Dead SureStart battery charger

[JohnH]

My old charger let out the magic smoke. I use it for electrolysis and think I may have shorted it out.

I know its worthless but it has memories for me and I would like to fix it.

Looking at it theres not much to it;

A transformer, an ammeter, a switch to change between 12v and 6v and a thing marked LT 213.

You can see the cooked transformer in the following pics;

So the question is, where can I find a replacement transformer. I've looked on RS but I dont know what I am looking at, only the £20-£50 they want to charge, so I'm not going there. I you've got any ideas please let me know.

I know its not really worth repairing, but it has sentimental value to me, so I would like to get it going again if posable.

 

[Dcal]

Do you need 6 and 12v?
How many amps?

I might have one that would do in a dead charger.

 

[Ross365]

Firstly, don't assume anything purely on the slightly blackened appearance. Get a multimeter on the job. Some transformers have temperature rated fuses built in.

Those old transformer where made in such a way as to create high impedance secondary windings, which acted as voltage regulators to some degree. Not sure if they still make such things given that we now have semiconductor regulators. They surely won't be cheap. The rectifier def needs checking.

 

[gaz1]

My old charger let out the magic smoke. I use it for electrolysis and think I may have shorted it out.

I know its worthless but it has memories for me and I would like to fix it.

I know its not really worth repairing, but it has sentimental value to me, so I would like to get it going again if posable.

if i wanted to quote the above

why use it in that sort of application where its heavily used compared to what it was designed for

as a battery charger is only temporary used

 

[Ross365]

Mmmm... "let he who is without sin..... "

 

[8ob]

why use it in that sort of application where its heavily used compared to what it was designed for

as a battery charger is only temporary used

Genuine question Gaz, is the use of an old school charger in an electrolysis tank considered heavy use? I thought they were the power source of choice

Bob

 

[123hotchef]

Genuine question Gaz, is the use of an old school charger in an electrolysis tank considered heavy use? I thought they were the power source of choice

Bob

I prefer a computer PSU myself now days

 

[Seadog]

The LT213 is a selenium rectifier.

 

[charliecambs]

Hi as an "oldie" electronics engineer I have a feeling that the Selenium type rectifier is used as part of the charge current control as they are (if I recall correctly) fairly resistive.
Early part of my career ( actually turned out to be 42 years!) was with "Newmarket Transistors Ltd" with Germanium transistors and so on which had some odd behaviours that we used to develop and market as a "feature" at increased price of course.

 

[gaz1]

Genuine question Gaz, is the use of an old school charger in an electrolysis tank considered heavy use? I thought they were the power source of choice

Bob

ok then i will say it how the average will think it

its old school power supply used for charging batterys its well designed old school tech where batterys are charged up from it, lets say 2 times a year overnight charging

its only air cooled it dosnt have a large transformer to spread the heat load, as its not a heavy duty unit as those have fans in use to further cool them its also not an industry unit either used more in a garage enviroment

so in use of the application of electrolysis you have changed its usage to be used only in temporary usage into a heavly used system with no cooling

the more you use it based on full charge cycle

that means your going to cook it
overheat the transformer wires
some older transformer have the over heat protection built inside of them you wont be able to replace them
many older transformers dont have this protection they also dont have cycle up and down tech
the parts for them are now hard to find

so bob we know welders they have that annoying overheat button but many older battery charging dont have this tech

so we use a temporary used charger system now into a cleaning system

its just done a 8hr cleaning stint but the materials need longer in the bath solution so you then further use the transformer now your taking that transformer past its cool down cycle it has no over heat protection what do you think is going to happen to it

 

[slim_boy_fat]

if i wanted to quote the above

Errr, you just did.

 

[500e]

Change Tx and S rectifier whats left

 

[voipio]

cycle up and down tech

Never heard of it. Google hasn't either, it would seem.

 

[Ross365]

The LT213 is a selenium rectifier.

Well, my recollection is that when they failed, the really stank the place out! And as Charliecambs said, definitely resistive - at least compared with a silicon one. Didn't many of the old chargers have copper oxide rectifiers with huge green fins?

 

[Alan Reynolds]

Hi as an "oldie" electronics engineer I have a feeling that the Selenium type rectifier is used as part of the charge current control as they are (if I recall correctly) fairly resistive.
Early part of my career ( actually turned out to be 42 years!) was with "Newmarket Transistors Ltd" with Germanium transistors and so on which had some odd behaviours that we used to develop and market as a "feature" at increased price of course.

As a techy who served 45 years including vacuum valves, selenium diodes and ‘geranium’ transistors, I agree with you that they have a higher resistance that silicon and lower reverse resistance. I was hoping this one had a 6v12v jumper, not a switch. I had a similar one to repair the other day that was dead after my neighbour borrowed it and connected it up wrongly. The fuse is in the jumper, just a bit of fuse wire but you can’t see it until you unscrew the legs of the jumper. Electrolysis takes very little current and these chargers cope easily with this. I know, I use them for exactly that. Any big 12v transformer will probably work. Remember OC81’s that you could take the can off of and make a photo transistor.

 

[Ross365]

The OC71's only needed the black paint scraping off to become photo transistors. And hold them between your fingers and watch the leakage current soar as the temperature went up a few degrees. I have small box of Newmarket transistors removed from 1960's Pye Radio telephones; lots of numbers like "GET333" or similar.

 

[johnik]

I have one that looks similar to that taking up space in the garage, pity you are not nearer, or i could post it if you wanted but that would probably cost a a weeks wages

 

[bricol]

Buy new battery charger.
Dismantle.
Place contents in old case (carefully)

 

[gaz1]

Never heard of it. Google hasn't either, it would seem.

How to charge all lead acid batteries; how to charge SLA lead acid batteries, a tutorial for engineers about lead acid chargers and charging.

12V SLA battery charger,lead acid battery charging techniques and algorithms,sealed lead acid batteries,Pb battery,SLA,VRLA,Gel,Flooded and AGM batteries.

www.powerstream.com

look for this
unregulated transformer based chargers

​

 

[Ross365]

How to charge all lead acid batteries; how to charge SLA lead acid batteries, a tutorial for engineers about lead acid chargers and charging.

12V SLA battery charger,lead acid battery charging techniques and algorithms,sealed lead acid batteries,Pb battery,SLA,VRLA,Gel,Flooded and AGM batteries.

www.powerstream.com

look for this
unregulated transformer based chargers

That PowerStream website is interesting.

For a long time, I've been using a battery charger I built myself from junk box bits. The transformer is tapped and I can switch to three taps to keep the current under 5A (for standard car batteries), and turn it down as full charge approaches. It has meters for both V and A and cuts itself off at 14.8 volts.

During the summer, a problem cropped up with it, and pushed for time, I foolishly bought a cheap "smart" charger off eBay (a FOXSUR). I was really pleased with it initially, but after just three months it stopped being smart and basically cooked a battery (continued to charge long after reaching 14.8V). Fortunately, it was an old battery I just kept in reserve.

Lesson; smart and cheap may not be compatible.