MF battery types

Hello there, I was just wondering, nowadays there are so many different types of maintenance free batteries, what are the advantages/disadvantages of these competing technologies? Calcium, Expanded Metal, etc.etc? how do each of these work?

I'm sure Burgerman would know this at the back of his hands. hehehe

Thanks guys.

Reply to
Brian Su
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Yep I do...

This is one of my sites...

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Basically all car bartteries are "starter" batteries (as against deep cycle batteried) These are designed to start engines, which means high starting currents (Cranking Amps or Cold Cranking Amps = CA / CCA) These are disharged by only about 5 percent on an average start, and charged right back up again by the alternator. To make BIG currents they use lots of thinn crap plate material with a thin coating of a sort of lead "sponge" to give big surface areas sat in the acid. If you deep cycle these all the lead sponge stuff drops inj the bottom and your battery is buggered... Deep Cycle Batteries use solid lead thicker plates so that they can be discharged to say 80 percent discharge regularly with little damage. But these do not have the plate area to develop masses of amps needed to turn over a cold diesel engine!

Acid spills! (so we "need" to fix it apparently!) There are two methods...

1, we turn acid into GEL (by adding silica gel xtals) but these types of battery are for want of more space and time pretty crap performance. 2, we use whats called AGM (Absorbed Glass Mat) batteries! These are the best by a country mile... Basically it has all the advantages of a true acid battery but can be sealed, non spill, etc.

Both wet acid, Gel, and AGM can be bought in both starter (high current short duration) as well as Deep Cycle (Golf carts, Wheelchairs etc)

Now to confuse the situation a little SOME deep cycle batteries (Optima that I sell, Hawker Odyssey and one or two clones) can also produce huge currents as well as be safe to deep cycle or discharge deeply... This is because both of these use pure lead plates, but very thin, and lots of them! The physical strength for this comes from the fact that the Optimas are built like a nicad, or capacitor and tightly rolled up into cylinder shapes rather than trying to make a lot of flat plates fit in a box! Not sure how the Hawker ones manage this... But they do.

They allow the battery to be "maintainance free" (less gassing when charged) at the expence of longevity, and other performance criteria. Batteries are a balancing act, with the "chemicals, additives, plate materials" used as a fancy sounding advertising copy...

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More here... (by bill darden but Icopied it! Its all a bit american but all correct.) There is much more to that squre thing under your bonnet than you think!

Reply to
Burgerman

I've noticed that Optima don't give any better a warranty than the likes of Halfords, despite the price?

Reply to
Dave Plowman

Nope. When batteries "fail" its invariably not actually a battery fault, but a lack of understanding on the part of a user. For example, a guy I know "cycled" his deep cycle batteries to dead flat like ni-cads, because some expert told him he should! His batteries lasted 10 cycles.... And that was an electric vehicle with lots of them! It was his error. No batery problem, but how do you prove this to a customer who is ignorant of the batteries requirements? And optimas are typically used in "extreme" situations, as a desperate attempt to cure a problem!

People buy an "optima" often because their battey "keeps going flat" either when they leave it for 6 months over winter in a custom or race car or a hardly ever used classioc (still connected running god knows what immobilisers, alarms, etc), or because they have four tons of car hi fi fitted and keep "deep cycling" their starter battery...

They fitted an optima to cure the original "problem". The real problem was that they were either taking out more than putting in on the wrong type of battery, or they allowed it to become discharged and sulphate. Easily seen by the discolouration when you chop it open incidentally...

The red ones which can't deep cycled incidentally, are starter batteries. So the warrantee is longer. Because the typical daily usage pattern is known. The Yellow ones are more of a problem... Its use is unknown, it could be used in a powerchair like mine and heavily deep cycled daily. Less than a year is the expected life in this situation. On the other hand the same battery used in a reserve power, backup system that lives on permenant float charge can be expected to be fine after 15 years.

Reply to
Burgerman

I once bought an AC Delco 'Freedom' battery for the old Rover, and its warranty was 3 years in a car, or 1 if used for a golf buggy etc. It made 3 years in the Rover - just. ;-)

Reply to
Dave Plowman

Out of interest, is there any way to rejuvenate a duff battery?

I've seen some tablets that are supposed to dissolve off the deposits on the plates, but I'm not convinced.

Got a battery here that's pretty shot though, and after being on charge for a while gets very hot, and boils electrolyte off quite a bit. Came out a car that had been stood unused since last November, and I don't know what sort of usage it had had before then either.

Reply to
Stuffed

Burger...

Are there any batteries that survive well in a "used from time to time during summer" scenario?

Reply to
Questions

Errr NO... Once you killed it its buggered...

And you shouildnt be!

Boiled electrolyte = overcharging... So its BUGGGGGGERERD.

Reply to
Burgerman

All batteries sulphate if they are not FULLY charged. That does not mean overcharged! If its connected to a vehicle then it goes flatter faster because the cars electrics, and electronics pull power out.

All batteries will deteriorate like this fast. Some faster than others...

A Caravan/boat type sunlight photocell charger should keep up though...

Reply to
Burgerman

Suspected as much, arse.

Shame - I budgeted myself a set amount for buying and MOTing the car it came in, and with 8 quid of that budget left, 3 quid for tablets seemed a better idea than tryign to haggle 5 quid far a battery at the breakers, seeing as I need a new liner in my mig too.

To be fair, well, no. It's buggered. Damn.

Reply to
Stuffed

A pity. I'm doing that anyway and batteries still die fast compared to a daily driver, and it's a pain taking the terminal off.

Reply to
Questions

Then you need a better (500ma output?) solar charger?

Reply to
Burgerman

Use a "smart" or "float" charger continuously charging your battery will keep it fully charged to prevent sulfation. For additional information on sulfation, please see Section 16 in the Car and Deep Cycle FAQ on

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Kindest regards,

BiLL.......

Reply to
Bill Darden

Hi Brian,

Please see Section 7.1 in the Car and Deep Cycle Battery FAQ on

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Kindest regards,

BiLL.......

Reply to
Bill Darden

Possibly, but then we seem to be getting towards the mains powered chargers which do much the same thing but have seen off batteries here and earned themselves a reputation for being expensive and no doubt better than the unregulated type, but not a real solution.

Best I've managed to come up with is to have the smart charger on a timer that turns on once per day for 15 mins, to simulate a sort of daily drive. Even so, this has still done batteries in two years, depending on the point where you come to test it, maybe three summers if it was new early in summer, not quite sure if it was 2 or 3 last time. Anyway, too quick for my taste when the other car (was) is still on an original ten year old battery and doesn't get charged.

This battery, I've gone a stage further, the charger comes on once per week for

15 mins and the battery is removed from the car entirely, during the coldest part of the year and then reconnected with the charger on daily. It's managed a second year so far, so it's not a worse technique.

I have a solar charger on the other car, it's a good idea when the car is kept outside but the triumph stays indoors unless it's a sunny day and I plan to drive it. Can't see a lot of difference between solar volts and charger volts is going on, maybe it is some subtle effect to do with inductance?

Reply to
Questions

No.

Your battery needs to be kept at its "float" voiltage 24/7 to give it the best service life. This needs a fancy maintainance charger.

Above float voltage causes damage... Below also causes damage...

Reply to
Burgerman

Burgerman,

Yeah I knew you had that optima site that's why I wanted to ask you. Anyway just recently one of the battery banks in my office's phone backup system got damanged. Actually, the battery bank is made up of 4

12v 45Ah 450CCA Maintenance Free AC delco batteries. In total they should reach 48v per battery bank. What happened is that one of the battery malfunctioned and dropped to a mere 3.x volts so the charger circuit activated. Of coz the total voltage would never reach 48v because of that single spoilt battery. The result? The entire building floor smell of sulphur for the entire day. Since the smell was there since morning, I reckon it had been overcharging for at least 15 - 20 hours. These are MF batteries.

So is that whole battery bank screwed or would replacing just that single battery work?

Thanks.

Reply to
Brian Su

Its always wise to connect up only identical same age batteriews of course, but cost obviously comes into it too... I would think just replacing the buggered one should be OK.

If theres time, charge each one individually with a decent charger before connecting them all up... By maintainance free does this mean you cannot check the level? Because all that boiling may have lowered it in some cells?

Only finish topping up after charging.

Reply to
Burgerman

I couldn't get inside my AC Delco Freedom battery to check the level. Put me off buying another - most can be checked even if it means ripping off a label, etc.

Reply to
Dave Plowman

Most car charging systems never fully charge the battery either - regardless of how long the engine is run.

Reply to
Dave Plowman

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