Thread: Assaulting n Battery

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Battery Chargers



Modern battery chargers 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.

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Some battery tips:

• 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

Good discharge

I am in favour of this method.

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Some battery tips:

• 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
• Car batteries 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.

Just replace your battery as soon as it stops cranking the engine properly when its cold, and always carry a set of jumper leads with you for emergency starts
The other day i was asked by someone in a out of they way place if i could give him a jump start, unfortunately i had left my set of jumper leads out of the vehicle when i had it cleaned, he did not have a set of jumper leads and is still probably still stuck on the edge of the road where i left him

Originally Posted by David48atTD

A monthly or bi-monthly full discharge

Does that include birthdays?

Originally Posted by petercallen

unfortunately i had left my set of jumper leads out of the vehicle when i had it cleaned

You could have gone home and got them.

Clever headline I see what you did there.

I find all this bipolarity revolting and charge you with Ohmiside

Drive from the bridge at the north end of Phuket to Rawai at the south end of Phuket to pick up set of jumper leads to start someones car (who is not a friend) that he has been driving all over Southern Thailand without his own set of jumper leads and a old battery, not likely in this century sport , i will leave that for someone like you to do

The Cow alternative charging method is much easier and simpler. Use it and charge it whenever you want and replace the battery when its f#cked.

Actually, you could last a lead acid battery for over 20 years or more. Problem is that in a car the voltage is never allowed to go high enough to solve all the sulphate cristals into the acid. Try charging one outside the car with a charger which is not voltage-controlled (like the old chargers often are) and monitor the voltage. It will peak out at 15.x to sometimes 16.x volts and then go down to a 14 or 15 v. When that is achieved, all sulphate is vack into the h2so4 solution.
In car system this is a problem, unless you are willing to charge the battery every other week or so to keep it in topcondition, but in a solar setup with some d.i.y. stuff you could let your batteries last much longer. Probably have to design your own charge controller...

This web site needs help. I go to ssearch for boxer dogs and get a page of ? I get to Tommy and get another page unrelated.
Then If I get on the original add; there is no place to leave a reply

^ A google search of TD is usually better than using the forum search function. You can add more keywords.

And for Tommy's "Boxer dog puppies for sale" thread, there is a Quick Reply area at the bottom of the page - for me anyway.

Perhaps you should start a new thread about it in the Troubleshooting and Suggestions forum, or perhaps a kindly mod could shift your post and my reply there. https://teakdoor.com/troubleshooting-and-suggestions/

Good advice. Thanks.
Just a few points that most of you probably know about jump starting a car with a dead battery.
If it's really dead, wait 5 minutes with the good car running. A little extra gas given on the accelerator pedal will help charge the dead battery faster.
When hooking up the cables, always touch the last cable (the negative, or black on the dead car) with your head turned.
As sometimes there is an explosive gas just on top of the battery and the spark can ignite it. (I've had this happen to me twice and once is enough, believe me)

Don't buy the cheap jumper cables. You need thick ones.
If you have the cheaper, thin ones, you'll probably notice how hot they get. That's inefficiency beling lost to heat, instead of transerring to the bad battery.
Of course: Never touch the red and black ends together. Big sparks, ruin your battery or voltage regulator.

Originally Posted by Neverna

^ A google search of TD is usually better than using the forum search function. You can add more keywords.

Can't think of a forum search function yet that I'd green.