Changing house bank from Trojan T-150 Plus to ??

[geoffr]

I am trying to figure out what to replace our dead house bank with.. So looking for some opinions:

The current House bank is 6x Trojan T-150 Plus (225 Ahr @ 6V), so 675 Ahr @ 12V. They take up all the available space in my "battery compartment". In the past we have had ample power (rarely below 70%), however there were only a couple of overnights and one laptop. This time around there will be weeks of sailing (a Pacific or Atlantic crossing is likely) and two laptops running.

We are a catamaran so I'd like to keep things light, but I'm not ready to head down the Lithium route.

The options I'm looking at are:

Trojan T-150 Plus (just replace what I have)
- 6x6V
- 3x225=675 Ahr (~330 usable Ahr)
- 62*6=372 Lbs
- (Best Trojan for $/Ahr and Ahr/Lbs from what I can tell)

Trojan T-125
- 6x6V
- 3x240=720 Ahr (~ 360 usable Ahr)
- 66*6=396 Lbs

Trojan T-145
- 6x6V
- 3x260=780 Ahr (~ 390 usable Ahr)
- 73*6=438 Lbs

Firefly Carbon Foam (Oasis G31)
- 6x12V
- 6*110=660 Ahr (330Ahr @ 50%, 528 @ 80% )
- 6*75=450 Lbs
- Cost looks to be a good bit higher than Trojan options
- Does it need a battery box?

Any options on what you'd choose?

[S/V Illusion]

Take a ‘system’ approach rather than looking just at battery component, I.e., do you have the right charging capacity for any option? Do you value weight over capacity? Do you have supplemental power sources, e.g., generator, solar, wind, etc..?

Just looking at the options absent any other consideration, it reminds me of the dilemma I have going to the donut shop trying to select among their choices.

[Stu Jackson]

Illusions right. Without stating your energy budget and the things he's mentioned, no one can answer that question for you. Are you willing to pay a premium for a product that may not have the direct proportionality of cost vs. benefit?


I know a couple who have invested heavily in Firefly batteries. They don't even know how to read a battery monitor! Not saying this is you, but they do long distance remote cruising. Clueless when it comes to electrical systems, but they've been doing it for years.

[geoffr]

Hi,

I agree knowing the power usage is needed, but it's rather hard to tell given I don't know the time usage for the two computers which is the new power draw along with an upgraded fridge (manual are only somewhat valid) from what I had last time... so yes it's a big guess at this point. I do have the full excel table of power usage etc... and I do regularly monitor the state of charge of the batteries underway via the BlueSky solar controler and a Xantrex Link 20

Currently have 290W of solar (expected to be upgraded by replacing two really old panels).

Alternator is 125A connected only to the house bank (controlled with a Balmer MC614)

I do have two Balmer Duo chargers for charging the thruster and starter banks

[sailorboy1]

if what you had was working fine and the batteries are just due for replacement, I would get would replace in kind (either Trojans or some other gold cart battery as they all are pretty much the same far I feel)

[john61ct]

Sticking to lead you won't get higher energy density without sacrificing reliability / longevity.

The only reason to spend more on Firefly is if you know chronic PSOC abuse is inevitable. Lots pricier, likely shorter lifespan, and you probably don't want to modify your compartment.

What are your inputs (in detail) besides solar?

If you want / need better reliability / longevity, see Trojan's RE line, or look at Rolls Surrette. but pricey.

[jhulmer]

I just installed 4 G31 Fireflys - they are heavy but so far so good. I've been assured that regular 70% to 80% discharge or PSC does not affect there life or capacity.

Don't take my word for it talk to this guy:

Tom Whitehead <tom@oceanplanetenergy.com>

https://www.bruceschwab.com/advanced...asis-group-31/

I have concluded that for now these Fireflys will carry me until the next best thing in battery technology comes about; Be it Lithium or some of the other rumors we are hearing of battery breakthroughs.

Jim

[roland stockham]

If you have the height it may be worth looking at 2v options. Higher capacity batteries generally have a longer service life (up to double) and are more robust. There are now lots of options aimed at the solar market that work equally well on a boat. As to power requirements laptops are pretty minimal and replacing the fridge with a newer one that has better insulation will probably save more than the extra laptop uses.

[Maka]

I love my 8D house battery. Deep cycle.

Buy at auto parts store vs Marine. Same battery, costs less.

[john61ct]

Originally Posted by jhulmer

I just installed 4 G31 Fireflys - they are heavy but so far so good. I've been assured that regular 70% to 80% discharge or PSC does not affect there life or capacity.

Well they certainly resist immediate damage from too-deep discharge and chronic PSOC better than any other lead chemistry.

That does not mean that their lives would not be much longer without such abuse.

Nor that they last any longer than other top quality AGM, in setups that avoid inflicting those conditions on the bank.

But if you do need them, I agree OceanPlanet is the best starting point to try to find a place with stock.

[john61ct]

Originally Posted by Maka

I love my 8D house battery. Deep cycle.

Buy at auto parts store vs Marine. Same battery, costs less.

I disagree.

There are only two makers of 8D batts that are true deep cycling, Rolls & Dyno, and

just like any such 12V in automotive BCI sizes,

you just won't find them in any mass retail channels.

[sailcrazy]

With 2 8-d batts if one fails-(1)how do you get it out/off the boat (~200lbs of surfuric acid, maybe hot sulfuric acid?....don't ask me how I know), and (2) You just lost half your installed battery capability. With 6 T105s you can easily remove one if it fails, have lost only 1/3 of your batt capability (assuming you set it up w/3-12v cells), and (3) it's easier to find replacements. We've sailed from the Philippines to Thailand, to and thru the Medd, and now the Caribbean. Our battery setup is 6-T105s, each 12v pair to an On/Off sw, to a common busbar, to a master On/Off sw and whole-house fuse, to the house load. We use an auto start battery for eng+genset starting that is recharged by a Duo-Charge from the house bank. The whole system is backed up with solar and a windgen. That setup has served us(only 2 onboard) well for nearly 15 years. If it ain't broke-don't fix it! But it must be tailored to your energy needs and use.

[geoffr]

On our boat 8Ds are out of the question as I have a hard enough time getting a Trojan T-105 in place - there is no way anyone could get an 8D in place without building a rig each time!

2V batteries would be an option.. but I think I'll stick with 6V (or 12V).

[Chuck34]

Have you done everything possible to keep power usage to a minimum? All lighting switched to LED's? Extra insulation for refrigeration?

[01kiwijohn]

two years ago, I changed my 4 T150 bank for US Battery same equivalent, on the recommendation from my local dealer (who handles both brands).
So far, so good.