12v sla battery charger

[artois]

hi all,
can any body help give advice on a charger i built. heres the circuit.
Automatic 12V Battery Charger : simple electronics
The only thing i did instead of using one ic lm393 i used two ics, its a bit of a ***** to do the pcb layout with all the transisters running to one chip so i thought to use 2, each using the same supply,so instead of using the ic as a dual i used it as a single. does this all make sense.Also i did not have a 15-0-15v tansformer only a 0-16v.The whole circuit does not seem to work as it pushes out nearly 22v out (no load) and when i connect a battery it keeps charging at 16+v.

Automatic 12V Battery Charger : simple electronics

guys ill try put the pcb here, hope it works.

 

[4pyros]

It should work. Can you post your new schematic?
You may have to tie the unused input pins of the chips to ground. Look at the data sheet for details.
Andy

 

[artois]

12v sla batt charger

hi andy, did u look at my pcb,ill try post the circuit

 

[artois]

hi andy like i said i used the same circuit but instead of 1 ic i used 2

 

[MikeMl]

The three step charger algorithm is the correct way to charge sealed or flooded lead-acid batteries, but it is only good if you use the correct voltage during the last two steps, CORRECTED for TEMPERATURE. Here are the correct voltages.

 

[artois]

Thanks mike I have seen that page and build this charger about 4 months ago and charge my sla at 30 deg cel to /cycle 14.5v
Battery Charger 12v SLA. I don't know, no one can tell me if this charger is fine. It charges at a pace controlled by the tra former,but the final voltage u can set fine to the mv. The only thing for a 12ah /20hr batt it takes about 2+ days from 11v-14.5v.pls have a look at the pcb I did and the schematic and earlier posts I posted. I would app if u can help me with this ,can I leave an e mail address here or not. Txs again

 

[MikeMl]

Are you saying that the current limiting is determined by what the transformer can deliver and not by the current comparator? What is the actual charging current?

There are two reasons to limit the charging current during step one of the charging algorithm: to protect the transformer/rectifier and to protect the battery. You will have to check the specs on the transformer, and the data sheet on the battery to determine which is the lower of the two, and set it appropriately.

 

[artois]

Thanks mike I have seen the power stream page and I build this charger about 4 months ago. - Battery Charger 12v SLA. I cycle charge the batt at 30 deg cel to 14.5v. The time factor is too long for me from 11v - 14.5v takes 2+ days ,It work nicely only no one can tell me if this is ok or if it can damage the batteries. I use it and the final voltage u can set to a very fine final voltage. Pls look at my earlier posts and pcb I did and if u can help me I would app it very much can I leave an e mail add here or not. Txs very much so far for all u guys help so far.

 

[artois]

Soory mike some how we jumped each other which charger are talking about the one I did 4 months ago or the one I'm having problems with.

 

[MikeMl]

The SCR-based battery charger charges at a low rate, so might take two days to fully charge a 12Ah battery. First, the wall wart is whimpy. It only puts out 12VAC, so the SCR can only conduct for part of half-cycle. Then, it only charges on half-cycles. I'm guessing that the average current is only 0.25A or so...

Have you measured the charging current into a depleted battery?

 

[artois]

Hi mike, I know the scr only pushes a meager current I changed the two1.8E to 1.2E resisters and put a normal 12v 500ma former added a fan boxed it now it all runs cool pushing out 300ma current
Taking a 12v 12a/h battery 2-3 days to charge, that's y I build the other charger where I need help. Pls look at the earlier posts for schematic and PCB I did and see if u can pls help me
txs John

 

[artois]

Hi guys I think mike is mad at me he aint talking to me no more.

 

[artois]

12v sla batt charger pcb

Guys I think mike is mad at me he aint talking to me!