Battery Charger Info?

[danny davis]

How does a Battery Charger Circuit work? its a current power supply?

It was a 12 volt rechargeable battery and has a floating voltage of 13.5 volts, the cut off voltage is 10 volts

How does a battery charger circuit work to know the floating voltage, nominal voltage and cut off voltage?

A Battery String: is battery that are connected in series

What is it called when batteries are connected in parallel?

To get the IDC of a battery, you turn the battery off and turn it up using a Current meter, why would you want to know the IDC of a battery? how much DC current charging?

 

[BradtheRad]

* A battery is charged when current flows backwards into its positive terminal. This requires that the source be a greater volt level than the battery.

* The supply must have sufficient available current.

* The charger circuit ought to be adjusted so it does not provide too great current, nor for longer than is necessary to fully charge the battery.

* An op amp (or two) is a cheap method to monitor the battery's volt level, and to devise a control circuit which (a) will alter charge rates to suit the battery's characteristics, and (b) will connect or disconnect a load based on whether the battery is above 10V.

* Batteries in series: easy to monitor, and to power a load, and to charge, etc. It is easy to hook up a voltmeter across each battery in turn, to check its state.

Batteries in parallel: not so easy to do the same things. Paralleling batteries is okay when necessary, however it is more trouble because you need to keep closer track as to whether any one battery is weaker than its parallel brothers. You cannot use a single voltmeter hooked up to one battery, unless you first disconnect it.

 

[tpetar]

How does a Battery Charger Circuit work? its a current power supply?

Lead Acid need voltage and current controlled charger.

It was a 12 volt rechargeable battery and has a floating voltage of 13.5 volts, the cut off voltage is 10 volts

How does a battery charger circuit work to know the floating voltage, nominal voltage and cut off voltage?

Float voltage depends from temperature. 13,5V is on higher temperature above 30C-35V, and 13,8V at 25C-27C and lower.
Cut Off voltage for lead acid starter C/10 should be 11,99V and for lead acid deep-cycle C/20 10,5V.

A Battery String: is battery that are connected in series. What is it called when batteries are connected in parallel?

In serie you get higher voltager, for example 2x12V 55Ah = 24V 55Ah
In parallel you get higher capacity and the same voltage, for example 2x12V 55Ah = 12V 110Ah

For serial and parallel connections of batteries you need to have all batteries the same age, model, capacity, the same exploatation life,.... also the same internal resistance as much as possible. Paralleling can be done with balancing circuits.

To get the IDC of a battery, you turn the battery off and turn it up using a Current meter, why would you want to know the IDC of a battery? how much DC current charging?

What is IDC of battery ? If you mean on charging current then use 10h time for cycling process (C/10).

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Properly measuring of lead acid should be done 24h of resting time after charging process, and you should read 12,72V-12,73V.

Declared manufacturer battery capacity is only for discharge in C/10 or C/20, for example starter C/10 55Ah - You will get 55Ah only if you discharge battery with maximum 5,5A during 10h. There is no 55Ah for 1h!!! Battery need time to produce power, its device with chemical process!!! That chemical factory have capacity of production as any factory, and capacity of factories are always linked with time. Always read manufacturers datasheets and look graph, specially for smaller batteries such as 7,2Ah,...

If you want longer life of lead acid batteries never discharge starter more then 30% (Its float battery for starting. For starting can give high amperage, but its not good for deep cycling). Deep cycle discharge with smaller currents but you can do complete cycle 100% of discharge, avoid higher currents on this type of batteries, specially for car starting. For solar systems, this type is often used in battery banks because C/20.

Very important thing is that you never leave lead acid battery empty or partially charged on longer time (24h or more), keep always full if possible. Process of sulphatisation will occur on lead plate. That process can be reversed with desulphatisation devices (you will not get battery as new for sure but can be used).

 

[danny davis]

Battery Charger Schematic

What does Each Section Do , because I don't know how this circuit works



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How does section#1 work?



How does section#2 work?



How does section#3 work?

 

[BradtheRad]

This schematic has a lot of things going on. It's too hard to figure out, unless we know where those connectors go, and what kind of battery is being charged, etc.

It's possible to make out a few things, such as the TL431 adjustable voltage reference (in section 2). I imagine it senses voltage (or current) at the battery, and sends a variable current through the opto-isolator, which tells the control IC what to do.

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This schematic has a lot of things going on. It's too hard to figure out, unless we know where those connectors go, and what kind of battery is being charged, etc.

It's possible to make out a few things, such as the TL431 adjustable voltage reference (in section 2). I imagine it senses voltage (or current) at the battery, and sends a variable current through the opto-isolator, which tells the control IC what to do.

 

[danny davis]

The tech i work with says its a PWM modulation power supply with a feedback loop ( opto coupler )
He says that the IC chip sends out a pulse width which pulses the pulse transformer

I'm not sure how this works or could understand him, can you figure it out?

What do you need to know in detail about the batteries , so I can ask to get the info?

 

[BradtheRad]

There seems to be such a variety of configurations used to charge batteries.
How to step up (or step down) the supply V,
how to get the best efficiency from the power supply,
how to avoid too great a charge rate,
how to avoid overcharging,
etc.

Your schematic may be designed to do the job properly for one situation, or for different situations. To understand everything it does, one would need to be familiar with the control IC, and the feedback circuit, and the transformer configuration. One would need to know what the supply V is, and what type of battery it is designed to charge, and at what volt level.
Etc.