Bench top power supply

[flatbelter]

Bench supplies are always worth having around, even if you aren't into electronics. I'm reconditioning a sealed lead acid battery by charging it every 24 to 48 hours through one of my supplies.

Does that work? I've given up on battery reconditioning, they seem to fail again just when you really need them.

Is it my imagination or have batteries (LA) taken a real nose dive in durability over the last 10 years? I seem to always lose at least one battery here every winter. Getting >2 years out of the tractors /yard equipment seems to be doing well.

Come to think of it, my battery chargers take a bit of maintenance too. The big roll around one tends to burn the cable end under the insulation at the battery clamp. undersized + wear = broken. Think I've fixed it 3 times in three years.

fb

 

[Hawkeye]

fb,

I got the idea from a book called Batteries in a Portable world (Isador Buchmann). I don't know what the limitations might be, but the storage voltage did increase a bit after the first couple of cycles. I don't know how well it works for regular LA batteries. I did try it with my old fishing battery and it seems to have improved, but I haven't tried trolling with it. I do carry oars. :biggrin:

 

[75Plus]

Here is the schematic of the bench power supply I referred to in my earlier post along with a picture of the supply. All the spec sheets I have rate the LM317T at 1.5 amps. In fact ECG warranted their ECG956, the LM317T equivalent, to output 1.5 amps.

I made an error in the earlier post regarding the value of the pot to control the current should be 100 ohms. I used 10 turn pots for both voltage and current control as they are more precise.

I submitted this as a construction project to the old 73 Magazine and it was published in December 1987. I believe I still have all the information that was submitted.





Joe

 

[churchjw]

Cool supply 75Plus I will print out the schematic and see if I can figure it out. Thanks for posting. Also thanks Flatbelter for the sites I will read them.

Jeff

 

[Hawkeye]

I stand corrected. 1.5 it is. One of the most versatile chips available. I like the short-circuit protection. Pretty hard to kill one.

 

[Hazegry]

hey could you guys help me I need a variable 12v-29v 15 amp power-supply. Does anyone have schematics for one?