Battery Life

[Dave_E]

Hi All,

The 8D and the 3 of the 4 6v GCB's are all 5 years old. They are kept on the charger 24/7. The last battery hydrometer reading showed almost all of the cells are the green.

Question for you all. What kind of battery life are you getting out of your flooded cell batteries?

Dave

 

[Dave_E]

Didn't see the recent post about batteries.

 

[firehoser75]

Dave,
So many variables it is hard to say. Most batteries are "murdered" by their owners, they don't usually just wear (age) out. Not recharging them regularly to a full 100% charge, or in other words operating them at a partial state of charge (PSOC) is the killer. It takes over 6 hours of charging (even with a properly sized and configured charger) to achieve this 100%. So unless you are going from dock to dock and plugging in, or have solar, or make long runs every couple of days (over 6 hours) and have a high output alternator with external regulation and temperature sensing, you are probably "murdering" your batteries. Other factors like regular depth of discharge factor in as well. Some people can expect only a couple of years (or even less) from their batteries. Others, who treat them at least a bit better, will get longer, sometimes much longer. If FLA's are well treated and are of a reasonable quality, they can last over 7 years, maybe more.
Lots of variation is possible due to charging equipment, settings, use, maintenance, etc. as well.
Hope that helps.

 

[MurrayM]

Our four 6 volt Exide GC135 golf cart flooded lead acid house bank batteries in series parallel are 6 years old and doing fine.

We keep our boat on shore power for six months when nights can be below freezing to run the heaters and charge the batteries, but don’t connect to shore power for the other six months of the year: we charge the batteries by using the boat.

I disconnected the shorepower last week and 24 hours later the starting battery and house bank showed 12.65 and 12.60 on the Smartguage.

We have an internally regulated Hamilton Ferris PowerMax LT100s alternator, which is a beast compared to the original Hitachi.

https://hamiltonferris.com/products/Alternators/PowerMax_LT_Small_Case/9

We hardly ever have a run longer than 6 hours...maybe a couple times a year. What I think makes them last is that we never even approach taking them to a 50% state of charge.

We usually anchor for a couple days, then motor 2 to 4 hours to the next stop, and go very lightly on anything electrical. We do stop and hover quite a bit photographing scenery and critters while running the engine at an idle.

Just hooked up 75 watts of solar panels, so it’s weird to go to the boat and see the batteries at 100% even though we haven’t been down there in a week!

Looking forward to cruising with the solar panels and being a little more carefree about electrical use

 

[Dave_E]

Thanks for the replies. This weekend I had a diver out to the boat and he unplugged our shore power for his compressor. For the hour and a half he was in the water I watched the batteries (5 years old remember). First thing they did after the surface charge went away was settle to 12.8V. So.... I left the battery charger off until this morning and watched the house bank with the voltmeter. It would go down to 12.75 after the water pump would run and then climb back to 12.8. I have all LED lighting and the refrigerator was on shore power. As I mentioned in the OP, the specific gravity in all but a couple cells is in the green. With todays state of the art chargers that "read" the batteries and keeps them topped up, can't see that keeping them on the charger 24/7 does them any harm at all. If I did the "hook" thing, I might feel different, don't know. We are marina to marina types with our longest trip around 7 hours... and I have 2 alternators. This boat has been to Alaska from Bellingham, WA four times. Two battery banks, 2 alternators (1 is high amp output), and a Northern lights generator and of course shore power. It's got way more than we'll use I'm sure.

 

[Pete Meisinger]

In my experience, the 8Ds will die long before the golf cart batteries. In fact they are probably nearly dead now.

pete

 

[Andy G]

A slight hijack, but not too much.

We have just replaced all our batteries after about 6 years(2x 260amp AGM's +1 x 160 amp unit). The previous set lasted about 8 years, so I was a little disappointed. The boat lives on shore power with a smart charger.

Before installing the new set I got a good marine electrician to go over our wiring. Well, that was an eye opener. A lot of the wiring had been an added on over the years and a lot of the old wiring was disconnected and left in place, some not even disconnected as it turns out. In short the old wiring was removed and replaced as well as the earth leads. We also found out that one of the battery regulators was faulty, incorrectly reading the charge.

The exercise was quite expensive, circa $2,000, but given the cost of batteries and the importance of the electrical system on the boat I thought this was money well spent. Additionally, hopefully this will give me an extra couple of years out of the new set of batteries.

 

[markpierce]

My 2011 new-boat's AGM batteries died in 2019.

 

[FF]

"In my experience, the 8Ds will die long before the golf cart batteries. In fact they are probably nearly dead now."

This is true as most 8D are simple start batteries , not built for deep cycle service like golf carts.

Special (surette)) 8D can be ordered as deep cycle , but are expensive.

In larger sizes the Surette 2 volts are probably longest lasting , but expensive and heavy.
Batteries | Rolls Battery

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Motive Power. 6 Volt; 8 Volt; 12 Volt; All. Product Line – 2V Motive Power · Product Line – Motive Power FS · Rolls Battery User Manual .

 

[MurrayM]

Just hooked up 75 watts of solar panels, so it’s weird to go to the boat and see the batteries at 100% even though we haven’t been down there in a week!

OOPS...should have said 150W of solar