Add a dedicated starter battery

dlochner · Feb 10, 2022

Battery voltage will tell you about the voltage but won't tell you about the battery's capacity. I suspect your batteries are long past overdue for replacement.

Small diesels do not need much current to start, but they do need a lot of current delivered quickly. New batteries should solve that problem, assuming all connections are clean and tight.

Don't be duped into buying "marine starting batteries" just buy good quality marine deep cycle, however even those are somewhat misleading.

Davidasailor26 · Feb 10, 2022

acudavid said:
Would these be a good choice? They are $95 a piece with core:

View attachment 202522

Doesn’t look like a great choice. Generally speaking anything rated in CCA or reserve capacity is not a deep cycle battery. Like Dave said, find a couple new true deep cycle batteries and they’ll provide more than enough starting current for a small diesel.

Carrying around a starting battery that doesn’t support deep cycle use is, IMHO, not a great use of weight for a sailboat.

Steve_Catalina · Feb 10, 2022

acudavid said:
Would these be a good choice? They are $95 a piece with core:

View attachment 202522

David, if this will be your dedicated starting battery this is fine. I use a basic auto battery as my dedicated starter on my c34. My house consist of 4, 6 volt golf cart batteries. Your needs for house may be way different.

Steve

Head Sail · Feb 10, 2022

acudavid said:
Would these be a good choice? They are $95 a piece with core:

View attachment 202522

That's fine but a little large IMHO. I use a small auto start battery because once I'm started, I have plenty of power.

Ralph Johnstone · Feb 10, 2022

acudavid said:
I think the previous owner ran them down over time, even though they are only a few months old. The volt meter puts them up around 13.5 volts a piece, but I think the amps are low and do not have any amp meter.

Forget amps as you have no data as to what your starter should pull.

Do an improvised load test. Clamp a voltmeter to your battery posts and check the voltage while cranking the battery with the stop pulled. Shouldn't drop by more than a few volts.

Next, do the same test at your starter terminals. If it's the same voltage as above with minimum drop, the battery's good, the wiring is good and the problem lies with the engine.

acudavid said:
I think the previous owner ran them down over time, even though they are only a few months old.

Batteries a few months old should not crap out.

Ralph Johnstone · Feb 10, 2022

acudavid said:
I plan to replace the two dc house batteries, but need to run the motor to burn out the carbon.

I'd suggest you get hold of a good book on diesels and forget the old wive's tales. Better still, the shop manual for your engine which may be in the archives here on site. Sounds like you've got a few power boaters around you. NOT a good source of information.

Proceed with the haul out and complete what needs to be done on the hard. There's lots you'll want to check under there so go at it with a good written list. Check the cutlass bearing, thru hulls, prop tightness, prop nut, exhaust interior, any transducers, etc, etc, etc.

It's a 40+ YO boat and you have no idea what maintenance it's seen. Now is the time to give it a re-birth.

twistedskipper · Feb 10, 2022

What some are saying here is before you replace batteries that are only a few months old, do some research on how to check that the wiring and starter are up to snuff. It’s not as easy as just replacing the batteries, but it could be a whole lot less expensive. Corrosion in the terminals or inside the wiring can really kill current-carrying capacity.
It’d be a shame to spend the money on the batteries only to find that the wiring condition is still holding you back.

Tally Ho · Feb 10, 2022

For starting the engine only, you can use the one you indicated. It would not be a good choice for a house bank. I like 6-volt Golf cart batteries wired in series to get 12 volts. Those are designed for heavy draw downs.

I have used Group 27 “deep cycle” batteries for starting and for my house bank in the past. Deep cycle marine batteries should show Amp Hours of capacity at a certain draw rate. My 6-volt batteries are 215 AH capacity for example. But for starting battery, almost anything should do. You aren’t drawing it down very long.

You really don’t “need” a starting battery either…they are extra insurance and they can keep your instruments from “browning out” when you start the engine and it drops voltage to the instruments. So a separate starting battery is a nice to have item.

But I don’t have one on my O’Day 322. I put 2 GC batteries in for a house bank, and use it t start the engine too.

No issues the first season with them.

Good luck with your new boat. Learn all you can about her, check out YouTube for a lot DIY videos and do what makes sense on your boat (not EVERYTHING you see on YouTube will work for you).

People on the forum are a great resource. We just need to know your “starting point” and hopefully we can give you good help and assistance.

Greg

Joe · Feb 11, 2022

Try Costo or walmart. That's my source. I think there's only 2 actual battery manufacturers anyway. You need to do some research that's a little more organized rather just "asking around". It's too easy to confuse fact with opinion. Kinda like facebook.
Deep cycle will be stated right on the label. The important feature is "reserve capacity" or amp hours AH. Deep Cycle batteries are meant to supply long, consistent amounts of power. Auto or starting batteries are built to supply large bursts of elec power for short periods and this most important feature is described as CCA or Cold Cranking Amps.
Instead of complaining that you don't have a multi meter, please....... go buy one. You can get a basic digital multi meter just about anywhere for under $20 and it's an important tool you should have on your boat.

Finally, get a copy of "the 12 volt Bible" . All your questions answered by qualified people. It's a small paper back. cheap too.

NYSail · Feb 11, 2022

Maybe before you get new batteries, check all your connections, especially the negative. Clean the connections at the battery and where negative attaches to the engine block as well as positive attaches to starter.

Davidasailor26 · Feb 11, 2022

+1 for the recommendation to get a digital voltmeter and check the voltage drop in the starting circuit before you assume the batteries are the root cause. Corrosion and poor connections in the wiring harness is a known issue causing starting troubles.

As for what to look for in a deep cycle battery, this is an excellent article on the types of things to look for -

What is a Deep Cycle Battery? - Marine How To

Light Cycle vs. Deeper Cycle NOTE: This article deals with FLOODED marine batteries, not AGM or GEL batteries. The Problem: The problem, as I see it, is one of dishonest marketing where multiple battery types wear the same clothes (sticker) and will perform differently when

marinehowto.com

Look through the rest of the articles on the site as well. Lots of good stuff there to learn from. A book like the one Joe mentioned above or Nigel Calder’s Boatowner’s Mechanical and Electrical Manual can be very helpful too.

dlochner · Feb 11, 2022

acudavid said:
@
Davidasailor26 "anything rated in CCA or reserve capacity is not a deep cycle battery. "

I don't know. How do I tell if it is a true deep cycle? I thought the DC stood for deep cycle. I would have thought Interstate was a good battery. Thx

DC means Direct Current.

What is a Deep Cycle Battery? - Marine How To

Light Cycle vs. Deeper Cycle NOTE: This article deals with FLOODED marine batteries, not AGM or GEL batteries. The Problem: The problem, as I see it, is one of dishonest marketing where multiple battery types wear the same clothes (sticker) and will perform differently when

marinehowto.com

sailme88 · Feb 11, 2022

NYSail said:
Maybe before you get new batteries, check all your connections, especially the negative. Clean the connections at the battery and where negative attaches to the engine block as well as positive attaches to starter.

This is your best suggestion... Before you run off buying batteries, make sure that they ARE needed or AREN"T.. Some of the procedures to employe are: have your current ( pun intended) batteries load tested. If they pass then you need to run down the connections at both ends. Make sure the connections are tight and absent ANY corrosion. You'll need to remove the connections from the rear of the starter. Insure no corrosion on either contact. IF the batteries test good and all connections are also good, remove the starter and have it bench tested. The starter gets it's ground from the block. Any corrosion along the mounting points is also a potential ground loss..

jviss · Feb 11, 2022

dlochner said:
DC means Direct Current.

Dave, are you serious? I was marveling at all of the bad information in this thread, and was shocked to see your comment. Now, if you can find me an AC battery, one that produces alternating current, you will really get my attention!

Interstate and others have adopted this supposed size, 27DC, to mean group 27, deep cycle, although that designation doesn't exist in the BCI spec.

That said, you buy deep cycle batteries by weight.

. Most of the garden variety, supposed deep cycle batteries, Interstate included, are junk.

Also, age doesn't matter, all by itself. You can get "brand new" Interstates that are junk, that are highly sulfated from poor handling and storage. Don't ask me how I know (the yard took them back, thankfully).

Flooded lead acid batteries can be converted into junk fairly quickly, by discharging them too deeply, storing them in a discharged state, or allowing them to sulfate.

A proper load tester is the only way to determine the condition of a lead acid battery. There are some "instant" ones, like the Argus (out of business), or the ones you can get on eBay, made in China, that can load a battery at the rate you are testing for, and time the length of time it takes to get to your low voltage set point. Messing with volt meters to try to evaluate a battery's health is a waste of time.

Getting the freshest, properly stored and handled battery is the most important. There's a Trojan distributor near me, and my house batts came from them. They were stored "dry charged," and the distro. filled them with acid before I picked them up. The date code of manufacture was the same month I bought them. To give you an idea of the difference between these and that Interstate, the Trojan weighs 20% more and costs three times as much.

These small diesels don't require much to start, as long as the wiring is in good shape. I installed a motor starting battery that was sized by finding out what size battery is in the tractor that the diesel came from. Yes, most sailboat diesels are small tractor engines, like Kubota, Mitsubishi, etc. A lawn and garden tractor battery with a trickle charger off the main bank will do the job.

BarryL · Feb 11, 2022

STOP

You need to do some more research and investigation.

No offense, but you are all over the place.

Cool down and think.

1. Does the engine turn over quickly? An M18 with a decent battery should spin quickly when the start switch is engaged. If it doesn't, it could be bad batteries, discharged batteries, bad starter, bad wiring, or bad grounding (same as bad wiring).

2. If the engine does turn over quickly, does it start easily? A WARM M18 engine should start in under 2 seconds. A cold one, with good working glow plugs, should start in 5 seconds. A cold M 18, without glow plugs, may take 30 seconds to finally fire up.

3. If the engine is cold, doesn't have good glow plugs, and doesn't turn over quickly it will probably NEVER start. If that's what you have, and you can't get it straightened out, you are best off using a short shot of starting fluid, wait a few seconds, and then give it a go. NOTE - this is not the preferred way to treat a diesel. However, IMO, a little starting fluid is better than minutes of cranking, which wears down the batteries, can backflood the engine, and wastes fuel.

Don't start just replacing things. First do some troubleshooting.
If the boat is at the dock, has shore power and an onboard charger, I find it hard to believe that the batteries are the problem in getting your engine started. That assumes that the battery charger is working.

The older Universal diesels are good engines. However, the wiring (alternator, starter, glow plugs, instruments) was suspect when new, and age has not improved them. There are lots and lots or articles on improving the wiring on those engines.

Good luck,
Barry

acudavid said:
What I do know is that the previous owner hit the glow plug for 90 + seconds, sprayed starter fluid in the intake of the Universal M 18 diesel, and cranked the motor incessantly until it started. He said the charger he bought at Oreilly's was overcharging the batteries.,

Head Sail · Feb 11, 2022

acudavid said:
What I do know is that the previous owner hit the glow plug for 90 + seconds, sprayed starter fluid in the intake of the Universal M 18 diesel, and cranked the motor incessantly until it started. He said the charger he bought at Oreilly's was overcharging the batteries., shortening their life.

If the batteries were bad, he woldn't be able to "hit the glow plug for 90+ seconds" and crank incessantly. If the charger was on while cranking, it should have started without the the incessive cranking. If the wiring was bad, he wouldn't be able to crank incessively either. I think you have engine problems. Get a diesel mechanic.

Add a dedicated starter battery

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