Charging 12V Gel Battery: Compatibility with Acid Battery Charger & Rectifiers

Hi, I bought a small 12v battery and I do not know if it can be charged with a charger like an acid battery

Theoretically yes, because gel is also acidic. Just check if you exceed the maximum charging current (usually written on it) and the maximum voltage, because you can damage it.
What is the rectifier and what battery?

Dawidowski0090 wrote:

Hi, I bought a small 12v battery and I do not know if it can be charged with a charger like an acid battery

You can, but only with rectifier with automation or microprocessor - this will protect the battery from overcharging, which is deadly for the gel battery. A simple trafo transformer + diode + ammeter is not suitable for this.

Hello, there are other chargers for gel batteries, remember that you can charge a gel battery with a current of no more than 10%

kaziu202 wrote:

remember that you can charge the gel battery with a current of no more than 10%

E there, the 0.1C recommendation applies to all types of acid batteries. Limiting the current, moreover, it is easy to ensure even putting a car bulb in a row with a car. It is more sensitive to watch the voltage - it can not exceed 14.4 V in any case, because the battery will be overcharged and destroyed.

Hello, there are other chargers for gel batteries, remember that you can charge a gel battery with a current of no more than 10%

The gel battery should be charged to the MAX 14V voltage, ideally not to exceed 13.8V. The question is, is he really gel (GEL) or is it just an ordinary AGM? AGM can be charged up to 16V, only these batteries are not suitable for cyclical operation. They feel best in a buffer job with a voltage of 13.5-13.7V.

Wlodek22 wrote:

The gel battery should be charged to the MAX 14V voltage, ideally not to exceed 13.8V.

Nonsense. The gel battery in cyclic work is loaded like all acidic aces up to a voltage of 2.4 V / cell or 14.4 V for a 12 volt battery. The 13.8 V voltage is suitable for buffer operation.

Wlodek22 wrote:

AGM can be charged up to 16V,

Even more nonsense and also harmful advice. AGM batteries are VRLA batteries with trapped electrolyte and safety valves. They must not be charged above 2.4 V / cell (14.4 V) as this will cause intensive gassing and destruction of the battery.

Wlodek22 wrote:

only these batteries are not suitable for cyclical operation.

Another nonsense - AGM batteries are adapted to cyclical work and often occur in this capacity - even more often than real gel, because AGM are more often used (mainly due to lower price and higher current efficiency).

So do not apply this nonsense and charge gel to 14.4V, and AGM chase in cyclic work. After the first experiments, you will verify your knowledge.

I do not know if this picture will help in anything

Wlodek22 wrote:

After the first experiments, you will verify your knowledge.

Next theoretician of alternative electrician. I have experience with AGM batteries and I do not have to verify anything.
For your reflection. Why are AGM batteries used in cars with a start & stop system? And in addition, the alternator keeps there "like a bull" 14.4 volts? Somehow such a battery does not fall after a week and they sometimes make tens of thousands of kilometers. In addition, such a battery is subjected several hundred times to a day and does not fall apart. How is it to your wisdom?

Added after 2 [minutes]:

Wlodek22 wrote:

and AGM chase in cyclical work.

And AGM often saw in off-grid solar installations where they worked for 2-3 years. There the work is very cyclic. And how is it to your wisdom?

The battery has only 1.3 AH.

The current will be tiny.
A good question is what exactly is the rectifier.

Because if you have one that has a peak on the level of 14.5-15V, it can be especially noticeable that the battery is allowed to be 14.9V. It is not an elegant solution and will be slow to charge in the final phase but the risk of overcharging is much lower.

The peak can be checked by connecting a capacitor (several dozen uF of age, remember that it must withstand 20V or more) and measuring the voltage on it. Normally, in cheap chargers you will see a peak voltage of 17-18V.

Dawidowski0090 wrote:

I do not know if this picture will help in anything

This is an AGM battery. You can charge it with a regular rectifier, but with a 3-4W light bulb (in series). End voltage as on the casing, do not allow discharging below 11V, store as fully charged as possible.

And what will happen as the voltage drops below 11v

Dawidowski0090 wrote:

And what will happen as the voltage drops below 11v

The battery will be deeply discharged and will sulphate which will reduce its efficiency. Do not discharge the battery below 11 volts and charge as soon as possible after unloading. It will prolong its life and efficiency.