House bank 6 volt vs 2 volt cells

[deckofficer]

Originally Posted by Capt Hugh Wilde

What is your history with these batteries and what are you using for a BMS with them?

Like Maine Sail I'm cycling them to see what they can do. Went from 18 nm to 80 nm with the same battery weight, LiFePO4 vs lead.

No BMS, just a bottom to top balance.

[Capt Hugh Wilde]

A good friend of mine who has been a marine electrician for a long time turned me on to these units, and he has been using them for a number of years and has had good result with them.
No more than they cost, I could not see not trying them.
Have any of you had any experience with them

I have already installed them, but it would be nice to get some added feed back on them.

http://www.engines1.com/images/nanop...nanopulser.pdf

[svinshallah]

From a purely statistical point-of-view, fewer bigger cells will be more reliable. If a group of cells has an MTBF(time to failure of 50% of the cells) of, say, 1200 hours, a bank of 6 cells will have a calculated MTBF of 200 hours. If you would use twice as many cells of half the capacity each, the calculated MTBF would drop to 100 hours. So 4 6-volt golf cart batteries (about 200AH each) would be twice as reliable as 4 12-volt batteries hooked in parallel.

What usually drives the decision is form factor and weight considerations.

[Capt Hugh Wilde]

I have looked at all the different views on this question and I believe I am going to recommend using 6 - 2 volt cells to build the bank.

Now the next question is.

We are planning to use Lifeline AGM batteries.
Is there an AGM brand that you prefer over Lifeline that makes a 2V cell?

And thank you all for your input on Lithium batteries, but my guy isn't ready to take that big a step yet. I wish he was.

[Capt Hugh Wilde]

I have a Victron Blue Solar MPPT 150/70 charge controller already installed, and this week the 3 - 290 watt LG solar panels came in.

Shouldn't have any trouble keeping this bank charged.
If all the hype is true, with good sun we can make 61 amps, that should make short work of it.

[zboss]

I am dredging up an old thread because I'm evaluating battery options since we had a little electronics issue in relation to lightning this summer. Our insurance company is covering the cost of replacing our battery bank and we have to select new batteries.

Currently we are using 4 x 6v (Trojan T-145p) but I am thinking we can fit 6 x 2 Volt Lifeline AGMs. We could sure use the Ah capacity and I am convinced that with their world wide distribution network that I should be able to get replacements just about anywhere.

A couple of notes before I ask my questions:

We have only one high amp charging source - our engine alternator is a Balmar 165 Amp. Then we have wind and solar but they top out at about 40 amps on a good day. Our shore power charger is a 70 AMP Mastervolt.

We currently use about 200 Ah a day but expect to almost halve that by replacing the fridge insulation and refrigeration equipment this summer.

This would mean we would only be discharging the batteries by about 8 to 10% a day (the 2 volts have a capacity of 1200 Ah). We could reduce weight and go with 900 Ah batteries but I like having the extra capacity for weeks where its cloudy.

I have a couple of questions about the lifeline 2 volt batteries:

1) What has been their historic reliability? Where do they fit on the scale of reliability?
2) Will cycling them by only 10% reduce their lifespan?
3) Will charging them with only 25 to 35 amps from the solar negatively impact their lifespan and performance?
4) How much space do I need to leave between the batteries for airflow and expansion?

[deckofficer]

For off grid homes I've had very good life from 2 volt AGM cells. On a boat for ease of replacement combined with a redundant bank I would opt for two strings of the 66 lb., 660 ahr @ 20 hour rate cells. In the highly unlikely scenario of a cell going bad you still have the other string. So total of (12) 2 volt cells in two series 12 volt strings. Total 1320 ahr @ 12 volts, ease of lifting them, and a redundant battery bank.

As to your questions,

1.) I've seen longer life spans from the 2 Volt cells than the common L16 6 volt.
2.) 10% DOD will lengthen cell life vs 50% DOD
3.) What shortens the life of a battery is spending time fully discharged. With any lead acid battery you should size it for max 50% DOD.
4.) Powering typical house loads and charging at 0.2C won't generate heat or cause expansion so they can be side by side with no problem.

[a64pilot]

Yeah, I'd like to have a dozen batteries totaling 1320 AH myself, only two problems, I can't afford that and I'd have nowhere to put all of them

[Capt Hugh Wilde]

Originally Posted by zboss

I am dredging up an old thread because I'm evaluating battery options since we had a little electronics issue in relation to lightning this summer. Our insurance company is covering the cost of replacing our battery bank and we have to select new batteries.

Currently we are using 4 x 6v (Trojan T-145p) but I am thinking we can fit 6 x 2 Volt Lifeline AGMs. We could sure use the Ah capacity and I am convinced that with their world wide distribution network that I should be able to get replacements just about anywhere.

A couple of notes before I ask my questions:

We have only one high amp charging source - our engine alternator is a Balmar 165 Amp. Then we have wind and solar but they top out at about 40 amps on a good day. Our shore power charger is a 70 AMP Mastervolt.

We currently use about 200 Ah a day but expect to almost halve that by replacing the fridge insulation and refrigeration equipment this summer.

This would mean we would only be discharging the batteries by about 8 to 10% a day (the 2 volts have a capacity of 1200 Ah). We could reduce weight and go with 900 Ah batteries but I like having the extra capacity for weeks where its cloudy.

I have a couple of questions about the lifeline 2 volt batteries:

1) What has been their historic reliability? Where do they fit on the scale of reliability?
2) Will cycling them by only 10% reduce their lifespan?
3) Will charging them with only 25 to 35 amps from the solar negatively impact their lifespan and performance?
4) How much space do I need to leave between the batteries for airflow and expansion?

I think the 900 amp hrs would give you enough, but if the have the room for the larger batteries, it never hurts, but going to them would nearly double your current battery capacity. Your current bank weighs 288 lbs, 6 1200 amp 2 volt Lifelines weight 714 lbs. The 900 Amp hr bank would weight 540 lbs.

I think the 900's would be your best bet.

[zboss]

Originally Posted by a64pilot

Yeah, I'd like to have a dozen batteries totaling 1320 AH myself, only two problems, I can't afford that and I'd have nowhere to put all of them

Its only 6 batteries. Either the larger 2v (1200 Ah) or the smaller 2v (900 Ah) both have the same footprint (by battery) as the Trojans. I currently have four batts and can make room for 2 more.

I may just as well go for the 900 Ah, I'm not sure it would make much difference at all in power, in a practical sense, but as a responder pointed out it is a lot less weight.

That would still give us 4 days of non-conservation-mode power. If it hits four days and I'm still down, I crank up the engine and go for a toot around the island for two hours, maybe catch some Tuna! Here is the thing, I had bought a Honda generator to make up for the fact that I only had one day of reserve power and if the sun didn't magically appear I had to run the engine, and I didn't want to do that on a regular basis. With this new battery bank and lower consumption, I'm in a situation where I may not need the generator.

[a64pilot]

Someone else was abdicating a dozen batteries I think, but I may have misread that.
I don't have a whole lot of of experience with this yet, but it seems once I get behind in the battery charge status, I have a heck of a time catching up, plus if you go AGM's you really want them fully recharged as much as possible. Only way I have been able to accomplish that is shore power or a generator or a long motoring, I'm better off with the generator as I can shove 185 amps that was as opposed to 140 with my Alternator. I'm discharging the bank as we speak with the idea of seeing in the morning if my Alt will really make full power or not now that I have an ammeter on it.
With AGM's I don't see anyway around a generator or frequent Marina visits etc.


Sent from my iPad Pro using Cruisers Sailing Forum

[zboss]

Originally Posted by a64pilot

Someone else was abdicating a dozen batteries I think, but I may have misread that.
I don't have a whole lot of of experience with this yet, but it seems once I get behind in the battery charge status, I have a heck of a time catching up, plus if you go AGM's you really want them fully recharged as much as possible. Only way I have been able to accomplish that is shore power or a generator or a long motoring, I'm better off with the generator as I can shove 185 amps that was as opposed to 140 with my Alternator. I'm discharging the bank as we speak with the idea of seeing in the morning if my Alt will really make full power or not now that I have an ammeter on it.
With AGM's I don't see anyway around a generator or frequent Marina visits etc.


Sent from my iPad Pro using Cruisers Sailing Forum

I saw that too... I guess if I had the room that would be nice but like you I do not.

If I were going to do a backup battery configuration instead of using six 2v batteries for the backup, I would use a single 12 volt firefly carbon foam connected to an echo charger. With 80% discharge capacity I could easily run most of my daily needs off that one battery. If we went into deep conservation mode I bet we COULD make 80 Ah work.

In fact, now that I have said that... two of those batteries aren't looking like such a bad idea

[ka4wja]

Okay, it's summer of 2018....and I realize this is an old thread and an almost 5 year old post of mine, but since I've been a happy Rolls customer and have decided to change, 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

Hugh,
You've gotten some good input and advice already (MaineSail and Jedi are great voices of knowledge), perhaps I can add some more and give some real-world experience / advice, as I have 2-volt cells making up my house bank.

1) In general "2-volt cells" have much thicker positive plates....allowing for deeper-cycling and much higher number of "cycles", than most other types of batteries used for house battery banks on-board, such as golf-cart batteries (and significantly better than what are typically sold as "deep-cycle" batteries!!!)
There is more to a house battery bank than its A/H capacity!!
Its ability to deep-cycle and its number-of-cycles in its lifetime, are just as important!!!

There was some discussion about this here...(have a look at post #26 here.)
http://www.cruisersforum.com/forums/...s-62379-2.html





2) Here, I'd like to qualify Nick's comment.... There actually is a THIRD reason to do this....
And, that is the size/shape of the space on-board for the batteries may need to be taken into consideration when choosing battery cells..
I do not have the room on my current boat for the very tall cells, but I did have room horizontally to install more cells....
So, on my current boat, I use 375 A/H 2-volt cells....in three strings of six cells in a string...
(Sorry Nick, but we all don't sail a Dashew-designed Sundeer, where tall/deep battery cells for your house battery bank was specifically part of the vessel's design.... Some of us need to make do with the space we have on-board!!!)







3) I currently have EIGHTEEN (yes, 18) Rolls "2-volt" deep-cycle cells, at 375 A/H each, as my house bank. (and I love 'em!!)
{see my article about them, along with the hi-res pictures of them, in the link..}
Battery

These are arranged in three strings of six-cells each, and the three strings in parallel, giving me a 12vdc house bank with 1125 A/H capacity....
(see pictures)
And, each cell only weighs 36 lbs!!!

I previously have had 12-volt 8D deep-cycle batteries (Rolls "Big Red" 8D's) as a house bank on-board before...(see one of them, somewhat, in this picture here... 4706107 )

And, in years past on a previous boat, I had 6-volt deep-cycle batteries (Rolls L-16's) in series/parallel...


I took these pictures before installing the hold-down bars, and before cleaning-up the wiring runs....but you get the point....










4) Next, I agree mostly with Nick (s/v Jedi), that there is a big difference between 10.5 volts out of a 10.5 volt battery (FIVE 2.1 volt cells), vs. 10.5 volts out of a 12.6 volt battery (a DEAD six-cell, 12.6 volt battery)!
And yes, five good cells (bypassing a bad cell) will most probably start almost any sailboat diesel and will run many electronics, and certainly will still run Nav Lights, pumps, etc....

But, amytom does have a point...
If you do loose a cell, you will need to replace it....so WHERE you are sailing, and how soon / how far away you are from a source of these 2-volt cells IS something to consider!!
You can certainly "get to port" with just 5 good cells, but I'd not recommend trying a circumnavigation with only 5 cells...

Further, the weight of the cells and your ability to install/move/replace them should also be a consideration....
(my cells weigh just 36 lbs each...and they are 375 A/H's...)





5) So, all the above in mind, you may wish to consider using two strings of six "2-volt cells", thereby giving you"
a) most of the "electrical and longevity advantage" of 2-volt cells..
b) the "reasonable size/weight advantage" of 2-volt cells...
c) should you have a VERY rare cell failure, you'd retain the ability to run one full six cell string as a "full-voltage battery" for voltage sensitive equipment, AND still have the full-current available from the other 5-cells, should you need it....


I do hope this helps some...
Fair winds...


John
s/v Annie Laurie

[boatpoker]

Not a fuse in sight in any of the photos posted and all with no visible ventilation system leading out of accommodation spaces and no positive terminal protection.

[ka4wja]

I'm happy to comment...

--- 250a fuse is under the large white crossmember...been there for years, but you can't see it in the pics...
I checked the terminals occasionally, but never needed to replace the fuse...


--- As for ventilation??
Yes, there is natural flow in and out-of the boxes, from the rear...again sorry it's not visible...but there are two large 4" diameter natural flow vents and one 4" diameter powered-blower vent...as well as one even larger (4" x 8") vent...

Boat is 19 years old, 3rd set of flooded lead acid batteries, and never a hint of out-gassed fumes/odors, etc...


I was just updating my postings of years ago, regarding 2-volt cells vs. 6-volt batteries....didn't know you all were so sharp.





--- As for "positive terminal protection"?? Inside the battery box?? I've very rarely ever seen that...
Now, outside of the battery boxes, is if you were installing batts in a bilge, or engine compartment, yes then do so....but, except for spraying terminal protector (to reduce corrosion) I've not added protection inside the battery boxes...(and yes, I sprayed after I took these latest pics)




Fair winds.

John