MF battery types

But it's not a long life. When I started motoring, a decent battery would give around 5 years - and this with a crude dynamo, or rather crude control gear. So despite all the advertising hype, there's not been much

*real* progress in lead acid design for many years - if at all. Perhaps the relative price has come down, but so has everything like this.

Yes that's indeed the situation, these are AC Delco MF batteries, they have the 'magic eye' build in hydrometer but that acts on 1 cell only. Also, all the boiling of the battery for so many hours till the whole building floor had an extreemly strong foul odor would make me think that there isn't much electrolyte left in the batteries.

What do you mean 'only finish topping up after charging'? Do you mean in a normal wet battery with filler cap, you should charge it fully then top up the battery water? why is this so?

Thanks burgerman.

But there was no "drain" on it allowing it to discharge and sulphate every single day even for a few hours as you sleep! For example my van has, engine management keeping its memory topped up, immobiliser, or car sterio, or clock, or burglar alarm, fuzy logic gearbox memory, electric seats, and electric ramp! As well as a radio reciever listening for my key code to unlock it via central locking and climate control memmory ... And a few more!

This is the one main thing that shortens life. Another is "maintainance free" batteries... The other metals (like calcium) help it to not gas as easily so no topping up. hence maintainance free. They do NOT help its longevity at all! Just the opposite...

At the moment the best option is pure lead plates, and thin starved glass mat seperator, soaked in acid (not gel!) The acid can gas if incorrectly charged but batteries like the Optimas, and Hawker Odyssey range are "recombinant" and recombine the oxygen/hydrogen back to water, so they do not dry out... So AGM batteries give the same longevity as an old type high quality pure lead acid battery, but still maintainance free. Best of both worlds... Plus the optimas use MUCH thinner pure lead spiral wound plates like a Ni-Cad battery. This allows much more plare are which is why an optima can give MORE cranking amps than a nominally "bigger" ah battery. Even the Deep Cycle ones can! Most deep cycle batteries cannot sucsessfully start a car unless it is oversize...

Avoid Gel batteries for starting duties at least - pretty crap, in that high currents, over charging blows bubbles in the gel, leaving big areas of battery plate bare! Then they go high resistance of course...

Because the plates need to be covered at least before you begin charging. If its pretty flat the level will rise as it charges and gets warmer, so if you topped up first then now its overfull and acid too dilute.

Oh yes there was. In those days any car parked in the street when dark had to have a parking light on it. They were 3 watts, so about 250mA - more than the quiescent load on a battery now.

It's not the battery at fault - it's the cheap charging kit in the car.

You'll often find batteries last longer in expensive cars (Mercedes and the like) simply because they have better charging circuits.

I think you'll find Dave P will disagree with you there.

Also, SWMBOs Escort is now 7 years old and still on the original battery. It usually only gets used once a week for about three miles each way (used to be about one) with the odd 250 mile round trip maybe once a month.

You are correct in that vehicle parastic (key off) loads tend to be greater that the natural self discharge on a lead-acid battery, but self discharge is what cause batteries to go flat when in storage. Depending on the plate chemistry and the temperature, it can be as much as 30% of the battery's capacity per month. Spiral wound AGM batteries like Optimas have very low self discharge rates; whereas, a standard (Sb/Sb) battery has very high rates. Higher temperatures will accelerate the rate too.

Kindest regards,

BiLL.......

Eh? When designing utility electronics it makes no sense not to do the job properly - the cost of the circuitry is tiny in mass production. In other words, it costs the same to make a good regulator as a poor one.

You'd have to explain that one - obviously large expensive cars have larger charging systems because they have a greater electrical load. But better? Don't think so. And the original battery in my 'expensive' car did just over 3 years.

Except that it doesn't. Cheap regulators are cheap - they're not as accurate, and don't last as long.

I can't - it's just how it is :)

Well that's what I've always read. From memory, the setup is much better in something like an E-Class Merc, than in a mid-90s Fiesta !

Easily checked with a voltmeter. And all the recent cars I've checked have been the same.

Can't see it, myself.