8D Flooded Start Batteries

How long do you guys get out of them on average?

We bought our boat with an 8D used as one of our start batteries. No record of when the PO purchased it. We replaced the battery eight years later. I take care of our batteries almost to the point of being committed to the ward!

Probably about 7 years or so if they are maintained. Do you need 8Ds or can you go smaller? I have 4Ds and they are overkill but the battery box is fiberglass and glassed into the hull so I haven’t messed with going smaller.

I got rid of those POS and installed 2 group 31 batteries

Had planned on leaving Hilton Head this morning but the engines wouldn't crank. We were on shore power for the last three days and the charger showed everything charged and on float.

Got a mechanic to come and check them out (still in a back brace and certainly can't deal with 8Ds!). The starboard one was completely dead, showing 10v and 10 CCA (out of 1400), so basically none!! The port, which had clearly been carrying the load was at 12.6v and 900 CCA. He said that could come back once we replace the bad battery.

These are only five years old and maintained by a Trace system. I checked levels in March and not since, we have only started using the boat this year in the last four weeks. We have been on this trip since Saturday and we ran outside for six hours on Monday with no trace of an issue until we got to this marina - then had what I thought was a thruster issue (which in hindsight was the battery issue as the thruster is run off the starts).

Sounds to me like a total early failure of the battery somehow.

Anyhow I had him replace both with 1800 CCA AGMs. We anchor out too much to be caught out.

Not cheap batteries and 165 pounds weight each! He needed another guy from their shop to come help with the lifting.

I had an 8D fail within 6 months while I was up the coast. They gave me a pro-rated rebate for the failed battery based on the original purchase price - but not the purchase price of the new battery in Bella Bella. My super expensive replacement is now on year 5.

We had a boat many years ago that had 5 8Ds in it. I paid a guy to do the install. What a PITA. Now the worst is the 4D start batteries but I replaced them 2 years ago so I hope they will last quite a while longer. I am going with Lithium for the house bank. They each weigh 23 pounds. Much nicer than the 4 or 8Ds.

Alaskan Sea-Duction said:

I got rid of those POS and installed 2 group 31 batteries

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I have 3 AGM 8Ds completed 7 seasons but will not replace in kind. A pair of GP31s are roughly equivalent and more reasonably handled.

I get about 10 years. You gotta keep the water over the plates and have a decent charger.

My current boat came with 21 year old 8ds, still held a charge. But they were Dyno Batteries.

I’m like Lepke 10 years on 8d’s but I too have Dyno 8d batteries. Menzies, how do your 8D’s get charged. My 8d’s are charged off of the house bank via a Smart ACR. Just using a standard ACR to charge start batteries will shorten their life. What happens with an ACR is start batteries get over charged, water boils out and the plates sulfate.

tiltrider1 said:

I’m like Lepke 10 years on 8d’s but I too have Dyno 8d batteries. Menzies, how do your 8D’s get charged. My 8d’s are charged off of the house bank via a Smart ACR. Just using a standard ACR to charge start batteries will shorten their life. What happens with an ACR is start batteries get over charged, water boils out and the plates sulfate.

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That could be the culprit. See pic below.

I had left this on while the boat was sitting idle for the last few months. When off the start batteries are charged by the alternators only - which he declared "golden" today both putting out 15 amps at idle (damn well should have been since they were just refurbished last September!).

When I took the cover off the battery box on the "better" battery there was liquid on top.

11 years out of start FLA 4D.
I have only 1.
It starts 2 propulsion engines and 1 generator. It has no other duties. It charges off a dumb regulator on the original 50 amp alternator that came on the Starboard engine. That alternator has no other duties.

koliver said:

11 years out of start FLA 4D.
I have only 1.
It starts 2 propulsion engines and 1 generator. It has no other duties. It charges off a dumb regulator on the original 50 amp alternator that came on the Starboard engine. That alternator has no other duties.

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Do you have a charged spare on board?

menzies said:

Do you have a charged spare on board?

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Yes.
4 6v GC FLA (House) available at the push of a button at the dash. In 26 yrs I have never had to use this. I have checked the solenoid periodically just to know that it is still there and operational.

Menzies, what engines do you have? A single Group 31 AGM is plenty to start our twin Lehman 135s and Westerbeke genset. A Balmar Duo Charge lets the alternators keep it topped up while we’re running. In an emergency, I can throw a switch and start any of the diesels with the house bank (a 1,248 A/H “charged spare”). I cursed my luck when I killed four 8D AGMs during the 2015 Polar Vortex. In retrospect, I see it as a lucky day which prodded me to redesign much of the electrical backbone on Stella.

menzies said:

How long do you guys get out of them on average?

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Buy Dyno batteries, charge them with a quality charger. Never worry. They last years, lots of years, under heavy use. Yes, I know you're on the east coast and Dyno is west coast. But shipping costs are small compared to failed batteries when you really need them.

angus99 said:

Menzies, what engines do you have? A single Group 31 AGM is plenty to start our twin Lehman 135s and Westerbeke genset. A Balmar Duo Charge lets the alternators keep it topped up while we’re running. In an emergency, I can throw a switch and start any of the diesels with the house bank (a 1,248 A/H “charged spare”). I cursed my luck when I killed four 8D AGMs during the 2015 Polar Vortex. In retrospect, I see it as a lucky day which prodded me to redesign much of the electrical backbone on Stella.

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Twin Luggers 174s.

However both the bow thruster and windlass run off the starts.

I need to leave the ACR off and let the alternators manage the starts. We have the Balmar.

Portage_Bay said:

Buy Dyno batteries, charge them with a quality charger. Never worry. They last years, lots of years, under heavy use. Yes, I know you're on the east coast and Dyno is west coast. But shipping costs are small compared to failed batteries when you really need them.

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Happened while a transient in Hilton Head. No time to shop around.

Not much you could do under the circumstances other than get the best battery you could and get going again.

menzies said:

Happened while a transient in Hilton Head. No time to shop around.

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Well I think I just discovered my issue.

Cruising from JAX to Marineland for a couple of days. I noticed the lights on my Glendinning controls started flashing. That's their alarm status. Usually a battery level issue. I went to the PH to check the voltage and found them reading at the top of the gauge - which goes to 32. (24v system). I pulled the throttles back and got it down.

When I had the new batteries installed in Hilton Head I had him check the alternators and they were "golden." I just had them refurbished last September.

So I suspect the Balmar regulator has gone bad. By trial and error I found that pulling the engines back to 1600 (we usually cruise at 1800) keeps the charge in the right place. I would imagine that I didn't notice the overcooking going to HH and that's how I over cooked the previous batteries.

She is going to the yard on monday for some new teak so I will have them look at it.

menzies said:

Well I think I just discovered my issue.

Cruising from JAX to Marineland for a couple of days. I noticed the lights on my Glendinning controls started flashing. That's their alarm status. Usually a battery level issue. I went to the PH to check the voltage and found them reading at the top of the gauge - which goes to 32. (24v system). I pulled the throttles back and got it down.

When I had the new batteries installed in Hilton Head I had him check the alternators and they were "golden." I just had them refurbished last September.

So I suspect the Balmar regulator has gone bad. By trial and error I found that pulling the engines back to 1600 (we usually cruise at 1800) keeps the charge in the right place. I would imagine that I didn't notice the overcooking going to HH and that's how I over cooked the previous batteries.

She is going to the yard on monday for some new teak so I will have them look at it.

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Hopefully, they’ll check to see if the settings have been compromised and try a reset. It takes a magnetic tool for the reed switch but is easy enough with plenty of how-tos on YouTube.

Over charge agms by high voltage is certainly a death sentence even for the new ones. Do whatever you have to to stop that immediately!

High Wire said:

Over charge agms by high voltage is certainly a death sentence even for the new ones. Do whatever you have to to stop that immediately!

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Yep, 1600 kept the charge around 27v and in the green.

Lost a knot and a half and will cruise home on that and to the yard on Monday.

I do wonder about the Balmar though - it just looks like an open small mother board in a very abrasive environment.

When I saw the words Menzies and 8D in the same post I thought we’d lost you.

8 D battery life

How long the battery will last depends on its usage. The life of my 8D's was determined by: 1. how many charging cycles. 2. The kinds of loads it carries...inverter vs start. 3. How badly abused...how far down do you draw the battery before recharging. Lead acids and gel-cell have different life spans.

Check with you local battery dealer, explain how it is used and he should be able to give you a reasonable estimated life span.

10 yrs.