Batteries Went Dead Overnight - Beginner

[theodyssey]

hi all.

am sure this question has been answered before, but am anchored up in Swansboro and trying to find answers quickly.

long story short - came back to the boat last night to find that my batteries had both died.

the facts:

- they're AC Delco Marine
- bought in June '15
- used for the first time Sept '16
- being new, didn't know about keeping them 'wet' - so to speak - and saw that all cells desperately needed water
- they had been working fine since then [boatyard + shore power], and for the past 3 days
- 2 days ago, I had been both charging my iPhone + Macbook [computer] all day.
- anchored in Swansboro 2 nights ago, used a few LED lights, kept my 12v cooler on
- and then sometime between yesterday morning and last night, they died

so I'm about to call Boat US for a jump start, but am wondering which of the above do you think contributed to this? [meaning - what lesson do I learn from this?]

many thanks!

ps - speaking of which, does anyone have a good emergency jump pack they use? am seeing some tiny ones on Amazon that can charge either a phone or give your diesel a jump

[Reefmagnet]

You need to define "died" and battery capacity I.e. Terminal voltage when discharged (an also preferably the value at "full charge") and amp hour capacity of the batteries. If voltages are abnormal, split the batteries if in parallel and see if one is noticeably different from the other after charging). It's possible one or both of your batteries has failed or maybe just sulphated, or you have simply drawn to much power between recharges. One of those cheap battery hydrometers that suck up the acid for testing can be used to find failed cells.

And those jump boosters work like a charm. Get a 1200 amp minimum model if you have a diesel inboard of not too big a size, otherwise buy the biggest bad ass one you can find. Ultimately though, installing a dedicated starting battery might be more prudent.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[a64pilot]

If I understand it's been three days since as charge, before they died?
Cooler running all the time? Need to know amp draw and capacity of the batteries, Just as a Swag if I understood your post, you just don't have three days worth of battery capacity.
Plus how are they charged normally? As in what battery charger?

My personal opinion on the booster is if I had one I am sure it would be dead when I needed it, but a start bank, probably not. Or start watching your bank a little more closely.

[NewMoon]

Originally Posted by a64pilot

Need to know amp draw and capacity of the batteries, Just as a Swag if I understood your post, you just don't have three days worth of battery capacity.

And if they're starting-oriented batteries rather than deep cycle, they are not likely to run a cooler for a day or two without recharging. Deep cycle (good for "house" use like running lights and coolers) will typically have specs like "reserve capacity" or "amp-hour" (AH) capacity. Starting oriented batteries will typically have specs like "cranking amps" (CCA or MCA), and may not even mention amp-hours.

[a64pilot]

Some of those peltier coolers I believe suck a few amps, yet do little actual cooling.

[sailortype]

agreed... if it's a 'Koolatron' type plug-in cooler it will draw 3-4 amps and will deplete your batteries very quickly, especially if batts are getting weak due to sulfation. I use mine only with an AC adaptor and shore power.

[ranger58sb]

Agree with basics: cooler probably sucked battery dry, since they're "AC Delco" I'd guess they're starting batteries, likely just not enough capacity to go that long -- with that draw -- without recharging.


If it's twin engines, I'd also guess it's one battery per engine... which means even less capacity on the circuit that powered the cooler.


Could help to know more about the boat (engine set-up, exact batteries, charging capability, etc.); might be able to strawman some simple improvements...


-Chris

[a64pilot]

Coming from others comments, if they are 12V batts and Delco, they aren't deep cycle even if the label says they are.


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[darylat8750]

I know that you are looking for a quick solution to your immediate problem and several responses have referenced that.

Even if you are not technically inclined you will have a much more pleasant boating experience if you make the effort to get a firm grasp of basic 12 volt batteries and systems.
There are sticky threads in the electrical forums that will get you started. If after you have read about the differences between start batteries and deep cycle batteries (in the lower cost end many of us prefer golf cart batteries) and the difference between flooded lead acid, AGM (still lead acid but with a glass mat to "stabilize" sort of, the acid) and the strengths and weaknesses of the different styles you will be able to ask questions here that will have enough information for us to give sensible advice. Pictures of the batteries and your electrical panel may also be helpful. Welcome to the forum!

[Salty Mike]

Don,t most of these little diesels have a hand crank with them?

OP: How long have these batteries been lasting between charges with this configuration?

[MaxWebXperienZ]

Measurements around a dead battery problem have to be done thoughtfully. I'm qualified to sound off on this subject: Electronics Engineer and Tow Truck Driver are both on my resume'. I could start most cars with "dead battery" by jamming a coin into the space between the battery post and the connector to make a good contact. Batteries can charge through a poor connection because they take in current slowly. Motor starting takes, by far, the most current so a battery can charge up through a resistive connection but when you hit the starter switch much of the voltage will appear across the connection.

Some measurements to make:
--voltage across the battery with no load measured directly on the posts
--voltage across the battery with light load measured directly on the posts
--voltage across the battery with light load measured on the connectors
--voltage across the battery with starting load measured on the connectors
--voltage from the post to it's connector under motor starting load
--charging voltage

A quick and dirty check of the battery connections is to stick a screwdriver or coin into the gap between the post and it's connector and see if lights get brighter or the starter works better. Battery post cleaning is very simple with a baking soda paste and some wire brushing.

[deblen]

Originally Posted by theodyssey

hi all.

am sure this question has been answered before, but am anchored up in Swansboro and trying to find answers quickly.

long story short - came back to the boat last night to find that my batteries had both died.

the facts:

- they're AC Delco Marine
- bought in June '15
- used for the first time Sept '16
- being new, didn't know about keeping them 'wet' - so to speak - and saw that all cells desperately needed water
- they had been working fine since then [boatyard + shore power], and for the past 3 days
- 2 days ago, I had been both charging my iPhone + Macbook [computer] all day.
- anchored in Swansboro 2 nights ago, used a few LED lights, kept my 12v cooler on
- and then sometime between yesterday morning and last night, they died

so I'm about to call Boat US for a jump start, but am wondering which of the above do you think contributed to this? [meaning - what lesson do I learn from this?]

many thanks!

ps - speaking of which, does anyone have a good emergency jump pack they use? am seeing some tiny ones on Amazon that can charge either a phone or give your diesel a jump

You "saw that all cells.. needed water" and the batteries were "bought in Jun '15"
Suggests to me that they have been overcharged ("boiled") either by your alt. or shore power charger.
No way should they need water in 6 mos.
Boiling them will substantially reduce their capacity.
Top them up with distilled water & re-charge them with a good 3 stage charger.Verify that they are being charged at 14.4V or so using a digital volt meter. This should revive them.

Suggest you install a battery switch & use one battery for starting only.

Google "Maine Sail" for bat. & switch wiring ideas.
Perhaps someone could post Maine's wiring link here-I can't access mine at the moment.

Welcome to boating!

Cheers/ Len

[grantmc]

Just on a battery booster. I bought a 600 amp booster for what I thought would provide an emergency starter backup. Boat has a 14hp diesel. it's a bit of a joke and the best it can do is cause the starter go make a little noise but not enough to actually turn at a speed for starting.

But aren't there big white flappy things up above to make the boat go?

[Reefmagnet]

Originally Posted by grantmc

Just on a battery booster. I bought a 600 amp booster for what I thought would provide an emergency starter backup. Boat has a 14hp diesel. it's a bit of a joke and the best it can do is cause the starter go make a little noise but not enough to actually turn at a speed for starting.

But aren't there big white flappy things up above to make the boat go?

I can start my 33 HP jobby with a 1200 amp pack which is labelled as being able to start large SUV engines. Have to confess that where I was at the time didn't need the glowplugs to be preheated first.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[reed1v]

Get an amp meter that tells you how many amps are being used throughout the day. You drained your charge. Plus dried out cells will loose their ability to get recharged fully. You basically killed the battery. Normally, wet cells do not lose their electrolyte very quickly if at all. Would find out why they went dry. Chances are if the level was way below the plates you may need to add electrolyte and not just water to the cells. In any event, read up on battery care and get a new set. Better luck next time.