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watzmann said:Hi All ,
i have a battery 12 VDC 7AH, i need to charge this battery but i don't have a 15 power supply ,
i'm going to buy a 15 volt transformer with a 1 or 2 A and use it , is it possible ...... or i'm wrong?
watzmann said:my battery is SLA one , and it's manual says cahrged at 15VDC 2 A.
i have another solution , i have a power supply provide 40 volts so i think i can limit that using LM7815 to be just 15 VDC
Automotive charging systems operate between 13 & 15 volts, typically 13.8-14.2 but 15v isn't too uncommon. Being a SLA type battery, he would have to manually monitor the charging process unless he opts for the smart charger as mentioned. Manual monitoring is a crap shoot since sooner or later one will get distracted and leave it heat up. It's not the preferred method to prolonging battery life.ericgibbs said:hi,
Is it a sealed lead acid battery SLA ?, if Yes, they are not charged with a 15Vdc supply.
audioguru said:How are you going to limit the voltage to 15V?
How are you going to limit the current to the 900mA max allowed from the power supply?
How are you going to detect when the battery is fully charged then switch it off so it doesn't overcharge?
watzmann said:limiting the voltage to 15 V by using LM338
limiting the current to max 900mA ..... this power supply max output is 900mA
i'll detect that my battery is full charged by using AVO meter each 15 minutes .
Finally i decided to buy a Tonger avery small one is sufficent for my robot .
watzmann said:please chemelec could recomend me a suitable charger i can buy.....because i'm actually i'm in trouble now as i can't charge my battery using power supply and then damage it and in the same time i can't use it well.
so tell me if i can build a good ghrager bymyself , or where can i buy a suitable one .
HarveyH42 Experienced Member said:**broken link removed**
This one looks simple to build, parts aren't exotic... .