Charging a 74 Ah 680A Battery: Estimating Duration, Monitoring Ammeter, and Signs of Full Charge

Hello, how about how long to charge the 74 Ah 680A battery?

The battery is fully discharged, unfortunately because it has not been used for a few months, I will mention that the battery is almost new because it is about over a year old and there is still a warranty on it.
I charge it with an old Soviet rectifier, it has a knob and an ammeter when connecting, from time to time I turned the knob so that the ammeter showed the value of 4.5 A, so how do I understand I should charge about 16 hours?

Now, after 15 hours when I got home, I noticed that tip A decreased to 3.5 A I understand that this is normal and as the battery is charged the value will decrease and I should not regulate it or is my guess wrong?

How do I know if my battery is charged?

1. I've been charging it for over 15 hours currently, the ammeter needle is at 3.5 A there is no excessive gassing, no plugs are unscrewed in it, it has its own venting on the sides.


2. I warn you that, unfortunately, I do not have a voltmeter (the voltmeter is used every hour and when the value on the battery is constant approx. 14.4 V, it means that it is charged, so somewhere I read it so well for my ears?)

3.The battery is maintenance-free, although it is acidic, but it should not be opened, so I do not have how to check the density of the electrolyte.

How do I know that the battery is charged so as not to overcharge it?

And a question for the future, because the battery is good, because it is almost new, but it will not be used for 2-3 months, what is the best way to keep it operational?
I was thinking about buying a meter and measuring the voltage and, for example, when it drops below 12 V, recharge it every month to 14.4 V is a good combination, but how to calculate the battery charging time when it is not fully discharged and what value should you set in A?

I know that there have already been topics about charging batteries, but I think that owners of old Soviet chargers will be useful, and information on how to keep the battery alive outside the car will also be worth its weight in gold.


And that is a separate issue

By the way, I am thinking of buying my own rectifier (this one is borrowed), there is a bit of it on the Allegro and I would definitely like to avoid buying some junk, I think that cheap chargers are good for nothing because there is no charging regulation there, it is known that depending on the battery capacity, you should charge with different values. Also, there are no fully automatic inventions that fully charge the battery by themselves and support it after charging, but they are, for example, 4 or 6 A.

I was thinking about this rectifier, I think it is a good design and probably universal would be suitable for various batteries?

http://allegro.pl/prostownik-6-12-24v-30a-rozruch-100a-bass-polska-i1220441696.html

Isn't it worth spending so much on a charger for home use and lending for a family and buying something cheaper?

I apologize for the length of the post, but I assume who asks does not err, and I prefer to ask rather than guess.

Thank you in advance for your quick reply

greetings

Adam K.

If the battery is completely discharged, it is a pity to have fun because sooner or later it will fall again in winter ..
if you have a capacity of 74Ah, start charging with the current

krzyska90 wrote:

But since it was under warranty and it fell by itself from the fact that it was not used (and it has no right to fall new)

He could, unfortunately, because I did not use the car for 5-6 months (I was abroad), the terminals were connected to the electronics in the car, and unfortunately I had no one to leave in the car's care. In the battery manual I write that it can be charged, so I think that it is not maintenance-free, and it is vented by itself, there is no way to remove the housing.

Anyway, this battery is ...

http://www.eakumulator.pl/auto.html

the model on this page is AK74

here you can see it better ...

http://www.sklepcentra.pl/sklep/akumulator-74....html?osCsid=908afaa624476516967d2a3696c44284

Seemingly maintenance-free and the manual says that it can be charged only there is no mention of how to get to the plugs to unscrew ...

ok, I took off the plugs, it was enough to remove one strip and they all take out with it. There is still no sign of gurgling after so many hours of charging, at most a slight hum (and this when putting your ear to the battery and listening hard), all the cells are full evenly so it seems ok.

Charging dropped to 3A. How long to charge, so far 16 hours more than when turned on, charging set to 4.5A?

Ok, I disconnected the battery from charging.

And regarding the charging of maintenance-free batteries, I have confirmed the information that you can charge as much as possible in the case of acid batteries (I do not know how in the case of gel batteries), I asked the representative of the center. Only you cannot fully discharge the battery because the seller, when accepting the battery, can check the voltage if it has dropped below 8.5 V, it is not in accordance with the intended use and may not accept the complaint.

When charging the battery with a constant current of 1C (i.e. 7.5A in your case), the charging takes about 16 hours. The lower the current, the better for the battery, but the charging takes longer. When charging with 3A current, charging should take about 40 hours.

If the voltage of the discharged battery was lower than 8V, unfortunately it is not suitable for further use. The lifetime of such a battery is 3-4 years, so since it is "about a year old" then it is not "almost new" again.

As for the charger, buy a microprocessor charger - you can leave it permanently connected to the battery and it will periodically recharge it when the need arises. Anyway, if you plan to not use the car for more than 2-3 weeks, you should disconnect the battery from the car's installation (just remove the clamp "-").