sla charging schematics ?

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hi,  after some schematics to charge 6 volt and 12 volt sla  ( sealed lead
acid ) batteries.... basically  dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a  week
or so , would be good....

any body have any  or know of any links ?




Re: sla charging schematics ?



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Go to 'jaycar' spend $59.95 and buy one of these.

http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD


No point in messing around getting the parts and building one. Probably cost
more.

Just check the rating you need before you buy.



Re: sla charging schematics ?



"Martin"

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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD


** No way unless you want your SLAs to explode.

Jaycar have this charger for SLA batteries:

http://www.jaycar.com.au/productView.asp?ID=MB3603&CATID18%&formCA%T&SUBCATID29%5

However, WES have 1 amp SLA chargers in 6 and 12 volt for less than half the
Jaycar price.



....   Phil




Re: sla charging schematics ?


hi, thanks,  but i really want to  make one not buy one, i reckon i`ve seen
one using a lm317 , but cant find  the schematic ,  and it would have cost
only 4 or 5 $  !!!

i`ve  got a heap of electronic conponents , so i`d rather use them , than
keep  buying  ready made stuff.....

mark k



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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD
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http://www.jaycar.com.au/productView.asp?ID=MB3603&CATID18%&formCA%T&SUBCATID29%5
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Re: sla charging schematics ?



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Just make the usual LM317 circuit, but 100 or 120 Ohm resistor for the
output to adj terminal to soak up the quiescent current, and put a series
diode from LM317 output to battery to stop the battery powering up the
charger when the mains is off.  Appropriate R and trimpot from Adj to
ground for desired output, add a switch for 6 and 12V operation -- no
magic there.

Set output voltage for say 13.5V float on 12V, half that for 6V battery,
only need small heatsink on the LM317.  

The schematic is basically from datasheet with the extra diode and lower
Adj resistor.  If you want reverse battery protection, add another diode
from battery minus to the series diode's cathode, and put in a polyswitch
or normal fuse to the battery.

Grant.
--
http://bugs.id.au /

Re: sla charging schematics ?



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 8<<<<<<<<<<<<<<<<<<<<<<

You didn't mention that. Sorry.



Re: sla charging schematics ?



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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD
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No doubt you have a reason to state the above. But I just contacted 'jaycar'
and they informed me that the above was fine on SLA's on a the trickle
setting. But then you never know I suppose. Don't think I'll bother next
time.



Re: sla charging schematics ?



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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD

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 He's probably right on this one. (odd, I'm on Phil's side for once..).

 Be careful what you state about Jaycar gear unless you test and
evaluate it properly.

 The term "trickle" when it comes to lead-acid batteries can mean MANY
things.  Usually it means a less-than-full charge rate that is selected
when the full rate charge is over.
 In other words, if you leave it long enough, you will fry your battery
anyway.

 What you want, is a float charge.  If they *meant* a float charge, they
would have SAID float charge.  And in fact, they DO say float on some of
their other chargers.


 The SLA battery may not "explode", but at the end of the day, there's
little difference between "explode" and "molten mass of toxic, corrosive
goop all over the desk".



 But hey, it's your money.

Re: sla charging schematics ?



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2D3522&form=KEYWORD
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I don't know about him but for SLa I'd aim at C/20, so they would be fine
for 160AmpsHr SLA (and at that size you could buy twice the capacity of
simple Deep Discharge Lead Acid batteries(at a decent battery seller and
not chains).

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What was the current of the trickle current? That is the catch 22. IME,
most SLAs are small stuff and the Jaycar plugpack SLA (@375ma?) can stuff
those if left on continuously.

Re: sla charging schematics ?



"Martin"
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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD
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** Well  -  Jaycar would say that, wouldn't they ?

But unless the SLA is a VERY  large example, that 8 amp charger will
certainly damage it on either setting.


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** Despite appearances, battery chargers that work well, are safe for the
battery and the user under all conditions are  NOT trivial designs.

The AC transformers used in mains powered types have to be sized just right
for the intended battery type and also must meet class 2 insulation and
safety requirements  -  they are "prescribed items" under the electrical
safety laws for that reason.

You are NOT likely to find anything suitable in your junk box !!!

Lead acid car battery chargers are  NOT  safe with  SLA batteries, or any
other type AFAIK.

It is very much a game of horses for courses.


....  Phil





Re: sla charging schematics ?



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http://www.jaycar.com.au/productView.asp?ID=MB3522&keywords=MB%2D3522&form=KEYWORD

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http://www.jaycar.com.au/productView.asp?ID=MB3603&CATID18%&formCA%T&SUBCATID29%5
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 Those suggestions are nice, and cheaper than the DIY method, are a lot
easier, probably a lot better, but they don't help the original poster
with his school project.

 His suggestion of using an LM317 adjustable regulator is probably the
more expensive option other than a fixed regulator which is cheaper, and
that you can regulate anyway.

 It smells like a school project, and non-compliance with component
requirement would result in a fail.


 Remember, his quoted prices of $4-$5 is component value only (and I
think is still overestimated) and of course does not include heatsink,
power supply, wiring, clamps, connectors, case etc, because the school
is only interested in the design.



 Unless of course Mark can show he *can* build it for $4-$5 complete,
instead of the commercial ~$30 or so.  In single quantities of course.
In bulk orders, China can build them for less than his quote anyway.

Re: sla charging schematics ?



 
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What level and what subject would they do this?



Re: sla charging schematics ?



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 Subject?  Er, when I was in school they called it "Electronics".  Who
would have thought?  And that was starting in year 8 or 9 I think.

 As far as level goes, this would require complicated mathematics
involving multiplication AND division, also with addition and
subtraction.  So that would be around year 10 or so?

 As long as you can teach the principal of voltage offsets, past that,
the above maths apply.

 But half the time they never bothered to properly explain theory of
operation either.  Shut up, here's a project, make the board and put it
together.

 A pass if yours flashes the lights in the correct order, and an
automatic fail if you ask stupid questions like "what does it do?".


 They don't teach you, (and you don't have to know) the detailed
workings of the inndards of the component you're working with, basic
theory of operation is enough to get you by for now.

 They taught us all about resistors and capacitors, but I didn't really
get to know all the implications of each type till well into my career.
 And even then, the importance of some types over others in specific
applications.  Especially the more common applications where you might
know *why* it's there, but not that you should be using a particular
grade of component there regardless of the fact that "everyone else"
appears to use garden variety.


 My point being, perhaps not with "school" but with private tutoring,
you can get on your way with apparently complex components in albeit
non-critical applications very early.

Re: sla charging schematics ?



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Wow, something useful,,,, or not. I thought it was mostly mickey mouse
subects now.


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Circuit analysis, 2nd year uni for me.

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Yes.


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 Well, that was then.  Now, I have no idea.  At my school, I heard they
canned the Electronics subject the year after I left, because the only
teacher teaching it had left, and no-one similarly trained filled their
place.

 I can only presume he was replaced by a highly trained individual
teaching English, and how many times one can say the word "like" within
a sentence and still make sense.

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 Oh, perhaps things *have* changed.  In my second year of TAFE, we were
learning about transistor theory.  That is, what happens, and why it
does what it does at the molecular level.  I'm quite sure it was dumbed
down a bit, but still.

 This was perhaps a nearly 20 years ago, but I'm sure classic bipolar
transistor theory hasn't changed *that* much. :-)

Re: sla charging schematics ?


its not a school project , and so what if it was ????



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Re: sla charging schematics ?



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 I'm not doing your homework for you.

 The answers you seek are available on the net, which you clearly have
access to since you're posting on newsgroups.

Re: sla charging schematics ?


well, what are you on here for ????

anyways , if you want to know, i have 2 sla batteries, a 6 volt and a 12
volt..
and IF YOU READ my earlier post , i was looking  sorta,  for a specific
schematic for charging them .

did i ask you to design one  ?     NO

did i ask you to build me one ?  NO

did i ask you for the parts  ? NO

SO TELL ME L, ,  WHAT HOME WORK  WAS IT THAT YOU WHERE GOING TO DO FOR ME ?


did you help your kids with their homework ? if you didnt , well, what can i
say.... ???



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Re: sla charging schematics ?



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As John said. It is basically my undestanding of the level at which this
might be YOUR project. In which case, you should be able to do something
as basic as search the internet and find a circuit that could be used and/
or modified.

The point about school work is that you should do the work and learn from
it and this is actually a good project for that. You do not learn much,
if anything if it is dished up to you.

Well, that has been given to you anyway. Now your job is to build it.

Good luck.


Re: sla charging schematics ?



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 Thank you.  That was what I *meant* to say.

 Clearly, diplomacy is not my strong point. :-)

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