Engine Battery Dead

[Ian_Rob]

In the three weeks since I was last aboard, my engine battery has died. The engine wouldn’t start and when I checked the voltage it read 3.2v. It is/was a Lead Acid, 70Ah ‘Dynamic Silver’ (24F) and just over over 5 years old. Its predecessor lasted 11 years. Any recommendations for a replacement?

 

[Tranona]

Similar size AGM stop start battery such as fitted tto cars like fiestas. Exide a good bet

 

[Fr J Hackett]

I fitted a Red Top ( Red Start) to a yacht 15 years ago from the details and pictures of the yacht on a brokerage site it's still there and presumably doing what it's intended to.

 

[Ian_Rob]

Similar size AGM stop start battery such as fitted tto cars like fiestas. Exide a good bet

Thanks T. I like the idea of fitting of an AGM. Is the charging regime the same as lead acids and therefore just a straightforward swap?

 

[Tranona]

Yes, straight swap in electrical terms. You should also be able to find one that is the same size and layout of terminals.

 

[ss2016]

Tranona, apologies but I am about to partially contradict you.

Ian, I asked VP that question about my boat. The answer does depend on your alternator so you may not have a problem. (My alternator is the standard one on a D6-400) This is what VP said in answer to me:

Alternator charging 13.8v -14.4v float charge voltage.

AGM batteries require 14.6v – 14.8v absorption charge voltage to fully charge.

The alternator is not adjustable for output; it is capped by the internal regulator.

The output voltage of our alternator/regulators would be an unhappy medium for AGM batteries – too low for absorption, too high for float.

Low regulator voltages around 13.5V are pretty good for floating AGMs, but will never charge them fully.

The higher regulator outputs of 14.4V are still a bit low for proper absorption voltage, but much too high for float. You could end with premature replacement of the AGM batteries.

 

[PaulRainbow]

In the three weeks since I was last aboard, my engine battery has died. The engine wouldn’t start and when I checked the voltage it read 3.2v. It is/was a Lead Acid, 70Ah ‘Dynamic Silver’ (24F) and just over over 5 years old. Its predecessor lasted 11 years. Any recommendations for a replacement?

That's a Calcium battery, which needs 14.8v to fully charge it.

I'd fit a bog standard lead acid battery.

 

[noelex]

A lifespan of just over five years is not unusual for a start battery, but just as a reminder, always check the charging system is working correctly after the new battery has been installed.

 

[VicS]

In the three weeks since I was last aboard, my engine battery has died. The engine wouldn’t start and when I checked the voltage it read 3.2v. It is/was a Lead Acid, 70Ah ‘Dynamic Silver’ (24F) and just over over 5 years old. Its predecessor lasted 11 years. Any recommendations for a replacement?

Having had some remarkably good lifespans for my car batteries I am now completely sold on Yuasa batteries . Two have lasted in excess of 10 years and the current one is about 8 years old and still going strong.

.

 

[Ian_Rob]

Thanks everybody. There is so much contradictory info online on batteries that I am rather confused.

I too understood that ‘AGM batteries require 14.6v – 14.8v absorption charge voltage to fully charge’ as VP says & ss2016 quotes above but the Exide AGM’s I have bought, specifically states 14.4 volts max in the brochures that stuck to the side of the battery (photo attached).

As it happens, that’s the absorption voltage that my QUICK SBC250 battery charger delivers if I change it to its GEL setting so hopefully that will be okay when using shorepower.

However, according to the SBC250 manual (graph attached) , it delivers a float charge 13.8 v on the GEL setting but as the battery brochure doesn’t give a recommended voltage for the float stage, I am not sure if that is okay or not.

I am now a little worried re the alternator output which I will have to check when I am next down………

 

[PaulRainbow]

An engine battery only has to do one thing, start the engine, so why not just use........... an engine start battery.

Decent lead acid is about £50, similar AGM at least double.

 

[Tranona]

The Exide IS a start battery - a type used in millions of cars to start the engine (both diesel and petrol). The difference from a cheap LA is that it has higher charge acceptance, lower self discharge and, because it is designed for stop start a much greater number of cycles and therefore longer life.

 

[PaulRainbow]

The Exide IS a start battery - a type used in millions of cars to start the engine (both diesel and petrol). The difference from a cheap LA is that it has higher charge acceptance, lower self discharge and, because it is designed for stop start a much greater number of cycles and therefore longer life.

It is a start battery intended for a specific application, STOP-START. Higher charge acceptance and lower self discharge are important in that application, not so in a typical boat. It costs at least twice as much as a standard starter battery, which will perform perfectly well in a boat and last for many years if looked after. If the battery is not looked after (typically, that means not fully charging it) it obviously doesn't last as long, but that applies to the AGM battery too, in fact, the AGM is more likely to suffer an early death in cases of under charging, due to the requirements for higher charging voltages which older alternators cannot supply.

From post #6, VP agree with me.

 

[B27]

Thanks everybody. There is so much contradictory info online on batteries that I am rather confused.

I too understood that ‘AGM batteries require 14.6v – 14.8v absorption charge voltage to fully charge’ as VP says & ss2016 quotes above but the Exide AGM’s I have bought, specifically states 14.4 volts max in the brochures that stuck to the side of the battery (photo attached).

As it happens, that’s the absorption voltage that my QUICK SBC250 battery charger delivers if I change it to its GEL setting so hopefully that will be okay when using shorepower.

However, according to the SBC250 manual (graph attached) , it delivers a float charge 13.8 v on the GEL setting but as the battery brochure doesn’t give a recommended voltage for the float stage, I am not sure if that is okay or not.

I am now a little worried re the alternator output which I will have to check when I am next down………

There are a lot of mis-conceptions about batteries 'requiring' certain charge regimes.
Talking about the absorption voltage without saying how you're going to define the end of the absorption phase is not helpful.

Charging regimes are a compromise between quick charging, efficient charging and gassing among other things.

What makers recommend varies with the application the battery is sold for.

You can charge a lead acid battery at 14.1V, but it will take a long time.
You can charge it at 15V, but it will gas a lot if you continue the charge too far towards 100% SOC.
14.4 is a typical figure for a dumb car alternator which doesn't have any intelligence to turn the volts down when the battery is full.

13.8 is on the high side for float, plain wet LA batteries will often dry out at this voltage over time.
But many batteries are sold into a world where they are cycled every day and not left to 'float' for days/weeks/months as happens with many yachts. The 'correct' float voltage will depend on what SOC you expect when you switch to float and how long you anticipate 'floating'.
More modern car batteries are more tolerant of 'abuse' , but the published info is a big limited.

 

[PaulRainbow]

There are a lot of mis-conceptions about batteries 'requiring' certain charge regimes.
Talking about the absorption voltage without saying how you're going to define the end of the absorption phase is not helpful.

Charging regimes are a compromise between quick charging, efficient charging and gassing among other things.

What makers recommend varies with the application the battery is sold for.

You can charge a lead acid battery at 14.1V, but it will take a long time.
You can charge it at 15V, but it will gas a lot if you continue the charge too far towards 100% SOC.
14.4 is a typical figure for a dumb car alternator which doesn't have any intelligence to turn the volts down when the battery is full.

13.8 is on the high side for float, plain wet LA batteries will often dry out at this voltage over time.
But many batteries are sold into a world where they are cycled every day and not left to 'float' for days/weeks/months as happens with many yachts. The 'correct' float voltage will depend on what SOC you expect when you switch to float and how long you anticipate 'floating'.

There is so much misinformation in the above i just don't have the time (or will) to correct it.

More modern car batteries are more tolerant of 'abuse' , but the published info is a big limited.

Nothing especially "more modern" about car batteries, they are all lead acid. Batteries in cars rarely get abused, they start the engine, you drive around and the battery gets charged. If you turn electrical consumers on the alternator will supply the [power without depleting the battery.

The "more modern" bit with respect to csrs is not the battery, but the way they are charged/managed. Most modern cars now have smart charging systems.

 

[Refueler]

Talking to Car Lectrics guy other day - I asked him if it was still situation that most cars do not fully charge batterys .. he reckoned still true. That cars charge set is to be slightly less than 100% ... anywhere 94% and up.

What annoys me with cars to day ... my Volvo and Range Rover are both bad for it. The audio and other systems that are alive run down the battery when parked. Gone are the days you could park your car for a month and go back to it and it was still well charged. Now lucky if car stands 2 weeks before battery is barely able to start the car !

 

[Tranona]

It is a start battery intended for a specific application, STOP-START. Higher charge acceptance and lower self discharge are important in that application, not so in a typical boat. It costs at least twice as much as a standard starter battery, which will perform perfectly well in a boat and last for many years if looked after. If the battery is not looked after (typically, that means not fully charging it) it obviously doesn't last as long, but that applies to the AGM battery too, in fact, the AGM is more likely to suffer an early death in cases of under charging, due to the requirements for higher charging voltages which older alternators cannot supply.

From post #6, VP agree with me.

Well, Bavaria fitted that Exide to all its boats in the 2013-2018 and may well still do. The properties are well matched to boat use and mine were still fine after 6 years starting a Volvo engine with every expectation of double that. The AGM in my Morgan which has a similar usage cycle to a boat engine - long periods of inactivity followed by short periods of intense use lasted 19 years. so depends on your time horizon - it may be twice the cost but is likely to last more than twice as long.

BTW the engine in post#6 was a D6 - 400. I have no idea what alternator is fitted nor how it is regulated but doubt it is the same as on the D1 and D2 yacht engines. OP does not say what his engine or alternator is, only talks about his shorepower charger, which is really not necessary for a start battery.

 

[B27]

There is so much misinformation in the above i just don't have the time (or will) to correct it.

Nothing especially "more modern" about car batteries, they are all lead acid. Batteries in cars rarely get abused, they start the engine, you drive around and the battery gets charged. If you turn electrical consumers on the alternator will supply the [power without depleting the battery.

The "more modern" bit with respect to csrs is not the battery, but the way they are charged/managed. Most modern cars now have smart charging systems.

Car batteries these days are often not pure 'lead acid' the 'lead' is an alloy containing among other things, calcium.
They also may recombine O2 and H2 gas products instead of drying out or needing water like a Trojan style battery..
That helps them tolerate overcharge from non-ideal solar regulation, or whatever.
Hence your premium OEM batteries are often still in the car after a dozen years, which would be unheard of when I first had a car.

 

[PaulRainbow]

Car batteries these days are often not pure 'lead acid' the 'lead' is an alloy containing among other things, calcium.

Calcium batteries require a 14.8v absorption charge, how many boat alternators can produce that ? Certainly not he OPs, his calcium battery didn't last long.

This is why i said "fit a bog standard lead acid battery.

They also may recombine O2 and H2 gas products instead of drying out or needing water like a Trojan style battery..

Again, this requires a higher charging voltage.

That helps them tolerate overcharge from non-ideal solar regulation, or whatever.
Hence your premium OEM batteries are often still in the car after a dozen years, which would be unheard of when I first had a car.

Better to fit a decent solar controller.

 

[Sandy]

Talking to Car Lectrics guy other day - I asked him if it was still situation that most cars do not fully charge batterys .. he reckoned still true. That cars charge set is to be slightly less than 100% ... anywhere 94% and up.

What annoys me with cars to day ... my Volvo and Range Rover are both bad for it. The audio and other systems that are alive run down the battery when parked. Gone are the days you could park your car for a month and go back to it and it was still well charged. Now lucky if car stands 2 weeks before battery is barely able to start the car !

Do you not 'disconnect'* the battery when away for long periods of time?

* have a hidden switch that a) stops the battery running down with all the 'faff' of modern vehicles b) confuses the car thief when they can't start your automobile.