Charging A Sealed Lead Acid Battery

charging sealed lead acid 12v battery +circuit

Would like to ask the following matters:

Whats the difference or result of the following matters? Is it possible? Assume it is a 12V battery.

a.) Charge using a DC/DC converter. Boost or buck the voltage level to an apropriate level before applying to the battery.

b.) Charge by simply applying a power supply of 12V to 14V.

c.) With a low voltage, I amplify the voltage using a transistor before applying it to the battery for charging.

d.) With a low voltage, I amplify the voltage using a transconductance op-amp before applying it to the battery for charging.

With all these cases, despite considering the efficiency, can I say that all the above will also charge the battery? As long as I apply a higher voltage to the battery for the current to flow to the battery. At this point, ignoring the amount of current flowing into the battery for charging. Just wondering....Confused.

Sorry, if everything mentioned above are nonsense...

14.2v lead-acid charger

hi,
Confusing....
can you post a schematic or something
mosh

moshing in lead acid battery

Maybe start by reading data/application info from battery manufacturers:

PowerSonic:
**broken link removed**
Yuasa:
**broken link removed**
Panasonic:
https://www.panasonic.com/industrial/battery/oem/chem/seal/index.html

ripple voltage for lead acid battery

These batteries are sealed and you must procead with caution when you charge them. They are charged by constant voltage and you can normaly find the charge voltage written on the side of the battery 14.2v dc (Yaso) coming to mind. Do not use a lead acid battery charger as these charge with a dirty dc voltage rippling with the mains . You can use a lab power supply and set the current to say 1amp limit and the voltage to 14.2v dc. You should find initial charge current high dropping to a low current as the charge compleates.

Barrybear

sealed lead acid battery flow charging

Sorry if my post is unclear: Basically, this is what I am doing, it is a college project =>

I'm developing a Battery Charger and Monitoring Unit, in which the source of this unit will be from a solar panel (7.5V) or a 240V AC supply. If one chooses to use the solar panel to charge a battery, the output voltage of the solar panel will be bosst up to an apropriate level for battery charging purposes. Whereas if one chooses to use the 240V AC supply for charging, the voltage level of 240V AC will be step-down to an appropriate level for charging purposes. The entire battery charging unit will come with a PIC microcontroller for the manipulation of certain matters, such as the duty ratio of the boost DC/DC converter, overcharge protection, display readings on a LCD and so on....

I was just asking about ways to charge a battery to make myself ready for questions which might be thrown by the accessors. One thing that I would like to reconfirm would be, is it through that in order to perform a charging process, I have to ensure that my charging source has a higher voltage as compare to the charging load for current to flow in a proper direction. Am I right to say that this is one very basic consideration or requirement needed for charging purposes?

Thanks in advance...

Added after 30 minutes:

Barrybear? From what you've said, does it mean that another main concern in my design would be the ripple voltage? Meaning, I should design an AC/DC converter which has a minimum output ripple voltage? By the way, all the while I thought that it wasn't an important issue about the ripple thingy as the current will still flow as usual to the battery when my source has a higher voltage level. Thanks for correcting me.

Added after 2 minutes:

One question Barrybear, sorry. Would like to ask how does the ripple voltage of the output of a charging circuit affects the charging process? Or it doesn't affect the charging process but it "spoils" the battery?

lm317 charger lead temperature compensation

try to see the data sheet of lm317 there are one application note that explain exactly what you are train to do ,
peraps you will have to do some modifications but only feel of
sorry about my poor english.

if you want email-me
fauser_gustavo@uol.com.br

devonsc, The second half of PowerSonic's techman.pdf (see above) explains various techniques and tradeoffs when charging sealed lead-acid batteries. Good read!

We extensively use sealed lead-acid batteries and the charger we use is a 3-stage charger and so far it works very well.
It follows description from CADEX:
http://www.intusoft.com/products/testdesigner.htm

The charging directions from most manufacturers is that 13.8 V applied continuously is acceptable. For faster charging 14.7 V applied until the current is the battery one hour capacity divided by 100. You can use current limiting on the charging source in both of the above methods. C/10 is a good value. Heat and high currents in or out are the main limiters of battery useful life.

Try looking this IC from TI:
https://focus.ti.com/docs/prod/folders/print/uc3906.html

First of all you should to know basics of your battery. That is battery nominal voltage ant it's capacity in Ah. Battery cell has minimum allowed operating voltage so as the maximal alloved voltage when it is charged. You may choose constant voltage, constant current or trickle charge method, it's up to you. Constant voltage method is acceptable if max. voltage of charger does not exceed battery voltage when it is assumed to be fully charged. Constant current charger usually assumes C/10 current. This means that charging current is 1/10 of battery capacity expressed in A. Charging time is in this case 10h. Trickle charging is fastest, but it requires appropriate algorithm for charging then voltage and temperature control of battery. To propperly control the time of charging it is allmost neccessary to monitor the battery voltage.

At GSM sites we use constant volatage charging with temperature compensation -3,5mV/degC (nominal temperature in Europe is assumed to be 20 degC, in America it is 25 degC). When temperature in battery room rise up controller have to buck output voltage of rectifiers in order not to overheat batteries which should lead to thermal runaway.

Capacity for solar batteries is usually given at C100 basis not C10 or C20.

First, you should study in detail your concrete battery datasheets. Then, ways of charging, overheat & undervolatge protection, storage etc.
See at some sites in Europe more about batteries eg. sonneschein, tudor www.tudor.se , oerlikon www.accuoerlikon.com, northstar, varta, hawker (use google...>).

You ask questions in advance. First try to read about batteries and its applications then try to make basis for your project. Then you will be able to aks more real and precise questions.

Regards.

Use the circuit in this web site

**broken link removed**

Good Luck

Have a look on this

there is design application note as well on it.

Battery Management - Battery Charge Management - UC3906 - TI.com

Or you can have a look on Bq24450 IC as well
its pretty good