Help needed with a lead/acid battery charger circuit

Thread Starter

Claudia94

Joined Mar 25, 2015
28
@WBahn i can't cause i can't pass that way, i like electricity and i am good at it, i designed electric installation of our house and it was very similar to the one designed by the engineer, cause it was fun to learn and enjoyable
but i am not good at eletronics, i already have black point with regulation since high school

and sorry for my english, i know when i write none sense grammar
 

WBahn

Joined Mar 31, 2012
29,979
@WBahn i can't cause i can't pass that way, i like electricity and i am good at it, i designed electric installation of our house and it was very similar to the one designed by the engineer, cause it was fun to learn and enjoyable
but i am not good at eletronics, i already have black point with regulation since high school

and sorry for my english, i know when i write none sense grammar
I assure you, your English in a LOT better than my French!

It's sad that you believe that it's fine for people to cheat and take credit for learning things they haven't or aren't even interested in putting forth an honest effort to learn. We are more than willing to help you learn and do a lot of handholding in the process, but we are seldom willing to just give you a solution when we know that your intent is to just take that solution and submit it claiming that it is YOUR work.
 
i may be the most stupid person to this date who signed up in this forum,, 3:23am and still reading , but all i read won't get un to my mind.

i am very stressed, and running out of time because i need something to show to my professor in the morning, i had a week but didn't come up with any thing :'( :confused:

what about the circuit proposed by dave , the one with the comparator
No, Claudia, 'stupid' is not among the adjectives I would use to describe you...;)

With newbie-jaded regards
HP:rolleyes:
 
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Thread Starter

Claudia94

Joined Mar 25, 2015
28
I assure you, your English in a LOT better than my French!

It's sad that you believe that it's fine for people to cheat and take credit for learning things they haven't or aren't even interested in putting forth an honest effort to learn. We are more than willing to help you learn and do a lot of handholding in the process, but we are seldom willing to just give you a solution when we know that your intent is to just take that solution and submit it claiming that it is YOUR work.
i swear i've been trying to learn these for 2 weeks, since i first started working on this project. so please don't judge me like that and say that i am not putting effort, i would like to see you try making effort learning physics, and mechanical things ,
and obviously my professor is not stupid to believe that i did the circuit , and i would tell him that i got help online if he asks. anyway i don't wan't to fast forward , cause i have feeling i am going to mess up big time.

@Dodgydave and specially @#12 thank you guys for your time.

any help is still welcome tho @WBahn makes me feel that i don't deserve it.
 
i swear i've been trying to learn these for 2 weeks, since i first started working on this project. so please don't judge me like that and say that i am not putting effort, i would like to see you try making effort learning physics, and mechanical things ,
and obviously my professor is not stupid to believe that i did the circuit , and i would tell him that i got help online if he asks. anyway i don't wan't to fast forward , cause i have feeling i am going to mess up big time.

@Dodgydave and specially @#12 thank you guys for your time.

any help is still welcome tho @WBahn makes me feel that i don't deserve it.
Well... There is a distinction between requesting assistance and 'outsourcing' your assignment...

Regards
HP
 
@WBahn after i graduate as mechanical technicien( not engineer)
Now that's a crying shame! -- Is your technical engineering potential commensurate with your (demonstrated) social engineering prowess, the world may be losing a prodigy! ;)

EDIT: It is not my intent to disparage you! 'Tis merely my distaste for academic duplicity 'speaking' :(

Regards
HP
 
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#12

Joined Nov 30, 2010
18,224
Remember post #28?
I'm only grouchy when I have little or nothing to work with?
You are contributing little or nothing to this circuit.
Every single part has been described to you and you can't even change the fuse!
What makes you think that is, "deserving"?
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
guys never mind,
deserving ? you know i am translating from my language to english, if you have knowledge in other languages, you would know that is not the rule. so if i say something, it probably means another thing , what i tried to say, is thay you shouldn't help at first place or something close to that meaning.

also you can't blame me, i speak english, french, german, italian, and now i am learning arabic, and i can speak all these languages, just like i am speaking english now,
one can't make his language perfect without practice, that is what i lack. also you lose interest at some point
 
guys never mind,
deserving ? you know i am translating from my language to english, if you have knowledge in other languages, you would know that is not the rule. so if i say something, it probably means another thing , what i tried to say, is thay you shouldn't help at first place or something close to that meaning.

also you can't blame me, i speak english, french, german, italian, and now i am learning arabic, and i can speak all these languages, just like i am speaking english now,
one can't make his language perfect without practice, that is what i lack. also you lose interest at some point
In all sincerity, one possessed of the discipline requisite of acquisition of four second languages should experience little difficulty in the attainment of fundamental engineering skills... :)

Best regards
HP
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
Hypatia, that doesn't make sense. also in the morning i was going down the stairs in a hurry, and i sprained my ankle, it made cracking noise, and fell off the stairs, hit my eye brow on a sharp edge, and was very painful i passed out, two hours ago i woke up in hospital with broken ankle and leg, and two stitches over my eye.

so guys i hope you are happy, cause i won't be going anywhere for a while .
hopefully this gives me more time to work on this myself
 
Hypatia, that doesn't make sense. also in the morning i was going down the stairs in a hurry, and i sprained my ankle, it made cracking noise, and fell off the stairs, hit my eye brow on a sharp edge, and was very painful i passed out, two hours ago i woke up in hospital with broken ankle and leg, and two stitches over my eye.

so guys i hope you are happy, cause i won't be going anywhere for a while .
hopefully this gives me more time to work on this myself
Sorry to learn of your injuries!:(

Well hey! I know I speak for all of us with my sincere extension of sympathy and best wishes for rapid convalescence!

Sincerely, please take care...
HP
 

WBahn

Joined Mar 31, 2012
29,979
Hypatia, that doesn't make sense. also in the morning i was going down the stairs in a hurry, and i sprained my ankle, it made cracking noise, and fell off the stairs, hit my eye brow on a sharp edge, and was very painful i passed out, two hours ago i woke up in hospital with broken ankle and leg, and two stitches over my eye.

so guys i hope you are happy, cause i won't be going anywhere for a while .
hopefully this gives me more time to work on this myself
Sorry to hear about your fall and the resulting injuries -- particularly being knocked unconscious as that could indicate a serious concussion. Please make sure it is checked out thoroughly.

As before, we are more than willing to help guide you toward a solution, but it has to be as part of you showing your efforts to that end.
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
Hello again, how is this ? and can i get help with calculation ?
in case you forgot : this circuit i need to charge 12v 200ah battery.

edit: the diode in top of the relay i chose 1n4004
 

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WBahn

Joined Mar 31, 2012
29,979
Trace the nodes that the battery will be connected to when the relay is set to charge the battery. You will be applying 20V directly to the battery. Also, your LED will light up when you are NOT charging the battery. Is that what you want?

Aside: How are you feeling after your mishap?
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
Trace the nodes that the battery will be connected to when the relay is set to charge the battery. You will be applying 20V directly to the battery. Also, your LED will light up when you are NOT charging the battery. Is that what you want?

Aside: How are you feeling after your mishap?
apart from feeling dizzy sometimes, i think i am getting better.


the led won't turn on , only if the battery is full it will turn on.
the relay is already set to charge the battery.
when voltage reaches 13.8v it will trigger the zener diode to allow current, when voltage starts to raise the npn will switch current to the relay, and it will switch off the charge, that's when the led turns on .
 

WBahn

Joined Mar 31, 2012
29,979
And when the relay is closed you have the 12V battery connected directly to the 20V supply. What is limiting the current?
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
i see you are right, can you give me some help ? i have no clue how to limit it .

what i did there is a mix of many circuits i saw online.
 

WBahn

Joined Mar 31, 2012
29,979
You need to take a step back and first establish what it is you are trying to do. As you have (hopefully) seen in your aero background, the hardest part of solving any problem is usually understanding just what the problem is that you are trying to solve.

It's fine to start with an abstract, generic goal of "charge two 12V batteries in parallel at the same time". But that is NOT enough to go on to start designing a circuit. Just as saying that you want to design a plane that can carry a 100,000 kg payload 10,000 km is not enough to start laying out plans for wing sections.

You need to get a lot more detailed. What is the maximum current that these batteries can handle when being charged? What constitutes a full charge? What is the permissible current profile during charging? What is lowest voltage that the "dead" batteries might start out at? How much total energy might need to be put into a battery? What is the longest that we can allow a charging cycle to take? Once you have these questions answered, then you look to see if they are even self-consistent and, if not, you go back to the customer and hammer out compromises until you have a set of specs that are not inconsistent.

Once you have answers to those questions, you are in a position to start evaluating circuit strategies. If you are looking for a constant current (but voltage-limited) charger that is going to be a different circuit than a constant voltage (but current-limited) charger.
 

Thread Starter

Claudia94

Joined Mar 25, 2015
28
well, it's not a specified batterie, it could be from a different manufacturer, but in the company where i am being a trainee they use 12v 200AH lead acid batteries, that's what matters for them, these are used to fire a very very high compression diesel engines( two batteries).

the charging current to use is 20A

these batteries won't be completely charged, they are just charged till 13.8v

charging should be through two phases: constant current, then constant voltage

the voltage per cell should never drop below 2.10v to prevent damage (12.6v)

every battery has it's capacity

a charging cycle can be long or short, but we won't fast charge our example battery

i know these things, but to apply it and design a charger is hard for me, and i already told you that my electronis knowledge is very basic

also something confusing me : my instructor told me that we won't charge the battery more than 13.8v, but when reading about charging batteries, the constant voltage phase starts at 13.8v. so my explanation is no full charge, just enough to fire a engine, then the engine does the rest and fully charge it.

again, please i ask your help. or give me what i should learn so, i get qualified to design the needed charger.
this forum is the only hope i still have.
 
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