


The short answer is, Yes....
{Comparing the $ per A/H, the expected life span (both # of cycles and years of service), 7 to 10 year warranties, and the real/actual capacity (in A/H).....and you'll see that they seem pricey, but are really pretty reasonable....}


The medium length answer Osirisail and Bill (btrayfors) gave you.....(and I agree with them...)


The long answer is, it depends on your use patterns and your charging set-up.....
Meaning if you're cycling daily and not going to be recharging completely....and/or going to be near civilization for years to come, then less expensive wet-types become more cost effective....

And, specificly to your case.....
Fix your charging system, and go over (redesign???) your electrical system......battery, wiring, monitoring, charging, solar, etc...house vs. starting.....lose the combiners/relays....actually making one large battery bank (use for house and starting is generally good idea!).....ALL BEFORE you buy any new batteries......


Details::::
I've used Rolls / Surettes batteries on various boats on/off for ~ 40 years.....and just recently (a month ago) changed out some 6+ year old (and badly neglected by my brother) Rolls batteries with new Rolls batteries.....
I answered a few messages about them (see quotes below) and wrote an article (w/ a few photos) about my recent change (see link)...






Don, Here are the links....
Battery

http://www.rollsbattery.com/pdf/12EHG375P.pdf


One last tidbit.....
Add as much solar as you can fit and afford, and you'll never regret it.....no matter what batteries, no matter how large/small your battery bank.....add as much solar capacity as you can fit / afford!!!



Don, aren't you glad I gave you the short answer first...


Fair winds..

John
s/v Annie Laurie

[waeshael]

Buy 6V Golf cart batteries, install where its easy to check water levels. Replace every three to five years at $120 a piece. If traveling they are available anywhere in the world where people golf!

The size of the bank depends only on what you can put in each day. Batteries should continually be charging, but keep the voltage below 13 volts to avoid boiling off the water.

Avoid those costly batteries. AGM is only good if you plan to roll the boat!
Rolls are too heavy and too costly.

[ka4wja]

wasehael,
Since I was just updating some of my own info in this old thread, I'm hesitant to delve deeply into what you wrote....but, in brief...

Originally Posted by waeshael

Buy 6V Golf cart batteries, install where its easy to check water levels. Replace every three to five years at $120 a piece. If traveling they are available anywhere in the world where people golf!
Nothing wrong with GC2's...and, yes they are rather ubiquitous...but, there is a LOT more to all of this, and much is discussed here in this thread...


The size of the bank depends only on what you can put in each day.
Rather simplistic....as it depends on a good deal more...especially since some sailors cannot replenish every day...
Just a few of the things: how long do you need to go before recharging? how deep can you discharge? what lifetime / lifecycles are you desiring? how much charging capacity do you have? how quickly can you get them to 100% charge (or how close to 100%?) what loads do you have (remember very light loads discharge less and heavy loads discharge more...even if the "same A/H's" is supposed used) vs. the "20-hr rate"?


Batteries should continually be charging,
On land, at a telco site, etc....yep, that's what happens...
But, on-board at sea?? Once the sun goes down, most charging is done for the night... (many that have tried wind gens have found them to produce little to any actual charging in wind speeds below 10 - 11kts, and nothing at all below 8kts....and remember this is at deck level in a protected anchorage, not what your masthead wind transducer is seeing)
And, while I use a towed-water-gen when on passage, doesn't work when at anchor... And, very few cruisers run an engine or genset 24/7!


but keep the voltage below 13 volts to avoid boiling off the water.
Huh??
First off, most wet-cell lead acid batteries (and many AGM's) have a required "float" voltage of 13.4 to 13.6vdc...and most have "absorption" charge voltages of 14.4 to 14.8vdc...
If you're never getting a charging voltage higher than 13vdc, then you're not really charging the batteries....

And, true deep cycle (wet-cell) batteries, such as traction batteries / telco standby batteries, etc. (which have thick lead-antimony plates) usually require voltages at the high end of these ranges or even higher, but they do use a fair bit of water!
(Of course GEL's will be damaged by 14.8vdc, we've not been discussing them)


Avoid those costly batteries. AGM is only good if you plan to roll the boat!
While I'm not a fan of AGM's, my opinion is based on the fact that they do need to be recharged to 100% much more critically than wet-types, and even more than GEL's...
Not, 'cuz they're costly...
But, to each their own opinion..


Rolls are too heavy and too costly.
Costly, yes...(but less costly than AGM's)
But, not "too heavy"???
One brand doesn't really weigh more than another (except for some differences in battery cases)...higher capacity batteries are heavier / heavier batteries are higher capacity!

I hope these brief comments / clarifications are helpful, but don't confuse things.

Fair winds.

John

[john61ct]

Yes, it takes all kinds.

If you are careless definitely spend the minimum, and you will replace frequently.

If you are meticulous Rolls will give you well over a decade. Some owners need / want that.

[patrickvan3]

Comparing Rolls performance to a good AGM battery is like comparing old Edison carbon filament bulbs to LED lights. Rolls batteries have very high internal cell resistance compared to an "equavalent" (as if there is one) AGM battery which has very low cell resistance. The terminal voltage under the same load will be MUCH lower for a Rolls than an AGM.

Rolls batteries are good for running anchor lights for long periods of time, not good for heavy long loads like AGM batteries will do.

Pretty much this.

We have two 8Ds in a lengthwise, double battery box under our seats – neatly tucked away and powers pretty much anything. I prefer having far more than I'll ever need.

[john61ct]

High CAR can be important in some scenarios.

Getting to 100% Full a few times per week - especially important for AGM in particular - still takes 5-6 hours after acceptance has started to decline.

So if I needed that I'd look at LFP.

Only other justification for paying the AGM premium is a need to install sideways.

[ranger58sb]

Originally Posted by john61ct

Only other justification for paying the AGM premium is a need to install sideways.

Nah.

When I had 3x G31s (Odysseys), I could service most of those, if necessary. Painful, though. So I changed to AGM and life got better.

When I replaced that bank of AGMs (after about 12 seasons) I changed to 4x GC2s, expanding the bank underneath some boat structure. Now, I would have to actually remove all 4 to service. I'm not doing that. In fact, I could only barely do that, physically, anyway.

The other 3x Odyssey G31 bank was installed in 2009, still good.

AGMs work for our situation, and they've made my life easier.

-Chris

[john61ct]

Yes of course, there are other installation / placement issues.

My point was to emphasize a strong reason is required to overcome the disadvantages.

IMO.

Many just assume AGM are better, the default.

Of course as always, "your rig your call" once you have all the information.

[ranger58sb]

Originally Posted by john61ct

My point was to emphasize a strong reason is required to overcome the disadvantages.

Of course as always, "your rig your call" once you have all the information.

I think I would have instead said "weigh all the pros and cons, and then choose your the best options."

I react to "dogmatic" statements, I guess... but I don't see a where it's ever a "one size fits all" problem/solution... nor do I see where "my disadvantage is your disadvantage" statement is helpful.

-Chris

[john61ct]

And of course many people are happy to pay 3-4x the per-AH per-year price just to not have to add water.

My apologies for not writing more precisely.