Replacing 8D

Hello all:

After 5 yrs of service, both my AGM 8D died together. I use them as all around, starting two NA 3208 and as house batteries. At 160lbs it a pain to get them out, my mechanic recomended, and I find reasonable, to replace the pair of 8D's with 4 group 31 batteries. For one, handling, cheaper and he has a Hatteras 38 with detroits and claims a single 31 starts the motors without any problems. I like the idea, I want to see if anyone has done so or any issues?
Ohana is always on shore power while in the marina and my 8kw Onan has his own batery, so I really do not require long term power from them.

orvals said:

Hello all: After 5 yrs of service, both my AGM 8D died together. I use them as all around, starting two NA 3208 and as house batteries. At 160lbs it a pain to get them out, my mechanic recomended, and I find reasonable, to replace the pair of 8D's with 4 group 31 batteries. For one, handling, cheaper and he has a Hatteras 38 with detroits and claims a single 31 starts the motors without any problems. I like the idea, I want to see if anyone has done so or any issues? Ohana is always on shore power while in the marina and my 8kw Onan has his own batery, so I really do not require long term power from them.

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When we took out our old 8D and out the new ones in (10), we used starboard and cardboard. also if you have a davit at your disposal that's always helpful. As for the 4 batteries instead of 2 , I'd say go with two of same. Some pics of when we did ours, needless to say its a 2+ Person job.

Another battery to look at is the Odyssey PC2250. It's designed to be half the size of an 8D so two of them will fit in a box designed for a single 8D.
Odyssey are terrific batteries but expensive.
ODYSSEY Batteries - Battery Specifications

If you have an additional 4-5cm of vertical space, you can fit 3 6V golf cart batteries in the same footprint of the old 8D. Six 6V GC batteries can be wired in series/parallel to supply up to 50% more amp hours than the 2 8Ds. At about 65 lbs each, they're much easier on the back.

Most series 31 I have seen are just starting batts , great for a start but die very early when deep cycled, as all starts do..

4 - 6V deep cycle golf cart batts , and 1 or 2 ser 31 would be a better choice.

Oddesy or similar big bucks batts would be fine , but the cost is excessive , unless you can and do set up for their rapid absorbtion ability with a massive alternator setup.

All the new mid-sized Sea Rays and Meridians at the dealership I worked at a few years came from the factory with Group 31s as start battery banks. The engines were mostly Cat 3116s, 3126s and Cummins of different models through the years.

orvals said:

After 5 yrs of service, both my AGM 8D died together. I use them as all around, starting two NA 3208 and as house batteries. At 160lbs it a pain to get them out, my mechanic recomended, and I find reasonable, to replace the pair of 8D's with 4 group 31 batteries. For one, handling, cheaper and he has a Hatteras 38 with detroits and claims a single 31 starts the motors without any problems. I like the idea, I want to see if anyone has done so or any issues?

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Our set-up is similar to yours: two main banks (each starts a Cummins 450C, runs half the house, runs half the bridge) plus a genset battery.

We have 3x Odyssey Group 31 (PC2150s) AGMs on each main bank, works fine. The oldest bank just finished it's 8th season.

Our bridge load (electronics) on the starboard bank is fairly significant, though, so I'm considering changing that older bank to 4x 6V golf cart batteries (series/parallel) instead... it looks like we have space to do that, and it would increase our available amp-hours on that bank from 300 to 440.

But the current set-up works well.

-Chris

orvals said:

Hello all:

After 5 yrs of service, both my AGM 8D died together. I use them as all around, starting two NA 3208 and as house batteries. At 160lbs it a pain to get them out, my mechanic recomended, and I find reasonable, to replace the pair of 8D's with 4 group 31 batteries. For one, handling, cheaper and he has a Hatteras 38 with detroits and claims a single 31 starts the motors without any problems. I like the idea, I want to see if anyone has done so or any issues?
Ohana is always on shore power while in the marina and my 8kw Onan has his own batery, so I really do not require long term power from them.

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Lots of good suggestions on replacement options from the group. If I were in your situation I would be pissed because I spent good money on AGMs and they failed at five years. You should figure out if your charging regime caused the failure and correct it. Good luck.

fryedaze said:

Lots of good suggestions on replacement options from the group. If I were in your situation I would be pissed because I spent good money on AGMs and they failed at five years. You should figure out if your charging regime caused the failure and correct it. Good luck.

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I've been really pleased with my 2x g31 Deka AGM house bank (first set lasted 11 summers of cruising).

The wisdom on Cruisers Forum (sailing-oriented) seems to be that AGM life span can be very disappointing if they don't get pretty thoroughly recharged.

Ours are well recharged, as we're underway for several hours most days on the water, with Balmar alternator and MC-614 regulator. When not on the water, or tied up for more than a day, the Freedom-10's smart charger is usually plugged in. Both regulators are set for AGM.

orvals said:

Hello all:

After 5 yrs of service, both my AGM 8D died together.

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I'll second that. . . failure after five years points to a bad charging system or drawing the batteries down too hard. I use nothing but lead acid wet cell 4 D's and they last at least 9 -10 years each.

If you're not over using your batteries, such as drawing them down hard with an inverter, then your battery charger is suspect. You should have this checked out before you replace those batteries. A Smart charger will maintain those batteries properly and double their life.

Edelweiss said:

I'll second that. . . failure after five years points to a bad charging system or drawing the batteries down too hard. I use nothing but lead acid wet cell 4 D's and they last at least 9 -10 years each.

If you're not over using your batteries, such as drawing them down hard with an inverter, then your battery charger is suspect. You should have this checked out before you replace those batteries. A Smart charger will maintain those batteries properly and double their life.

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...and a state of charge (SOC) meter will always keep you aware of the battery charge state.

I had to change out my two 8D house batteries last year and I figured it may be the last time I might be able to do it solo....with the odd angles and such. I'm looking seriously at the six golf cart battery setup but depending on how much solar I have by that time, it may be wiser to spend the dough for the high-tech units Reubin talks about on his hi-brid Cat.

I just spent the weekend re doing all my batts. For the start bank I ended up using 4 grp24 AGM's. Very happy with results and cost. Had to make new cables too.

You'll never hear me complaining about house batteries dead and inverter problems. I have three Group 4Ds wet cells with watering systems. When I'm out my engines have 200 amps of alternators and my generator supplies a 40 amp modern three bank battery charger.
I looked at all my loads and changed my entire lighting load to LED. My refrigeration will run all day on the alternators and all night on the batteries. Then back to the generator or alternators or shore power. In my opinion expensive AGMs or gels and solar or inverters and clap trap are for blow boaters and tree huggers. I just do not have time or money for so little in return.

I use old style flooded grp 31's. Inexpensive, and one guy can handle easily. My 8.3l Cummins will start on one down to 40F (not real zippy though), and the second is a backup. I get at least five years out of them.

I don't see enough advantage in the the other battery types to warrant the additional cost.

orvals said:

Hello all:

I use them as all around, starting two NA 3208 and as house batteries.

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As suggested by others, there may be a better way. Most of us have separate house and start batteries. Maybe a step back and a fresh look at systems, chargers, inverter etc may be in order. If you don't want to change anything other than new batteries, at least consider a BMK to tell you battery state and health.

Depending on your battery location, I would look at the Lifeline AGM GPL-L16T. They come in 2, 6 or 12v models and three will fit in an 8D space but give you more amp hours.
As for the five years on your 8Ds - I would be trying to figure out why only 5 yrs.

Have you thought of using a product like Battery Minder - 12v Battery Charger, Battery Desulfator, Battery Maintainer, Charger
or nanopulser - :: NANOPULSER.COM.SG :: ???

These products claim to rejuvenate batteries that are dead from sulfation. I haven't tried either of them myself but have been thinking it may be a good idea to put one of them on my 5 YO battery bank. They claim to keep the batteries in like new condition.

Check out their websites and their claims.

Thanks for all the replies. I bought my Californian just 6 months ago and previous owner did use to buy top of the line equipment, hence the agm bateries. He did tell me the previous charger had died and the current charger is less than a year old. I do not recall the brand, but my mechanic did check it and told me " that is a very good charger, brand new". So, what went on with the bateries before me or what use he gave them, I do not know.
In my experience from many years on sailboats, all the magic agm, gel, or whatever claim to sell a really expensive battery, never worked. A well kept lead acid deep cycle will last very long if properly mantained. New to power boats, what I really want is enough juice to start my Cats. As I mentioned, when I need power, I start my generator. I' m in the tropics and we run the A/C all the time.
That being said, I do not want to spend $1600 in a pair of AGM 8D' s that might fail in 5 years. I do like the
Idea of having a battery that one person can carry, in case they go bad, I can take them out and have them tested, or exchanded or replaced.

I have 2 8D wet cell batteries, one for the house and one for house loads. I've had very good luck with them, I agree they are a pita to change but if taken care of that is not very often. I'll probably be to brittle to change mine when the time comes. If so I'll pay someone to do it, my cables & clamps are in good condition and adding more connection points required by multiple batteries add possible points of failure and maintenance. Some systems because of the amount of draw from different items need large battery banks because the owners don't have a generator or have one and prefer not to use it. If I'am carrying a generator around and my battery bank is large enough to carry the load overnight and what's required when the mains aren't running then I don't need to add the weight and sacrifice the room required by adding a bunch more batteries and inverter.

Update!

Finally replaced both AGM 8D's with regular lead acid 4D's. Charger was fine, my mechanic went to check hoses, belts and clamps, by chance touched port engine alternator and it was very hot... i.e shorted. Probable cause to damage or ruin the AGM's so that might had been the culprit. Rebuilt the alternator for $125.
New batteries, oil, coolant, thermostats and belts.... Ready to put more hours on the old 3208's

Sorry, I have to correct something on my previous post, just learned that the caterpillars do not have thermostats, they are temperature regulators!

>very hot... i.e shorted.<

If the alt was hot all that was most likely shorted was the internal V regulator.

Leading the field wire out will allow the use of a MARINE 3 or 4 stage V regulator .

Far shorter charge times underway.