Thoughts on new batteries for yanmar 3YM 30.

[Scott T-Bird]

I've heard some people say you can go with automotive batteries. I see 680 CCA on Amazon for an AGM battery for $123 . any thoughts? that's about 20% of the price for a marine battery of the same type on west marine .Thanks

You can use a small automotive battery as a starting battery. You will want deep cycle batteries to run all the house loads. This is just conventional knowledge among all sailors. Basically, it's universal. The only question is how many amp hours do you want for your house loads and do you intend to match a pair of batteries for your house bank?

You can recognize a deep cycle battery because it will say "DEEP CYCLE" right on the label. When you are looking at the specifications, you should be looking at the 20-hour rating for amp hours (ah) (and seek the most for the money - but many labels will also be misleading). A Grp 27 battery will be about 90ah and and Grp 31 will be about 105 ah or maybe a bit more.

Your boat has two pans that are sized for 4D-sized batteries. If you have 2 of those, each with about 200 ah wired in parallel than you have about 400 ah. Based on 50% discharge (max) you should have about 200 ah available when fully charged. I believe that is the standard issue for a Catalina 320. I sincerely hope that you are not intending to purchase a single, small battery to replace the start bank and the house bank that your boat is set up for, but that is for you to tell us.

You should tell us what you have. I suspect that you may have 2 4D deep cycle batteries and probably a small Grp 24 or 27 start battery. But maybe that isn't what you have at all. Why are you looking for batteries? What do you want to replace? I won't be surprised if you already have AGM batteries.

I wouldn't totally dismiss AGM batteries if that is what you already have and your charging set-up is geared up for them. But they are expensive and don't provide the economy of LiFePo4. We already know that you have a junk charger, though, so you should be thinking about matching your charger with the batteries you want to buy. I also don't know why you would dismiss LiFePo4 batteries based on one video that probably mis-represents their usage. LiFePo4 may seem like they are high-priced, but they are the most economical choice when considering the usage. They are currently the go-to choice for anybody intending to outfit their boat for optimum performance. But, we also don't know how you intend to use your boat, so that actually makes a huge difference in any decision making.

Your tendency to steer towards the cheapest-priced sources is disconcerting to many of us. You will get mostly negative responses, I think. I, for one, have never believed in magic bullets (or free lunches).

Deep Cycle Batteries Explained | Battery Zone

Deep Cycle Batteries Explained on the Battery Zone website.

www.batteryzone.co.nz

 

[NYSail]

Just my opinion but buying batteries from west marine is a waste of money. They are just rebranded…….

 

[Richard19068]

I've heard some people say you can go with automotive batteries. I see 680 CCA on Amazon for an AGM battery for $123 . any thoughts? that's about 20% of the price for a marine battery of the same type on west marine .Thanks

Ted; Everyone so far has been trying to answer your question in a vacuum. You have to provide information about how you use your batteries to get any kind of meaningful reply. If all you do is day sailing and hook up every night an automotive battery might be just fine. But how is anybody supposed to advise you with really no information about what you do? Or are they supposed to have some insight from prior posts?

 

[Ted10028]

Ted; Everyone so far has been trying to answer your question in a vacuum. You have to provide information about how you use your batteries to get any kind of meaningful reply. If all you do is day sailing and hook up every night an automotive battery might be just fine. But how is anybody supposed to advise you with really no information about what you do? Or are they supposed to have some insight from prior posts?

Looking for a good general solution. Not sure what I or next owner will be doing . Short term will be day sailing with shore power but some overnights too. Do most sailers keep a jump starter onboard?

 

[Richard19068]

Looking for a good general solution. Not sure what I or next owner will be doing . Short term will be day sailing with shore power but some overnights too. Do most sailers keep a jump starter onboard?

I might get flamed for this but I would check out a couple of your local big box hardware/home stores (Sam's Club, Home Depot, Walmart Costco...) and see what they offer for flooded lead acid "deep cycle" marine/ RV batteries. I would get two but if you go with one a portable jump starter would be some insurance.

Edit: I see on your profile you are moored. If that is the case I would invest in some minimal solar panel charging. 25 to 50 watts.

Flame on.

 

[Davidasailor26]

I might get flamed for this but I would check out a couple of your local big box hardware/home stores (Sam's Club, Home Depot, Walmart Costco...) and see what they offer for flooded lead acid "deep cycle" marine/ RV batteries. I would get two but if you go with one a portable jump starter would be some insurance.

Edit: I see on your profile you are moored. If that is the case I would invest in some minimal solar panel charging. 25 to 50 watts.

Flame on.

That might not be as bad of an idea as you suggest. At least at one time Sam’s club batteries were the same as West Marine and other manufacturers, just relabeled - Battery Buyers = Good News

 

[Tally Ho]

I got 2) 6-volt golf cart batteries (Duracell’s) at Sam’s Club a few years ago and installed them as my house bank (215AH total).

They have held up well for my needs… day sailing and a few 2-3day outings on the hook.



I don’t even have a separate starter battery for my 2GM20F (Yet).

Greg

 

[NYSail]

I am pretty sure Duracell 6volt batteries are East Penn/deka which are fairly decent quality for flooded type. And a great price!

Greg

 

[dlochner]

I

I am pretty sure Duracell 6volt batteries are East Penn/deka which are fairly decent quality for flooded type. And a great price!

Greg

I think the 12v are/were made by East Penn. The 6v batteries in Greg's photo don't have the right caps for an East Penn battery. East Penn uses a battery cap that removes all 3 caps at once. These are Deka Batteries, definitely made by East Penn.

 

[JRT]

I'm on this path too, my system is updated and has been working for the house bank golf cart batteries, but my starter is toast after 3 years mostly because accesing it is a pain.. My boat is 100% plugged in and charging in my marine so AGM maybe a good choice for my needs as we are day sailers only. My orientation is not correct due to limitations in space so this is another reason I'm considering agm too.

I have read all the Marina how too and it is great. But the issues with POC keep being assumed by a lot of people that is how people keep boats on mornings. I'm comfortable with AGM in my application because I have an updated modern smart charger, and plug in end of day sail every day.

 

[dlochner]

I'm on this path too, my system is updated and has been working for the house bank golf cart batteries, but my starter is toast after 3 years mostly because accesing it is a pain.. My boat is 100% plugged in and charging in my marine so AGM maybe a good choice for my needs as we are day sailers only. My orientation is not correct due to limitations in space so this is another reason I'm considering agm too.

An AGM for the start battery would be a good choice if the battery is difficult to access since start batteries are subject to short high loads and are quickly recharged from the alternator. Going with AGMs for the house bank would be unnecessarily expensive, especially if the GC bank you have is working well.

 

[Ted10028]

I am pretty sure Duracell 6volt batteries are East Penn/deka which are fairly decent quality for flooded type. And a great price!

Greg

don't we need 12 V batteries?

 

[dlochner]

don't we need 12 V batteries?

The 6v batteries are arranged in series to get 12v. In my photo, there are 2 pairs of 6v batteries arranged in series and parallel to get 460 ah at 12 v.

 

[kloudie1]

two 6 volt batteries wired in series.. A very good way to get real deep cycle performance in lead-acid.. Use two good GC2 (golf cart) batteries to replace each of the humongus 8D's (4 in total)
What is a Deep Cycle Battery? - Marine How To

 

[Scott T-Bird]

Looking for a good general solution. Not sure what I or next owner will be doing . Short term will be day sailing with shore power but some overnights too. Do most sailers keep a jump starter onboard?

No, I don't think most sailors keep a jump starter on board - particularly not sailors with a boat similar to your 320. But some sailors are always questioning about these things and perhaps it makes sense on boats that have a very limited capacity for battery banks.

You have a fridge, no? Do you want to keep it running while on a mooring? Don't you have electronics and a wheel pilot on your boat? You have lighting for sure. You want to stay overnight. You need a basic house bank that is going to provide you with at least 100 ah available capacity. I think, at a minimum, you should have two Grp 31 deep cycle batteries (providing a total rating of 200 ah) and a small start battery. You will be much better off with two 4D-sized deep cycle batteries but it sounds like you want to minimize. Everybody suggests golf cart batts, but I'm not sure they fit in your compartment. I just measured mine and it provides just 9.5 inches under the wood blocking. The studs on my batts make a total height of 10.5" and that just barely fits under the lid under the cushions. I think golf cart batts are taller and may not fit.

You also have a windlass, right? And you have a fresh water pump, a macerator pump , a pump to drain the shower. Perhaps you have a pump to provide water at the anchor locker? I put my windlass on the start battery and bought a Grp 27 AGM start battery because it is very hard to reach at the forward end under the saloon settee and I didn't want to maintain a wet-cell battery. (P.O. had a gel cell there).

If you want your fridge to run while keeping the boat on a mooring, you will need solar. Previous owner of my boat was on a mooring and he had a junk charger that was inadequate (and never used). But he installed flexible solar panels on the bimini top to keep his fridge running. I'm in a slip with power so I removed the solar panels (they were very worn down anyway) and replaced the charger. He had also upgraded the alternator with external regulator because he was counting on motoring to re-charge batts.

If you depend only on motoring to recharge batteries, then you will slowly kill your batteries by chronic undercharging. In that case, you may as well buy the least expensive wet-cell batteries and just replace them often (by all means do not buy AGM). But it sounds like you are uncertain about how long you will keep the boat .... this also affects advise greatly. Most of us are long-term owners so we set up our systems for longevity, based on our needs and wants, and not to just get by.

 

[Maine Sail]

Features of AGM Batteries
Low internal resistance.
The AGM battery charges faster than a gel or flooded battery.
Offers an 80% Depth of Discharge (DoD).
Excellent recovery performance.
Low-temperature startup capabilities.
Leak-proof, and low-maintenance.

according to this AGM battery is always going to have deep cycle capability? what do you think?

Any AGM that is saying 80% DoD is ok is a manufacturer to run from. Not all AGM batts are deep-cycle..

 

[rgranger]

No, I don't think most sailors keep a jump starter on board - (snip)

I have one... it also will charge my phone. It was only $120 at Walmart and also has a tire pump... so I can pump a trailer tire if needed. I bought it for the boat but so far I mostly use it for the lawn mower... and bicycles

But it is very handy....

 

[Scott T-Bird]

Any AGM that is saying 80% DoD is ok is a manufacturer to run from. Not all AGM batts are deep-cycle..

You talked about that in your article ... my take is that when they suggest 80% DoD, then the number of cycles will be significantly reduced and that information may also be presented in the specs (so it isn't necessarily misleading).

Another point is that if he only intends to keep the boat for a few years, he may not care if 80% discharge reduces the cycles ...

 

[Ward H]

I think the 12v are/were made by East Penn. The 6v batteries in Greg's photo don't have the right caps for an East Penn battery. East Penn uses a battery cap that removes all 3 caps at once. These are Deka Batteries, definitely made by East Penn.

View attachment 223652

The connected caps and posts look just like my Duracell Ultra BCI GC2 Deep Cycles I bought from Batteries Plus. From Maine Sail's post I always believed they were made by East Penn. Installed them in 2018 and they appear to be still going strong.

 

[PNWE36]

Hi, One of the things I like about this forum is the wide variety of experience and knowledge. Nothing like a question about batteries for a sailboat to get lot's of great input. To reply to your original question. Sounds like you are looking for an economical start battery for a 3YM30. My current sailboat which I have owned for 18 months has that engine. It came with a start battery purchased in 2019. Energy Power 24M-10-MF 950 MCA 730 CCA distributed by Energy Power, Atlanta Georgia This is a maintenance free flooded battery. It is still in good condition and starts the engine as expected. In Canada these batteries are CDN $150. I would guess in the US they would be US $110, fairly economical.
My previous sailboat had the older Yanmar 3GM30 which is the predecessor to the 3YM30. On that boat I purchased Costco Group 27 Marine flooded batteries labelled "Deep Cycle". These are made by Interstate batteries. I am in Canada but I am quite sure Costco US sells them. I had 1 start battery and 2 house batteries. I purchased them Spring 2015 and replaced the house batteries only in 2021. The start battery was still fine.
They were still okay but I could only run my fridge for 2 days in the summer instead of 3 to 4. I would let the battery go down to 11 V before charging. The old batteries are still in use. I gave them to my friend and he uses it for a trolling motor.

The boat had the original 2003 three stage charger. Typically when cruising I would be on shore power every 4 days. Hard to get a full charge from the standard alternator.
My boat had the ability to isolate the start battery and I was diligent in doing this so I could always start the engine when needed.
The Costco batteries were not maintenance free which I preferred as I like monitoring acid level. I topped them up every Spring and Fall.
Always kept the terminals clean
Always had them on the charger at the home base including all Winter.