Qaisar Azeemi
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All you want to know about batteries could be found in battery university. Please read the following article, I think it will be helpful and will answer to your questions.Qaisar Azeemi said:so it means i can charge my flooded lead acid batteries 24v(2 12v in series) 200AH by appling 27v on its terminals and a current of a minimum of 10% of its AH rating (i.e; 20A ) to 30% of its AH rating i.e; 60A.
Nice example and nice explaination Sajjadthank you. so it means i can charge my flooded lead acid batteries 24v(2 12v in series) 200AH by appling 27v on its terminals and a current of a minimum of 10% of its AH rating (i.e; 20A ) to 30% of its AH rating i.e; 60A.
OR
for a 6v 4.5ah sla battery the charging current must not be more than (4.5*30)/100 = 1.35A ....
and minimum current must not be less than 10% of its AH rating 0.45A for above example.
am i right in my concept????
oh yes you was right. i just check it again. most of the series connected battries to the UPSes one battery is overcharged and the other is less charged. in one set one battry have 12.3V while the other have approximately 15V.... but i am astonished the overcharged one was not heated up.. it was quite cool..... :-/
Such a powerful system needs huge battery banks and you are charging them with Lm317! are you nuts? This will take your whole life to charge those batteries.
I wont recommend flooded batteries as i have experienced, a little heat in the batteries makes the water evaporate, plus these batteries charging is usually detected by their gravity gauge.
I would recommend you to use Sealed lead acid batteries. Charging flooded type or sealed lead acid batteries with voltage 13.4-13.8V is fine and don't do harm to it but its a slow charging, you cant even use a 2 stage charger on sealed lead acid batteries as i will describe.
First you need to know what a 3 stage charger is.
1st. stage is constant current mode. in this stage fixed current is injected into batteries till the batteries voltage reaches 13.8V, if both batteries are not at the same voltage level this stage assures that they do. after that 2nd stage. in 2nd stage constant voltage is applied (14.4-15V) till when very little current is left going in the batteries. for healthy batteries if current is less than 100mA and for partially healthy batteries its less than 400mA. At this stage the batteries are charged. then at stage 3 the voltage is further reduced to 13.4.-13.8V,this is standby float charging.
You need a big power supply regulated by lm317 or lm338. Since you need high current to charge batteries fast so you need a powerful external pass power transistor. and you may go up to 30 Amps of charging current.
For your batteries to live longer, dont discharge them below 70% of their current capacity.
I will try to make a simple schematic for your understanding if i get time and try to post it.
---------- Post added at 12:02 ---------- Previous post was at 11:56 ----------
Notice when you use the ups then one battery will be discharged and loosing its health while the other battery will no be discharged fully. Then at sometime you will replace that dead battery with a new one. Then the new one will not be fully discharged and the old one will lose its health eventually. This process will be on going and you will keep paying for it.
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