Replacing Batteries.

[griervictoria]

I have an R31 2014, with factory installed batteries. I am noticing that the house batteries are not holding their charge for more than 8 hours of normal use.
My question is firstly what type of battery are you currently recommending to replace house batteries and secondly, as my starter and thruster batteries seem to be still doing the job should I replace them as well? If so should they all be the same kind, AGM or flooded cell?

 

[Dale777]

griervictoria,

I also have a 2014 R31 which still has factory AGM batteries. They seem to be doing just fine. So when you say the "...house batteries are not holding their charge for more than 8 hours of normal use." It might help to quantify a bit more what "normal use" means." Does that mean?

1. You are anchored out
2. Wine frig on
3. Refrigerator on
4. Cabin lights on
5. Anchor light on
6. Chart plotter on
7. VHF radio on
8. Inverter on
9. Microwave used
10. Hairdryer used, etc
11. Charging cell phones and laptops

Since the 4 house batteries give only 440 Amp-Hours when fully charged and you can only use about 1/2 of that capacity with AGM batteries, you have about 220 Amp-Hours at your disposal. 50% State-of-Charge is about 12.06 volts. Do you ever go below that number? If so, you will definitely shorten their life. How many Amp-Hours do you estimate you use during this 8 hour period? Of course, during the daylight hours, I assume you have a solar panel which will partially recharge the batteries.

If the house batteries are, indeed, almost dead, I suggest you replace them with AGM batteries. Why? Because in a 2014 R31 those batteries are secluded so far forward in the cockpit hatch such that it is almost impossible to monitor and water any wet cell batteries that go there. To get at these batteries, you need to clear out that hatch completely then crawl into that space with a flashlight to deal with the batteries - not something I want to do regularly. I think some owners have installed a battery watering system so all you have to do is periodically squeeze a bulb. However, if it is too difficult to monitor how that watering is working, I don't care to use this approach.

The typical AGM deep cycle battery should last 4-8 years, depending on several variables - type of charger, whether they have been too deeply discharged often, temperature, etc.

 

[griervictoria]

Thank you Dale 777 for your helpful information. By normal use I mean anchored out, with main fridge only on, no chart plotter, no VHF, Sirius radio on sometimes, inverter on and maybe microwave used once, head pump flushing, and water pump for dishes or drinking water. Certainly no hairdryer. Cabin lights (LEDs) in the evening
It seemed we could sit at anchor for at least two days with this amount of use when the boat and the batteries were new.
Yes the house batteries have been run down to 11-11.5v in the past, so I am resigned to replacing them.
My second question was whether to have the engine and thruster batteries replaced at the same time or to have them load tested and leave if they ore ok.
I agree with you that I am not going to crawl into that hatch area and top up batteries. I believe the factory supplied ones were Universal AGMs so are sealed. Thanks for your help.

 

[Dale777]

griervictoria,

Sorry that I ignored your other question about the start and thruster batteries. If you decide to replace them, I would recommend AGM batteries for the same reason mentioned about the location of the house batteries.

However, if they seem to be working okay, I think you could get by with keeping them for a while longer, IF they have not been allowed to discharge below 50% state-of-charge. As I said earlier, the AGM batteries have a typical life of 4-6 years if cared for properly. My reasoning for taking a chance on the current start and thruster batteries is that they are in separate banks from the house batteries. If you installed new replacement house batteries, then that bank becomes the backup for the start and thruster batteries. If the start batteries were to unexpectedly fail, you have a Parallel switch so that you can parallel the start and house batteries to get the engine started and get you home. Then you can replace the start batteries.

As for the house batteries that have been "...run down to 11-11.5v in the past...", I suspect that is why they are failing to hold a charge as long as before. Running them down to below about 12.06 volts will definitely shorten their lives. The 12.06 volts is an approximation, since it is hard to check actual voltage when batteries are in use. When not in use (open circuit for about 12 hours) the 50% state-of-charge is about 12.3 volts. When in use the 50% state-of-charge is about 12.06 volts. Even these numbers vary depending on the battery type.

 

[griervictoria]

Very good information about the banks of batteries, since they are so inaccessible and difficult to read the labelling.
I will indeed hold off on the starter and thruster battery replacement because of the capability to use all batteries in parallel.
As a routine, I always disconnect shore power before firing up the engine and this has given me the confidence to know that the starting battery is adequately charged (at least at the start of the trip).
It was a bit amusing when we anchored, a couple of weeks ago, I had to go to the parallel mode using engine and thruster batts first thing in the morning in order to grind the coffee for the crew, as house batteries were so low.
Thanks for your help. Jim

 

[Levitation]

We have had this discussion a number of times.
I am of the camp that says replacing an $80 battery every 3 years is preferable to replacing a $280 battery every 6 years. The downside to the $80 battery is you must keep it watered. I don't find it a downside as it puts me in there to pull the cable clamps, shine and put fresh grease on them (once a year). You might try servicing the clamps and see if it helps.
Actually my current set of $80 batteries was installed in 2012 and still going strong.

As always - ymmv, sar, bni :mrgreen:

 

[knotflying]

It sounds like inaccessibility lends itself to AGM, but Denny's point about servicing terminals etc. is also compelling. The water fill system for flooded is pretty full-proof. You can't overfill the cells, so once installed it is pretty easy. With that said if one were to decide to change battery type you will need to change all of the batteries to the same type because the charger and solar panel settings require battery type for charging purposes. Unfortunately you only have one choice for all your batteries.

 

[Doc of the Bay]

Hi - I too have a R31 2011 hull #4

My batteries are dying. Reading the posts I guess AGM are the way to go. Anyone know what spec's I need to know to order them?

Anyone using lithium?

John

 

[baz]

...snip...
Anyone using lithium?

John

Lithium ion batteries are available for replacing the marine deep cycle batteries. However, they will come at a price of around $2,800 for 4 batteries with each being 50 Ah. If you go up to 100Ah then expect to pay around $5,200.

For example see https://www.lithiumion-batteries.com/products/12v-100ah-lithium-ion-battery/

I asked Andrew about Lithium batteries for the Ranger Tugs the other week and he just smiled at me. 😱

 

[Oregon Trail]

There is an interesting youtube video that discusses the reasons you might want to consider Lithium batteries. This is a cruising couple and they offer some compelling arguments that may or may not apply to your situation:

https://www.youtube.com/watch?v=J-kND4PaZm8
(Gone with the Wynns)

Good luck with whatever you choose!

 

[stwendl]

You can get automotive lithium batteries for much less, like used leaf batteries. The problem with lithium is that the voltage is either to low or to high and you need to be sure that ALL consumers can tolerate those voltage. Charging and management is a different matter altogether, especially the output of the alternator which needs to be changed.

 

[baz]

There is an interesting youtube video that discusses the reasons you might want to consider Lithium batteries. This is a cruising couple and they offer some compelling arguments that may or may not apply to your situation:

https://www.youtube.com/watch?v=J-kND4PaZm8
(Gone with the Wynns)

Good luck with whatever you choose!

What a thoroughly enjoyable couple the Wynns are. They make me chuckle all the time with their freewheeling attitudes and weird jokes. 🙂 RVing... Sailing.. what is next I wonder ?

Their video did not touch on the weight comparison between the AGM vs. Lithium.

 

[Stevan47]

Hi guys: Just out of interest, what sort of life span should I get from a pair of batteries in my 2008/2009 R21? When I bought the vessel in November 2013 (second hand from the dealer) it already had two 12V, 600CCA, sealed/low maintenance batteries, both manufactured in Jan 2012. It is now 2017 and they are still going strong - at least there has been no difficulty starting the engine and/or powering the auxilliary equipment (lights, stereo, VHF, Chart plotter, bilge pump, heater, etc). I have looked into the inspection port in the top of each battery and it is still showing green (as advised by manufacturer). Noting they are now over five years old, should I be looking at buying two new ones now and ditching the current batteries before they die? I don't want to leave it till the day I really need to start/re-start, especially when trying to up-anchor and get back alongside in bad weather. Your thoughts? Regards, Stevan

 

[knotflying]

There is that old saying,"Don't fix it if it ain't broken." Your batteries seem to be performing, but at 5 years you are having a good run. I would do a load test and see how that works out. If they test well then keep them. I am a proponent of the good old fashioned flooded batteries (maintenance free are similar) and I replace mine every three years, regardless of state. This is a bit overkill. Your batteries will often give your a warning that they are losing life, such as discharging more quickly. Hey if you are flush with cash buy new ones, if not do a load test and then decide.

 

[baz]

You can get automotive lithium batteries for much less, like used leaf batteries. The problem with lithium is that the voltage is either to low or to high and you need to be sure that ALL consumers can tolerate those voltage. Charging and management is a different matter altogether, especially the output of the alternator which needs to be changed.

I'm extremely interested in knowing what all is involved with replacing our current RT installed batteries with Lithium ion batteries.

I know it's an expensive proposition, but putting that aside I want to understand what the challenges are. Like many new technologies, the initial entry price has a tendency to fall over time as production and volume sales unfold.

The Wynns (mentioned above) have obviously made the switch to Lithium on their Cat and seemed very happy having made the switch. From what I've read about their exploits I've yet to hear info on battery weight advantages, changes to Lithium battery charging, changes to other things on their boat to accommodate the switch to Lithium, etc. For example, I have just purchased a 12v 50 Ah Lithium ion battery (weighing only 10 Lbs for heavens sake) for my trolling motor and it came with its own charger. The Torqeedo electric motor uses a Lithium ion battery and it comes with a charger as well, and can be charged via solar device. Are these special battery chargers I ask ?

I think I'm going to start a separate posting for us to discuss Lithium ion batteries. 🙂

 

[baz]

It sounds like inaccessibility lends itself to AGM, but Denny's point about servicing terminals etc. is also compelling. The water fill system for flooded is pretty full-proof. You can't overfill the cells, so once installed it is pretty easy. With that said if one were to decide to change battery type you will need to change all of the batteries to the same type because the charger and solar panel settings require battery type for charging purposes. Unfortunately you only have one choice for all your batteries.

Mike: If one were to replace all the boat's 12v batteries with Lithium ion batteries would the battery chargers (Promariner for example and the solar charger) have to be reprogrammed or replaced ? I would think and hope this would not be necessary but do realize lithium -ion batteries require some different approach to charging. I could be wrong as when I had my Torqeedo motor/battery which I believe had a lithium ion battery it could be charge with a regular 12v connection or a solar charger accessory, thus nothing really special. The battery was an 18 Ah 29.6 volt if I recall.

 

[knotflying]

Charging a battery type is different for each battery because of the construction. The absorbsion rate is different, hence magnitude of charge is different. A lower charge rate will not hurt a battery requiring higher charge rate, but can be damaging if the situation were reverse. I am not familiar with lithium technology and could not tell you what charge setting would work well for them. I would say either call the charger manufacturer or the battery manufacturer. The Torqeedo battery is lithium and takes a very slow charge. This is probably an indication of they type setting required.

 

[Todd]

Don't forget your primary charging system, the alternator. How will LI batteries work with that?

 

[Connerkip]

A number of articles have been written regarding the safety of lithium ion batteries on boats. Catastrophic fires and explosions could result. Search "lithium ion boats fire" on the Internet. Generally the articles focus on the benefits versus the risks.
The batteries do require very well engineered management systems, which I don't believe our chargers meet. It seems each cell within the battery is monitored and charges to avoid over charging or over consumption, which can cause them to explode.

For instance it always baffled me how my torqueedo could put out almost 30v but charge with less than 15v. If you look inside the torqeedo, it looks like it has umpteen c cell batteries in it. I can only surmise the battery management system cycles through them on by one to charge them. It requires a small computer to monitor each.

Just food for thought.

 

[Scotty Mac]

I just replaced my battery and purchased from Sams Club $179.00 each for group 31. Best price around