will this battery charging circuit really work

[johnathon007]

I found this website while looking for a cheap battery charger and just want to know if it is complete BS or if it will actualy work as described. [it looks to good to be true to me but ive been wrong before.] 3 Dollar Battery Charger

 

[Birdman Adam]

I'm pretty sure it will work, but I would end up shocking myself. I'm not so sure about the DC pulses breaking down sulfation though.

Remember: This circuit uses 120VAC. You could kill yourself! I wouldn't do it. Because I would fall asleep, and the battery would cause a fire...

 

[bychon]

Yes. This will charge batteries and it's somewhat adjustable. The problems include having live mains voltage danger and no self limiting when the battery gets fully charged. If you're a competent technician and you "mother hen" this, it will charge batteries.

 

[johnathon007]

I would be using a timer with it to make sure it doesnt over charge and all of it would be in a project box so getting shocked shouldnt be a problem i was just worried that a single diode might not be enough but i guess i can give it a try. I have everything needed laying around so it shouldnt be hard at all.

 

[MikeMl]

The circuit depicted should only be used to "equalize" flooded-cell lead-acid batteries; never use it on sealed lead-acid (SLA) or AGM batteries. This is a "constant-current" type of charger; it is not a "voltage limited" charger, which is what should be used for routine recharging and float-charging of lead-acid batteries.

An "equalization" is a controlled-overcharge, during which the electrolyte bubbles and is used up (that's why not to use this on SLAs), The specific gravity of the electrolyte is driven to a higher level than normal, and by overcharging some cells in the battery, the other cells are brought up to higher level of charge to hopefully equalize the state-of-charge in all six cells. It should not be done for more than four hours once per month; it is hard on the battery.

If you insist on using this for "recharging", rather than for equalization, then you will have to monitor the battery closely during charging. Watch for it to begin gassing, heating, or periodically measure the terminal voltage (under charge). Quit when the battery voltage reaches ~14.6V. Do not leave this thing connected to a battery overnight, or it will be toast.

 

[bychon]

It only takes one diode to rectify. Use a diode that is rated for at least 200 volts, but diodes rated at 1000 volts cost the same price as the 200 volt diodes in 1 amp size.

 

[mneary]

......and all of it would be in a project box so getting shocked shouldnt be a problem.....

Remember that the battery and everything connected to it is at mains potential. Since the circuit shouldn't be used on SLA or AGM batteries, and flooded batteries must be in a well ventilated place it seems it will be difficult to find a safe place to use this.