Car Battery Chargers: Charging Current Explained

Hi.

How do typical car battery chargers charge the batteries?

Constant current or constant voltage???

I have this old battery charger here; it says "Einhell Battery Master" and has markings indicating either 11 or 22 amps.

A lead-acid battery should be charged with a current that is one-tenth of its capacity, so my 61Ah battery should be charged with a maximum of 6 amps.

Can I use this charger to charge a 3.2Ah 12V lead-acid battery, or will the charger damage the battery?

Sometimes you just want to ride with two wheels on the road, and right now, mountain biking under a full moon isn't much fun – that's why I have a powerful light on my bike.

"Thank you."
m,

Is it perhaps more specific about the type? 'Batterymaster' is printed on almost all Einhell products .

'In the worst case, simple chargers only have a diode as a rectifier, while better ones use a bridge rectifier. However, these chargers apply full voltage to the battery, directly from the transformer through the rectifier. This results in a DC voltage of around 16-18V. Therefore, the battery MUST be monitored, and it should be disconnected as soon as it starts bubbling. For lead-gel batteries, these devices are absolutely lethal! (You can only use them for lead-gel batteries for a short charge, i.e., just enough to get the vehicle started again).'

Then there are the regulated chargers, which will be explicitly labeled as such. These limit the voltage to 13.8 - 14.1V. You can connect a battery to one and simply forget about it.
Disadvantage: High price. Rarely found in hardware stores.

I just looked at the catalog again: even the regulated models from Einhell have 'electronic' written on them everywhere... so I guess you have a completely ordinary battery drainer .

Charging currents aren't that important. Starter batteries can handle a lot of current. After preheating and during cold starts, the alternator can actually supply quite a bit of current, often between 50-80 amps.
When it comes to small lead-acid batteries, one should be cautious and preferably consult the datasheets. Most can handle 50A in discharge mode, but when charging, you need to pay attention due to heat generation. My scooter battery is a lead-acid battery, but the currents are relatively low in that case.

Your charger will essentially fry your 3.2 device if you don't stand right next to it with a stopwatch.

CU Gremlin.

Hello.

'Lead-gel' refers to the fact that the electrolyte is bound within a gel, which is pressed into the plates during manufacturing under pressure. If you overcharge these batteries even once, something the Einhell battery is definitely capable of doing, it's game over because the gel won't return to the plates on its own.

That's why car batteries are always filled with liquid. The flammable gas that is produced is ignited at a platinum catalyst and recombined into water.
Within the cell, which functions as a closed system, the acidity remains constant.

There is a lot of information available from the manufacturers regarding lead-acid batteries.
Short: Constant charging at 13.8 volts - cycle charging at 14.4 volts. Possible current limiting is needed because lead-acid batteries have low enough internal resistance to potentially exceed the maximum charging current.