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Battery stuff, need help!!!

Noa Baril

Jun 22, 2016
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Jun 22, 2016
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Hey guys,
I wanted to make my self a battery chager, but I actually dont know much, just the basic and a little bit more.
My question is : If I charge a 12V battery with a current at 2A, will it output 2A? If not, can you tell me how much it will output and how it work?

An other question is, I got 3 packs of laptop batteries (3 x 12 batteries) and I plug them in parallel. (the 12 batteries are plug in series but the whole thing (the pack) is plug in parallel) like this :

{ (battery) -> plug in series -> (battery) } -> plug in parallel <- { (battery) -> plug in series -> (battery) }
.....................(12 batteries)............................(x3 packs)..............................(12 batteries)



And I wonder, if I charge the whole thing (3 pack) together with an input of 12V 10A will it output 10A, will it even work? If there is a problem, can you please tell me how to fix it.


Thanks you.
 
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shrtrnd

Jan 15, 2010
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I'd just buy a commercial one unless you really want to design and build your own.
The first thing you need to do, is tell us if you want to recharge the NiCad, or Ni-MH batteries.
(Nickel Cadmium, or Nickel Metal Hydride, as their trickle-charging current values are different.)
 

Noa Baril

Jun 22, 2016
6
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Jun 22, 2016
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I really dont know, that was in some not that old laptop but, you know, not very new, so i think they are like some commun battery that industrie use. I really dont know. I can actually only tell that they are red. I konw its not helpfull, but the problem, i took them out of their case long time ago. I've writed on a paper their spec. but lost it.
The only thing I know is these are 12V 15A (but i only want them at 10A)
 

Noa Baril

Jun 22, 2016
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Jun 22, 2016
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Like is know they can go to 15A, but even tho, Its more common to charge at 10A so.... yea.
 

dante_clericuzzio

Mar 28, 2016
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Mar 28, 2016
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It will not necessarily output 2A but it depends on how much the amp needed during the charging...the easiest way it by observing the amp during the charging as the battery charges increase the amp required is decrease because the resistant of the battery increased - i did this a couple of days ago while charging my phone. The charging goes like this

Using 5 volt 1.5 Amp charger

The phone battery charges left 6%
Initial charge consumed = approximately 550 mA
As the charges increase to 14% the amp consumed reduced to 490 mA
20% - 35% = 480 amp to 470 amp
39% - 43% = 450 amp
44% - 50% = 440 amp

Although i didn't observe completely but the last time when the charges was 90% the amp consumed only 270 mA

Use a multimeter or volt/amp meter to measure the amp during charging
 

Noa Baril

Jun 22, 2016
6
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Jun 22, 2016
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So this means that, if I input example 10A, the battery will take only what it need?
(of cource there is a litmit)
 

shrtrnd

Jan 15, 2010
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Don't even think about doing whatever it is you're doing!
You apply 10 amps to your set-up, it is either going to start a fire or explode, ... maybe both.
People recharge batteries with a small TRICKLE CURRENT, applied over a specified period of time.
YOU DO NOT HAVE THE BASIC KNOWLEDGE NECESSARY TO ATTEMPT WHAT YOU WANT TO DO.
 

Herschel Peeler

Feb 21, 2016
401
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Feb 21, 2016
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401
Hey guys,
I wanted to make my self a battery chager, but I actually dont know much, just the basic and a little bit more.
My question is : If I charge a 12V battery with a current at 2A, will it output 2A? If not, can you tell me how much it will output and how it work?

An other question is, I got 3 packs of laptop batteries (3 x 12 batteries) and I plug them in parallel. (the 12 batteries are plug in series but the whole thing (the pack) is plug in parallel) like this :

{ (battery) -> plug in serie -> (battery) } -> plug in parallel <- { (battery) -> plug in serie -> (battery) }
.....................(12 batteries)............................(x3 packs)..............................(12 batteries)



And I wonder, if I charge the whole thing (3 pack) together with an input of 12V 10A will it output 10A, will it even work? If there is a problem, can you please tell me how to fix it.


Thanks you.

What the battery will put out is a characteristic of the battery. You could charge it at 1 Amp and get 10 Amps out. It depends on the battery. Keep in mind charging current is not always consistent. Charging from a power supply (constant voltage source) as the battery charges up charge current will decrease. So you may see a lot of charge in the early stages but slower progress towards the end.
When charging a battery from a dumb charger I monitor voltage and current and track progress in Microsoft Excel. Tracking Amp-hours going in. You can expect to pump x Amp-hours in to get x Amp-hours out, up to the limits of the battery.
Charge rate should not exceed a certain percentage of the Amp-hour capacity of the battery. Specifics depend on the battery. I use 10% as a general rule and expect to charge for at least 10 hours. Monitor the voltage on the battery with the charger disconnected. Stop when you get a full charge.
specifics of all this depends on the type of battery you are charging.
This is a less than perfect substitute for a properly designed battery charger, but it works.
 

HellasTechn

Apr 14, 2013
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My question is : If I charge a 12V battery with a current at 2A, will it output 2A?

That has to do with the battery characteristics and has nothing to do with the charge current.
like mentioned here.

What the battery will put out is a characteristic of the battery. You could charge it at 1 Amp and get 10 Amps out. It depends on the battery.
 

HellasTechn

Apr 14, 2013
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Don't even think about doing whatever it is you're doing!
You apply 10 amps to your set-up, it is either going to start a fire or explode, ... maybe both.
People recharge batteries with a small TRICKLE CURRENT, applied over a specified period of time.
YOU DO NOT HAVE THE BASIC KNOWLEDGE NECESSARY TO ATTEMPT WHAT YOU WANT TO DO.
that was an example god dammit. Aint gonna put 10A!!!

Take it easy there boys.

Yes it is always recommended that you use a specific charger for each kind of battery. That is a general rule of thumb but again that does not necessarily mean that if you use higher current the battery will explode.
Again all that have to do with the chemistry of the battery.
 

dante_clericuzzio

Mar 28, 2016
33
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Mar 28, 2016
Messages
33
So this means that, if I input example 10A, the battery will take only what it need?
(of cource there is a litmit)
Yes it will not try if you have a charger that says 2 amp current rating and observe the measurement using multi meter it will usually takes around 500 mA the most common for smart phone. But certainly there are some special or quality charger that could deliver 1 Amp...in my experience i used 1 Amp charger but it only deliver 660 mA that is already feeling very hot on the charger....if it deliver more than that without proper circuit protection on the charger it could easily fried.
 
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