Power supply 3

No. Read the description at the site.

But i am

It is still charging a bit, but not because of Q1.

You did not post a reference to what you call "this one".

For reverse polarity protection:

N/O v====o-----+ Charger (+)-----------o---- | +---------o---^ N/C | | | [Buzzer] --- | | | /| | +-----+-----| / |---|

Because I am a bit confused for the gate 1-8 on the LM 301. Even with the description, I do not understand. I think because of the capacitor, the charger do not turn back on. otherwise it would.

oups...

I am just starting out, I dom not know what is better, Actually I found only one circuit, which was extremely complex and had other components beside it, So I did not bother. so what does the other sophisticated circuits have more?

ken

Hi Ed, I have analyzed your circuit, and wouldn't mind some clearing up. this is actually the first time working with relays so please bare with me. I can see from you diagram that the relay is powered from the positive of the battery to the negative. If I look here:

ken

The description says: "When the current falls below 150mA, the charger automatically switches to a lower 'Float' voltage to prevent overcharging. At the point that a full charge is reached, Q1 will bias and the LED will light."

You don't need to understand the LM301 operation - the description tells you that the charger will switch to 'Float' voltage, so there will be a very small charge. Google "float charge" if you don't already understand it.

It also tells you that Q1 will cause the LED to light. That's the only thing Q1 does - it does not control charging at all.

Forget that circuit. It is not properly labeled. It has resistors with values expressed in volts - that's wrong, and impossible for you to follow.

Ed

Correct.

Correct.

Incorrect.

Is that it ?

Correct. If the battery is dead, the relay will not energize, and the charger will not be connected to the battery. You can't charge a dead battery with this circuit. However, if your battery is so weak that it cannot energize the relay, it is already so badly damaged that it is not worth charging.

Well, my diagram was missing a connection to the (+) side of the battery, but you figured it out. That's pretty good. And I think you understand the circuit pretty well, except you indicated that you have not worked with relays before. I'll attach the updated diagram, and an explanation of relays, below.

The only other thing that comes to mind in the "missing" department is this - you may be missing information on battery charge and discharge characteristics, so I'll briefly mention that, too.

I left out the connection from the (+) side of the battery. Here's the corrected diagram:

For reverse polarity protection:

N/O v====o-----+-- to battery (+) Charger (+)-----------o---- | +---------o---^ N/C | | | [Buzzer] --- | | | /| | +-----+-----| / |---|

you have the buzzer connected to the charger when there is no battery why not power it from the battery instead ? Bye. Jasen

You could do that. To me, it makes more sense to have the charger provide the power. It provides audible indication of the following problems:

All of those should be avoided. With the buzzer connected so that it gets power from the battery, only #1 will sound the buzzer.

I don't see that any of the above thinking is compelling, making it mandatory that the buzzer be powered from the charger - it just seems to tip the balance toward doing it that way.

Ed