Optima -v- lead acid

[stefan_r]

The perennial question I know.

Am looking at replacing my lead acid batteries, 4 x 110ah, with Optima gel batteries...Optima only do up to 55ah each.

Lead acid Varta (so good brand) £115 each delivered.
Yellow Optima £150 each.

So:

(1) Will I get a 50% longer service life from the Optimas to cover the 50% uplift in price from Lead to Gel? Don't enjoy replacing batteries at the best of times.

(2) If you read the bumpf the Optimas are okay to have a lower ah as they run longer at a 100% output and then sharply drop off to almost nothing whereas Lead slowly loses output. So on average does a 55ah gel give me something nearer to 100ah to compare to the Lead battery? Or is that rubbish??

(3) Have I missed anything?

I am using these in a motor boat so topping off the charge is no issue...I am not bluewater cruising.

The use I will have is largely anchor for a few hours, an have typical domestic consumers. Fridge couple of amps/hour; lights negligible; Eberspacher D3 couple of amps; water pump for sink/shower; electric bog 20 amps but unles it's a curry night very infrequent use!

All in all say 30 amps/hour?????

 

[wotayottie]

Optima are lead acid batteries. Gel like AGM refers to the inmternal construction of a lead acid battery.

On a mobo, unless you go daft, there should never be any question of the batteries getting low. So I personally would use ordinary leisure / semi traction type batteries which seem to last for years even in my sailing boat. The more amp hours the better if your alternator is man enough to charge them.

 

[VicS]

[ QUOTE ]
Optima gel batteries

[/ QUOTE ] As wotayottie says they are not gel batteries. They are absorbed glass mat (AGM) and it is this that makes them spill proof. They are compact in size by virtual of their spiral construction. The red top ones are only suitable for engine starting, not deep cycling, but the yellow and blue ones are dual purpose.

You need to consider the cold cranking amps but the figures quoted look quite high.

You need to be a bit clearer in you mind about the units. Amps is the current flow to any bit of gear. Amp hours is the unit of capacity of a battery. Basically amps multiplied by the time in use (in hours) gives you the amount of battery capacity used in Ah

In your examples :
the fridge uses 2 amps so in 24 hours it uses 48 Ah, except that it probably runs intermittently, (say half the time ) so that makes its daily consumption 24 Ah.
Lights probably more than you think unless they are LEDs so look at the wattage, tot up the number in use and divide by 12 (assuming you have a 12volt system) to get the current in amps then multiply by the number of hours in the day in which they will be in use to get a daily consumption in Ah.
Heater a couple of amps, multiply that by the number of hours it will be in use per day.

Water pump will use typically something like 6 amps, but check it on the nameplate or instruction book, so multiply 6 by the time in hours it will run in a day.

Estimate the time the toilet pump runs and muliply that by 20.

Repeat the process for any other electrics and don't dimiss too many items as having negligible consumption.

Add them altogether and you'll get an idea of your daily consumption in Ah. It is probably wise not to discharge the batteries below 50%.

 

[Boatman]

Agree with VigS below... (calculate usage)

However if you look after the open lead acid batteries (ie check water levels, voltage etc) they will last just as well. I wouldn't spend the extra on Optima. (I have used them and they are great but not in a marine context)

As a blue water cruiser I have found that (no name) truck batteries seem to work best. Providing that the electrical system is well thought out and correctly configured and they are alot cheaper.

VigS says not to discharge below 50% I would say not below 65% (I know it's not a lot of diff) and you should be able to extend the battery life by a number of years.

 

[boatmike]

I would not quite agree that they are no good in a marine environment. They are in fact very well suited being anti-spill and there are no real disadvantages that I can think of. The main advantage of them is that they are considerably lighter though, and if this is not a consideration I would question their justification as they are more expensive. Personally I would not reduce the amp-hour capacity significantly either.

 

[charles_reed]

Flat vs tubular plate

batteries. Is probably the question you're posing.

Tubular-cell lead-acid batteries have been around for about 35 years in the FLT industry.
It's one of the ways you maximise plate area. One of the characteristics of tubular cell batteries is that they give full voltage up to about 80% discharge, then nowt - try pushing a 4.5 tonne FLT to its charging station and you'll appreciate the disadvantage.

The Optima batteries have patented a spiral wound plate (I can think of lots of disadvantages of that) and combined with impregnated mat construction make for the enormous bulk of the batteries for very restricted capacity.

Having seen threads on batteries, I'm convinced that the number of apocryphal claims made by battery manufacturers is legion, and they find their most gullible faithful among the boating population.

In a word, having been involved with battery manufacturers since 1978, I'd save your money and buy a good industrial battery from a reasonable 2nd tier manufacturer - it'll probably last longer than the Optima, give 70% more capacity for the same size and save you 35% on purchase price.

 

[wotayottie]

Re: Flat vs tubular plate

[ QUOTE ]

In a word, having been involved with battery manufacturers since 1978, I'd save your money and buy a good industrial battery from a reasonable 2nd tier manufacturer - it'll probably last longer than the Optima, give 70% more capacity for the same size and save you 35% on purchase price.

[/ QUOTE ]

Couldnt agree more. I've no doubt that Optima are good well made batteries - but the trick in battery manufacture as in so many other products these days is to brand the product so you dont compete on price and can charge a lot more for it. Think Harley Davidson or BMW or Gap.

 

[Trundlebug]

Re: Flat vs tubular plate

You can buy perfectly sound 100Ah lead acid leisure batteries for less than half of what you've been quoted.

For example, Towsure do them for £45. www.Towsure.com
Now do the maths again on the economics. It's a no brainer!!

It's also worth considering your battery compartment size and shape. If you replace with odd shaped tubular whotsits or multiples of smaller rated units, considerable re-jigging of the battery wiring may be required. If you do direct replacements, they're always a standard size and therefore much quicker and easier to fit. Worth thinking about when it's a job you dislike...

Best of luck

 

[Anonymous]

Re: Flat vs tubular plate

[ QUOTE ]
I'd save your money and buy a good industrial battery from a reasonable 2nd tier manufacturer

[/ QUOTE ]I agree. For a MoBo, lunch and occasional overnights but basically a marina boat rather than a cruising liveaboard boat you just don't need the best. For a liveaboard at anchor for months of the year, personally I think it's worth paying for a first tier manufacturer such as Varta. Trojans have had ([edit: changed 'not' to 'note'] note the tense) a superb reputation but they are expensive and hard to fit into many yachts.

HOWEVER, if the boat is going to be left abandoned for months at a time and the owner doesn't do regular jobs such as topping-up, then there is much to be said for maintenance-free provided the charging is set up accordingly (not easy with all alternators).

 

[samwise]

We have an Optima as our dedicated engine start battery. The reasoning being that it has excellent cold cranking performance, holds charge for a long time and is essentially a fit and forget device. Our boat is parked abroad and unattended for fairly long periods so for this application the Optima suits us well. The domestic banks are all standard issue lead acid which I believe still provide best value for money. They are trickle sharged on solar.

 

[neale]

Another vote for the optima based on car use.

I have a second car that doesn't get used very often, sometimes for a couple of months at a time. The standard Lead Acid batteries were nearly always flat when I needed to start it cos there is a constant drain through the clock and radio memory etc etc.

Tried an Optima AGM and it has been fantastic, always starts like it was last run only yesterday.

Don't know why it should be the case as there is still the same small drain on the battery, the Optima just seems to cope with it better.

 

[Anonymous]

That makes sense if the Optima holds up to 20% capacity remaining and gives good CCA. It isn't good for sulphation of the cells. When I used to leave car for many months I used a small 25 x 15cm solar panel on croc clips, through the bonnet top, door seal and left the solar panel on the dash. Worked wonderfully, easily replacing the leakage, clock, radio, etc. and the car used to start as though it had just been run. I suppose you could buy a solar panel that size for the difference between an Optima and a normal battery?

 

[ex-Gladys]

I have Squadron AGM house batteries. The main benefit as I discovered earlier this year was their ability to take a deep discharge. Don't know how, but the three got taken down to 4V. After a good trickle charge and since they've been ashore repeated conditioning charges with a smart charger they are sitting at 12.70, which is only a gnat's down on their fully charged 12.78