Battery Charger Simple Repairs

[Tom Wesenberg]

Batteries should be charged at no more than 10% of their rated amp hours, so if you have an 80 amp hour battery, you should limit the charge rate to 8 or fewer amps. I like these small 4 to 6 amp chargers, and they can be bought for less than $10 at swap meets. Just make sure the meter has numbers, so you can see what's actually happening.

This is one I bought a couple years ago for probably $3 or $4. It was a little beat looking and the charging cord was brittle with several cracks. The power cord was nice and flexible, but had one crack next to the cord lock, so I cut out the 1" where the wires were half broken, then spliced it just inside the case. The clamps were rusty, so for $1.45 I bought a new pair. Four feet cost 60 cents, the cord was 60 cents and the cord lock was 15 cents, so total cost except paint, which I already had, was $2.80, and with care this should last another 50 years.

For the charge cord I bought 6 feet of new wire at the surplus store, and a new pair of GB battery clamps at Menards. Two rubber feet were missing and the other two were cracked, so I bought new ones at the surplus store, as well as one missing cord lock for the charge cable. The main part of the case was a mess from someone setting it too close to the battery while it was charging, thus getting acid drops on it, so I sandblasted it and painted it blue. I used a paint brush to clean out the cob webs and thick layer of dust. I labeled the + and - inside the case to be sure the new charge cord didn't get mixed up.

I twisted the wires together, soldered them, then slipped heat shrink over them. Also notice the white heat shrink on the charge cord. I did this so the wire won't continue to pull apart after I pulled it apart for 9". I prefer to splice the wires just inside the case, rather than unsolder them at the component, as there is less chance of damaging a component, plus I gain a couple inches of wire length.

Notice the two selenium rectifiers riveted to the rear panel. Sometimes they can go bad, mostly from storing the charger in a damp place and letting it get rusty. If they go bad you can use diodes of high enough rating to replace them. If the transformer goes bad it isn't worth buying a new one, but do save the other parts as spares for another charger.

I'm not a fan of trickle chargers, but will use these for a light top off charge once in a while over the long winter storage.

[DaWizard]

Excellent.

Very nicely done.

[1930artdeco]

Great write up Tom. An worker gave me a 6v charger from the 40's I am guessing. All the wires are shot, which is no big deal to replace. Is there any way to check and see if the rest is still good?

Mike

[SAJ]

Nice one Tom. I get huge pleasure from resurrecting old tools and appliances (workshop ones not kitchen and household ones !) too.
It's not to save money for me either, but to bring back to life some quality item made yesteryear with the technology that existed then.
It can get quite involved because some of my favourite things are old machine tools from the 1800's up to the 1960's. My favourite lathe is a Seneca Falls tool room lathe from 1898. I do light stuff on it and heavier stuff on my Dean Smith and Grace lathes from the 1960's. Or my Cincinnati Millacron mill from the 60's.
I just got given a Kondia Power Mill from 1968, and I am "restoring" this. Inverted commas because I am patching the paintwork otherwise it will be too pristine to actually use.
Please keep feeding the restorations Tom. Do other barn members enjoy these as much as I do?
SAJ in NZ

[Tom Wesenberg]

Originally Posted by 1930artdeco

Great write up Tom. An worker gave me a 6v charger from the 40's I am guessing. All the wires are shot, which is no big deal to replace. Is there any way to check and see if the rest is still good?

Mike

Does it use a rectifier tube, or is it new enough to use selenium rectifier?

If it has a bad rectifier tube I'd think that could be hard to find and fairly expensive.
I'd clean it up and make sure the 120 volt wires are in good condition, then plug it in and measure the DC output voltage.

[1930artdeco]

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I will try and take a picture of it tonight and get back to you. I have not opened it or looked at it for awhile. Projects, projects projects.

Mike

[C26Pinelake]

a nice job by a true professional. WAyne.

[Doug in NJ]

Great write up! And these days, it's getting harder to find new battery changers with 6 and 12 volt output.

Doug

[BILL WILLIAMSON]

Found a like NEW Ultrasonic Foot Washer, in the dumpster, behind the drug store, with the cord snipped off.
With a new cord & warm water & Tide & PURPLE Aquarium Gravel, it cleans small parts, like a CHAMP !----The GRAVEL tickles my FEET!
Bill Clean

[PC/SR]

Tom: Old tubes are available at Antique Electronic Supply, https://www.google.com/search?q=tube...utf-8&oe=utf-8 The go to place for radio restorers.

[1930artdeco]

Tom,

Here is what I have-or what is left of it. The company was incorporated in 45 and is now inactive-for whatever that is worth. I am guessing it is from the 50's.

Mike

[Tom Wesenberg]

Originally Posted by 1930artdeco

Tom,

Here is what I have-or what is left of it. The company was incorporated in 45 and is now inactive-for whatever that is worth. I am guessing it is from the 50's.

Mike

I can't see the AC cord nor the charge cables, but I'd assume they are bad and need to be replaced, so just replaced them noting which side is positive on the clamps. The internal wiring to the full wave selenium rectifier looks OK, and I wouldn't touch it. If any of the insulation on the wires is cracked between the transformer and rectifier, then you can coat it with liquid tape. If you want an ammeter to check what's happening, you can simply add it in series between either clamp and the battery. I'd bet you have a good charger that just need the two cords.

1930 Coupe, that is a nice quality charger you have, and very handy to have one with adjustable output.

[ronn]

Join Date: Dec 2010
Location: FRESNO, CA
Posts: 9,550


Re: Battery Charger Simple Repairs
Found a like NEW Ultrasonic Foot Washer, in the dumpster, behind the drug store, with the cord snipped off.
With a new cord & warm water & Tide & PURPLE Aquarium Gravel, it cleans small parts, like a CHAMP !----The GRAVEL tickles my FEET!
Bill Clean


nice find Bill!
I like to buy used crock pots for about 5. and put vinegar in them and drop a small part in for cleaning............................

[1930artdeco]

Hi Tom,

Thanks for the input. Yes the cords are shot totally but the clamps are still good! My intention is eventually to buy a darkroom timer and use that in between the charger and the wall. I had not thought about putting an ammeter in the circuit but that is a great idea. Is there a way to test the rectifier with out plugging in a battery?

Mike

[mhsprecher]

Thanks for this post. Very timely. I have an old one of mine that quit working, but I am not sure how to get it going again. I will send a PM for some advice.

[Special Coupe Frank]

Originally Posted by 1930artdeco

Tom,

Here is what I have-or what is left of it. The company was incorporated in 45 and is now inactive-for whatever that is worth. I am guessing it is from the 50's.

Mike

That's a selenium-rectifier charger. Those big squares are cooling fins for the rectifier stack.

Selenium rectifiers can degrade over the years, but a good electronics guy can re-fit with a modern rectifier, and return the unit to service.

I have a Sears Allstate vertical charger, 6-12-24 volt from the late 1940's with a bad selenium rectifier... will be getting it to an electrical engineer friend for repair this winter.

Frank

[jrelliott]

Tom, you are man after my own heart. You are a man of many talents. I too hate to throw things away when they break and will try to fix them. I picked up a Rayovac Charger years ago at a swap meet in Tucson for $.50 as they said it would not work. Took a chance and was a blown fuse inside. Being an Electronics Technician and had a degree in Electrical Engineering, was not a problem. Now you can hardly repair anything Electronic as they make it difficult to find parts and then everything is surface mounted inside. Still have signal generators and O scope.

[Tom Wesenberg]

Originally Posted by 1930artdeco

Hi Tom,

Thanks for the input. Yes the cords are shot totally but the clamps are still good! My intention is eventually to buy a darkroom timer and use that in between the charger and the wall. I had not thought about putting an ammeter in the circuit but that is a great idea. Is there a way to test the rectifier with out plugging in a battery?

Mike

I would just plug it in after the new wires are on, then reads the DC voltage at the battery clamps. If it measures low or the needle vibrates, then try the AC scale, because that could indicate a bad rectifier.

[jhowes]

I have a battery charger that the meter has died in. Do you have a source of new amp meters? Thanks By the way did the Kingston carb. arrive? Jack

[Tom Wesenberg]

Originally Posted by jhowes

I have a battery charger that the meter has died in. Do you have a source of new amp meters? Thanks By the way did the Kingston carb. arrive? Jack

Yes, it did arrive, Thanks Jack.

I've also been looking for a meter lens, but no luck so far. Two of our good surplus stores have closed this year, so good stuff is now even harder to find.