Batteries - Life Span?

C

ctelfer38

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Haslar UK
www.classic-cruising.com
I have two battery banks, each of two Delco batteries. Two heavy dutybatteries connected to give 140AH for the engine starter and two deep cycle batteries connected to give capacity of 140AH to the domestic/instrument system. Engine is Volvo Penta 2003 with a standard alternator and there is a trickle charger which tops up when in a marina. The domestic bank seems to last no more than two seasons before the batteries begin to lose their charge - despite regular checks and topping up with Ionised water. What experience are others having with life span of reasonably well maintained batteries? Any comments or advice welcomed. Any opinions on 'non-maintenance' gel filled batteries or indeed of favoured battery brands? /forums/images/graemlins/cool.gif
 
Domestic 8-10 years, engine/domestic 5-7. I don't have a dedicated engine battery.

The problem lies in your "trickle-charger". You need a pulse-charger such as a switch mode charger.

Lead acid batteries won't stand overcharging - likewise a dumb charger will promote an hysteresis effect, with the charge stopping earlier and earlier in the cycle.

Personally, for marine use, I'd recommend a conventional flooded lead-acid battery, built to industrial (fork-lift or golf-cart) specs. Low maintenance (or sealed batteries) are for the lazy/incompetent.

Curiously I have 2 sealed batteries in my boat currently - but that's another story - they're definitely inferior in almost every aspect to the one flooded, industrial lead-acid battery I have.
 
Agree with Charles - you need a smart charger that varies its output to suit the need.

Also Ah is not the critical thing for the engine battery its cranking current (CCA). On my V2003 I had a RedFlash 17Ah gel battery with high CCA for starting - worked a treat and quite small - half a shoe-box size.
 
A 2 year life is poor and indicates the batteries are poor quality or they are having a very hard life.
The most common battery mistreatment is excessive discharge and /or undercharging.
How many AHRS do you draw from your system before recharging? What voltage are they charged at ?
If the calculations show they are cycled between say 30 and 70% 2 years is about what would be expected from an average” deep cycle” battery. If however you have maintained them between 60 and 90% a 2 year life is very poor and it is time to try a new brand.
 
Two heavy duty batteries for engine start is overkill. If i really is a dedicated engine start battery that you don't ever run the domestics off, then one battery should be fine. This might mean that you can rewire the batteries to give you 420 Ah of domestic capacity.

I suspect that the real problem is that you might be regularly discharging your domestics to less than 50% of their capacity and then compounding this by not recharging them to anywhere near 100%.

How do you charge the batteries? Can you describe your charging system and the way that you run things in more detail?
 
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Low maintenance (or sealed batteries) are for the lazy/incompetent.


[/ QUOTE ]
Ouch...
My domestic batteries are so buried in my port-side cockpit locker - under the flooring - that to check the level means removing all locker contents then to raise the boards and clamber down to do so. Sealed batteries are a boon in this situation and are still in use after four years since I bought the boat - I don't know their installation date but when I do have to replace them it will be with similar, sealed ones.
 
I agree with the other posters that:
a) You may not be charging the batteries correctly
b) You may be discharging them too heavily. I suspect this is more likely

You might find a visit to batteryuniversity.com useful as this gives good info. Re the discharge issue they say;"Lead-acid does not like deep cycling. A full discharge causes extra strain and each cycle robs the battery of some service life. This wear-down characteristic also applies to other battery chemistries in varying degrees. To prevent the battery from being stressed through repetitive deep discharge, a larger battery is recommended. Lead-acid is inexpensive but the operational costs can be higher than a nickel-based system if repetitive full cycles are required."

You may find this graph useful too - it shows battery life cycles relative to discharge depth for lead acid:
http://www.mpoweruk.com/life.htm#dod

You seem to be over-specced on the cranking front. I cranked and started my 6KVA genset 60 times in a row from a 80amh Lifeline AGM battery - I was quite impressed! (but don't ask why I had to do it..).

You might want to decommision one of the crankers and use the space to increase your house bank (remember to put the pos and neg cables at the extreme ends of the 'bank').

We use Trojan T105s ("golf cart") for the house bank and I have switched to Lifeline AGMs for cranking, but that's because we leave the boat for months (not I hope because we are lazy and incompetent!). The AGMs have a low self discharge rate whereas the Trojans are kept topped up by the solar panels.

If mixing your battery types be careful to observe that they may require different charging regimes. That's why I don't charge my AGMs from the AC charger - mine does not have the right settings for that and in any case they don't need it.

An advantage of the 6v lead acid Trojans is that they are a little taller and you get more power per square foot (if you have the headroom). I got 1150AMH into a box where I had only 860AMH before. They units are typically less heavy to shift around too (as you need two to make one 12v unit), though you have the one-off hassle of wiring them up to make 12v.
 
I'd ignore that quote!

My previous service set (4 x102 amp) Delco sealed maintenance batteries lasted 16 years and were then used by friends long after that. I have replaced them with an identical set and they are near perfect after about six years.

However, our regime on degree of discharge before re-charging is pretty strict - virtually never more than 10-15% - dealt with by the use of an Adverc, windgen, (towed gen on the long, transat type passages) and solar panels. We have a 30amp switchmode charger for over-wintering or our VERY rare use of marinas.
 
Thanks to all for the responses. My 'trickle' charger is one which converts to ' maintenance' mode when the batteries are fully charged, so I do not think they are being overcharged from that source. My practice is to leave the charger on when the yacht is unattended as I have a float bilge pump and a gas alarm on standby mode. I am wondering if my problem is that my deep cycle batteries are not being discharged enough before recharging takes place. As I now understand it, on advice received from elsewhere, that can shorten the life span - or is this nonsense? /forums/images/graemlins/cool.gif
PS just seem the last two replies. Many thanks.
 
[ QUOTE ]
[ QUOTE ]
Low maintenance (or sealed batteries) are for the lazy/incompetent.


[/ QUOTE ]
Ouch...
My domestic batteries are so buried in my port-side cockpit locker - under the flooring - that to check the level means removing all locker contents then to raise the boards and clamber down to do so. Sealed batteries are a boon in this situation and are still in use after four years since I bought the boat - I don't know their installation date but when I do have to replace them it will be with similar, sealed ones.

[/ QUOTE ]

Perhaps I should have added "and those who have overfull lockers". Batteries in 30C ambient need checking weekly - in UK monthly.

Gel and GF filled batteries, need charging at a higher voltage, but lower current for far longer than conventional flooded batteries. You'll also find them very loath to provide power, take much out of them and the volts drop off fast and you need to let them rest.
Though I haven't tested them personally they're also alleged to have rather less than 50% working/rated capacity.

You takes your pick, lower efficiency or more work - that's saving effort (or in plainspeak laziness?)
 
It is true - many traction battery manufacturers recommend regular annual cycling for little-used batteries - full discharge and full re-charge twice, under controlled conditions.

However I suspect that you've plate sulphation, best countered by a conditioning charge from a smart charger.

Why not take them out and along to a decent battery specialist, who should be able to rectify things or tell you if they are really dead.

I'm afraid your regime, as described, will result in fairly rapid battery deterioration.
 
[ QUOTE ]
Perhaps I should have added "and those who have overfull lockers"

[/ QUOTE ]
Who said anything about "overfull"? My lockers are capacious and are used as intended. Living aboard a small boat places demands on storage and one's possessions seem to grow to fill the available space.

Even my most severest critic, my wife, would not describe me as lazy or incompetent afloat; in another environment, for example, home and garden, that is another matter.
 
[ QUOTE ]
I suspect that you've plate sulphation, best countered by a conditioning charge from a smart charger.

[/ QUOTE ]

I am curious as to why plate sulphation might be thought a cause. Batterystuff.com lists these causes of sulphation, none of which I would think apply in the OP's situation:
# Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
# Battery is stored without some type of energy input.
# "Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
# Undercharging of a battery, to charge a battery (lets say) to 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incomplete charging cycle.
# Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.
# Low electrolyte level - battery plates exposed to air will immediately sulfate.
# Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on battery charging.
# Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.

I certainly had an issue with sulphation on my old bank. My charger can't equalise so I have installed a Megapulse (advocated here) which will hopefully protect the new(ish) bank.
 
Ive been using gel batteries now on my live aboard here at Hampton court and on my last 2 sail boats and found them to be great.
Especially for domestics
Had no problems at all with them
Can be left for long periods without a charge, Fully discharged and recharged countless times and totally abused in every way with no obvious sign of any performance drop
obviously a correct battery charger for gel cells is needed but otherwise a good idea for someone that needs to put batteries somewhere hard to get at
Also have a pair on my 4x4 and these have been going strong for 3 years now.
Draw backs are that they are expensive to buy and very heavy compared to a similar sized lead acid battey.
Otherwise i would fully recommend a good quality gel cell set up for those that dont want to or cant visit the battery tray very often
Joe
 
That depends on the temperatures they have to endure. All my batteries are Turkish made sealed ones, except one. That one needs a litre of de-ionised water very two weeks, due to the 40 C temperatures it has to endure.
 
[ QUOTE ]
Thanks to all for the responses. My 'trickle' charger is one which converts to ' maintenance' mode when the batteries are fully charged, so I do not think they are being overcharged from that source. My practice is to leave the charger on when the yacht is unattended as I have a float bilge pump and a gas alarm on standby mode. I am wondering if my problem is that my deep cycle batteries are not being discharged enough before recharging takes place. As I now understand it, on advice received from elsewhere, that can shorten the life span - or is this nonsense? /forums/images/graemlins/cool.gif
PS just seem the last two replies. Many thanks.

[/ QUOTE ]

So questions :

When starting engine - how long does it usually take to start ? Is it a lazy starting engine or quick to fire up ? This determines how much power taken out of start battery bank.

Once engine started how long do you run engine for and for how long do you charge only to start battery bank before changing to charge both battery banks - start and domestic ?

If you have VSR or other similar change system that auto links battery banks to charge - which bank is providing sensing for charging ?

When on shore power are you charging both banks separately or jointly of same charger ?

Is shore powered charger a "Halfords" or other land based charger .... any idea of rated amps charge rate before it drops to maintenance charge ?

How long are your boat trips and how depleted are your battery banks ? (I ask because the banks you have are larger than many boats have for weekending / occasional cruise jobs - particularly that huge Engine start bank !)

Once we have the above info - we can then be a little more close to real answers instead of the usual "experts" supposition.

So far I have following comments based on info already given :

Engine start bank is far too big for normal use. If charge state reduces - it's difficult for a standard alternator to bring that up again to full in short - reasonable time. Particularly if you have an auto click in to charge domestic as well once engine starts or sensing indicates etc. The Domestic bank is big as well and that adds to the sheer amount of work that alternator has to do.
Second most land based auto chargers with maintenance mode cannot charge up large banks properly - they are not designed for it. The circuitry is designed for car batterys in single form. I have a good maintenance car charger and if I connect 2 batterys to it parrelleled, the charger cannot drop to maintenance without considerable time period - such that it indicates it's not working as designed.
So far I think part of the problem is sheer size of battery banks and inadequate charging arrangements - but once we have answers to my questions above - we can then see if correct or not.

As to sulphation - bit early and presumptious IMHO to start on that track - sulphation is a distinct possibility if answers to above are in one vein - but as a result of - not the reason. Lets find the cause - not the result.

/forums/images/graemlins/wink.gif
 
Refueller, thank you for the questions and comments.
Engine starts instantly.
Engine hours are substantial.
Yacht does long distance passages - Baltic and return for example.
Trickle charger is indeed a 'Halford's' type
Charging splitter works automatically - giving each bank required feed.

Your questions plus earlier replies replies prompt me to reduce my engine bank by one battery and to have my deep cycle batteries checked for condition with my supplier.
Thanks for the interest. /forums/images/graemlins/cool.gif
 
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