Lithium Ion Replacement

Jan 25, 2007
286
Cal Cal 33-2 cape cod
I've got two heavy lead acid batteries Exide Nautilus dual purpose 27MDP (whatever that means) that do their job., which is start the engine & run the LED lights & GPS while sailing. So one battery is weak, I'm going this weekend to try and save her, maybe fill with distilled water, clean all fittings, and try to charge her again?

1) Can I buy one Battleborn 12v 100Ah ready to drop in her place?

2) Do I connect it to the other Lead Acid one?

3) Do I buy 2 Battleborn 12v 100Ah and connect them to my electrical system?

The reason I ask, I read the following below that led me to believe, without changing my charging/electric system, and lack of any electrical skill set...
I could righty tighty and lefty loosey my way into a stronger system....or cause an electrical fire?

"Weighing in at a sleek 29 lbs, the 100 amp hour, 12 volt Battle Born Battery runs circles around the competition. The Battle Born Battery also requires no new hardware to run in your boat. Just pull out that grungy old lead acid battery (use two hands, those suckers are heavy), drop in this elegant upgrade, and get yourself out there. " from Battle born website....
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
The reason I ask, I read the following below that led me to believe, without changing my charging/electric system, and lack of any electrical skill set...
I could righty tighty and lefty loosey my way into a stronger system....or cause an electrical fire?

"Weighing in at a sleek 29 lbs, the 100 amp hour, 12 volt Battle Born Battery runs circles around the competition. The Battle Born Battery also requires no new hardware to run in your boat. Just pull out that grungy old lead acid battery (use two hands, those suckers are heavy), drop in this elegant upgrade, and get yourself out there. " from Battle born website....
They are over simplifying the installation.

The batteries will benefit from a specific charging profile. If you do not have a modern smart charger that can be set to charge LiFePo batteries, then your charger will damage the batteries.

The alternator and regulator are also a factor, the output needs to match the charging needs of the battery. An externally regulated alternator will work best.

If you are thinking about rehabbing your old dying battery, save your time, just buy a new set. How old are the current batteries?

These 2 articles will answer many of your questions:


 
Jan 25, 2007
286
Cal Cal 33-2 cape cod
The current batteries are only 4 years old. One of them is good, in that, it's holding a charge, the other one seems to dim the lights after a few hours. I'm not sure how much the alternator puts out to charge both batteries, my question being, like you said, Is the alternator/regulator appropriate for the Lithium Ion? Thanks.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
The current batteries are only 4 years old. One of them is good, in that, it's holding a charge, the other one seems to dim the lights after a few hours. I'm not sure how much the alternator puts out to charge both batteries, my question being, like you said, Is the alternator/regulator appropriate for the Lithium Ion? Thanks.
If it is the stock, internally regulated alternator, it is highly unlikely that it is adequate. Given the cost of LiFePo, I would be certain it was before investing.
 
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JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Just a guess but if it is old and unknow when replaced then I would go with no. The links have a lot of technical info but the short answer is this is not a drop in exercise reguardlss of the marketing material claims. You would be better off going to 2 6V golf cart batteries for each batterry replacement, keep same charging system and significantly increase your capacity plus reduce the single lifting weight of the monster batteries.
 

Mr Fox

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Aug 31, 2017
204
Marshall 22 Portland, ME
I would second JRT’s recommendation. Seriously keep it simple unless your passion is electrics or you will be doing loooooooong cruises and can justify the cost of an upgrade.

To run any lithium batteries you’ll need a new externally regulated alternator, (in most simple application) a single lead battery wired direct to alternator for starting, and a dc/dc charging system capable of running the correct charging profiles for the battery types. Plus all new wiring and battery switches for the new set up. That’s the tip of the iceberg, things can get way more complicated if you want. Basic lifepo4 setup is easily thousands of dollars (unless you are doing it all yourself).

Don’t trust any manufacturers that tell you a direct replacement with no additional work is possible. If that were actually true (I wish it were) no one would buy lead acids anymore.
 

Joe

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Jun 1, 2004
7,999
Catalina 27 Mission Bay, San Diego
You realize, I hope, that the BattleBorns will run close to $1,000 apiece. As the other guys have told you, revamping your charging system is important. I have never seen any one recommending mixing battery types when connecting to chargers. Another heads up, when it's time for the battery to go.... it will go...don't waste your time trying to save it. Look for the purchase date and life expectancy on the outside of the box somewhere, if you're six months past that, time to replace. Also.... replace them both at the same time. You can find this, plus more info about everything boating, by checking in to the West Marine Advisor

4 years is about average for a lead acid battery, maybe even a little above average, I get about 36 to 42 mos from a 30 month battery from Costco or Walmart. Also you want "deep cycle" batteries, not multi purpose or car batteries... many sailors swear by the Trojan 6 volt T-105 run in series... they are golf cart type batteries.

If it were me, I would make sure the boat was equipped with a good quality "smart" charter, that is hard wired to your boat's shore power system and the boat's alternator. Then I'd pick up 2 Group 27 deep cycle marine batteries from Costco or Walmart... they're around $90 - 100 apiece. I've been using them for years... do the math, it'll make sense.
 
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JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
If you are considering $1000 in batteries you should consider updating you charging system.


This is the charger I have, it is very flexible and can be used for multiple battery types and setups.


My shore power is also upgraded to Smartplug too

 
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Mr Fox

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Aug 31, 2017
204
Marshall 22 Portland, ME
There’s enough info available on this forum so you can really learn how to make a proper system. Bottom line - drop in replacement is a marketing strategy for separating people from their money.
 
Aug 21, 2019
156
Catalina 315 18 Grosse Pointe Park, MI
My understanding is that if you use a standard alternator to charge LiFePO4 batteries, there is a danger that you can over load and thus ruin a standard internally regulated alternator. There are also alternators that have separate regulators that can handle LiFePO4 batteries. But they are expensive. For my boat the 90 amp alternator replacement is about $100, the externally regulated alternator more like $1000. Also, if you use the Lead acid charger setting on a LiFePO4 battery, it will not fully charge it.

My solution to this is to use a Lead acid battery as a starter battery, connected to the alternator, and use the LiFePO4 batteries for the house bank. The LiFePO4 batteries are connected to the Lead acid battery though a DC to DC charger. This separates them electrically. On Amazon you can find a DC to DC charger for $100 to $200. This is a pretty common installation setup on RVs.

Most commercial LiFePO4 batteries will have a built in BMS (battery management system) that protects the battery from inappropriate charging. I purchased 2 Lion brand, 105 Ah, LiFePO4 batteries from Costco for about $1400. The technical representative at Lion told me to use any charger that has a Li setting. I can already hear the groans from some "experts" reading this. But, since Lion offers a lifetime guaranty on their batteries and Costco will double the guaranty on a purchase like this. I am not worried.

I have not installed these yet, so I cannot speak from experience with them. But really, if it so hard that one needs a PhD in battery science, I doubt if anyone would buy them.
 
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CarlN

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Jan 4, 2009
603
Ketch 55 Bristol, RI
I would just replace both of your current batteries with the same thing (which are 2 Group 27 size batteries "dual purpose" - which are in between a starting battery and a deep-cycle). The other one is likely to fail within a year or so. While installing a couple of Battleborn Lithium batteries is not not nearly as scary as some are making it out - it will likely cost you $2500 and require new cases and tie downs. And there will be adjustments to your charging -- that Battleborn could help you with but why spend the time and money? If your current batteries met your needs until one failed, then dropping two new ones into the same cases should set you up for another 4-5 years for $350. BTW your current batteries are called "flooded". The people at the store may try to talk you into AGM's but stick with flooded unless you have solar panels or plug into a slip to keep them properly charged. When you install the new batteries, clean the ends of the cable until they are shiny and put some "dielectric grease" on them and the battery lugs before bolting to stop corrosion. Also look at where the cables attach to the engine and remove and clean up those connections too. Corrosion can make even a new battery seem weak.
 
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