Battery Charge

[Sylvi]

In this way once when the battery got charged that battery current comes to UPS (or computer power supply) and damage or burn the power unit ????

once i tried to charge a car battery from 12V 5A power pack and after few min i got the burning smell and when check transformer have burned out.

'Mensoft'

What you write is very difficult to understand what I wrote is to take off the two wires from the UPS Battery and use only that charging circuit from the ups for the Battery to charge not to connect any other units to that charger.

There are two types of UPS units one is with a inverter the computer is supplied from the inverter that has bigger battery which can go on for several hours moment powver fails the battery will supply the 230volts continuously without a interruption.

Other type takes few seconds to supply the 230 volts or you have to manually on same. this is the type which is used in home computers.

other type is used for people who wants their computers on 24 hours a day.

The transformer which got burnt out is nothing to do with the charging that transformer would have had some defect or you have connected the battery wires in a wrong way due to that the rectifier would have got burnt then the transformer had got burnt off.

It is very difficult to find the fault without examining the burnt battery charger transformer.

If you want to find out any thing on battery chargers please do call me. 2573690/0712222420. I will help you.

Sylvi Wijesinghe.

[Sylvi]

Guys this is something i found sometime ago and i built it myself so it works perfectly. unfortunately someone "borrowed" it and is no longer with me, im gonna build a new one and ill fill in on the details ASAP

This is an automatic car battery charger with an indicator lamp to indicate when the battery is fully charged and it will automatically cut off the power to the battery as well so no harm keeping it plugged in for a while. But i would advice you to remove it once the battery is fully charged cause no point in stressing the triac and the transformer unnecessarily. And not for the faint of heart

Here is the original site i found it from, has the parts index (http://www.aaroncake...howcomments=all)

I build this on a veroboard but you can take a printout of this and take it to Ravi PCB in Maradana and they will make a printed circuit board for you. All of the components can be bought locally ( i got them from Senith YBMA borella), some parts that might be missing such as th TRIAC and the SCR; if thats the case try to find a similar component.

'The Stig',

The circuit on your post, you and I can build but who is new to electronics will find difficult to build.

That is the reason I gave a very simple circuit any one can build.

Please do not misunderstand me I am not underestimating your electronic knowledge

Sylvi Wijesinghe.

[The Stig]

'The Stig',

The circuit on your post, you and I can build but who is new to electronics will find difficult to build.

That is the reason I gave a very simple circuit any one can build.

Please do not misunderstand me I am not underestimating your electronic knowledge

Sylvi Wijesinghe.

I did say "not for the faint of heart" when i gave the circuit

I understand, what you gave is simple rectifying circuit anyone can build but its functionality is limited. For an instance you cant know when the battery is fully charged, my one is a bit more advanced but much more functional cause it has an indicator to show when the battery is fully charged and will also cut off current to the battery once its full to prevent any damages due to overcharging.

and if you give this design to a any electronic shop who makes "printed circuit boards (PCB)" they will draw the paths in copper and all one has to do is put the right components in the right place and solder. I think anyone who can make a rectifying circuit can build this if this circuit is given on a PCB.

[Iroshw]

Hi all,

Do you have any idea about this Battery Charger? It says 12V 1250ma and not overcharging. My Car battery is 45ma. I was thinking about a Battery Charger since sometimes my battery is dead.

http://####/en/12v-1250ma-car-battery-charger-for-sale-colombo

And if you know a good place to purchase a battery charger (cheaper one) please let me know.

Edited March 26, 2013 by Iroshw

[Sylvi]

Iroshw,

According to the posted specifications of the advertisement. The advertised unit is very cheap for the price.

1250 ma means that charger will charge your battery only 1.25 Amperes. If the battery is very badly down,

About 75% then you have to keep the charger for one full day or more for a full charge.

This unit is good for motorists who do not use car daily to keep the battery in good condition.

If I am not mistaken this unit is a electronic unit without a step down transformer.

I have not come across any battery chargers less than that in the market.

Today to assemble a battery charger 3 amperes, with a ampere meter.

Cost you more than Rupees 4000/=.

Sylvi Wijesinghe.

[Iroshw]

Iroshw,

According to the posted specifications of the advertisement. The advertised unit is very cheap for the price.

1250 ma means that charger will charge your battery only 1.25 Amperes. If the battery is very badly down,

About 75% then you have to keep the charger for one full day or more for a full charge.

This unit is good for motorists who do not use car daily to keep the battery in good condition.

If I am not mistaken this unit is a electronic unit without a step down transformer.

I have not come across any battery chargers less than that in the market.

Today to assemble a battery charger 3 amperes, with a ampere meter.

Cost you more than Rupees 4000/=.

Sylvi Wijesinghe.

Hi Sylvi,

I bought this Charger yesterday. It was a house near Pannipitiya (Kalalgoda) and this guy is selling it at home (no shop). But it is a new item and he had 10 chargers. He said that he bought a lot from Hong Kong and sold during last few weeks. When I emailed this guy he said that he will deliver it to my place. But you know, I didn't want to lose my 1750 rupees . SO I said I will come and purchase it.

My battery was fully dead and I tried this charger yesterday. It worked. The only issue was, as he said the LED gets Red when charging and Green when fully charged. But my charger works other way. But it is ok since it charged my battery. Then I tested it from a tester, it is 13V. I'm not sure why it is 13V instead of 12V, please advise. It is a small portable charger. And my concern is there is no Earth Wire/Pin (two pin plug). It took more than 7-8 hours to charge. But it is ok since normally what I do is, taking my battery to the nearest Battery Shop and give them to charge, and the next day picking up. So I can save my both traveling cost and charging cost also my time. Sylvi, could you pls let me know, how this affect my electricity bill ? I mean per one time charge?

And Sylvi, this guy gave me 7 days warranty. I didn't say anything but I said I will try one time and if it not worked, I will return it back. He agreed. What do you think about this warranty period? I'm not sure what will happen to this item after few weeks or months .

Whatever happens, I think this tiny charger is a good solution for battery charging problems. I can take it anywhere I go. As you said, it is worth for the price.

###

Irosh

Edited March 26, 2013 by MADZ

[Crosswind]

Hi Sylvi,

I bought this Charger yesterday. It was a house near Pannipitiya (Kalalgoda) and this guy is selling it at home (no shop). But it is a new item and he had 10 chargers. He said that he bought a lot from Hong Kong and sold during last few weeks. When I emailed this guy he said that he will deliver it to my place. But you know, I didn't want to lose my 1750 rupees . SO I said I will come and purchase it.

My battery was fully dead and I tried this charger yesterday. It worked. The only issue was, as he said the LED gets Red when charging and Green when fully charged. But my charger works other way. But it is ok since it charged my battery. Then I tested it from a tester, it is 13V. I'm not sure why it is 13V instead of 12V, please advise. It is a small portable charger. And my concern is there is no Earth Wire/Pin (two pin plug). It took more than 7-8 hours to charge. But it is ok since normally what I do is, taking my battery to the nearest Battery Shop and give them to charge, and the next day picking up. So I can save my both traveling cost and charging cost also my time. Sylvi, could you pls let me know, how this affect my electricity bill ? I mean per one time charge?

And Sylvi, this guy gave me 7 days warranty. I didn't say anything but I said I will try one time and if it not worked, I will return it back. He agreed. What do you think about this warranty period? I'm not sure what will happen to this item after few weeks or months .

Whatever happens, I think this tiny charger is a good solution for battery charging problems. I can take it anywhere I go. As you said, it is worth for the price.

Irosh

13V is normal

[CJ5]

Hello Sylvi

I have a SELMAR 6/12V battery charger from the UK with charging meter etc etc. I got it a few years ago and was working fine until recently. Now I find that it does not charge. Where or who do you reckon could fix it??????

[Sylvi]

Hello Sylvi

I have a SELMAR 6/12V battery charger from the UK with charging meter etc etc. I got it a few years ago and was working fine until recently. Now I find that it does not charge. Where or who do you reckon could fix it??????

CJ5,

Just drop your charger at my place when you pass this way. Will do the need full.

Sylvi Wijesinghe.

[Sylvi]

Hi Sylvi,

I bought this Charger yesterday. It was a house near Pannipitiya (Kalalgoda) and this guy is selling it at home (no shop). But it is a new item and he had 10 chargers. He said that he bought a lot from Hong Kong and sold during last few weeks. When I emailed this guy he said that he will deliver it to my place. But you know, I didn't want to lose my 1750 rupees . SO I said I will come and purchase it.

My battery was fully dead and I tried this charger yesterday. It worked. The only issue was, as he said the LED gets Red when charging and Green when fully charged. But my charger works other way. But it is ok since it charged my battery. Then I tested it from a tester, it is 13V. I'm not sure why it is 13V instead of 12V, please advise. It is a small portable charger. And my concern is there is no Earth Wire/Pin (two pin plug). It took more than 7-8 hours to charge. But it is ok since normally what I do is, taking my battery to the nearest Battery Shop and give them to charge, and the next day picking up. So I can save my both traveling cost and charging cost also my time. Sylvi, could you pls let me know, how this affect my electricity bill ? I mean per one time charge?

And Sylvi, this guy gave me 7 days warranty. I didn't say anything but I said I will try one time and if it not worked, I will return it back. He agreed. What do you think about this warranty period? I'm not sure what will happen to this item after few weeks or months .

Whatever happens, I think this tiny charger is a good solution for battery charging problems. I can take it anywhere I go. As you said, it is worth for the price.

###

Irosh

Irosh,

Crosswind is correct on his post.

The charger what you have bought from this person is definitely a Electronic circuit charger, some what like we use for Cellular telephone charger.

It is OK for that price, some times they last very long. Be careful not to change the polarity when you connect to the battery.

If you change the polarity and connect to the battery, then the charger can get effected. Normally this type of electronic charges a limited Warranty.

Sylvi Wijesinghe.

[Rumesh88]

@Irosh

Just to add my two cents to the thread, as pointed out by Sylvi the charger you bought is of electronic switched mode converter having only two wires to connect to the mains supply. It may not have the grounding pin but it is not an issue. This type of converters have many advantages over the conventional and bulky transformer type ones but only disadvantage being the vulnerability to voltage surges on mains so avoid using it when you have lightnings. They have conversion efficiency in the region of 90% to 95% and the impact on your electricity bill for a full charge from a flat battery would be as follows.

Assuming you have 45Ah battery and your charger delivering 1.25A at 14 volts it would cost (Time in hours)X(Power in Watts)/1000 KWh CEB units for a full charge from a flat battery. Taking a conversion efficiency of 90% and a charging efficiency of 90% this would work out to (((45/1.25)/90%) X ((14X1.25)/90%))/1000 Units. My apologies for unwanted maths part but the whole thing works out to 0.78 units. So this would cost you around 1 unit over a period of around 40 hours, the time for a full charge from a zero point. You may tweak my assumptions in the above calculation to your liking if you wish.

However the practical situation is that you will have some charge left in the battery and would not take full 40 hours for a charge. A terminal voltage value of 13V after a charge shows that the battery is fully charged but it is not an indicator of a good battery. Instead measure the terminal voltage after a full charge with your headlights on. You should get a reading of around 12V. Keep this reading as a reference so that you can monitor the performance of the battery over a period. Hope the explanation is clear enough.