My 8d starting battery may dead, advice?

I purchased the boat in August, but just got a chance to check the water level in the battery. It took 2.5 gallons to fill it up. So maybe damaged?
How to have it tested?
If toasted what is recommended for replacement? The previous owner thought maybe I could down size to a 4d. He replaced the engine a couple years back with JD 4045, so he thought it could maybe use less starting power?
If replacing with a 8d what is a good economical battery? Interstate has one for 260$
Thanks

Is this just the starting battery or is it a house battery, or both?

If you do a quick forum search, we just had a thread about this not too long ago.

2.6 boat dollars it takes more effort to think about it than doing it

Mach_cat said:

I purchased the boat in August, but just got a chance to check the water level in the battery. It took 2.5 gallons to fill it up. So maybe damaged?
How to have it tested?
If toasted what is recommended for replacement? The previous owner thought maybe I could down size to a 4d. He replaced the engine a couple years back with JD 4045, so he thought it could maybe use less starting power?
If replacing with a 8d what is a good economical battery? Interstate has one for 260$
Thanks

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Probably dead....occasionally you can fill them up and a good charger will bring them back....

Or ones that I have had with bad water loss and they only lasted months at best before overheating and twice causing a nighttime scramble to disconnect and put ashore.

I would check with JD and see, but my bet is you can go way smaller than even a 4D.

I have a group 34 Optima battery for my JD 4045tfm75 which is more than adequate. Now if you're going to run house loads (refrigerator, etc) you probably need something else.

Ted

9 months is long enough to produce a new human being, much too long to check battery fluid level.
2.5 gallons is a lot of water. What is the battery doing after its big drink? Is it charging up and holding? Can you hit it with an equalizer charge? At least check it before you replace it, that said, it does not bode well.
At the risk of drawing in the snake oil supporters and opponents, a potion claimed to desulphate and revive a battery is cadmium sulfate,sold here as Inox Battery Conditioner. I found seriously underwatered batts not long after purchase, used it on the 2 of 3 batts which tested ok, dumped/replaced the one that didn`t, got a year out of the 8D "connected" to the other 8D, and 3 years out of the 6D serving the genset. Did the stuff help, not sure, I`d have to test(treat one and not the other) identical batts to know, search it yourself, see what you think, it gets a good rap.

This is only the starting battery, house batteries are 2 8d gel batteries.
I was overseas in India until Christmas so no way to check them.
Having work done on the boat and they pulled the starting battery to get space, so I was able to get the water checked easy.

Ted I believe you and have the same engine, yours is turbo charged too?
I may have many more questions for you. My boat goes in the water in 2 weeks so I am learning her systems.

Ed

Mach_cat said:

This is only the starting battery, house batteries are 2 8d gel batteries.
I was overseas in India until Christmas so no way to check them.
Having work done on the boat and they pulled the starting battery to get space, so I was able to get the water checked easy.

Ted I believe you and have the same engine, yours is turbo charged too?
I may have many more questions for you. My boat goes in the water in 2 weeks so I am learning her systems.

Ed

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That's your first mistake.

Yes mine is turbo charged. If you have other questions you can PM me.

Ted

gaston said:

2.6 boat dollars it takes more effort to think about it than doing it

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Actually that is 0.26 boat dollars.

I hate 8D batteries. They are stupid bloody back breakers. If you have to have the amps, replace it with two lighter batteries. Do I sound angry? It's a personal thing.

I would replace it with something much smaller since it is just for starting. Smaller will be easier to install.

HopCar said:

I hate 8D batteries. They are stupid bloody back breakers. If you have to have the amps, replace it with two lighter batteries. Do I sound angry? It's a personal thing.

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its not that personal I am equally angry about 8Ds.

Is a Goup 31 enough to start that engine? If so, that would be nice.

Is the start battery easily accessible? If not, consider an AGM. If it is easy to get to, then I would just put a cheap wet LA in there. A start battery only has to one thing, and that isn't that hard. If a cheap AL battery craps out on you, that is what jumper cables are for.

Somewhat easy, drop through small hatch do some yoga moves and yes you can get to it. If I was younger it would a cinch.
The house batteries are harder to get to they are gel.

Mach_cat said:

Somewhat easy, drop through small hatch do some yoga moves and yes you can get to it. If I was younger it would a cinch.
The house batteries are harder to get to they are gel.

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Sounds like my house and thruster batteries. If you dread the prospect of checking on the water level every day, then go with AGM, or use a watering system as was recommended to me. One of the problems is that even if the battery is easy to reach, it may not be easy to see inside the cell to see the level. That is where one of those watering systems would be nice.

FWIW, I think that when I have to replace the 4 sealed LA 8D batteries in my aft lazarette, I may convert to golf cart batteries and use a watering system. The LA batteries have worked well on this boat for 7 years and I've had good luck with them in my other boats.

Replace the 8D with two group 31 and that should provide MORE than enough oomph to crank that engine smartly. They should fit into the tray the 8D left.

Just fill the space left with blocking so the batteries cannot move around. Leave a space between them, but blocked, about 3/4" for air. Not likely they will build any heat when recharging but that air space will prevent excess recharge heat build up. Yeah I'm being picky but I've done that.

C lectric is spot on.

Would not be a bad idea to check your battery charger for overcharging.

Mach_cat said:

If toasted what is recommended for replacement? The previous owner thought maybe I could down size to a 4d. He replaced the engine a couple years back with JD 4045, so he thought it could maybe use less starting power?

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You should be able to look up minimum cranking specs (CCAs/MCAs) for the JD 4045. Your starter may also have a tag with minimum cranking specs.

Once you know that, you can decide how much battery you need as a replacement.

Usually you'd want a bit of a cushion, but I'd guess maybe a pair of G31s would work... pending what you learn about specs.

If you're not able to inspect water levels often or easily, you might want to investigate sealed batteries, perhaps AGMs. Lots of threads about those.

-Chris

HopCar said:

I hate 8D batteries. They are stupid bloody back breakers. If you have to have the amps, replace it with two lighter batteries. Do I sound angry? It's a personal thing.

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8Ds have helped my spinal specialist afford a bigger boat.

0.26 of a boat dollar. Buy 2 - 12 volt sealed batteries from Costco. Long warranty, hordes of power, long warranty.

Someone else mentioned the charger already, but in all seriousness, I would look at that very carefully. You don't want to install a new battery until you are sure your charger is working properly.

If you added that much water to an 8D, it really sounds like the charger boiled it all out. And If this is not a modern marine "smart" charger, then by all means replace it before you install the new battery.

I dumped my 8D's long ago and down sized to a more manageable 4D LA battery and you don't lose much in CCA's. I have used Interstate and found them to be a good battery that will last 9 - 10 years, if you don't kill them with a bad charger or an inverter.

I may have been the person referenced before that started an identical thread when I boiled off all the water in my 6 house bank batteries.

Listen very carefully to @Edelweiss -- I ended up having to replace my battery charger as well, after it fried my starter. Since replacing it my electrical system has been solid as a rock.

Also, take my advice and don't tell your wife that the reason you need to spend a couple hundred dollars on new batteries because you didn't check the water level for a few months... she still reminds me of that fact. ;-)

There is overcharging happening if you feel you need to check battery levels daily. Two weeks is recommended by Trojan.

8d is very heavy. Recommend 2 smaller batteries that fit in same box wired together. You can probably get more amp hours as well if desired with this configuration.

Called the Battery folks and got the following quotes,

6 of the 2000 series is $360 for all.

6 of the T 105 are $515 for all, the

L16's are expensive as always $296 each

All with trade in and Ca$h payment

239 693 9400,,, 3911 Palm Beach Blvd.Ft Myers FL

Hope this helps folks with local price dickering.

Utilizing as house bank and also as twin engine starter batts... I have four, LA, deep cycle group 31's in parallel. Been 8 years since purchasing them at Battery Plus store. Sill doing good.

For gen set I have one, LA group 27 starter batt

Kept as an "emergency" batt I have one, LA group 27 starter batt isolated in separate black batt box and kept at 100% charge.

This simple, inexpensive. full-scope battery set up works well for us. We are conservative using batt power. Gen set often runs 1 to 1.5 hrs mid morn and mid eve. Keeps batts charged as well as fridge cool and phones, computers charged. Powers stove/oven when needed too!

I replaced my 8D start battery with a 4D for starting a pair of 6BTA Cummins. Plenty of CCA for the job.

I bought a single G31 from Costco for $90 that replaces my 8D start for 2 Perkins 4.236's. It never has a problem starting my twins, back to back. And it comes with a 100% 60 month no-questions-asked warranty. It would be a piece of cake to parallel 2 of these G31's in an 8D box as a great replacement package for most 8D start installations.