Battery charger

[zachtheterrible]

anyway, will my 12v 1A supply charge a 12V 7.2Ah sealed lead acid battery?

It will, but it will take much longer than a 12V 5A supply because it will not be able to provide sufficient amperage. When I was chargin the battery w/ my power supply I was reading 4.5 amps.

 

[danielsmusic]

will it stop charging automaticly when it is finished?

do they have the symbol for ohms , in there ..

Ω

 

[zachtheterrible]

Yes. Read this whole thread and you will see that the battery will quit sucking current when it gets full, accept for a small trickle current.

 

[Someone Electro]

How do you do it'

Press Shift and Alt then type in a number and then relese Shift and Alt

This aculy displays the charagcter of the ASCII code you enterd.So you cant enter higher than 255

Those icons are on the small numbers in the Arial font.
heres what some nembers put out.


1 ☺
2 ☻
3 ♥
4 ♦
5 ♣
6 ♠
7 •
8 ◘
9 ○
10 ◙
11 ♂
12 ♀
13 ♪
14 ♫
15 ☼
16 ►
17 ◄
18 ↕
19 ‼
20 ¶

 

[danielsmusic]

well, with a 12 volt battery will i need 15v iv been on google and some sites say charge it a 15v. 12v will not put anything through, my multimetre says 0A, when i charge a 6v battery at 8 volts it works.

 

[zachtheterrible]

Daniel, I don't understand you, are you charging two diferent batteries? Or are you trying to charge the 6v w/ 8v and 12v?

 

[danielsmusic]

yea i have 2, 1 6V one. 1 12V one. the 6V charges fine at 8V. at the moment my power supply will only go up to 12V and that is not charging the 12V battery. i only want a trickle, i don't want to destroy them.

do i need 13 - 15V to charge the 12V battery?

 

[williB]

What is the voltage at the terminals of the 12V battery ?
have you measured it?
A healthy fully charged SLA battery will be above 12V

 

[zachtheterrible]

You should be perfectly safe charging the 12V @ 13-15V. The battery in my truck is charged to 14V. Yes, do as willib said and check the voltage on the 12v battery. If it is already at 12v and you try and charge it with 12v it won't do anything at all.

 

[Nigel Goodwin]

If it's any help?, the nominal voltage of a car battery is 13.8V.

 

[danielsmusic]

thanks, i didn't want to blow up a car battery. one last question, will a ni-cad battery "shut off" when charged or do i need a circuit to do that?

 

[williB]

most dumb chargers , built for Ni-Cads or NiMH batteries , will continue charging them well after they are " done ".. making them very hot and ultimately destroying them..

 

[danielsmusic]

thanks, i will just need to charge the batterys like my "dumb" charger thanks!

 

[audioguru]

Don't ever try to charge a Li-Ion or Li-Po lithium battery. When overcharged and therefore hot, lithium burns hotter than magnesium (white-hot).

 

[zachtheterrible]

Don't ever try to charge a Li-Ion or Li-Po lithium battery. When overcharged and therefore hot, lithium burns hotter than magnesium (white-hot).

Wow, so those stories about cell phones literally burning through stuff are actually true. I always thought they were old wives tales :shock:

 

[danielsmusic]

so if i drop the Li-Po into water it will go crazy and set on fire? magnesium and water don't mix.

 

[Nigel Goodwin]

so if i drop the Li-Po into water it will go crazy and set on fire?

No, only if you drop lithium in to water, the batteries are safe.

 

[audioguru]

Lithium and Magnesium are never safe.
The Brits sent battleships down to fight the Falkland Islands war. The ships were made of magnesium and caught on fire!
They didn't burn when they were wet on their journey down there.

The dead Li-Ion battery from my son's laptop is crammed full of electronics to prevent over-charging that will set it on fire. :lol:

 

[Nigel Goodwin]

The ships were made of magnesium and caught on fire!
They didn't burn when they were wet on their journey down there.

Bit of inaccuracy!, some parts were made of lightweight alloys, some of which included magnesium and aluminium.

No body would build anything of magnesium!, if nothing else it's too expensive :lol:

BTW, WW1 and WW2 ships had no trouble burning either!.

 

[audioguru]

Bit of inaccuracy!, some parts were made of lightweight alloys, some of which included magnesium and aluminium.

Sorry, I watched American news reports showing a faulty missle piercing the magnesium skin of the battleship which set it on fire. Some missles went completely though the flimsy ship and out the other side, setting both sides on fire.

Reminds me of the flimsy Japanese Zero planes (made from rice-paper?) that were faster and could climb steeper than the American heavier ones. When a Zero went into a steep dive, it fell apart. Many times you see a film clip from an American plane chasing a Zero, and the Zero blows-up before even being shot at. :lol: