Smart and cost effective 12-V 160 AH lead acid battery charger

[taij72]

Hi all,

I am searching for cost effective design for 12-V 160 AH lead acid battery charger. I will use it as part of an offline UPS that I intend to build. Charging should be accomplished in 8 hours.

any help on this?

Thank you.

Taysir

 

[schmitt trigger]

160 amp hours in 8 hours plus charging losses, you are realistically talking at a 14v, 25 amp charger, or 350 watts.

350 watts can be done with a linear regulator, if you can tolerate an additional 100 to 200 watts in regulator losses, and can safely dissipate the heat.

 

[taij72]

Thank you schmitt. Have you any suggested circuits for this?

 

[schmitt trigger]

I have an old circuit from GE's SCR Manual.....ultra simple. Let me find it and scan it.

 

[schmitt trigger]

sorry for the delay. I could'nt find the book.
Here it is.
Adjust the SCR type and transformer size to handle the required current.

 

[amjadali56]

here is a SMPS battery charger with UC3842/43/44 and LM358 short circuit protection, 315W, 16Amps, LED indicators and fully automated.

 

[dick_freebird]

Here's what I have going, inthis vein:

- RV "converter" 12V 100A output
- Automotive starting battery
- 2kW MSW inverter

Battery was free and has several friends hanging
around. Converter, about $150 on eBay, this is the
largest and can source 1200W continuous to the
inverter when power is up. Inverter was cheaper,
on sale at Harbor Freight.

Whether this is "cost effective" comes down to your
needs and what you expect of batteries. I have gone
through a dozen UPSes in the last few years mainly
due to the SLA batteries dying, at over $100 a pop.
I have four vehicles that I swap starting batteries on
every couple of years, and the reserve capacity on
those fat boys is way, way higher than the puny
12A7 SLAs you get in sub-kW UPSes.

With one workstation and two docked laptops my
running load is 200A for the office "computing core".
I figure 1kW of power at a few hours' "hang time"
is good.

 

[aqildad]

amjadali56 .. attached do not contain schematic diagram .. . . do any one else have circiut diagram for the same

 

[Tihomir Grozev]

You can get any chinese power supply, that is 12V 30A and to redesign the current protection and to change the voltage to 13.8 not 14.4, insteed to build it from 0, hellooo...

 

[aqildad]

tihomir grozev : which power supply you mean ????

 

[amjadali56]

amjadali56 .. attached do not contain schematic diagram .. . . do any one else have circiut diagram for the same

I think in case of posted PCB, why some one bother to ask for digram? aren't the PCB enough??

 

[aqildad]

sir i am learner and want to learn from schematic and then apply this idea on PCB .

 

[amjadali56]

sir i am learner and want to learn from schematic and then apply this idea on PCB .

I am sorry to say that I did not bother to draw a diagram, just jumped to the PCB and worked rather fine for me, though there are some changes required but I think these simple things can easily be sorted out. the final win is PCB and there it is cheers

 

[aqildad]

is it possible for you sir to redraw the pcb for us ?

 

[amjadali56]

is it possible for you sir to redraw the pcb for us ?

Give me a day or two.... I will redraw and fix the bugs.

 

[aqildad]

Also plz post the circuit as wel

 

[Gapoo]

Dear kindly show the schematic of your charger. I have following queries.

1) Are you sure that diode at E$25 is 1N4148 ?
2) What is the part number of the MOSFET at E$23 ?
3) Path of feedback is very long, will it effect the performance ?

Thank You.
Regards,
Gapoo.

 

[amjadali56]

Dear kindly show the schematic of your charger. I have following queries.

Thank You.
Regards,
Gapoo.

1) Are you sure that diode at E$25 is 1N4148 ?
2) What is the part number of the MOSFET at E$23 ?
3) Path of feedback is very long, will it effect the performance ?

1) Yes it is 1N4148 but you can use any high speed diode.
2) 600v 5Amps like i used IRFP450.
3) yes it effects.

further More:
Also the MOSFET pull down resistor is not 22R replace it with 10K.
Overall performance (1: Not good. 2: voltage adjust Poor. 3: No Battery reverse Protection)
I am working on update version.

 

[Gapoo]

We can mutually fix bugs by discussing here if you want.

 

[Gapoo]

What is the part number of the component at E$23 ? In PCB and Parts list only 40V/30A is written.