Hellwo everyone,
since you are addressing the charging issue could you please give me some information on how to estimate the minimum and maximum current for charging and also the right volatage I am planning to charge a 12 V 12AH battery like scooter batteries,
any good links to estimate these ?

 

Typical charging current is around 1/10 Capacity.
so about 1.2 Amps for your 12AH Batterys.

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is it possible to get a larger and enhanced image of the powersonic charger, and also what is the amperage of the output? i am looking for one about 3 amps out, and the voltage output of the transformer. the battery is 12volt 18Ah, cycle use charge voltage is 14.4-15.0volts and initial current is less than 5.4 amps. if i can get one about 5 amps, than all the better.

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Do you want a "larger and enhanced image" of the schematic or the charger? The charger is rated at 1.25A out. If you went with a larger current transformer, and rectifier, and LM350, you could get 3A out. There is also the possibility of adding external pass transistors to the Powersonic charger to boost it to 5A: http://www.national.com/mpf/LM/LM317.html

Ken

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I believe an LM338 will also get you 5 amps out in the same circuit.

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thanks. i might try this idea but i am still searching for a charger to see what i can find. would a 3amp lead acid battery charger be okay to charge a sealed lead acid battery?
because i found this and it seems to suit my needs:
http://www.uoguelph.ca/~antoon/gadgets/labc2.htm

i edited the schematic to what i actually need. (P2, R5 and S1 are removed, so the charger is only for 12v)

Attached Images

la charger+float.JPG (39.5 KB, 18 views)

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As it says on the Schematic, This charger is "Not for use on Gell Cells".
** I am quite sure it is also Not good for use on Sealed Lead Acid batterys for the same reason.
That Extra High Current can cause problems in these batterys, resulting in premature battery failure.

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Try this site and he has a good document to speak and detailed circuitry towards the end of the downloadable pdf file.

http://www.geocities.com/vk3em/sla-c...a-charger.html

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i could use an lm350k, which is 3amps (battery rated at 5.4)

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As I told you before: Typical charging current is around 1/10 Capacity.
"So for a 5.4 A/H battery, your charge rate should be about 540 mA".

Charging at 3 amps will distroy the battery.

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sorry about that part...i forgot to say that that battery is 18Ah and has a 5.4 amp max charging current

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I feel that the SLA batteries can't be frequently charged at a rate more than prescribed. Generally we may have to follow manufacturers recommendations as regards charging rate, let it be 10, 16 or 20 hr rate. Perhaps due to urgency we may charge at higher rare but such attempts must be minimal for better life of the battery.

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what current is suitable for a 20hr charge rate? (now i know what the '20HR' means)

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I meant charging at a current =AH capacity/20 as 20hour rate. However, please study the instructions contained on the battery regarding normal and fast charge rates and let us follow them, as the manufacturer knows better about its products.I feel charging current need not exceed AH capacity/16 or AH/20. for best possible life of the battery.

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here is where i bought it:

http://www.jaycar.com.au/productView...Max=&SUBCATID=

it was on special to.
the picture is the best i could get from my camera.

Attached Images

12-18.JPG (34.7 KB, 15 views)

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