Charging Batteries: Ammeter Not Dropping to Zero with Homemade Rectifier - Transformer, Diodes

This is a lawful symptom - you have a voltage on the transformer a little higher than the voltage. battery is fully charged and electricity is flowing. In the event of unattended charging, it will overcharge the battery. Charge on time and it will be OK. Regards

If the ammeter does not show zero, it means that the charging current is still flowing. Or the gauge itself is inaccurate. Measure this current with another ammeter connected in series with the battery being charged.

I know from experience a case that the battery was damaged and it could have been standing under the charger for a week and it was still flowing 3A.

Hello.
If the voltage of the unloaded charger is higher than the voltage of the battery during charging (even when the battery is charged), current will flow. This current will depend on the above rectifier voltage, battery voltage, and the internal resistance of the charger, battery, and leads.
So in the case of such a simple rectifier structure without any automation, it is normal that the current flows to the puki the rectifier is connected to the battery and is turned on. The only thing that changes is the value of the charging current (it will be lower (even much lower) after charging the battery).
Greetings.

Hello. When writing about the rectifier, you did not write anything about it about the output voltage. Have you measured them? Perhaps it is too high and when charged, energy is used to gass it excessively, or you have a defect in the battery itself? Greetings.

Hello.

elel wrote:

If it's without a battery, it's way too much. Take an electrolytic capacitor (any capacity, voltage at least 25 V) under this rectifier and then measure the voltage and you will see what I'm talking about. The battery is only a larger capacitor and will also be charged to the same voltage as the capacitor, maybe a little less. The voltage of the charger must be such that when the battery is fully charged, the voltage will be 13.8 - 14.4 V with the charger connected. If you have frequently and long charged with this invention, check how much electrolyte you have in your cells and if possible, top up with distilled water, if necessary.

It is not quite like that. The battery cannot be treated as a capacitor, because the DC capacitor (not counting the small voltage ripples) has a resistance of hundreds of megohms, while the battery has an electrolyte that conducts electricity and this current causes the source voltage (in this case the rectifier) to drop, so I dare claim that the rectifier voltage you entered is absolutely correct. I would look for the reason elsewhere. Greetings.

Hello.
If the rectifier does not have a capacitor in it (usually there is no one, although I already saw that it was at the output: e.g. 1000?F), the capacitor will boost the voltage times the square of 2.
So if it is 13V on an unloaded rectifier, it will be 18.3V with the capacitor, and if it is 14V it will be 19.9V with the capacitor. If these are the tensions, then they really are too high.
To be able to recharge the battery, the rectifier must have a slightly higher peak voltage (i.e. with the capacitor) than the battery voltage when fully charged.
It does not change the form of things that the battery will never be charged to the rectifier voltage, so there will always be some (even very small) current flowing until the knock, the rectifier will not be turned off. No stabilizers will help. You would have to use a system that controls the battery voltage and turns off the rectifier after the battery reaches 14.2V (13.8V in the case of a gel battery).
In the case of such a simple rectifier structure, it is best to charge the battery for a specific time, depending on the battery capacity and charging current. It would be advisable to additionally check the voltage on the battery, and if it reaches the value for a fully charged state, stop charging.
Of course, another thing is the harmfulness of charging the battery with too much current. Ideally, the charging current should not exceed the ten-hour current.
Greetings.

If the rectifier voltage is less than the battery voltage, the charger will not charge the battery.

Hello.
I was charging the battery discharged to zero.
After 12 hours the tip did not drop from 6A.
after 24 hours the tip fell from 6A to 4A.
After about 30 hours, the pointer dropped from 4A to 3A.
After 30 hours The current on the rectifier terminals with the 15.8V battery, the 12.7V on the rectifier terminals without the battery, 13.8V on the battery without the rectifier.
After plugging the meter in series and using the 2.3 A rectifier.
Is everything OK?
It's a new monthly battery that I have discharged with my daytime running lights for a few hours.

And the rectifier is what, please, Sir?

Sorry. I didn't think ...

panpodziemia100 wrote:

The current on the rectifier terminals from the 15.8V battery,

Or is it the tension?

panpodziemia100 wrote:

Is everything OK?

Yes.

Thanks.
Tension - fact
How much should I charge the 72 Ah battery with this charger next time with the potentiometer set to "8" because 30h is rather too much ...

Until the charging current stabilizes at the lowest value for a period of approx. 4 - 6 hours.

Thank you and best regards

Recently, I was charging the battery with such a charger as in the photo. In fact, I just recharged it, because the car was left unused for a long time. I set the current to 8. From time to time I looked at the ammeter and the current gradually decreased. After about 3 hours, the charger disconnected the charging. There was nothing on the ammeter and the LED was green. I have not disconnected the battery yet and after some time it started charging again. This time with a much lower current, of the order of 3-4A (even though it was set to 8). After some time, the charger disconnected the charging again. This is where I finished my reloading.

Hello.

zybex wrote:

... the charger disconnected charging ... ... after some time it resumed charging ... ... After some time the charger disconnected charging again

Yes, because this invention heats up a lot, and so that it does not burn, it has a bimetallic thermostat on the transformer (if it can be called a transformer), which temporarily turns it off to cool it down.
I know, because once I had such a rectifier under repair, and when I looked inside, I was scared.
I even took photos, and as far as I remember, I even published them somewhere on the forum.
Trash, trash, and trash again, plus the level of security - no comment.
Greetings.

Hello, I have a problem with my rectifier, so far everything was ok, the guest checked the diodes, said that they were ok, the problem is that when I connect to the battery, whatever it was, the ammeter drops below zero on the bottom of the scale what is it about help I am green in it, I will add that the 6v and 12v options are the same.

Moderated By c2h5oh:

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The visitor switched the ampere's outputs

Most likely, this is how it looks like from this description.

I changed the cables from the ammeter and it's good I have no idea who could pass it and pp what, maybe the rectifier ran somehow, but now it is connected as if the other way around.