BATTERY?

[Guystapo]

OK Gang ..I know this topic has been covered 1000 times but I am changing out batteries soon in my Catalina 34...looking at 4D or 8D or GC4s for house batteries ..or any other options ? Whats your thoughts ??

 

[Don S/V ILLusion]

8ds are too heavy to easily manage physically and have no advantage over other options. As to the others, too many variables to suggest any one choice is best.

 

[dlochner]

If there is room, I'd lean towards the GCs for the simple reason they are lighter at 65+ lbs than the other options.

 

[jssailem]

or any other options ? Whats your thoughts ??

Your replacement thoughts "looking at 4D or 8D or GC4s for house batteries" can be done. You have the other parts of your electrical system already in place (the delivery infrastructure and the charging systems).
There have been, what are considered, improvements in battery design that provide lighter weight and more power in a smaller package. This does not mean lower cost or that the new batteries may not work with your other systems.

The choice is yours and your pocketbook as to which path is "better or best".

I decided to install a new group of batteries for my house. I purchased four 100amphr LiFePO4 batteries from WattCycle at about $185 a battery.
The advantages of WattCycle vs Dyno Deep Cycle FLA batteries:

1. Longer charging life cycles (5000 vs 700).
2. More power is provided before recharging (80%. vs 50%)
3. Lighter weight (20lbs vs 65lbs)
4. Small size.

Disadvantages:

1. Need for modifying charging systems to accommodate the LiFePO4 batteries
2. some rewiring of battery systems
3. Additional hardware to protect the alternator from LiFePO4 shut off.

Your systems may vary, these were the basics I faced and resolved.

 

[Hayden Watson]

In 2022, I dropped in a couple of 460Ah 8D LFP batteries into my motorhome and have 920Ah total with about 850Ah usable capacity. Total cost including shipping was $2,400. The last time I checked they had dropped in price.

Each one weighed 90-lbs.

 

[Hayden Watson]

Your replacement thoughts "looking at 4D or 8D or GC4s for house batteries" can be done. You have the other parts of your electrical system already in place (the delivery infrastructure and the charging systems).
There have been, what are considered, improvements in battery design that provide lighter weight and more power in a smaller package. This does not mean lower cost or that the new batteries may not work with your other systems.

The choice is yours and your pocketbook as to which path is "better or best".

I decided to install a new group of batteries for my house. I purchased four 100amphr LiFePO4 batteries from WattCycle at about $185 a battery.
The advantages of WattCycle vs Dyno Deep Cycle FLA batteries:

1. Longer charging life cycles (5000 vs 700).
2. More power is provided before recharging (80%. vs 50%)
3. Lighter weight (20lbs vs 65lbs)
4. Small size.

Disadvantages:

1. Need for modifying charging systems to accommodate the LiFePO4 batteries
2. some rewiring of battery systems
3. Additional hardware to protect the alternator from LiFePO4 shut off.

Your systems may vary, these were the basics I faced and resolved.

Comments on items above.
Advantage #2 With LFP, you can discharge lower than 80% because the testing of 5000 cycles is for 100% charge cycles from 3.65v to 2.50v per cell [14.6v to 10.0v for a nominal 12v battery] Unlike the traditional flooded acid batteries (FLA), you cannot over discharge the cells because they have a BMS that will stop all discharging when the cells get too low which prevents damage. With FLA anytime you go below 50% SOC you are degrading the battery but there is nothing that will prevent you from doing that. The LFP with its BMS will shut off discharging before the cells are damaged. I have mine set more conservative and stop discharge at 12.0v.

Disadvantage #1. You MAY need to modify the charging system, depending on what you already have. Most modern multi-phase chargers have or can be customized to safely charge LFP. The key is to have bulk / absorption voltage no higher than 14.4v (I prefer 14.1v) and a float voltage that is no higher than 13.5v ( I prefer a bit lower than that for float and set mine at 13.3v)

Disadvantage #3. Here again, you MAY need to modify the wiring system, depending on what you already have. On my boat, I already had an externally regulated alternator that fed current to the house and start batteries through a battery isolator. The start and house were completely seperate from each other with each on its own master battery switch. I did not need to do anything to my wiring when I installed a 560Ah LFP house battery for the first year. I did end up making some significant upgrades later because I was now able to charge much faster and had 5-times more battery capacity. I now have two 30A Victron IP22 chargers for use from shore or generator. I also have a 250A large frame alternator on my 23-hp diesel with a Zeus regulator that lets me charge from the propulsion engine at 190A so that I can fully recharge the battery from 0-SOC to 100-SOC in under 4-hours. I also changed out my old diode battery isolator to an ArgoFET 200-2 which wastes less power in the loss caused by the diodes.

Disadvantage #3. Here again, you MAY need to modify the charging system to protect your alternator, depending on what you already have. In my case I did not. I already had the start and house isolated with alternator output going through the battery isolator so if the LFP were to shut off charging, the alternator output would still be dumping to the house battery, so it did not have any problem with alternator diode boom.

In the current market, it is far less expensive to go with quality LFP that FLA.

 

[Calif. Ted]

I run 4D's which weigh about 110 lbs. I used to run FLA's but last 2 sets have been AGM's. Battery tray is fiberglass and any spilt acid will burn into it, I choose to not deal with battery acid anymore. I used to be able to manhandle them alone but last time hired someone to do the heavy lifting and still managed to crank my back. I've never changed sizes because nothing fits well and don't need more battery cables and terminals to maintain.

 

[smokey73]

Always an interesting discussion but it always seems, when talking about the cost, to just list the price of the batteries. What would be useful is for those who have made the conversion to give us an idea of the "total cost" to convert, assuming you do it yourself (just equipment). OF COURSE the number will be different for each of us who did or may be considering such a conversion based on our starting configuration such as current alternator capacity, is it externally regulated, how is our charging system configured etc. Also when the conversion was done ($ for batteries has come down) and what battery capacity was achieved will make a difference but how about we start with an assumption.

What has to be done for "best" if not "maximum" utilization of converting from a typical 1990's 30 to 40 foot boat with original equipment wiring system, 1-2-Both battery switch, reasonably modern charger, stock internally regulated <100amp alternator. @jssailem you list 4 100AH LFP @ $185 each ($740 for batteries) but what else did you have to do? What was the cost? @Hayden Watson you say it is far less expensive but what is the conversion cost? Inquiring minds would like to know. Those that have made the conversion (and it seems there are quite a few), what was the wild guess at the total equipment costs?

 

[Hayden Watson]

... @Hayden Watson you say it is far less expensive but what is the conversion cost? Inquiring minds would like to know. Those that have made the conversion (and it seems there are quite a few), what was the wild guess at the total equipment costs?

Conversion cost is such a wide-open problem. For me, I was able to drop in my DIY 560Ah battery with no additional stuff into my 1988 C30 so my conversion cost was $1,400. That was the total cost for eight EVE 280k cells @ $150 each ($1,200) plus $110 for the JK BMS and $90 for mics bits and bobs. That gave me 560Ah total capacity in the space that was designed to fit two group 27 batteries. I was fortunate in that 29-years-ago, the previous owner had upgraded the wiring to have an isolated start battery which was on its own master switch and a battery isolator that kept everything seperate but allow the alternator to charge both. He had also installed an externally regulated alternator, so I was all set.


Years prior I had installed a Victron IP22 to replace my old Newmar charger because the Newmar cooked an AGM in less than two years. The IP22 is a great charger that can be fully custom programs to charge any way you want.

I also converted my motorhome from six CG2's with a total of 645Ah or about 322Ah usable to 920Ah of LFP. On it, I did not need to add anything because the factory installed Magnum 2012 has all of the programmability needed to set up the charging. I also do not need to worry about isolating the LFP because Tiffin did that from the factory. I also do not need to worry about limiting the output of the engine alternator because, due to the 90' of wire from the engine to battery and back, it self-limits to 60A current due to the voltage drop. Total cost for conversion was $2,400 for a pair of 460Ah drop-ins.

 

[smokey73]

@Hayden Watson so lets work backwards from you description? Assuming an "solar charging capabilities are priced separately)

Suppose one has a relatively modern charger that allows the necessary functions to program for LFP and just needs to add a dc to dc charger?
Charger change $0 (if not, it could be $500 to $800 more)
DC to DC charger $200

New externally regulated alternator with enough charging amps to take advantage of the LFP capabilities plus belt upgrades, and protection circuit?
Alternator & belt upgrade $1200 plus/minus (anyone have a good number for this)

Wiring changes to isolate the start battery?
Anybody have a good guess? ($ start with $500 as a starting point)

So, @Hayden Watson for your 920AH of usable LFP installation plus "other stuff"
$1400 batteries including bms and misc
DC to DC Charger $200
Alternator upgrade $1200
Wiring upgrades and misc $500
TOTAL about $3300 - Does that sound about in the ballpark?

@jssailem for your 400AH of usable LFP plus "other stuff"
$740 batteries (you didn't say if the bms was included so I will assume it was not)
$200 BMS system
DC to DC charger $200
Alternator upgrade $1200
Wiring Upgrade and misc $500
Total about $2800 - does that sound about right?

SO - the conversion costs seems to be about $3000 more or less. Does that seem to be a reasonable estimate?

 

[dlochner]

Hey guys, The OP didn't ask about a conversion to LFP and it may not be appropriate for the way he uses his boat or his skill level with the installation. You're answering questions that weren't asked.

 

[smokey73]

The OP asked "any other options?" LFPs are another option and depending on where he stands with his existing equipment (re things needed to do to make the conversion, ie charger, externally regulated alternator, etc) it may be a cost effective option. He didn't tell us much about his boat.

 

[jssailem]

Yes. The numbers are about right. The batteries I bought are full contained units. BlueTooth access, BMS included with battery pack. Mainsail did a review of the batteries I purchased.

I’ll have some fuses and wires to buy so that I can parallel the 4 batteries to get 400 amp hrs. The DC to DC Charger, my current charger can provide dock plug in power and the 105 amp alternator can produce 60 amps when running on the auxiliary.

When considering bling for the boat it can be helpful to consider future needs/desires and plan accordingly.

 

[Hayden Watson]

The following is my opinion and as we all know, there are as many opinions as there are commentors. For background I have been researching LFP for 15-years and using it for 4. I have built my own battery for the boat from raw prismatic cells and bought prebuilt sealed batteries for my motorhome.
I can only speak from my boat's setup. Others will be different which is why I said that cost are a difficult target to shoot at because the starting point is always different. I will answer each of your questions in red text within your message.

@Hayden Watson so lets work backwards from you description? Assuming an "solar charging capabilities are priced separately) I have no solar on either my boat or motorhome so cannot speak to that side of things.

Suppose one has a relatively modern charger that allows the necessary functions to program for LFP and just needs to add a dc to dc charger? If you do not have an external regulated alternator and do not want to go that route, you will need a DC-to-DC charger or you will need to modify your alternator to have a high temperature cutout. This video shows how to add a cheap thermal switch to a stock internally regulated alternator so that it can safely charge LFP. Then with the ArgoFET isolator, you change your FLA and LFP together. The safe charging parameters for the FLA are just fine for the LFP as long as you do not use the battery temperature compensation which would drive the voltage too high for the LFP.

Charger change $0 (if not, it could be $500 to $800 more)
DC to DC charger $200 Not needed with battery isolation.

New externally regulated alternator with enough charging amps to take advantage of the LFP capabilities plus belt upgrades, and protection circuit? This is the best option for charging from the engine. My boat came with a 108A Ample Power 108A alternator when I bought it 27-years ago and with external regulation with a regulator that monitors alternator temperature, you can safely and quickly pump as much power as you can make into the LFP. My 108A ran just fine off the stock 3/8" belt.
Alternator & belt upgrade $1200 plus/minus (anyone have a good number for this) I can only speak from my costs. I purchased a 250A large frame Denso Hairpin Stator alternator from Tucson Alternator Exchange who makes high output alternators primarily for the AZ and UT offroad community. Given that they are typically running in rigs in 120º temperatures in the SW deserts, they are built with the highest quality parts to handle the high loads from big winches and huge light bars. This was the lowest output of this build type, and I could have gotten the same case with 400A. I did not get the Pure Power brand of alternator that they sell. Mine was a fully custom build to my specifications and it cost me $375 which I picked up at their shop when I was visiting my daughter. [They do ship world wide but it was nice to meet them.] I also installed a multi-rib belt kit from Balmar which cost $440. I could have run that alternator with my old regulator but it did not have alternator temperature monitoring. for the first years use, I built a simple temperature limiting regulator that turned on at 13.2v and turned of with the battery hit 14.2v. It also would turn off when the alternator temperature got to 90ºC which was very conservative because TAE suggested a cast temp max of 105ºC. The total cost of building my simple regulator was $50 with most components costing less than $10 from Ali Express. That said, this year I am upgrading to the Cadilac of regulators, the Zeus which has set me back $715 on sale. my 35-year-old 23-HP Universal M25XP handles the new alternator just fine. Total cost of alternator, belt kit and simple regulator. $865. Typical output to battery 190A.


Wiring changes to isolate the start battery? $0 for me because it had been done by the previous owner. My C30 came to me with two battery switches, a battery isolator and all primary wires from the alternator to the batteries made with 2/0 wire so I was set for any output up to about 250A.
Anybody have a good guess? ($ start with $500 as a starting point) The AroFET 200-2 sells for about $120. then you need a second battery switch which I see for about $40. Then you will need to add wiring to meet your desired power output.

So, @Hayden Watson for your 920AH of usable LFP installation plus "other stuff"
$1400 batteries including bms and misc I have two LFP setups. 560Ah on my C30 and 920Ah on the motorhome. The 560Ah cost me $1400 to build. The 920Ah was a pair of prebuilt 460Ah batteries in sealed 8D cases with a purchase price of $1,005 each and with shipping and exchange fees, came to $2,400 total. The useable power for each of these is about 90% of the total capacity. Those costs all include the BMS which is essential to any LFP and is built into any prebuilt battery you can buy.
DC to DC Charger $200
Alternator upgrade $1200 Only if you get from Balmar which in my opinion are very over priced. My alternator has the exact same complonents as the Balmar XT-250 except that my TAE has a true 2" foot case instaed of the 1" foot case with a 1" shim. The true 2" foot is a much stronger mount. Mine is also not powder coated. Powder coating an alternator is a very stupid idea because the powder coating is a thermal insulator. Why would anyone do anything that would reduce the ability to get rid of heat from the inside of an alternator. Bare aluminum is a fantastic heat sink.
Wiring upgrades and misc $500
TOTAL about $3300 - Does that sound about in the ballpark? For me on my boat, I went from a usable capacity of 105Ah to 500Ah for just the cost of the battery and simple regulator $1,400 + $50 or $1,450 total and that is what I used for the first full season. After that, it worked so fantastically that I decided to upgrade so that I could recharge the full 500Ah in 3-hours instead of the 10-hours my old system required. Was it necessary, no. Is it nice to fully recharge your battery with a 3-hour relocation after sitting at anchor for 5-days in silence, you bet!
The old setup had a 210Ah Lifeline AGM in a 4D case that was totally fried after 7-years and had cost me $600. This was at discount because the previous AGM I had purchase from this supplier completely lost the ability to hold a charge in two years. The Lifeline 4D current sells for $800 so getting a 460 Ah LFP for $1,250 with a usable capacity of 4-times as many usable Ah was a no brainer for me.
I personally did not have luck with AGM on my house bank although my start AGM is 14 years old and still starts on the first try with 10-seconds of glow plug.

@jssailem for your 400AH of usable LFP plus "other stuff"
$740 batteries (you didn't say if the bms was included so I will assume it was not)
$200 BMS system
DC to DC charger $200
Alternator upgrade $1200
Wiring Upgrade and misc $500
Total about $2800 - does that sound about right?

SO - the conversion costs seems to be about $3000 more or less. Does that seem to be a reasonable estimate? As I have said before, the cost depends greatly on what your boat currently has from the alternator and charger to the batteries. FWIW, the BMS is built into any battery you can buy. I personally would only consider a battery that has an unlocked Bluetooth BMS. I would not consider any battery that does not have a Bluetooth BMS such as the Battle Born or Dakota brands because you cannot see what is happening inside. I have seen a new line of Battle Born batteries that have Bluetooth BMS but with a substantial markup which still makes them 2-3 times as expensive as a similar battery from another manufacturer.