For rechargeable batteries, the decline will depend upon the battery chemistry, how the battery is used, and how it is maintained and charged.
For nickel-based batteries (NiMh or NiCd), the battery performance will decline mostly because of crystalline formation. It isn’t a memory issue (inasmuch as the battery isn’t remembering how hard it worked on previous occasions), but it is caused by partial discharging and, sometimes, poor charging.
What happens is that the crystals within the chemistry of the battery tend to group and grow into larger crystals, which increases resistance within the cell and causes the battery to seem empty before it really is.
The best avoidance practice is to “exercise” the battery every month or two with a good discharge and then a full charge or, if the cells are already delivering poor performance, to put them through a “reconditioning” programme on a suitable diagnostic device. The latter isn’t viable for cells costing a few $, but it makes a great deal of sense for power tools batteries, mobile phone batteries and similar.
For lead acid based batteries, a similar problem occurs with sulphur build up and, in this case, a multi-stage charger will often do the job and, if not, our diagnostic tools can put the battery through a thorough programme lasting, sometimes, for several days (but the batteries love every minute of it).
use fancy technology and sensors to look after the batteries in their care. For small batteries, the ideal charger will have “negative delta v cut-off” and temperature sensing. It’ll know when the battery reaches peak charge, and it will stop bothering it, other than giving it the occasional nudge.
For big batteries (lead acid), your charger should be multi-stage and, at least, should know when to go into float mode (minimal pulses to maintain a battery at peak power). Ideally the charger will also offer a desulfation stage, and might have several other interesting stages and flashing lights to entertain you.
Importantly, either you or the charger should know what type of battery you are charging and react accordingly. Both the fast charge and the float charge voltages need to change depending upon whether the battery is gel (13.8v and 13.2v respectively will work nicely), AGM (14.4v and 13.8v) or flooded/wet cell (14.8v and 14.2v). A 13.8v charge won’t hurt a flooded cell battery, but a 14.8v charge will harm a gel battery, quickly, and cost you more than a new charger would have done.
Don’t leave small batteries (NiMh, NiCd, Li-Ion) on charge for long after they are fully charged, and certainly not for days on end
A monthly or bi-monthly full discharge and charge works well for small batteries (but don’t do it every time you charge them, just occasionally) but it is bad for lead acid batteries
Most rechargeable batteries don’t reach full capacity until they have been discharged and charged a few times (a dozen or so). Prior to that, they are probably about 90% of true maximum
Don’t leave a lead acid battery on charge for more than a day after it is fully charged unless your charger has “peak detection” or “float mode”
There is a myth that lead acid batteries discharge if they stand on concrete. It was true a few decades ago, when batteries had cases made of wood and tar, and even when their cases were porous rubber, but a modern battery doesn’t mind concrete!
Don’t use a car battery in a boat (the plates aren’t designed for marine conditions, and it won’t last well – so false economy)
Don’t use a starting (cranking) battery for an application that will run it down more than a few % before it is recharged
Keep an eye on temperature during charging. Batteries that get noticeably hot should be allowed to cool off
Leave the caps closed ON a lead acid battery during charging. They are vented, and don’t need to be open
If you are maintaining a battery by adding distilled water, do it after charging, not before (unless the plates are uncovered at the top, in which case JUST cover them before charging)
Old chargers are (usually) not as good for batteries as new chargers. If you are using a device that was manufactured in the good old days, it’ll probably cost you in battery replacement or performance
The electrolyte in a lead acid battery can settle (stratify) if the battery isn’t moved (eg in a solar storage bank) which leaves the cells with concentrated acid at the bottom, and acidy water at the top – which reduces capacity. For static batteries, an occasional good charge will cause them to bubble and will mix the electrolyte. This equalising charge is worth doing about once per month – with a serious charger
If you are charging unprotected LiPo batteries (eg for radio control applications), make sure that they are tended (not left unattended) and that they are in a suitable charging bag or similar
If your phone is losing charge too quickly, check that Bluetooth and wireless are turned off when you aren’t using them. These two are the usual culprits
If your laptop is usually plugged in, and it is capable of running without the battery, take the battery out until you might need to unplug it. The battery does not like being constantly charged by the laptop power supply, and will be much happier if it is fully charged, then discharged almost fully before being plugged in again
If your car battery is registering 10 volts, it’s a good sign that 1 of the 6 2 volt cells may have failed. It almost certainly isn’t for lack of charge
But…if someone left the lights on and your car battery is completely flat, and if it won’t charge, it may be that your charger doesn’t see enough volts to start charging. Get the battery checked, because a good battery specialist will have, and sometimes even sells, rescue chargers to handle this situation
If you have a bank of batteries, maybe for solar storage, or for the house system on a boat for example, if one battery fails then get it out of the pack quickly, because it will “bring the others down” if it can. In the same way, don’t buy one new battery and put it into a bank of old batteries (over 6 months old). If you do, the old batteries will “cannibalise” the new one, until it is reduced to the same condition as they are – batteries don’t like tall poppies
Battery life is, to some extent, a function of design. Some batteries are designed to “put a quart in a pint pot”. Like anything that is highly-stressed, or running as fast as it can, the pace may be unsustainable
are generally oblong, with a plastic case and a combination of lead and acid inside, which is where the similarity ends. They might look alike, but there is a huge difference between a quality battery and a cheap battery – and high cranking amps isn’t always a sign of a good battery – in some cases it just means more acid and less (expensive) lead. Good lead acid batteries are surprisingly heavy
In general, buy the best and most suitable battery, not the cheapest, and you won’t be disappointed.
At Battery Business we test batteries for free.
We restore batteries when we can.
If a battery can’t be restored, we will recycle it for you. You can drop off old batteries with us at your local store 7 days a week.
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